tag:blogger.com,1999:blog-38970935155592910142023-11-16T04:26:11.697-08:00Electric MotorData of Electric Motor, Electrommagnetic, Ac Motor, DC Motorsmart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comBlogger57125tag:blogger.com,1999:blog-3897093515559291014.post-39769823917686749432010-10-02T03:22:00.000-07:002010-10-02T03:22:34.306-07:00Dynamic Model , Proportional Integral and Derivative Control of Brushless DC Motor<div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="color: blue; font-family: Arial,Helvetica,sans-serif;"><b>Proportional Integral and Derivative Control of Brushless DC Motor</b></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><b>Abstract</b></div><div style="font-family: Arial,Helvetica,sans-serif;">Brushless DC (BLDC) motors are one of the electrical drives that are rapidly</div><div style="font-family: Arial,Helvetica,sans-serif;">gaining popularity, due to their high efficiency, good dynamic response and low</div><div style="font-family: Arial,Helvetica,sans-serif;">maintenance. In this paper, the modeling and simulation of the BLDC motor was done</div><div style="font-family: Arial,Helvetica,sans-serif;">using the software package MATLAB/SIMULINK. A speed controller has been designed</div><div style="font-family: Arial,Helvetica,sans-serif;">successfully for closed loop operation of the BLDC motor so that the motor runs very</div><div style="font-family: Arial,Helvetica,sans-serif;">closed to the reference speed. The simulated system has a fast response with small</div><div style="font-family: Arial,Helvetica,sans-serif;">overshoot and zero steady state error.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">http://www.eurojournals.com/ejsr_35_2_05.pdf</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: blue; font-family: Arial,Helvetica,sans-serif;"><b>Dynamic Model of the BLDC Motor</b></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">It is assumed that the BLDC motor is connected to the output of the inverter, while the inverter input terminals are connected to a constant supply voltage, as shown in Fig.1. Another assumption is that there are no power losses in the inverter and the 3-phase motor winding is connected in star.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="font-family: Arial,Helvetica,sans-serif;">http://www.eurojournals.com/ejsr_35_2_05.pdf</div>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-17866912625551454972010-09-15T05:44:00.000-07:002010-09-15T05:44:25.219-07:00Basic brushless motor control<div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgALVIps5se3n3tQXnG-BV3OhJ20FGSirZUitPRyvFlR1oZgFT-Zu_35RoVO_AWsPxjEAHFMwT1i6kkIcQEsgVcYjp4gaGPT4qyZlj1STffMZqy5WjECr6JfqnvfrSVdqY3VGrYvXY6hvM/s1600/Basic+brushless+DC+Motor+01.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgALVIps5se3n3tQXnG-BV3OhJ20FGSirZUitPRyvFlR1oZgFT-Zu_35RoVO_AWsPxjEAHFMwT1i6kkIcQEsgVcYjp4gaGPT4qyZlj1STffMZqy5WjECr6JfqnvfrSVdqY3VGrYvXY6hvM/s320/Basic+brushless+DC+Motor+01.JPG" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">The control consists of logic circuitry and a power stage to drive the motor. The control’s logic circuitry is</div><div style="font-family: Arial,Helvetica,sans-serif;">designed to switch current at the optimum timing point. It receives information about the shaft/magnet</div><div style="font-family: Arial,Helvetica,sans-serif;">location (signals from the Hall devices), and outputs a signal, to turn on a specific power device, to apply</div><div style="font-family: Arial,Helvetica,sans-serif;">power from the power supply (not shown) to specific windings of the brushless motor.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">http://www.motioncontrolonline.org/files/public/BrushlessOperation.pdf</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="color: blue; font-family: Arial,Helvetica,sans-serif;"><b>Brushless DC Motor Control Made Easy</b></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><b>INTRODUCTION</b></div><div style="font-family: Arial,Helvetica,sans-serif;">This application note discusses the steps of developing</div><div style="font-family: Arial,Helvetica,sans-serif;">several controllers for brushless motors. We cover sensored,</div><div style="font-family: Arial,Helvetica,sans-serif;">sensorless, open loop, and closed loop design.</div><div style="font-family: Arial,Helvetica,sans-serif;">There is even a controller with independent voltage and</div><div style="font-family: Arial,Helvetica,sans-serif;">speed controls so you can discover your motor’s characteristics</div><div style="font-family: Arial,Helvetica,sans-serif;">empirically.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">The code in this application note was developed with</div><div style="font-family: Arial,Helvetica,sans-serif;">the Microchip PIC16F877 PICmicro® Microcontroller, in</div><div style="font-family: Arial,Helvetica,sans-serif;">conjuction with the In-Circuit Debugger (ICD). This</div><div style="font-family: Arial,Helvetica,sans-serif;">combination was chosen because the ICD is inexpensive,</div><div style="font-family: Arial,Helvetica,sans-serif;">and code can be debugged in the prototype hardware</div><div style="font-family: Arial,Helvetica,sans-serif;">without need for an extra programmer or</div><div style="font-family: Arial,Helvetica,sans-serif;">emulator. As the design develops, we program the target</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7epzDvr8B1OI8130Rrse8XdE1SOjWXOauWRjxL0F868Lkpnd-f-BJVdlOZUB8vbqT0OsZVmgyE3fi48wksJQ4desP29mg2O0enzLiwr-0KYA93L70FbaF03wbvOhKOEPSj5qVrUErQyk/s1600/Basic+brushless+DC+Motor+02.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7epzDvr8B1OI8130Rrse8XdE1SOjWXOauWRjxL0F868Lkpnd-f-BJVdlOZUB8vbqT0OsZVmgyE3fi48wksJQ4desP29mg2O0enzLiwr-0KYA93L70FbaF03wbvOhKOEPSj5qVrUErQyk/s320/Basic+brushless+DC+Motor+02.JPG" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">http://www.jimfranklin.info/microchipdatasheets/00857a.pdf</div>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-22737323329810433192010-03-16T04:12:00.000-07:002010-03-16T04:12:00.346-07:00Brushless DC Motor modification and winding<div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless DC Motor modification</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">My first speed 300 motor died after about half year of flying. In order to have better performances, I decide to change the engine into brushless. There are several choices of brushless motor in the market, such as the Hacker and Astro. By the way, there has been a mania for using modified CD-Rom motor in our RC models. Needless to say, I have joined the groups that are trying to find out the potential of these wildly available and low-price CD-Rom motors. </div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://www.angelfire.com/blues/heli_project/brushless.htm" rel="nofollow" target="_blank">more</a> </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless motor winding by Utah Fyers #1 video</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">Video Radio control electric brushless motor winding tutorial </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/iHYlWKICkqc&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/iHYlWKICkqc&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless motor winding by Utah Fyers #2 video</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">Tutorial on brushless motor winding presented by Utah Flyers. </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/9o9vopQqMH0&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/9o9vopQqMH0&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><br />
<div style="color: #0b5394;"><span style="font-size: large;"><b>Buy Cheap Brushless DC Motor</b></span></div><div style="color: #0b5394;"><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B001GQER06&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe> <iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B000U7ZW92&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe></div>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-23576431704252089042010-03-14T04:02:00.000-07:002010-03-14T04:02:00.133-07:00Waveform of a Brushless DC Motor<div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">Brushless DC Motor COMMUTATION SEQUENCE</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgE3m_tsL_GU1qXJjAy1aIM287rJrZjjxTbqXogv7xa10UM-nR9-NJWqmp1hzOM1qR5MddgyIo4YBXm55bGB9sIQmbvpKD83l7KJyctUzHqZUP9j8ed0x-paXzhQB0e1q2e3ju_NM37WXY/s1600-h/Waveform+of+a+Brushless+DC+Motor.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgE3m_tsL_GU1qXJjAy1aIM287rJrZjjxTbqXogv7xa10UM-nR9-NJWqmp1hzOM1qR5MddgyIo4YBXm55bGB9sIQmbvpKD83l7KJyctUzHqZUP9j8ed0x-paXzhQB0e1q2e3ju_NM37WXY/s320/Waveform+of+a+Brushless+DC+Motor.JPG" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="font-family: Arial,Helvetica,sans-serif;">Figure shows an example of Hall sensor signals with</div><div style="font-family: Arial,Helvetica,sans-serif;">respect to back EMF and the phase current. Figure 8</div><div style="font-family: Arial,Helvetica,sans-serif;">shows the switching sequence that should be followed</div><div style="font-family: Arial,Helvetica,sans-serif;">with respect to the Hall sensors. The sequence numbers</div><div style="font-family: Arial,Helvetica,sans-serif;">on Figure correspond to the numbers given in Figure 8.</div><div style="font-family: Arial,Helvetica,sans-serif;">Every 60 electrical degrees of rotation, one of the Hall</div><div style="font-family: Arial,Helvetica,sans-serif;">sensors changes the state. Given this, it takes six steps</div><div style="font-family: Arial,Helvetica,sans-serif;">to complete an electrical cycle. In synchronous, with</div><div style="font-family: Arial,Helvetica,sans-serif;">every 60 electrical degrees, the phase current switching</div><div style="font-family: Arial,Helvetica,sans-serif;">should be updated. However, one electrical cycle</div><div style="font-family: Arial,Helvetica,sans-serif;">may not correspond to a complete mechanical revolution</div><div style="font-family: Arial,Helvetica,sans-serif;">of the rotor. The number of electrical cycles to be</div><div style="font-family: Arial,Helvetica,sans-serif;">repeated to complete a mechanical rotation is determined</div><div style="font-family: Arial,Helvetica,sans-serif;">by the rotor pole pairs. For each rotor pole pairs,</div><div style="font-family: Arial,Helvetica,sans-serif;">one electrical cycle is completed. So, the number of</div><div style="font-family: Arial,Helvetica,sans-serif;">electrical cycles/rotations equals the rotor pole pairs.</div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://www.jimfranklin.info/microchipdatasheets/00885a.pdf" rel="nofollow" target="_blank">more </a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>BLDC Motor Waveforms</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">Figure is a graphical representation of the BEMF formulas</div><div style="font-family: Arial,Helvetica,sans-serif;">computed over one electrical revolution. To</div><div style="font-family: Arial,Helvetica,sans-serif;">avoid clutter, only the terminal A waveform, as would</div><div style="font-family: Arial,Helvetica,sans-serif;">be observed on a oscilloscope is displayed and is</div><div style="font-family: Arial,Helvetica,sans-serif;">denoted as BEMF(drive on). The terminal A waveform</div><div style="font-family: Arial,Helvetica,sans-serif;">is flattened at the top and bottom because at those</div><div style="font-family: Arial,Helvetica,sans-serif;">points the terminal is connected to the drive voltage or</div><div style="font-family: Arial,Helvetica,sans-serif;">ground. The sinusoidal waveforms are the individual</div><div style="font-family: Arial,Helvetica,sans-serif;">coil BEMFs relative to the coil common connection</div><div style="font-family: Arial,Helvetica,sans-serif;">point. The 60 degree sinusoidal humps are the BEMFs</div><div style="font-family: Arial,Helvetica,sans-serif;">of the driven coil pairs relative to ground. The entire</div><div style="font-family: Arial,Helvetica,sans-serif;">graph has been normalized to the RMS value of the coil</div><div style="font-family: Arial,Helvetica,sans-serif;">pair BEMFs.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjpVEiuFd5bFS9lpWMzPi0eC8OHWlTpvSPFKObY_G3mhJnUYH-TGS_J2SAssaIdDL3g7SiY94G-VVH6fIl88paXr4udzoWPLGPsk5B-CSHT-pYQPHBSWUMCeXfIHaatXUu3nyV9IwJdCXQ/s1600-h/Waveform+of+a+Brushless+DC+Motor+2.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjpVEiuFd5bFS9lpWMzPi0eC8OHWlTpvSPFKObY_G3mhJnUYH-TGS_J2SAssaIdDL3g7SiY94G-VVH6fIl88paXr4udzoWPLGPsk5B-CSHT-pYQPHBSWUMCeXfIHaatXUu3nyV9IwJdCXQ/s320/Waveform+of+a+Brushless+DC+Motor+2.JPG" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">Notice that the BEMF(drive on) waveform is fairly linear</div><div style="font-family: Arial,Helvetica,sans-serif;">and passes through a voltage that is exactly half of the</div><div style="font-family: Arial,Helvetica,sans-serif;">applied voltage at precisely 60 degrees which coincides</div><div style="font-family: Arial,Helvetica,sans-serif;">with the zero crossing of the coil A BEMF waveform.</div><div style="font-family: Arial,Helvetica,sans-serif;">This implies that we can determine the rotor</div><div style="font-family: Arial,Helvetica,sans-serif;">electrical position by detecting when the open terminal</div><div style="font-family: Arial,Helvetica,sans-serif;">voltage equals half the applied voltage.</div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://www.jimfranklin.info/microchipdatasheets/00857a.pdf" rel="nofollow" target="_blank">more </a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>BEMF waveforms and the zero-crossing points</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">The fact that one of the windings is not energized during each sector is an important characteristic of six-step control that allows for the use of a sensorless control algorithm. When a BLDC motor rotates, each winding generates BEMF, which opposes the main voltage supplied to the windings according to Lenz’s Law. The polarity of this BEMF is in the opposite direction of the energizing voltage. Figure 2, below, shows ideal BEMF waveforms and the zero-crossing points.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjjBHq8f6AlL-r8EQYuykDLjDohO_2cnfsOpLWb9DfRSkJKLUceliGxrtC1GidcnRy6LvRL3DiVdr7PVMRn5BBJ3y97YqnPkzsTts26PcT2dRNS1jySvc-36_OvlM0ag29OzDpmaxlW9bU/s1600-h/Waveform+of+a+Brushless+DC+Motor+3.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjjBHq8f6AlL-r8EQYuykDLjDohO_2cnfsOpLWb9DfRSkJKLUceliGxrtC1GidcnRy6LvRL3DiVdr7PVMRn5BBJ3y97YqnPkzsTts26PcT2dRNS1jySvc-36_OvlM0ag29OzDpmaxlW9bU/s320/Waveform+of+a+Brushless+DC+Motor+3.JPG" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"> <a href="http://www.designnews.com/article/279139-Sensorless_Control_of_a_Brushless_DC_Motor.php" rel="nofollow" target="_blank">more</a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Waveform of a Brushless DC Motor ESC video</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">E-flite EFLA311, 20 A ESC driving an E-flite 450 motor. </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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<div style="color: #0b5394;"><span style="font-size: large;"><b>Buy Cheap Brushless DC Motor</b></span></div><div style="color: #0b5394;"><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B0014CGXWC&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe> <iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B000PSWUVY&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe></div>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-87242493122104770452010-03-12T03:58:00.000-08:002010-03-12T03:58:00.455-08:00Brushless DC Motor Maintain Video<div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless dcmotor maintain Part 1</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">Video how to take off brushless dc motor</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="295" width="480"><param name="movie" value="http://www.youtube.com/v/6iFTO54uGM0&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/6iFTO54uGM0&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="295"></embed></object></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless dc motor maintain Part 2</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">Video how to clean brushless dc motor</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="295" width="480"><param name="movie" value="http://www.youtube.com/v/Pt7O2qiuP4g&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/Pt7O2qiuP4g&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="295"></embed></object></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless dc motor maintain Part 3</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">Video how to assemble brushless dc motor</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="295" width="480"><param name="movie" value="http://www.youtube.com/v/DJlLstmmie4&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/DJlLstmmie4&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="295"></embed></object></div><div style="color: #0b5394;"><span style="font-size: large;"><b><br />
</b></span></div><div style="color: #0b5394;"><span style="font-size: large;"><b>Buy Cheap Brushless DC Motor</b></span></div><div style="color: #0b5394;"><br />
</div><div style="color: #0b5394;"><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B0014CGXWC&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe> <iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B000PSWUVY&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe></div>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-62825233856772874412010-03-09T03:58:00.000-08:002010-03-09T03:58:21.082-08:00Brushless Motor Construction<div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless DC (BLDC) Motor Fundamentals</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxI1nJCkziLf5UNdxX4N9wrX-bBcJ3-wSzosWq13X3DNjva0kyduLhZSIvP_dk-qdrF3INvOPhJdFiscQqO7MpJeF5oW_PE3CJsRjryZ9r2AKJCoHwWW4tc0CrvbHQT8M6uL0TtE5Vydk/s1600-h/Brushless+Motor+Construction.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxI1nJCkziLf5UNdxX4N9wrX-bBcJ3-wSzosWq13X3DNjva0kyduLhZSIvP_dk-qdrF3INvOPhJdFiscQqO7MpJeF5oW_PE3CJsRjryZ9r2AKJCoHwWW4tc0CrvbHQT8M6uL0TtE5Vydk/s320/Brushless+Motor+Construction.JPG" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">CONSTRUCTION AND OPERATING PRINCIPLE</div><div style="font-family: Arial,Helvetica,sans-serif;">BLDC motors are a type of synchronous motor. This</div><div style="font-family: Arial,Helvetica,sans-serif;">means the magnetic field generated by the stator and</div><div style="font-family: Arial,Helvetica,sans-serif;">the magnetic field generated by the rotor rotate at the</div><div style="font-family: Arial,Helvetica,sans-serif;">same frequency. BLDC motors do not experience the</div><div style="font-family: Arial,Helvetica,sans-serif;">“slip” that is normally seen in induction motors.</div><div style="font-family: Arial,Helvetica,sans-serif;">BLDC motors come in single-phase, 2-phase and</div><div style="font-family: Arial,Helvetica,sans-serif;">3-phase configurations. Corresponding to its type, the</div><div style="font-family: Arial,Helvetica,sans-serif;">stator has the same number of windings. Out of these,</div><div style="font-family: Arial,Helvetica,sans-serif;">3-phase motors are the most popular and widely used.</div><div style="font-family: Arial,Helvetica,sans-serif;">This application note focuses on 3-phase motors.</div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://www.jimfranklin.info/microchipdatasheets/00885a.pdf" rel="nofollow" target="_blank">more</a> </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless DC Motor - Basic structures</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh67NlzP2CvXPWIbvVJeAf1CbOcYiHZ8-n10Sleu6gDKywuf8rx6vAsMG6jCYY-ogt_XKv6fMkDarvuolRpoactsGRaGt016M9CLHFcm1sy0h6bXb6VnKV51Pnluxb-bKlDPUl9rA8YzIw/s1600-h/Brushless+Motor+Construction+2.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh67NlzP2CvXPWIbvVJeAf1CbOcYiHZ8-n10Sleu6gDKywuf8rx6vAsMG6jCYY-ogt_XKv6fMkDarvuolRpoactsGRaGt016M9CLHFcm1sy0h6bXb6VnKV51Pnluxb-bKlDPUl9rA8YzIw/s320/Brushless+Motor+Construction+2.JPG" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">The construction of modern brushless motors is very similar to the ac motor, known as the permanent magnet synchronous motor. Fig.1 illustrates the structure of a typical three-phase brushless dc motor. The stator windings are similar to those in a polyphase ac motor, and the rotor is composed of one or more permanent magnets. Brushless dc motors are different from ac synchronous motors in that the former incorporates some means to detect the rotor position (or magnetic poles) to produce signals to control the electronic switches as shown in Fig.2. The most common position/pole sensor is the Hall element, but some motors use optical sensors.</div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://services.eng.uts.edu.au/cempe/subjects_JGZ/ems/ems_ch12_nt.pdf" rel="nofollow" target="_blank">more</a> </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless Motor Construction Video</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">Machining A Brushless Motor with a lathe and drill press. Just a quick slide show of some motor contsruction tips before I added a small milling machine to my hobby shop. John </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="295" width="480"><param name="movie" value="http://www.youtube.com/v/mbU-uOdKgOc&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/mbU-uOdKgOc&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="295"></embed></object></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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<div style="color: #0b5394;"><span style="font-size: large;"><b>Buy Cheap Brushless Motor</b></span></div><div style="color: #0b5394;"><br />
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</div>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-9899418329217449022010-03-05T04:13:00.000-08:002010-03-05T04:13:00.211-08:00Brushless motor winding<div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless DC Motor modification</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">A picture is worth hundreds of words. Here is a wiring diagram for the star configuration that I have found from the net. you are better to do this with great circumspection or it would be easily end up with a burned ESC. The first photo shown above is one group of the windings on the stator. Two groups are wound in the second photo while all three groups are wound in the last photo. The starts of each three groups are soldered together and the three ends are the phase wires that connect to the brushless controller.</div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://www.angelfire.com/blues/heli_project/brushless.htm" rel="nofollow" target="_blank">more </a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless Motor Winding Diagrams</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvs3FgFeN7Sdw3couc_g2TxGNIrioDYVOd0YuNOm-arf5UEUYCk5XMMXJ9NEGNOiNJ2v1eSJhQ4NxZHE7dHbJ7oAVt8kIweQQk02HX0KAhS-MqJUBkm6CtDJ41sfHZ5sNaUUW5nkXEwlA/s1600-h/Brushless+motor+winding+02.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvs3FgFeN7Sdw3couc_g2TxGNIrioDYVOd0YuNOm-arf5UEUYCk5XMMXJ9NEGNOiNJ2v1eSJhQ4NxZHE7dHbJ7oAVt8kIweQQk02HX0KAhS-MqJUBkm6CtDJ41sfHZ5sNaUUW5nkXEwlA/s320/Brushless+motor+winding+02.jpg" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">The 'standard' Star diagram for</div><div style="font-family: Arial,Helvetica,sans-serif;">9-tooth stators & 12 magnets</div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://www.bavaria-direct.co.za/models/motor_info.htm" rel="nofollow" target="_blank">more</a> </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</b></span></div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless motor winding by Utah Fyers #1</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">Radio control electric brushless motor winding tutorial video</div><div style="font-family: Arial,Helvetica,sans-serif;"></div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/iHYlWKICkqc&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/iHYlWKICkqc&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless motor winding by Utah Fyers #2</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">Tutorial on brushless motor winding video presented by Utah Flyers. </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/9o9vopQqMH0&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/9o9vopQqMH0&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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<div style="color: #0b5394;"><span style="font-size: large;"><b>Buy Cheap Brushless Motor</b></span></div><div style="color: #0b5394;"><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B0015KF18U&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B000PSWULO&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe></div>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-34467550035704706482010-03-01T04:07:00.000-08:002010-03-01T04:07:00.609-08:00Home Built Brushless DC Motor Video<div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless DC Motor</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">Video of a Home Built Brushless DC Motor </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/SjydA8Ykrls&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/SjydA8Ykrls&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushless DC motor</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">Three students (16-17 years old) from the "Stedelijk College" in Eindhoven, the Netherlands designed and made this motor in one day! The motor turns with approximately 2000 rpm!</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/gZd2A2IhOo8&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/gZd2A2IhOo8&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Homemade brushless motor</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">This is my homemade brushless motor. Or you could call it a fan! It's made from old junk and surplus components mostly. Better description is in the video!</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/H07RQ1OJZEk&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/H07RQ1OJZEk&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>home made brushless dc motor</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">Video home made brushless dc motor battery: Align 3 cell li-po 11.1v Reed switch 8 neodymium magnets no bearings were used (performance would have improved greatly if bearings were used on the spindle)</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/_cl17vKS7yc&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/_cl17vKS7yc&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><br />
<div style="color: #0b5394;"><span style="font-size: large;"><b>Buy Cheap Brushless DC Motor </b></span></div><div style="color: #0b5394;"><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B000PSWUS2&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B000PSWUVY&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe></div>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-33552800743030427822010-02-25T04:01:00.000-08:002010-02-25T04:01:34.087-08:00Basic Brushless DC Motor<div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Basic brushless DC Motor</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMNGAre9gmBiIm1dRSxM4Y-7kTurhnnj9mGZ_4CzKP387nUWgIbGv7DePlImhgnw04sJNeZN6GvqM3gfvbDH4bZgn14PzIF-RJNvYfK754l3wKVfaDdMR4MEkyRJezOT3GFbKHKbBGZgo/s1600-h/Basic+brushless+DC+Motor+01.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMNGAre9gmBiIm1dRSxM4Y-7kTurhnnj9mGZ_4CzKP387nUWgIbGv7DePlImhgnw04sJNeZN6GvqM3gfvbDH4bZgn14PzIF-RJNvYfK754l3wKVfaDdMR4MEkyRJezOT3GFbKHKbBGZgo/s320/Basic+brushless+DC+Motor+01.JPG" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">However, if, at the appropriate time, current is shut off in winding “R”, and turned on in winding “S”, then the rotor continues to move. Again at the appropriate time, shut off “S” and turned on “T”. By continuation of this timing sequence, complete rotation occurs. What is occurring, is that the field set up by the stator is being switched, and the rotor tries to catch up to it.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">In this example, the explanation was simplified by exciting only one winding at a time. In reality, the stator consists of a three phase Y–connected winding, and two or three windings are actually energized.. This makes efficient use of windings and development of higher motor torques.</div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://www.motioncontrolonline.org/files/public/BrushlessOperation.pdf" rel="nofollow" target="_blank">more </a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Basic Brushless Motor Basics</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdJwRru-NJ6_bQerxuEbvQVtDd7vdOLimhD0JRvWVm61YsjFwtWPAQ1rOonqh6656kljB5Pk0qSuinFbnQ72LllEJwtjVi8Uk6bRK0BUFg6xsBf8x5-b1BavpZWYAHwWxVCkPqKjeDzOA/s1600-h/Basic+brushless+DC+Motor+02.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdJwRru-NJ6_bQerxuEbvQVtDd7vdOLimhD0JRvWVm61YsjFwtWPAQ1rOonqh6656kljB5Pk0qSuinFbnQ72LllEJwtjVi8Uk6bRK0BUFg6xsBf8x5-b1BavpZWYAHwWxVCkPqKjeDzOA/s320/Basic+brushless+DC+Motor+02.JPG" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">In its simplest form, a brushless dc motor consists of a permanent magnet, which rotates (the rotor), surrounded by three equally spaced windings, which are fixed (the stator). Current flow in each winding produces a magnetic field vector, which sums with the fields from the other windings. By controlling currents in the three windings, a magnetic field of arbitrary direction and magnitude can be produced by the stator. Torque is then produced by the attraction or repulsion between this net stator field and the magnetic field of the rotor.</div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://www.copleycontrols.com/Motion/pdf/Brushless_Motor_Basics.pdf" rel="nofollow" target="_blank">more</a> </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Basic Brushless DC Motors</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">Conventional dc motors are highly efficient and their characteristics make them suitable for use as servomotors. However, their only drawback is that they need a commutator and brushes which are subject to wear and require maintenance. When the functions of commutator and brushes were implemented by solid-state switches, maintenance-free motors were realised. These motors are now known as brushless dc motors. In this chapter, the basic structures, drive circuits, fundamental principles, steady state characteristics, and applications of brushless dc motors will be discussed.<br />
<a href="http://services.eng.uts.edu.au/cempe/subjects_JGZ/ems/ems_ch12_nt.pdf" rel="nofollow" target="_blank">more</a> </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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<div style="color: #0b5394;"><span style="font-size: large;"><b>Buy Cheap Brushless DC Motor</b></span></div><div style="color: #0b5394;"><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B000BRH4E2&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B0014CGXWC&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B0014DONAU&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe></div>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-76397167144227230612010-02-17T20:08:00.000-08:002010-02-17T20:08:00.579-08:00Brushed DC Motor control by using PIC Microcontroller<div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Low-Cost Bidirectional Brushed DC Motor Control</b></span></div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Using the PIC16F684</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;"><b>INTRODUCTION</b></div><div style="font-family: Arial,Helvetica,sans-serif;">This application note discusses how to use the</div><div style="font-family: Arial,Helvetica,sans-serif;">Enhanced, Capture, Compare, PWM (ECCP) on the</div><div style="font-family: Arial,Helvetica,sans-serif;">PIC16F684 Microcontroller for bidirectional, brushed DC (BDC) motor</div><div style="font-family: Arial,Helvetica,sans-serif;">control. Low-cost brushed DC motor control can be</div><div style="font-family: Arial,Helvetica,sans-serif;">used in applications such as intelligent toys, small</div><div style="font-family: Arial,Helvetica,sans-serif;">appliances and power tools. The PIC16F684 takes</div><div style="font-family: Arial,Helvetica,sans-serif;">Microchip's Mid-Range Family of products to the next</div><div style="font-family: Arial,Helvetica,sans-serif;">level with its new ECCP peripheral. The ECCP</div><div style="font-family: Arial,Helvetica,sans-serif;">peripheral builds on the technology of the CCP module</div><div style="font-family: Arial,Helvetica,sans-serif;">with added features such as four PWM channels for</div><div style="font-family: Arial,Helvetica,sans-serif;">easy bidirectional motor control through the hardware.</div><div style="font-family: Arial,Helvetica,sans-serif;">This application note focuses on using the ECCP in</div><div style="font-family: Arial,Helvetica,sans-serif;">PWM mode using the full-bridge configuration. Using</div><div style="font-family: Arial,Helvetica,sans-serif;">the ECCP allows easy interfacing to a full-bridge</div><div style="font-family: Arial,Helvetica,sans-serif;">configuration for bidirectional BDC motor control.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcCBJCmef9qTvkkqBO1zFsr6dPrssMiBnXEkf4abjQjQEczrxjUrqm3I5vMLuCXwoekW4D4RtAsLLqXp1Cv-vf9oa3DpK-YW9SzfAtfJhBVzoR-EXgL4xlti1LXQQ4NN94HDgnP8qyPO4/s1600-h/Brushed+DC+Motor+control+pic+01.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcCBJCmef9qTvkkqBO1zFsr6dPrssMiBnXEkf4abjQjQEczrxjUrqm3I5vMLuCXwoekW4D4RtAsLLqXp1Cv-vf9oa3DpK-YW9SzfAtfJhBVzoR-EXgL4xlti1LXQQ4NN94HDgnP8qyPO4/s320/Brushed+DC+Motor+control+pic+01.JPG" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://oretano.iele-ab.uclm.es/%7Emhidalgo/temas/tema2/AN893a_PIC16F684sensorless.pdf">more</a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Brushed DC Motor control by using PIC microcontroller</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;">I used PIC microcontroller to realize the control of BLDC motor. In the video, you can observe how the PID parameter affect the performance of motor. The different magnitudes (due to different PID parameters) </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/82Lh5lEK_ts&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/82Lh5lEK_ts&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">Efficient Brushless DC motor and Permanent Magnet Synchronous Motor Control</div><div style="font-family: Arial,Helvetica,sans-serif;">Demonstration of advanced sensorless algorithms such as field oriented control and trapezoidal control using sinusoidal drive for Brushless DC (BLDC) and Permanent Magnet (PM) Synchronous Motors</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"></div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/22fHmW4nYsE&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/22fHmW4nYsE&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><br />
<div style="color: #134f5c;"><span style="font-size: large;"><b>Buy PIC Microcontroller Project Book</b></span></div><div style="color: #134f5c;"><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=0071437045&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=090570570X&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=0470694610&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe></div>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-27787609730690400262010-02-14T20:19:00.000-08:002010-02-14T20:19:00.234-08:00Brushless DC Motor Control using PIC18 Microcontroller Video<div style="font-family: Arial,Helvetica,sans-serif;"><b>Video </b><b>Developing Brushless DC (BLDC) motor control using PIC18Fxx31 Microcontroller - Part 1</b></div><div style="font-family: Arial,Helvetica,sans-serif;">BLDC motors can be designed to operate from a high voltage or low voltage source. The following seminar explores BLDC control using PIC18F Microcontroller devices. </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/j1mlnYLtPxE&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/j1mlnYLtPxE&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><b>Video </b><b>Developing Brushless DC (BLDC) motor control using PIC18Fxx31 Microcontroller - Part 2</b></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/e7dCqSffcKA&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/e7dCqSffcKA&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><div style="font-family: Arial,Helvetica,sans-serif;"><b><br />
</b></div><div style="font-family: Arial,Helvetica,sans-serif;"><b>Video </b><b>Developing Brushless DC (BLDC) motor control using PIC18Fxx31 Microcontroller - Part 3</b></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/QC8RzDmDZfM&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/QC8RzDmDZfM&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><b>Video Developing Brushless DC (BLDC) motor control using PIC18Fxx31 Microcontroller - Part 4</b></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/_suQfKVaSk4&hl=en_US&fs=1&rel=0"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/_suQfKVaSk4&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object></div><br />
<div style="color: #134f5c;"><span style="font-size: large;"><b>Buy PIC18 Microcontroller Book</b></span></div><div style="color: #134f5c;"><br />
</div>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-13332889342330917722010-02-08T19:54:00.000-08:002010-02-08T20:29:35.178-08:00Sensorless Brushless DC Motor control using a Microcontroller Data and algorithm<div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Sensorless Brushless DC Motor Control with Z8 Encore! MC™ Microcontrollers</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;"><b>Abstract</b></div><div style="font-family: Arial,Helvetica,sans-serif;">This application note discusses the closed loop control of a 3-Phase Brushless</div><div style="font-family: Arial,Helvetica,sans-serif;">Direct Current (BLDC) motor using the Z8 Encore! MC™ Family of</div><div style="font-family: Arial,Helvetica,sans-serif;">Microcontrollers series microcontrollers (MCUs). The Z8 Encore! MC™ product</div><div style="font-family: Arial,Helvetica,sans-serif;">family is designed specifically for motor control applications, featuring an on-chip</div><div style="font-family: Arial,Helvetica,sans-serif;">integrated array of application-specific analog and digital modules. This in turn</div><div style="font-family: Arial,Helvetica,sans-serif;">results in fast and precise fault control, high system efficiency, and “on-the-fly”</div><div style="font-family: Arial,Helvetica,sans-serif;">speed / torque and direction control, as well as ease of firmware development for</div><div style="font-family: Arial,Helvetica,sans-serif;">customized applications.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">This article further discusses ways on how to implement a sensorless feedback</div><div style="font-family: Arial,Helvetica,sans-serif;">control system using a “Phase Locked Loop” along with Back EMF sensing.</div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://www.zilog.com/docs/z8encoremc/appnotes/an0226.pdf" rel="nofollow" target="_blank">more</a> </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Sensorless control of 3-phase brushless DC motors</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;"><b>Introduction</b></div><div style="font-family: Arial,Helvetica,sans-serif;">This application note describes how to implement sensorless commutation control</div><div style="font-family: Arial,Helvetica,sans-serif;">of a 3-phase <a href="http://dcacmotors.blogspot.com/2009/12/brushed-dc-motor-basics-video.html" target="_blank">brushless DC motor</a> (BLDC) with the low cost ATmega48</div><div style="font-family: Arial,Helvetica,sans-serif;">microcontroller. A general solution, suitable for most 3-phase BLDC motors on the</div><div style="font-family: Arial,Helvetica,sans-serif;">market is presented. The full source code is written in the C language, no assembly</div><div style="font-family: Arial,Helvetica,sans-serif;">is required. Adaptation to different motors is done through the setting of parameters</div><div style="font-family: Arial,Helvetica,sans-serif;">in the source code.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">The ATmega48/88/168 devices are all pin and source code compatible. The only</div><div style="font-family: Arial,Helvetica,sans-serif;">difference is memory sizes. This application note is written with ATmega48 in mind,</div><div style="font-family: Arial,Helvetica,sans-serif;">but any reference to ATmega48 in this document also applies to ATmega88/168.</div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://www.atmel.com/dyn/resources/prod_documents/doc8012.pdf" rel="nofollow" target="_blank">more</a> </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b style="color: #38761d;">Brushed DC motor control using the LPC2101 microcontroller</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;"><b>Introduction </b></div><div style="font-family: Arial,Helvetica,sans-serif;">This application note demonstrates the use of a low cost NXP Semiconductors LPC2101 microcontroller for bidirectional brushed DC motor control. </div><div style="font-family: Arial,Helvetica,sans-serif;">The LPC2101 is based on a 16/32-bit ARM7 CPU combined with embedded high-speed flash memory. A superior performance as well as their tiny size, low power consumption and a blend of on-chip peripherals make these devices ideal for a wide range of applications. Various 32-bit and 16-bit timers, 10-bit ADC and PWM features through output match on all timers, make them particularly suitable for industrial control. </div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">Brushed DC (Direct Current) motors are most commonly used in easy to drive, variable speed and high start-up torque applications. They have become widespread and are available in all shapes and sizes from large-scale industrial models to small motors for light applications (such as 12 V DC motors). </div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://www.nxp.com/documents/application_note/AN10513.pdf" rel="nofollow" target="_blank">more</a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="color: #38761d; font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b>Sensorless BLDC Motor Control Using MC9S08AC16</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;"><b>Introduction</b></div><div style="font-family: Arial,Helvetica,sans-serif;">This application note describes the design of a 3-phase</div><div style="font-family: Arial,Helvetica,sans-serif;">sensorless BLDC motor drive with Back-EMF</div><div style="font-family: Arial,Helvetica,sans-serif;">zero crossing. It is based on Freescale’s MC9S08AC16</div><div style="font-family: Arial,Helvetica,sans-serif;">that can be effectively used for motor-control</div><div style="font-family: Arial,Helvetica,sans-serif;">applications.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;">The concept of the application is that of a speed-closed</div><div style="font-family: Arial,Helvetica,sans-serif;">loop drive using Back-EMF zero crossing technique for</div><div style="font-family: Arial,Helvetica,sans-serif;">positional detection. It serves as an example of a</div><div style="font-family: Arial,Helvetica,sans-serif;">sensorless BLDC motor control system using</div><div style="font-family: Arial,Helvetica,sans-serif;">Freescale’s MCU and 3-Phase BLDC/PMSM</div><div style="font-family: Arial,Helvetica,sans-serif;">Low-Voltage Motor Control Drive. It also illustrates</div><div style="font-family: Arial,Helvetica,sans-serif;">the usage of general on-chip peripherals for</div><div style="font-family: Arial,Helvetica,sans-serif;">motor-control applications.</div><div style="font-family: Arial,Helvetica,sans-serif;">This application note includes a description of the</div><div style="font-family: Arial,Helvetica,sans-serif;">controller features, basic BLDC motor theory, system</div><div style="font-family: Arial,Helvetica,sans-serif;">design concept, hardware implementation, software</div><div style="font-family: Arial,Helvetica,sans-serif;">design including the FreeMaster software visualization</div><div style="font-family: Arial,Helvetica,sans-serif;">tool, application setup, and demo operation.</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEguSKPOGL8kfnKSJXpquRH4rUDfW0l51hc1OLzvHEOFDncTMt3tbJ9onA9ov8upT3SktMtPHy1obD-UYX19qibZXwiRbvmYCOlnRnwT65gJIFkmCVZRyD7ta-lOpSKcdQCI2grv8tMq0Co/s1600-h/Sensorless+Brushed+DC+Motor+control++uC+01.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEguSKPOGL8kfnKSJXpquRH4rUDfW0l51hc1OLzvHEOFDncTMt3tbJ9onA9ov8upT3SktMtPHy1obD-UYX19qibZXwiRbvmYCOlnRnwT65gJIFkmCVZRyD7ta-lOpSKcdQCI2grv8tMq0Co/s320/Sensorless+Brushed+DC+Motor+control++uC+01.JPG" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://www.freescale.com/files/microcontrollers/doc/app_note/AN3832.pdf" rel="nofollow" target="_blank">more</a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div style="font-family: Arial,Helvetica,sans-serif;"><span style="font-size: large;"><b style="color: #38761d;">Sensorless Brushless DC Motor Control with PIC16 Microcontroller</b></span></div><div style="font-family: Arial,Helvetica,sans-serif;"><b>INTRODUCTION</b></div><div style="font-family: Arial,Helvetica,sans-serif;">There is a lot of interest in using Brushless DC (BLDC)</div><div style="font-family: Arial,Helvetica,sans-serif;">motors. Among the many advantages to a BLDC motor</div><div style="font-family: Arial,Helvetica,sans-serif;">over a brushed DC motor, we can enumerate the</div><div style="font-family: Arial,Helvetica,sans-serif;">following:</div><div style="font-family: Arial,Helvetica,sans-serif;">• The absence of the mechanical commutator</div><div style="font-family: Arial,Helvetica,sans-serif;">allows higher speeds</div><div style="font-family: Arial,Helvetica,sans-serif;">• Brush performance limits the transient response</div><div style="font-family: Arial,Helvetica,sans-serif;">in the DC motor</div><div style="font-family: Arial,Helvetica,sans-serif;">• With the DC motor you have to add the voltage</div><div style="font-family: Arial,Helvetica,sans-serif;">drop in the brushes among motor losses</div><div style="font-family: Arial,Helvetica,sans-serif;">• Brush restrictions on reactance voltage of the</div><div style="font-family: Arial,Helvetica,sans-serif;">armature constrains the length of core reducing</div><div style="font-family: Arial,Helvetica,sans-serif;">the speed response and increasing the inertia for</div><div style="font-family: Arial,Helvetica,sans-serif;">a specific torque</div><div style="font-family: Arial,Helvetica,sans-serif;">• The source of heating in the BLDC motor is in the</div><div style="font-family: Arial,Helvetica,sans-serif;">stator, while in the <a href="http://dcacmotors.blogspot.com/2009/06/dc-motor-lecture-vedio.html" target="_blank">DC motor</a> it is in the rotor,</div><div style="font-family: Arial,Helvetica,sans-serif;">therefore it is easier to dissipate heat in the BLDC</div><div style="font-family: Arial,Helvetica,sans-serif;">• Reduced audible and electromagnetic noise</div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
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</div><div class="separator" style="clear: both; font-family: Arial,Helvetica,sans-serif; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEbimm4Gbn9wo4eMGXsj-lUL3YGqYsoIkqDivkgq477JDZ0wLSRHBuJNpeWu5uvvnIZKbW6iGx95ZpAHekWKHHfm4X6RtETuKxW_OtfdDzx7sBaR9o_h2aXPqwlUbAEX2cvFsD1995Zao/s1600-h/Sensorless+Brushed+DC+Motor+control++uC+02.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEbimm4Gbn9wo4eMGXsj-lUL3YGqYsoIkqDivkgq477JDZ0wLSRHBuJNpeWu5uvvnIZKbW6iGx95ZpAHekWKHHfm4X6RtETuKxW_OtfdDzx7sBaR9o_h2aXPqwlUbAEX2cvFsD1995Zao/s320/Sensorless+Brushed+DC+Motor+control++uC+02.JPG" /></a></div><div style="font-family: Arial,Helvetica,sans-serif;"><a href="http://ww1.microchip.com/downloads/en/AppNotes/01175A.pdf" rel="nofollow" target="_blank">more</a></div><div style="font-family: Arial,Helvetica,sans-serif;"><br />
<a href="http://circuitelec.blogspot.com/2009/07/brushless-dc-motors-theory-and-driver.html" target="_blank">Brushless DC Motors Theory and Driver Circuit</a><br />
<br />
<span style="font-size: large;"><b style="color: #38761d;">Buy Brushless Motor Speed Controller</b></span><br />
<iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B0014CGXWC&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B000U7ZWAQ&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B000PSWUS2&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe></div>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-73497009021551966752010-01-08T02:21:00.000-08:002010-02-08T20:06:43.359-08:00Sensorless Brushed DC Motor control using a dsPIC Data and algorithm<span style="font-family: arial;">This web seminar explains a sensorless Brushless Direct Current (BLDC) motor control algorithm, implemented using the dsPIC® digital signal controller (DSC).</span><br />
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<span style="font-family: arial; font-size: 130%;"><span style="color: #33cc00; font-weight: bold;">Sensorless Brushed DC Motor control using a Majority Function Part 1 of 2</span></span><br />
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<object height="344" style="font-family: arial;" width="425"><param name="movie" value="http://www.youtube.com/v/moz_GyOdBZw&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/moz_GyOdBZw&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br />
<br />
<span style="font-family: arial; font-size: 130%;"><span style="color: #33cc00; font-weight: bold;">Sensorless Brushed DC Motor control using a Majority Function Part 2 pf 2</span></span><br />
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<object height="344" style="font-family: arial;" width="425"><param name="movie" value="http://www.youtube.com/v/unhQ2ToXZO0&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/unhQ2ToXZO0&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br />
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<span style="font-family: arial; font-size: 130%;"><span style="color: #33cc00; font-weight: bold;">How a BLDC controller work - Giovanni Garraffa</span></span><br />
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<object height="344" style="font-family: arial;" width="425"><param name="movie" value="http://www.youtube.com/v/5k7D2rlWyDk&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/5k7D2rlWyDk&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br />
<br />
<span style="font-size: 130%;"><span style="color: #33cc00; font-family: arial; font-weight: bold;">Using the dsPIC30F for Sensorless BLDC Control</span></span><br />
<span style="font-family: arial; font-weight: bold;">INTRODUCTION</span><br />
<span style="font-family: arial;">This application note describes a fully working and</span><br />
<span style="font-family: arial;">highly flexible software application for using the</span><br />
<span style="font-family: arial;">dsPIC30F to control brushless DC (BLDC) motors</span><br />
<span style="font-family: arial;">without position sensors. The software makes</span><br />
<span style="font-family: arial;">extensive use of dsPIC30F peripherals for motor</span><br />
<span style="font-family: arial;">control. The algorithm implemented for sensorless</span><br />
<span style="font-family: arial;">control is particularly suitable for use on fans and</span><br />
<span style="font-family: arial;">pumps. The program is written in C and has been</span><br />
<span style="font-family: arial;">specifically optimized and well annotated for ease of</span><br />
<span style="font-family: arial;">understanding and program modification.</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgepDnFQp4yJmFi0ECDdoODlTlXB6xmBRotMQZuFF7WOLPMf5MYIeyx7QTI1dDToon7pywUX9Ha1vLj1xYZ8MBrlo6q9PVbkid04i99VDpwLOmO32YqdLjJjFMEXA2QEYsFBVJlk3dAXlI/s1600-h/Sensorless+Brushed+DC+Motor+control++dspic+01.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5428001882568993554" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgepDnFQp4yJmFi0ECDdoODlTlXB6xmBRotMQZuFF7WOLPMf5MYIeyx7QTI1dDToon7pywUX9Ha1vLj1xYZ8MBrlo6q9PVbkid04i99VDpwLOmO32YqdLjJjFMEXA2QEYsFBVJlk3dAXlI/s320/Sensorless+Brushed+DC+Motor+control++dspic+01.JPG" style="cursor: pointer; display: block; height: 239px; margin: 0px auto 10px; text-align: center; width: 320px;" /></a><br />
<br />
<a href="http://ww1.microchip.com/downloads/en/appnotes/Sensorless%20BLDC%2000901a.pdf" rel="nofollow" target="_blank">more</a><br />
<br />
<br />
<span style="font-size: 130%;"><span style="color: #33cc00; font-family: arial; font-weight: bold;">Sensorless BLDC Motor Control Using dsPIC30F2010</span></span><br />
<span style="font-family: arial; font-weight: bold;">INTRODUCTION</span><br />
<span style="font-family: arial;">This application note describes how to provide sensorless</span><br />
<span style="font-family: arial;">BLDC motor control with the dsPIC30F2010</span><br />
<span style="font-family: arial;">Digital Signal Controller. The technique used is based</span><br />
<span style="font-family: arial;">on another Microchip application note: Using the</span><br />
<span style="font-family: arial;">dsPIC30F for Sensorless BLDC Control (AN901).</span><br />
<span style="font-family: arial;">This application note explains how to apply the</span><br />
<span style="font-family: arial;">dsPIC30F2010 device to the hardware and software</span><br />
<span style="font-family: arial;">described in AN901, which uses the dsPIC30F6010</span><br />
<span style="font-family: arial;">device and dsPICDEM™ MC1 Motor Control Development</span><br />
<span style="font-family: arial;">Board. The 80-pin dsPIC30F6010 has 144</span><br />
<span style="font-family: arial;">Kbytes of Flash Program Memory, 8 Kbytes of RAM</span><br />
<span style="font-family: arial;">available and abundant I/O. The 28-pin</span><br />
<span style="font-family: arial;">dsPIC30F2010, on the other hand, has limited I/O, only</span><br />
<span style="font-family: arial;">12 Kbytes of Flash program memory and 512 bytes of</span><br />
<span style="font-family: arial;">RAM. As you can see, the resources are finite.</span><br />
<span style="font-family: arial;">This application note prescribes changes to the hardware,</span><br />
<span style="font-family: arial;">software and user interface described in AN901</span><br />
<span style="font-family: arial;">to facilitate the easy transfer of the code to the</span><br />
<span style="font-family: arial;">dsPIC30F2010 device.</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhimh3e9ZgtDCS4pLWZD2xLsjsqWtwnbbcAofKZrr4YK202nnckHKR_GQhONNKJVswIgT31cXx_g3VQ2TxiwNKuLI4asWYXQFwDzNRWhyphenhyphenVBlHQQcHwYRhmzB786j9SfVlCk4oQoRLcbjns/s1600-h/Sensorless+Brushed+DC+Motor+control++dspic+02.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5428001993612687250" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhimh3e9ZgtDCS4pLWZD2xLsjsqWtwnbbcAofKZrr4YK202nnckHKR_GQhONNKJVswIgT31cXx_g3VQ2TxiwNKuLI4asWYXQFwDzNRWhyphenhyphenVBlHQQcHwYRhmzB786j9SfVlCk4oQoRLcbjns/s320/Sensorless+Brushed+DC+Motor+control++dspic+02.JPG" style="cursor: pointer; display: block; height: 174px; margin: 0px auto 10px; text-align: center; width: 320px;" /></a><br />
<br />
<a href="http://ww1.microchip.com/downloads/en/AppNotes/00992A.pdf" rel="nofollow" target="_blank">more</a><br />
<br />
<div style="color: #3d85c6;"><span style="font-size: large;"><b>Buy Brushless DC Motor control </b></span></div><div style="color: #3d85c6;"><br />
</div><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=0824753844&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B000PSWUNM&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B001GQGLBY&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-74471603005705165182009-12-17T22:30:00.000-08:002010-02-01T01:53:04.544-08:00Brushed DC Motor Basics Video<span style="color: #3333ff; font-family: arial; font-weight: bold;">Brushed DC Motor Basics Part 1 of 2</span><br />
<span style="font-family: arial;">This video on brushed DC motor basics is part 1 of a four part series of web seminars that will go into motor control drive topologies, pulse width modulation ( PWM ), and the new enhanced PWM.</span><br />
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<object height="344" style="font-family: arial;" width="425"><param name="movie" value="http://www.youtube.com/v/0-YXBxzKx7g&hl=en_US&fs=1&"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/0-YXBxzKx7g&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br />
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<span style="color: #3366ff; font-family: arial; font-weight: bold;">Brushed DC Motor Basics Part 2 of 2</span><br />
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<object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/v4l0TnCGoSc&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/v4l0TnCGoSc&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br />
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<br />
<span style="font-size: 130%;"><span style="color: #33cc00; font-family: arial; font-weight: bold;">Brushed DC Motor Fundamentals</span></span><br />
<span style="font-family: arial; font-weight: bold;">INTRODUCTION</span><br />
<span style="font-family: arial;"><iframe align="left" frameborder="0" marginheight="0" marginwidth="0" scrolling="no" src="http://rcm.amazon.com/e/cm?t=electritransf-20&o=1&p=8&l=bpl&asins=B0016HUVX2&fc1=000000&IS2=1&lt1=_blank&m=amazon&lc1=0000FF&bc1=000000&bg1=FFFFFF&f=ifr" style="height: 245px; padding-right: 10px; padding-top: 5px; width: 131px;"></iframe>Brushed DC motors are widely used in applications</span><br />
<span style="font-family: arial;">ranging from toys to push-button adjustable car seats.</span><br />
<span style="font-family: arial;">Brushed DC (BDC) motors are inexpensive, easy to</span><br />
<span style="font-family: arial;">drive, and are readily available in all sizes and shapes.</span><br />
<span style="font-family: arial;">This application note will discuss how a BDC motor</span><br />
<span style="font-family: arial;">works, how to drive a BDC motor, and how a drive</span><br />
<span style="font-family: arial;">circuit can be interfaced to a PIC® microcontroller.</span><br />
<br />
<span style="font-family: arial;"><span style="font-weight: bold;">PRINCIPLES OF OPERATION</span></span><br />
<span style="font-family: arial;">The construction of a simple BDC motor is shown in</span><br />
<span style="font-family: arial;">Figure 1. All BDC motors are made of the same basic</span><br />
<span style="font-family: arial;">components: a stator, rotor, brushes and a commutator.</span><br />
<span style="font-family: arial;">The following paragraphs will explain each component</span><br />
<span style="font-family: arial;">in greater detail.</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi0lml-Z3PavsUwS3a8flnBIx0YCVVyF1ax5Vs_Yamp1tvpbtfvmehyphenhyphenQOc6Jv65Q59nD8Aviaz8QOJ9xJS5o6ksslXi6ERs_RkXFxK7XTY-hGc2trFFY3fd9kzLUZ9qeLaCfdzjqmSAsDY/s1600-h/Brushed+DC+Motor+Basics+01.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5428000325098402866" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi0lml-Z3PavsUwS3a8flnBIx0YCVVyF1ax5Vs_Yamp1tvpbtfvmehyphenhyphenQOc6Jv65Q59nD8Aviaz8QOJ9xJS5o6ksslXi6ERs_RkXFxK7XTY-hGc2trFFY3fd9kzLUZ9qeLaCfdzjqmSAsDY/s320/Brushed+DC+Motor+Basics+01.JPG" style="cursor: pointer; display: block; height: 191px; margin: 0px auto 10px; text-align: center; width: 320px;" /></a><br />
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<span style="font-family: arial;">SIMPLE TWO-POLE BRUSHED DC MOTOR</span><br />
<a href="http://www.me.psu.edu/sommer/me445/AN905a.pdf" rel="nofollow" style="font-family: arial;" target="_blank">more</a><br />
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<span style="color: #33cc00; font-family: arial; font-weight: bold;">AC or DC? Brushed or Brushless?</span></span><br />
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<span style="font-family: arial;">DC Motors provide high power in a small package. Oriental Motor manufacturers a wide range of AC and brushless DC (BLDC) products. So why choose one technology over the other? There are several key differences between the different technologies.</span><br />
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<span style="font-family: arial; font-weight: bold;">Motor Construction</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbLHo8CstaQMWFcHa2GhlUKh8eYiwrzEDELbUfIOn7TIIhvu1WyyxbHYlqVAYMFKDA97DZcwYK56iG9t7m1573Xblojsu-KVgoDEGeFpyAzswqskdq334OO1xm2P36WnacgPgyNniC0RA/s1600-h/Brushed+DC+Motor+Basics+02.JPG" onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}"><img alt="" border="0" id="BLOGGER_PHOTO_ID_5428000135314523842" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbLHo8CstaQMWFcHa2GhlUKh8eYiwrzEDELbUfIOn7TIIhvu1WyyxbHYlqVAYMFKDA97DZcwYK56iG9t7m1573Xblojsu-KVgoDEGeFpyAzswqskdq334OO1xm2P36WnacgPgyNniC0RA/s320/Brushed+DC+Motor+Basics+02.JPG" style="cursor: pointer; display: block; height: 225px; margin: 0px auto 10px; text-align: center; width: 300px;" /></a><br />
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<span style="font-family: arial;">Brushed DC motors depend on a mechanical system to transfer current, while AC and brushless DC motors use an electronic mechanism to control current. The brushed motors have a wound armature attached to the center with a permanent magnet bonded to a steel ring surrounding the rotor. As the brushes come into contact with the commutator the current passes through to the armature coils.</span><br />
<a href="http://www.orientalmotor.com/newsletter/february_2007.htm" rel="nofollow" target="_blank">more </a><br />
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<div class="tag_list">Tags: <span class="tags"><a href="http://technorati.com/tag/DC+Motor" rel="tag" target="_blank">DC Motor</a></span></div>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-89510740805017943562009-12-13T01:27:00.000-08:002009-12-13T01:29:56.561-08:00Video A simple DC Motor and Homopolar Motor<span style="font-family: arial; font-weight: bold;">A simple DC Motor DIY</span><br /><span style="font-family: arial;">a simple DC motor made from a few wires, couple of magnets and a battery </span><br /><br /><object style="font-family: arial;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/OS-ihkq8mKI&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/OS-ihkq8mKI&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-family: arial; font-weight: bold;">The simplest motor of the world</span><br /><br /><span style="font-family: arial;">A motor made only by a wire and a magnet. It uses one AAA battery. </span><br /><object style="font-family: arial;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/zOdboRYf1hM&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/zOdboRYf1hM&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-family: arial; font-weight: bold;">World's Simplest Motor - Homopolar Spiral</span><br /><span style="font-family: arial;">The homopolar spiral motor is one of the simplest and most easy to make motors in the world. </span><br /><br /><object style="font-family: arial;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/Xnxf1WeXxgk&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/Xnxf1WeXxgk&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><br /><span style="font-family: arial; font-weight: bold;">Homopolar Motor - 5 minutes ready to work</span><br /><br /><object style="font-family: arial;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/U9greHLiR5c&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/U9greHLiR5c&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-24176695602463135612009-12-05T05:45:00.000-08:002009-12-05T05:48:23.036-08:00How DC electric motor works Video<span style="font-family: arial; font-weight: bold;">How DC motor works Video</span><br /><br /><object style="font-family: arial;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/yPeKC9a3WzE&hl=en_US&fs=1&"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/yPeKC9a3WzE&hl=en_US&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-family: arial; font-weight: bold;">Direct Current Electric Motor Video</span><br /><br /><object style="font-family: arial;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/Xi7o8cMPI0E&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/Xi7o8cMPI0E&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-family: arial; font-weight: bold;">Video DC electric motor explained by Mr. Burshkin</span><br /><span style="font-family: arial;">Mr. Burshkin explains how the standard DC motor works </span><br /> <br /><object style="font-family: arial;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/uxPQ5JLdoE8&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/uxPQ5JLdoE8&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-8182929645791097502009-11-27T07:53:00.000-08:002009-11-27T07:57:57.219-08:00Electromagnetism and Magnetism Hand Rules<span style="font-family: arial; font-weight: bold;">What is the magnetic field?</span><br /><br /><object style="font-family: arial;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/uj0DFDfQajw&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/uj0DFDfQajw&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-family: arial; font-weight: bold;">Electricity & Magnetism Hand Rules (part one)</span><br /><br /><object style="font-family: arial;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/9Zy0VHBXxLU&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/9Zy0VHBXxLU&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-family: arial; font-weight: bold;">Electromagnetism 2 & 3: The Left Hand Rule</span><br /><br /><object style="font-family: arial;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/hjDrqsy6kH0&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/hjDrqsy6kH0&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-family: arial; font-weight: bold;">The Right Hand Rule and the Magnetic Field Straight Wire</span><br /><br /><span style="font-family: arial;">This animation demonstrates a right hand rule showing the relation between the direction of current flow in a wire and the direction of the resulting magentic field around that wire.</span><br /><br /><object style="font-family: arial;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/9p3t9NOfCtA&hl=en_US&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/9p3t9NOfCtA&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-90554977149286318502009-08-10T10:04:00.000-07:002009-08-10T10:13:34.754-07:00D.C. motors - TORQUE/SPEED CURVES<span style=";font-family:arial;font-size:100%;" ><span style="font-weight: bold;">TORQUE/SPEED CURVES</span><br />In order to effectively design with D.C. motors, it is necessary to understand their characteristic curves. For every motor, there is a specific Torque/Speed curve and Power curve.<br /></span><span style="font-size:100%;"><br /></span><span style=";font-family:arial;font-size:100%;" > </span><center style="font-family:arial;"> <span style="font-size:100%;"> <img src="http://lancet.mit.edu/motors/colorTS1.jpg" alt="[Characteristic Torque/Speed Curve for a D.C. Motor]" /><br /> </span></center><span style=";font-family:arial;font-size:100%;" ><br /><br />The graph above shows a torque/speed curve of a typical D.C. motor. Note that torque is inversely proportioal to the speed of the output shaft. In other words, there is a <em><span style="color:FIREBRICK;">tradeoff</span></em> between how much torque a motor delivers, and how fast the output shaft spins. Motor characteristics are frequently given as two points on this graph:<br /> </span><ul style="font-family:arial;"><span style="font-size:100%;"> <li>The <span style="color:FIREBRICK;">stall torque,</span><img src="http://lancet.mit.edu/motors/Ts.gif" alt="[Ts]" />, represents the point on the graph at which the torque is a maximum, but the shaft is not rotating. </li><li>The <span style="color:FIREBRICK;">no load speed,</span><img src="http://lancet.mit.edu/motors/Wn.gif" alt="[Wn]" />, is the maximum output speed of the motor (when no torque is applied to the output shaft). </li></span></ul> <span style=";font-family:arial;font-size:100%;" > <a name="sect3.1"></a> The curve is then approximated by connecting these two points with a line, whose equation can be written in terms of torque or angular velocity as equations 3) and 4):<br /><br /><img src="http://lancet.mit.edu/motors/eqn3-4.gif" alt="[3) T=Ts-W*Ts/Wn; 4) W=(Ts-T)*Wn/Ts]" /><br /><br /> <table border="0"> <tbody><tr> <td> The linear model of a D.C. motor torque/speed curve is a very good approximation. The torque/speed curves shown below are actual curves for the green maxon motor (pictured at right) used by students in 2.007. One is a plot of empirical data, and the other was plotted mechanically using a device developed at MIT. Note that the characteristic torque/speed curve for this motor is quite linear.<br /><br />This is generally true as long as the curve represents the direct output of the motor, or a simple gear reduced output. If the specifications are given as two points, it is safe to assume a linear curve.<br /><br /> </td> <td valign="top" align="center"> <img src="http://lancet.mit.edu/motors/gmaxonthumb.gif" alt="[green maxon motor used in 2.007]" /><br /> </td> </tr> <tr> <td colspan="2" align="center"> <img src="http://lancet.mit.edu/motors/gmaxonts.gif" alt="[empirical torque/speed curve]" /> <img src="http://lancet.mit.edu/motors/finalpeterzi.gif" alt="[mechanically drawn torque/speed curve]" /> </td> </tr> </tbody></table><br /><br />Recall that earlier we defined power as the product of torque and angular velocity. This corresponds to the <span style="color:FIREBRICK;">area</span> of a rectangle under the torque/speed curve with one cornerat the origin and another corner at a point on the curve (see figures below). Due to the linear inverse relationship between torque and speed, the maximum power occurs at the point where <img src="http://lancet.mit.edu/motors/W.gif" alt="W" /><span style="color:FIREBRICK;"><strong> = ½</strong></span> <img src="http://lancet.mit.edu/motors/Wn.gif" alt="Wn" />, and <img src="http://lancet.mit.edu/motors/T.gif" alt="T" /><span style="color:FIREBRICK;"><strong> = ½</strong></span> <img src="http://lancet.mit.edu/motors/Ts.gif" alt="Ts" />.<br /><br /> </span><center style="font-family:arial;"> <span style="font-size:100%;"> <img src="http://lancet.mit.edu/motors/colorTS3.jpg" alt="[power represented as area under torque/speed curve]" /> <img src="http://lancet.mit.edu/motors/colorTS2.jpg" alt="[power represented as area under torque/speed curve]" /> <img src="http://lancet.mit.edu/motors/colorTS4.jpg" alt="[power represented as area under torque/speed curve]" /><br /><br /></span><div style="text-align: left;"><span style="font-size:100%;">http://lancet.mit.edu/motors/motors3.html<br /><br /></span><span style="font-weight: bold; font-family: arial;" class="lgtext">HOW TO PLOT SPEED/TORQUE AND CURRENT/TORQUE CURVES</span> <br /><span style="font-family: arial;">On every bulletin sheet there is sufficient data for you to plot the speed/torque and current/torque curves for each armature available in that particular motor size. Even though ratings are provided for each motor, seldom will you ever operate at that point. You really must draw at least a speed/torque curve to tell the speed at which the motor is going to run. Then, plotting the current/torque curve on the same graph will tell you the amperes required at your particular load point.</span><br /><br /><span style="font-family: arial;" class="lgtext">ILLUSTRATION 1</span><span style="font-family: arial;"> </span><span style="font-family: arial;" class="boldtext">SPEED/TORQUE AND CURRENT/TORQUE CURVES 150A100-10 (DMR) @ 27 VDC</span><br /> <img style="width: 329px; height: 229px; font-family: arial;" src="http://www.motortech.com/BUL1_E-1.GIF" /><br /><span style="font-family: arial;">http://www.motortech.com/BULL_E-1.htm</span><br /><br /><br /><span style="font-size:100%;"> </span></div></center>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-70898958701944706392009-07-18T20:52:00.000-07:002009-11-28T02:29:04.011-08:00Basic DC Generators and Magnet Generator Lecture Video<span style="font-family: arial; font-weight: bold;">Lecture - DC Generators 1 Lecture Video</span><br /><br /><br /><object style="font-family: arial; font-weight: bold;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/6dF3LDzb-tE&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/6dF3LDzb-tE&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-family: arial; font-weight: bold;">Lecture - DC Generators 2 Lecture Video</span><br /><br /><object style="font-family: arial; font-weight: bold;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/0v2qCOtT3yA&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/0v2qCOtT3yA&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-family: arial; font-weight: bold;">Simple generator Video</span><br /><br /><object style="font-family: arial; font-weight: bold;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/k7Sz8oT8ou0&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/k7Sz8oT8ou0&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><br /><span style="font-family: arial; font-weight: bold;">Magnet Generator Video</span><br /><br /><object style="font-family: arial; font-weight: bold;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/f3Y3fZ6ajuk&hl=en&fs=1"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/f3Y3fZ6ajuk&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><br /><span style="font-family: arial; font-weight: bold;">Simple Electric generator Video</span><br /><br /><object style="font-family: arial; font-weight: bold;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/9Hkol87nMw0&hl=en&fs=1"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/9Hkol87nMw0&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-family: arial; font-weight: bold;">Simple Electric generator II Video</span><br /><br /><object style="font-family: arial; font-weight: bold;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/3O6YIVrtnDo&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/3O6YIVrtnDo&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-2768765227269202192009-07-12T02:34:00.000-07:002009-07-12T02:34:00.502-07:00Linear Motor and Linear Stepper Motors<h3 style="font-family: arial;">What is a Linear Motor?</h3><strong style="font-family: arial;">Author: <a title="Alexis Gibrault" href="http://www.articlesbase.com/authors/alexis-gibrault/10099.htm">Alexis Gibrault</a></strong><br /><p style="font-family: arial;">A linear motor is-simply speaking-an electric motor that uses a linear force mechanism to generate the power needed for a said application. In contrast to a rotational electric motor (found in automobiles, appliances, and commonly-used electrical equipment), a linear motor generates its energy output through exclusively linear scientific principles; i.e. there is no torque or rotation to produce accelerated force through the electrical current magnetic field relationship. Linear motors are used for a variety of purposes, which include high velocity trains, military weaponry, spacecraft exploration, robotic technologies, medical advancement, and automated engineering systems whose job is to produce mass amounts of a specified product.<br /><br />There are two basic types of linear motors: low-acceleration and high-acceleration. Low-acceleration motors are typically used for applications in which endurance is favored over high bursts of electromechanical power or energy. These types of linear motors are engineered for Maglev trains, automated applications systems, etc. High-acceleration motors are the more common of the two, and produce higher velocity outputs for shorter amounts of time; such as used in firearms, military equipment, spacecraft propulsion, and the like. Low-acceleration linear motors are designed to accelerate an object up to a continuous stabile speed, while high-acceleration linear motors will accelerate an object up to a very high speed and then release the object. Typically, the low-acceleration linear motor will be engineered with one winding system on one side of the motor and magnets on the other side to create the electromagnetic repulsion necessary for successful application force; this is called linear synchronous design. The high-acceleration linear motor will generally be constructed of a three-phase winding on one side and a conductor plate on the other side of the motor to meet the intended engineering objective; this is called linear induction design.<br /><br />Linear motors offer a number of advantages in this ever-evolving technological world. Whether the high power application your company or organization requires necessitates a low- or high-accelerated lateral motor system, linear motors assure faster acceleration and higher velocities as well as higher success rates in automated accuracy, repeatability, and long-term reliability.<br /><br /></p><strong style="font-family: arial;">About the Author:</strong><br /><p style="font-family: arial;">Alexis Gibrault has written a number of informative articles on linear motors, types, and uses, as well as discussions on other facets of technology engineering. For more information on linear motors and examples of, please visit: <a href="http://www.airex.com/products/linear.htm%3Cbr%20/%3E%3Cbr%3E">Airex Corporation Linear Motors</a></p><p style="font-family: arial;">Article Source: <a href="http://www.articlesbase.com/technology-articles/what-is-a-linear-motor-65122.html" title="What is a Linear Motor?">http://www.articlesbase.com/technology-articles/what-is-a-linear-motor-65122.html</a></p><br /><br /><br /><br /><h3 style="font-family: arial;">Linear Stepper Motors Technology</h3><strong style="font-family: arial;">Author: <a title="Gordon Petten" href="http://www.articlesbase.com/authors/gordon-petten/5972.htm">Gordon Petten</a></strong><br /><p style="font-family: arial;">A linear induction motor is made up of an inductor which is made of individual cores with a concentrated polyphase. Linear motors can be directly substituted for ball screw drives, hydraulic drives, pneumatic drives, or cam drives.</p><p style="font-family: arial;">A linear induction motor is basically what is referred to by experts as a "rotating squirrel cage" induction motor. The difference is that the motor is opened out flat. Instead of producing rotary torque from a cylindrical machine it produces linear force from a flat machine. The shape and the way it produces motion is changed, however it is still the same as its cylindrical counterpart. There are no moving parts, however and most experts don't like that. It does have a silent operation and reduced maintenance as well as a compact size, which appeals many engineers. There is also a universal agreement that it has an ease of control and installation. These are all important considerations when thinking about what type of device you want to create. The linear induction motor thrusts ratio varies depending mainly on the size and rating. Speeds of the linear induction motor vary from zero to many meters per second. Speed can be controlled. Stopping, starting and reversing are all easy. Linear induction motors are improving constantly and with improved control, lower life cycle cost, reduced maintenance and higher performance they are becoming the choice of the experts. Linear motors are simple to control and easy to use. They have a fast response and high acceleration. Their speed is not dependant on contact friction so it is easier to pick up speed quickly.</p><p style="font-family: arial;">Stepper motors are a special kind of motor that moves in discrete steps. When one set of windings is energized the motor moves a step in one direction and when another set of windings is energized the motor moves a step in the other direction. The advantage of stepper motors that the position of the motor is "known". Zero position can be determined, if the original position is known.</p><p style="font-family: arial;">Stepping motors come in a wide range of angular resolution and the coarsest motors typically turn 90 degrees per step. High resolution permanent magnet motors are only able to handle about 18 degrees less than that. With the right controller stepper motors can be run in half-steps, which is amazing.</p><p style="font-family: arial;">The main complaint about the stepper motor is that it usually draws more power than a standard DC motor and maneuvering is also difficult.</p><br /><strong style="font-family: arial;">About the Author:</strong><br /><a style="font-family: arial;" href="http://www.intellidrives.com/">Linear Motors and Stepper Motors</a><p style="font-family: arial;">Article Source: <a href="http://www.articlesbase.com/technology-articles/linear-stepper-motors-technology-31692.html" title="Linear Stepper Motors Technology">http://www.articlesbase.com/technology-articles/linear-stepper-motors-technology-31692.html</a></p>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-26801851024634460572009-07-08T02:32:00.000-07:002009-07-08T22:45:25.263-07:00Operating Analysis of Different Stepping Motor Control Mechanisms<strong style="font-family: arial;">Author: <a title="s.sankar" href="http://www.articlesbase.com/authors/s.sankar/79766.htm">s.sankar</a></strong><br /><p style="font-family: arial;">This section covers all types of motors, from the elementary circuitry needed to control a variable reluctance motor, to the H-bridge circuitry needed to control a bipolar permanent magnet motor. Each class of drive circuit is illustrated with practical examples, but these examples are not intended as an exhaustive catalog of the commercially available control circuits, nor is the information given here intended to substitute for the information found on the manufacturer's component data sheets for the parts mentioned. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">This section only covers the most elementary control circuitry for each class of motor. All of these circuits assume that the motor power supply provides a drive voltage no greater than the motor's rated voltage, and this significantly limits motor performance. The next section, on current limited drive circuitry, covers practical high-performance drive circuits. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"><strong>Variable Reluctance Motors</strong></p> <p style="font-family: arial;">Typical controllers for variable reluctance stepping motors are variations on the outline shown in Figure 3.1: </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Figure 3.1 </p> <p style="font-family: arial;">In Figure 3.1, boxes are used to represent switches; a control unit, not shown, is responsible for providing the control signals to open and close the switches at the appropriate times in order to spin the motors. In many cases, the control unit will be a computer or programmable interface controller, with software directly generating the outputs needed to control the switches, but in other cases, additional control circuitry is introduced, sometimes gratuitously! </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Motor windings, solenoids and similar devices are all inductive loads. As such, the current through the motor winding cannot be turned on or off instantaneously without involving infinite voltages! When the switch controlling a motor winding is closed, allowing current to flow, the result of this is a slow rise in current. When the switch controlling a motor winding is opened, the result of this is a voltage spike that can seriously damage the switch unless care is taken to deal with it appropriately. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">There are two basic ways of dealing with this voltage spike. One is to bridge the motor winding with a diode, and the other is to bridge the motor winding with a capacitor. Figure 3.2 illustrates both approaches: </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Figure 3.2 </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">The diode shown in Figure 3.2 must be able to conduct the full current through the motor winding, but it will only conduct briefly each time the switch is turned off, as the current through the winding decays. If relatively slow diodes such as the common 1N400X family are used together with a fast switch, it may be necessary to add a small capacitor in parallel with the diode. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">The capacitor shown in Figure 3.2 poses more complex design problems! When the switch is closed, the capacitor will discharge through the switch to ground, and the switch must be able to handle this brief spike of discharge current. A resistor in series with the capacitor or in series with the power supply will limit this current. When the switch is opened, the stored energy in the motor winding will charge the capacitor up to a voltage significantly above the supply voltage, and the switch must be able to tolerate this voltage. To solve for the size of the capacitor, we equate the two formulas for the stored energy in a resonant circuit: </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">P = C V2 / 2 </p> <p style="font-family: arial;">P = L I2 / 2 </p> <p style="font-family: arial;">Where: </p> <p style="font-family: arial;">P -- stored energy, in watt seconds or coulomb volts </p> <p style="font-family: arial;">C -- capacity, in farads </p> <p style="font-family: arial;">V -- voltage across capacitor </p> <p style="font-family: arial;">L -- inductance of motor winding, in henrys </p> <p style="font-family: arial;">I -- current through motor winding </p> <p style="font-family: arial;">Solving for the minimum size of capacitor required to prevent overvoltage on the switch is fairly easy: </p> <p style="font-family: arial;">C > L I2 / (Vb - Vs)2 </p> <p style="font-family: arial;">Where: </p> <p style="font-family: arial;">Vb -- the breakdown voltage of the switch </p> <p style="font-family: arial;">Vs -- the supply voltage </p> <p style="font-family: arial;">Variable reluctance motors have variable inductance that depends on the shaft angle. Therefore, worst-case design must be used to select the capacitor. Furthermore, motor inductances are frequently poorly documented, if at all. </p> <p style="font-family: arial;">The capacitor and motor winding, in combination, form a resonant circuit. If the control system drives the motor at frequencies near the resonant frequency of this circuit, the motor current through the motor windings, and therefore, the torque exerted by the motor, will be quite different from the steady state torque at the nominal operating voltage! The resonant frequency is: </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">f = 1 / ( 2 (L C)0.5 ) </p> <p style="font-family: arial;">Again, the electrical resonant frequency for a variable reluctance motor will depend on shaft angle! When a variable reluctance motors is operated with the exciting pulses near resonance, the oscillating current in the motor winding will lead to a magnetic field that goes to zero at twice the resonant frequency, and this can severely reduce the available torque! </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"><strong>Unipolar Permanent Magnet and Hybrid Motors</strong></p> <p style="font-family: arial;"><strong> </strong></p> <p style="font-family: arial;">Typical controllers for unipolar stepping motors are variations on the outline shown in Figure 3.3: </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Figure 3.3 </p> <p style="font-family: arial;">In Figure 3.3, as in Figure 3.1, boxes are used to represent switches; a control unit, not shown, is responsible for providing the control signals to open and close the switches at the appropriate times in order to spin the motors. The control unit is commonly a computer or programmable interface controller, with software directly generating the outputs needed to control the switches. </p> <p style="font-family: arial;">As with drive circuitry for variable reluctance motors, we must deal with the inductive kick produced when each of these switches is turned off. Again, we may shunt the inductive kick using diodes, but now, 4 diodes are required, as shown in Figure 3.4: </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Figure 3.4 </p> <p style="font-family: arial;">The extra diodes are required because the motor winding is not two independent inductors, it is a single center-tapped inductor with the center tap at a fixed voltage. This acts as an autotransformer! When one end of the motor winding is pulled down, the other end will fly up, and visa versa. When a switch opens, the inductive kickback will drive that end of the motor winding to the positive supply, where it is clamped by the diode. The opposite end will fly downward, and if it was not floating at the supply voltage at the time, it will fall below ground, reversing the voltage across the switch at that end. Some switches are immune to such reversals, but others can be seriously damaged. </p> <p style="font-family: arial;">A capacitor may also be used to limit the kickback voltage, as shown in Figure 3.5: </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Figure 3.5 </p> <p style="font-family: arial;">The rules for sizing the capacitor shown in Figure 3.5 are the same as the rules for sizing the capacitor shown in Figure 3.2, but the effect of resonance is quite different! With a permanent magnet motor, if the capacitor is driven at or near the resonant frequency, the torque will increase to as much as twice the low-speed torque! The resulting torque versus speed curve may be quite complex, as illustrated in Figure 3.6: </p> <p style="font-family: arial;">Figure 3.6 </p> <p style="font-family: arial;">Figure 3.6 shows a peak in the available torque at the electrical resonant frequency, and a valley at the mechanical resonant frequency. If the electrical resonant frequency is placed appropriately above what would have been the cutoff speed for the motor using a diode-based driver, the effect can be a considerable increase in the effective cutoff speed. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">The mechanical resonant frequency depends on the torque, so if the mechanical resonant frequency is anywhere near the electrical resonance, it will be shifted by the electrical resonance! Furthermore, the width of the mechanical resonance depends on the local slope of the torque versus speed curve; if the torque drops with speed, the mechanical resonance will be sharper, while if the torque climbs with speed, it will be broader or even split into multiple resonant frequencies. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"><strong>Practical Unipolar and Variable Reluctance Drivers</strong></p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">In the above circuits, the details of the necessary switches have been deliberately ignored. Any switching technology, from toggle switches to power MOSFETS will work! Figure 3.7 contains some suggestions for implementing each switch, with a motor winding and protection diode included for orientation purposes: </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Figure 3.7 </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Each of the switches shown in Figure 3.7 is compatible with a TTL input. The 5 volt supply used for the logic, including the 7407 open-collector driver used in the figure, should be well regulated. The motor power, typically between 5 and 24 volts, needs only minimal regulation. It is worth noting that these power switching circuits are appropriate for driving solenoids, DC motors and other inductive loads as well as for driving stepping motors. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">The SK3180 transistor shown in Figure 3.7 is a power darlington with a current gain over 1000; thus, the 10 milliamps flowing through the 470 ohm bias resistor is more than enough to allow the transistor to switch a few amps current through the motor winding. The 7407 buffer used to drive the darlington may be replaced with any high-voltage open collector chip that can sink at least 10 milliamps. In the event that the transistor fails, the high-voltage open collector driver serves to protects the rest of the logic circuitry from the motor power supply. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">The IRC IRL540 shown in Figure 3.7 is a power field effect transistor. This can handle currents of up to about 20 amps, and it breaks down nondestructively at 100 volts; as a result, this chip can absorb inductive spikes without protection diodes if it is attached to a large enough heat sink. This transistor has a very fast switching time, so the protection diodes must be comparably fast or bypassed by small capacitors. This is particularly essential with the diodes used to protect the transistor against reverse bias! In the event that the transistor fails, the zener diode and 100 ohm resistor protect the TTL circuitry. The 100 ohm resistor also acts to somewhat slow the switching times on the transistor. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">For applications where each motor winding draws under 500 milliamps, the ULN200x family of darlington arrays from Allegro Microsystems, also available as the DS200x from National Semiconductor and as the Motorola MC1413 darlington array will drive multiple motor windings or other inductive loads directly from logic inputs. Figure 3.8 shows the pinout of the widely available ULN2003 chip, an array of 7 darlington transistors with TTL compatible inputs: </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Figure 3.8 </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">The base resistor on each darlington transistor is matched to standard bipolar TTL outputs. Each NPN darlington is wired with its emitter connected to pin 8, intended as a ground pin, Each transistor in this package is protected by two diodes, one shorting the emitter to the collector, protecting against reverse voltages across the transistor, and one connecting the collector to pin 9; if pin 9 is wired to the positive motor supply, this diode will protect the transistor against inductive spikes. </p> <p style="font-family: arial;">The ULN2803 chip is essentially the same as the ULN2003 chip described above, except that it is in an 18-pin package, and contains 8 darlingtons, allowing one chip to be used to drive a pair of common unipolar permanent-magnet or variable-reluctance motors. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">For motors drawing under 600 milliamps per winding, the UDN2547B quad power driver made by Allegro Microsystems will handle all 4 windings of common unipolar stepping motors. For motors drawing under 300 milliamps per winding, Texas Instruments SN7541, 7542 and 7543 dual power drivers are a good choice; both of these alternatives include some logic with the power drivers. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"><strong>Bipolar Motors and H-Bridges</strong></p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Things are more complex for bipolar permanent magnet stepping motors because these have no center taps on their windings. Therefore, to reverse the direction of the field produced by a motor winding, we need to reverse the current through the winding. We could use a double-pole double throw switch to do this electromechanically; the electronic equivalent of such a switch is called an H-bridge and is outlined in </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Figure 3.9</p> <p style="font-family: arial;">As with the unipolar drive circuits discussed previously, the switches used in the H-bridge must be protected from the voltage spikes caused by turning the power off in a motor winding. This is usually done with diodes, as shown in Figure 3.9. </p> <p style="font-family: arial;">It is worth noting that H-bridges are applicable not only to the control of bipolar stepping motors, but also to the control of DC motors, push-pull solenoids (those with permanent magnet plungers) and many other applications. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">With 4 switches, the basic H-bridge offers 16 possible operating modes, 7 of which short out the power supply! The following operating modes are of interest: </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"><strong>Forward mode, switches A and D closed. </strong></p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Reverse mode, switches B and C closed. </p> <p style="font-family: arial;">These are the usual operating modes, allowing current to flow from the supply, through the motor winding and onward to ground. Figure 3.10 illustrates forward mode: </p> <p style="font-family: arial;">Figure 3.10</p> <p style="font-family: arial;">Fast decay mode or coasting mode, all switches open. </p> <p style="font-family: arial;">Any current flowing through the motor winding will be working against the full supply voltage, plus two diode drops, so current will decay quickly. This mode provides little or no dynamic braking effect on the motor rotor, so the rotor will coast freely if all motor windings are powered in this mode. Figure 3.11 illustrates the current flow immediately after switching from forward running mode to fast decay mode. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Figure 3.11</p> <p style="font-family: arial;"><strong>Slow decay modes or dynamic braking modes. </strong></p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">In these modes, current may recirculate through the motor winding with minimum resistance. As a result, if current is flowing in a motor winding when one of these modes is entered, the current will decay slowly, and if the motor rotor is turning, it will induce a current that will act as a brake on the rotor. Figure 3.12 illustrates one of the many useful slow-decay modes, with switch D closed; if the motor winding has recently been in forward running mode, the state of switch B may be either open or closed: </p> <p style="font-family: arial;">Figure 3.12</p> <p style="font-family: arial;">Most H-bridges are designed so that the logic necessary to prevent a short circuit is included at a very low level in the design. Figure 3.13 illustrates what is probably the best arrangement: </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Figure 3.13</p> <p style="font-family: arial;">Here, the following operating modes are available: </p> <p style="font-family: arial;">XY ABCD Mode </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">00 0000 fast decay </p> <p style="font-family: arial;">01 1001 forward </p> <p style="font-family: arial;">10 0110 reverse </p> <p style="font-family: arial;">11 0101 slow decay </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">The advantage of this arrangement is that all of the useful operating modes are preserved, and they are encoded with a minimum number of bits; the latter is important when using a microcontroller or computer system to drive the H-bridge because many such systems have only limited numbers of bits available for parallel output. Sadly, few of the integrated H-bridge chips on the market have such a simple control scheme. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"><strong>Practical Bipolar Drive Circuits</strong></p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">There are a number of integrated H-bridge drivers on the market, but it is still useful to look at discrete component implementations for an understanding of how an H-bridge works. Antonio Raposo (ajr@cybill.inesc.pt) suggested the H-bridge circuit shown in Figure 3.14; </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Figure 3.14</p> <p style="font-family: arial;">The X and Y inputs to this circuit can be driven by open collector TTL outputs as in the darlington-based unipolar drive circuit in Figure 3.7. The motor winding will be energised if exactly one of the X and Y inputs is high and exactly one of them is low. If both are low, both pull-down transistors will be off. If both are high, both pull-up transistors will be off. As a result, this simple circuit puts the motor in dynamic braking mode in both the 11 and 00 states, and does not offer a coasting mode. </p> <p style="font-family: arial;">The circuit in Figure 3.14 consists of two identical halves, each of which may be properly described as a push-pull driver. The term half H-bridge is sometimes applied to these circuits! It is also worth noting that a half H-bridge has a circuit quite similar to the output drive circuit used in TTL logic. In fact, TTL tri-state line drivers such as the 74LS125A and the 74LS244 can be used as half H-bridges for small loads, as illustrated in Figure 3.15: </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Figure 3.15</p> <p style="font-family: arial;">This circuit is effective for driving motors with up to about 50 ohms per winding at voltages up to about 4.5 volts using a 5 volt supply. Each tri-state buffer in the LS244 can sink about twice the current it can source, and the internal resistance of the buffers is sufficient, when sourcing current, to evenly divide the current between the drivers that are run in parallel. This motor drive allows for all of the useful states achieved by the driver in Figure 3.13, but these states are not encoded as efficiently: </p> <p style="font-family: arial;">XYE Mode </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">--1 fast decay </p> <p style="font-family: arial;">000 slower decay </p> <p style="font-family: arial;">010 forward </p> <p style="font-family: arial;">100 reverse </p> <p style="font-family: arial;">110 slow decay </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">The second dynamic braking mode, XYE=110, provides a slightly weaker braking effect than the first because of the fact that the LS244 drivers can sink more current than they can source. </p> <p style="font-family: arial;">The Microchip (formerly Telcom Semiconductor) TC4467 Quad CMOS driver is another example of a general purpose driver that can be used as 4 independent half H-bridges. Unlike earlier drivers, the data sheet for this driver even suggests using it for motor control applications, with supply voltages up to 18 volts and up to 250 milliamps per motor winding. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">One of the problems with commercially available stepping motor control chips is that many of them have relatively short market lifetimes. For example, the Seagate IPxMxx series of dual H-bridge chips (IP1M10 through IP3M12) were very well thought out, but unfortunately, it appears that Seagate only made these when they used stepping motors for head positioning in Seagate disk drives. The Toshiba TA7279 dual H-bridge driver would be another another excellent choice for motors under 1 amp, but again, it appears to have been made for internal use only. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">The SGS-Thompson (and others) L293 dual H-bridge is a close competitor for the above chips, but unlike them, it does not include protection diodes. The L293D chip, introduced later, is pin compatible and includes these diodes. If the earlier L293 is used, each motor winding must be set across a bridge rectifier (1N4001 equivalent). The use of external diodes allows a series resistor to be put in the current recirculation path to speed the decay of the current in a motor winding when it is turned off; this may be desirable in some applications. The L293 family offers excellent choices for driving small bipolar steppers drawing up to one amp per motor winding at up to 36 volts. Figure 3.16 shows the pinout common to the L293B and L293D chips: </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">Figure 3.16</p> <p style="font-family: arial;">This chip may be viewed as 4 independent half H-bridges, enabled in pairs, or as two full H-bridges. This is a power DIP package, with pins 4, 5, 12 and 13 designed to conduct heat to the PC board or to an external heat sink. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">The SGS-Thompson (and others) L298 dual H-bridge is quite similar to the above, but is able to handle up to 2-amps per channel and is packaged as a power component; as with the LS244, it is safe to wire the two H-bridges in the L298 package into one 4-amp H-bridge (the data sheet for this chip provides specific advice on how to do this). One warning is appropriate concerning the L298; this chip very fast switches, fast enough that commonplace protection diodes (1N400X equivalent) don't work. Instead, use a diode such as the BYV27. The National Semiconductor LMD18200 H-bridge is another good example; this handles up to 3 amps and has integral protection diodes. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">While integrated H-bridges are not available for very high currents or very high voltages, there are well designed components on the market to simplify the construction of H-bridges from discrete switches. For example, International Rectifier sells a line of half H-bridge drivers; two of these chips plus 4 MOSFET switching transistors suffice to build an H-bridge. The IR2101, IR2102 and IR2103 are basic half H-bridge drivers. Each of these chips has 2 logic inputs to directly control the two switching transistors on one leg of an H-bridge. The IR2104 and IR2111 have similar output-side logic for controlling the switches of an H-bridge, but they also include input-side logic that, in some applications, may reduce the need for external logic. In particular, the 2104 includes an enable input, so that 4 2104 chips plus 8 switching transistors can replace an L293 with no need for additional logic. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">The data sheet for the Microchip (formerly Telcom Semiconductor) TC4467 family of quad CMOS drivers includes information on how to use drivers in this family to drive the power MOSFETs of H-bridges running at up to 15 volts. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;">A number of manufacturers make complex H-bridge chips that include current limiting circuitry; these are the subject of the next section. It is also worth noting that there are a number of 3-phase bridge drivers on the market, appropriate for driving Y or delta configured 3-phase permanent magnet steppers. Few such motors are available, and these chips were not developed with steppers in mind. Nonetheless, the Toshiba TA7288P, the GL7438, the TA8400 and TA8405 are clean designs, and 2 such chips, with one of the 6 half-bridges ignored, will cleanly control a 5-winding 10 step per revolution motor. </p> <p style="font-family: arial;"> </p> <p style="font-family: arial;"><br /></p> <p style="font-family: arial;"> </p><strong style="font-family: arial;">About the Author:</strong><br /><p style="font-family: arial;">Assistant professor in lord venkateswara engineering college.I am doing phd in sathyabama university, Tamil Nadu,India.</p><p style="font-family: arial;">Article Source: <a href="http://www.articlesbase.com/electronics-articles/operating-analysis-of-different-stepping-motor-control-mechanisms-590072.html" title="Operating Analysis of Different Stepping Motor Control Mechanisms">http://www.articlesbase.com/electronics-articles/operating-analysis-of-different-stepping-motor-control-mechanisms-590072.html</a></p>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-11583900434623660942009-07-01T06:01:00.000-07:002009-07-01T06:09:25.988-07:00Linear Motors and Stepper Motors ,Open Loop Solutions and Current Limiting for Stepping Motors<span style="font-size:130%;"><span style="font-weight: bold;font-family:arial;" >Linear Motors and Stepper Motors</span></span><br /><span style="font-family:arial;">By </span><a style="font-family: arial;" href="http://ezinearticles.com/?expert=Gordon_Petten">Gordon Petten</a><br /><br /><span style="font-family:arial;">A linear induction motor is made up of an inductor which is made of individual cores with a concentrated polyphase. Linear motors can be directly substituted for ball screw drives, hydraulic drives, pneumatic drives, or cam drives.</span><br /><br /><span style="font-family:arial;">A linear induction motor is basically what is referred to by experts as a “rotating squirrel cage” induction motor. The difference is that the motor is opened out flat. Instead of producing rotary torque from a cylindrical machine it produces linear force from a flat machine. The shape and the way it produces motion is changed, however it is still the same as its cylindrical counterpart. There are no moving parts, however and most experts don’t like that. It does have a silent operation and reduced maintenance as well as a compact size, which appeals many engineers. There is also a universal agreement that it has an ease of control and installation. These are all important considerations when thinking about what type of device you want to create. The linear induction motor thrusts ratio varies depending mainly on the size and rating. Speeds of the linear induction motor vary from zero to many meters per second. Speed can be controlled. Stopping, starting and reversing are all easy. Linear induction motors are improving constantly and with improved control, lower life cycle cost, reduced maintenance and higher performance they are becoming the choice of the experts. Linear motors are simple to control and easy to use. They have a fast response and high acceleration. Their speed is not dependant on contact friction so it is easier to pick up speed quickly.</span><br /><br /><span style="font-family:arial;">Stepper motors are a special kind of motor that moves in discrete steps. When one set of windings is energized the motor moves a step in one direction and when another set of windings is energized the motor moves a step in the other direction. The advantage of stepper motors that the position of the motor is "known". Zero position can be determined, if the original position is known.</span><br /><br /><span style="font-family:arial;">Stepping motors come in a wide range of angular resolution and the coarsest motors typically turn 90 degrees per step. High resolution permanent magnet motors are only able to handle about 18 degrees less than that. With the right controller stepper motors can be run in half-steps, which is amazing.</span><br /><br /><span style="font-family:arial;">The main complaint about the stepper motor is that it usually draws more power than a standard DC motor and maneuvering is also difficult. </span><a style="font-family: arial;" href="http://www.intellidrives.com/">Rotary Tables</a><br /><br /><a style="font-family: arial;" href="http://www.intellidrives.com/">Linear Actuators</a><br /><br /><span style="font-family:arial;">Article Source: </span><a style="font-family: arial;" href="http://ezinearticles.com/?Linear-Motors-and-Stepper-Motors&id=203980">http://EzineArticles.com/?expert=Gordon_Petten</a><br /><br /><br /><br /><br /><h3>Open Loop Solutions and Current Limiting for Stepping Motors</h3><strong>Author: <a title="s.sankar" href="http://www.articlesbase.com/authors/s.sankar/79766.htm">s.sankar</a></strong><br /><p>There is good reason to run a stepping motor at a supply voltage above that needed to push the maximum rated current through the motor windings. Running a motor at higher voltages leads to a faster rise in the current through the windings when they are turned on, and this, in turn, leads to a higher cutoff speed for the motor and higher torques at speeds above the cutoff. </p> <p> </p> <p>Microstepping, where the control system positions the motor rotor between half steps, also requires external current limiting circuitry. For example, to position the rotor 1/4 of the way from one step to another, it might be necessary to run one motor winding at full current while the other is run at approximately 1/3 of that current. </p> <p> </p> <p>The remainder of this section discusses various circuits for limiting the current through the windings of a stepping motor, starting with simple resistive limiters and moving up to choppers and other switching regulators. Most of these current limiters are appropriate for many other applications, including limiting the current through conventional DC motors and other inductive loads. </p> <p> </p> <p> </p> <p><strong>Resistive Current Limiters</strong></p> <p>The easiest to understand current limiter is a series resistor. Most motor manufacturers recommended this approach in their literature up until the early 1980's, and most motor data sheets still give performance curves for motors driven by such circuits. The typical circuits used to control the current through one winding of a permanent magnet or hybrid motor are shown in Figure 4.1. </p> <p> </p> <p>Figure 4.1</p> <p>R1 in this figure limits the current through the motor winding. Given a rated current of I and a motor winding with a resistance Rw, Ohm's law sets the maximum supply voltage as I(Rw+R1). Given that the inductance of the motor motor winding is Lw, the time constant for the motor winding will be Lw/(Rw+R1). Figure 4.2 illustrates the effect of increasing the resistance and the operating voltage on the rise and fall times of the current through one winding of a stepping motor. </p> <p>Figure 4.2</p> <p>R2 is shown only in the unipolar example in Figure 4.1 because it is particularly useful there. For a bipolar H-bridge drive, when all switches are turned off, current flows from ground to the motor supply through R1, so the current through the motor winding will decay quite quickly. In the unipolar case, R2 is necessary to equal this performance. When the switches in the H-bridge circuit shown in Figure 4.1 are opened, the direction of current flow through R1 will reverse almost instantaneously! If R1 has any inductance, for example, if it is wire-wound, it must either be bypassed with a capacitor to handle the voltage kick caused by this current reversal, or R2 must be added to the H-bridge. </p> <p> </p> <p>Given the rated maximum current through each winding and the supply voltage, the resistance and wattage of R1 is easy to compute. R2 if it is included, poses more interesting problems. The resistance of R2 depends on the maximum voltage the switches can handle. For example, if the supply voltage is 24 volts, and the switches are rated at 75 volts, the drop across R2 can be as much as 51 volts without harming the transistors. Given an operating current of 1.5 amps, R2 can be a 34 ohm resistor. Note that an interesting alternative is to use a zener diode in place of R2. </p> <p> </p> <p>Figuring the peak average power R2 must dissipate is a wonderful exercise in dynamics; the inductance of the motor windings is frequently undocumented and may vary with the rotor position. The power dissipated in R2 also depends on the control system. The worst case occurs when the control system chops the power to one winding at a high enough frequency that the current through the motor winding is effectively constant; the maximum power is then a function of the duty cycle of the chopper and the ratios of the resistances in the circuit during the on and off phases of the chopper. Under normal operating conditions, the peak power dissipation will be significantly lower. </p> <p> </p> <p> </p> <p><strong>Linear Current Limiters</strong></p> <p><strong> </strong></p> <p>A pair of high wattage power resistors can cost more than a pair of power transistors plus a heat sink, particularly if forced air cooling is available. Furthermore, a transistorized constant current source, as shown in Figure 4.3, will give faster rise times through the motor windings than the current limiting resistor shown in Figure 4.1. This is because a current source will deliver the full supply voltage across the motor winding until the current reaches the rated current; only then will the current source drop the voltage. </p> <p> </p> <p> </p> <p> </p> <p>Figure 4.3</p> <p>In Figure 4.3, a transistorized current source (T1 plus R1) has been substituted for the current limiting resistor R1 used in the examples in Figure 4.1. The regulated voltage supplied to the base of T1 serves to regulate the voltage across the sense resistor R1, and this, in turn, maintains a constant current through R1 so long as any current is allowed to flow through the motor winding. Typically, R1 will have as low a resistance as possible, in order to avoid the high cost of a power resistor. For example, if the forward voltage drops across the diode in series with the base T1 and VBE for T1 are both 0.65 volts, and if a 3.3 volt zener diode is used for a reference, the voltage across R1 will be maintained at about 2.0 volts, so if R1 is 2 ohms, this circuit will limit the current to 1 amp, and R1 must be able to handle 2 watts. R3 in Figure 4.3 must be sized in terms of the current gain of T1 so that sufficient current flows through R1 and R3 to allow T1 to conduct the full rated motor current. </p> <p> </p> <p>The transistor T1 used as a current regulator in Figure 4.3 is run in linear mode, and therfore, it must dissipate quite a bit of power. For example, if the motor windings have a resistance of 5 ohms and a rated current of 1 amp, and a 25 volt power supply is used, T1 plus R1 will dissapate, between them, 20 watts! The circuits discussed in the following sections avoid this waste of power while retaining the performance advantages of the circuit given here. </p> <p> </p> <p>When an H-bridge bipolar drive is used with a resistive current limiter, as shown in Figure 4.1, the resistor R2 was not needed because current could flow backwards through R1. When a transistorized current limiter is used, current cannot flow backwards through T1, so a separate current path back to the positive supply must be provided to handle the decaying current through the motor windings when the switches are opened. R2 serves this purpose here, but a zener diode may be substituted to provide even faster turn-off. </p> <p> </p> <p>The performance of a motor run with a current limited power supply is noticably better than the performance of the same motor run with a resistively limited supply, as illustrated in Figure 4.4: </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p>Figure 4.4</p> <p> </p> <p>With either a current limited supply or a resistive current limiter, the initial rate of increase of the current through the inductive motor winding when the power is turned on depends only on the inductance of the winding and the supply voltage. As the current increases, the voltage drop across a resistive current limiter will increase, dropping the voltage applied to the motor winding, and therefore, dropping the rate of increase of the current through the winding. As a result, the current will only approach the rated current of the motor winding asymptotically In contrast, with a pure current limiter, the current through the motor winding will increase almost linearly until the current limiter cuts in, allowing the current to reach the limit value quite quickly. In fact, the current rise is not linear; rather, the current rises asymptotically towards a limit established by the resistance of the motor winding and the resistance of the sense resistor in the current limiter. This maximum is usually well above the rated current for the motor winding. </p> <p> </p> <p> </p> <p><strong>Open Loop Current Limiters</strong></p> <p> </p> <p>Both the resistive and the linear transistorized current limiters discussed above automatically limit the current through the motor winding, but at a considerable cost, in terms of wasted heat. There are two schemes that eliminate this expense, although at some risk because of the lack of feeback about the current through the motor. </p> <p> </p> <p> </p> <p><strong>Use of a Voltage Boost</strong></p> <p> </p> <p>If you plot the voltage across the motor winding as a function of time, assuming the use of a transistorized current limiter such as is illustrated in Figure 4.3, and assuming a 1 amp 5 ohm motor winding, the result will be something like that illustrated in Figure 4.5: </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p>Figure 4.5</p> <p> </p> <p>As long as the current is below the current limiter's set point, almost the full supply voltage is applied across the motor winding. Once the current reaches the set point, the voltage across the motor winding falls to that needed to sustain the current at the set point, and when the switches open, the voltage reverses briefly as current flows through the diode network and R2. An alternative way to get this voltage profile is to use a dual-voltage power supply, turning on the high voltage for as long as it takes to bring the current in the motor winding up to the rated current, and then turning off the high voltage and turning on the sustaining voltage. Some motor controllers do this directly, without monitoring the current through the motor windings. This provides excellent performance and minimizes power losses in the regulator, but it offers a dangerous temptation. </p> <p> </p> <p>If the motor does not deliver enough torque, it is tempting to simply lengthen the high-voltage pulse at the time the motor winding is turned on. This will usually provide more torque, although saturation of the magnetic circuits frequently leads to less torque than might be expected, but the cost is high! The risk of burning out the motor is quite real, as is the risk of demagnitizing the motor rotor if it is turned against the imposed field while running hot. Therefore, if a dual-voltage supply is used, the temptation to raise the torque in this way should be avoided! </p> <p> </p> <p>The problems with dual voltage supplies are particularly serious when the time intervals are under software control, because in this case, it is common for the software to be written by a programmer who is insufficiently aware of the physical and electrical characteristics of the control system. </p> <p> </p> <p> </p> <p><strong>Use of Pulse Width Modulation</strong></p> <p> </p> <p>Another alternative approach to controlling the current through the motor winding is to use a simple power supply controlled by pulse width modulaton (PWM) or by a chopper. During the time the current through the motor winding is increasing, the control system leaves the supply attached with a 100% duty cycle. Once the current is up to the full rated current, the control system changes the duty cycle to that required to maintain the current. Figure 4.6 illustrates this scheme: </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p>Figure 4.6</p> <p>For any chopper or pulse width modulator, we can define the duty-cycle D as the fraction of each cycle that the switch is closed: </p> <p>D = Ton / (Ton + Toff) </p> <p>Where </p> <p>Ton -- time the switch is closed during each cycle </p> <p>Toff -- time the switch is open during each cycle </p> <p>The voltage curve shown above indicates the full supply voltage being applied to the motor winding during the on-phase of every chopper cycle, while when the chopper is off, a negative voltage is shown. This is the result of the forward voltage drop in the diodes that are used to shunt the current when the switches turn off, plus the external resistance used to speed the decay of the current through the motor winding. For large values of Ton or Toff, the exponential nature of the rise and fall of the current through the motor winding is significant, but for sufficiently small values, we can approximate these as linear. Assuming that the chopper is working to maintain a current of I and that the amplitude is small, we will approximate the rates of rise and fall in the current in terms of the voltage across the motor winding when the switch is closed and when it is open: </p> <p> </p> <p>Von = Vsupply - I(Rwinding + Ron) </p> <p>Voff = Vdiode + I(Rwinding + Roff) </p> <p>Here, we lump together all resistances in series with the winding and power supply in the on state as Ron, and we lump together all resistances in the current recirculation path when the switch(es) are open as Roff. The forward voltage drops of any diodes in the current recirculation path have been lumped as Vdiode; if the off-state recirculation path runs from ground to the power supply (H-bridge fast decay mode), the supply voltage must also be included in Vdiode. Forward voltage drops of any switches in the on-state and off-state paths should also be incorporated into these voltages. </p> <p>To solve for the duty cycle, we first note that: </p> <p> </p> <p>dI/dt = V/L </p> <p>Where </p> <p>I -- current through the motor winding </p> <p>V -- voltage across the winding </p> <p>L -- inductance of the winding </p> <p> </p> <p>We then substitute the specific voltages for each phase of operation: </p> <p> </p> <p>Iripple / Toff = Voff / L </p> <p>Iripple / Ton = Von / L </p> <p>Where </p> <p>Iripple -- the peak to peak ripple in the current </p> <p>Solving for Toff and Ton and then substituting these into the definition of the duty cycle of the chopper, we get: </p> <p>D = Ton / (Ton + Toff) = Voff / (Von + Voff) </p> <p>If the forward voltage drops in diodes and switches are negligable, and if the only significant resistance is that of the motor winding itself, this simplifies to: </p> <p>D = I Rwinding / Vsupply = Vrunning / Vsupply </p> <p>This special case is particularly desirable because it delivers all of the power to the motor winding, with no losses in the regulation system, without regard for the difference between the supply voltage and the running voltage. </p> <p>The AC ripple Iripple superimposed on the running current by a chopper can be a source of problems; at high frequencies, it can be a source of RF emissions, and at audio frequencies, it can be a source of annoying noise. For example, with audio frequency chopping, most stepper controlled systems will "squeel", sometimes loudly, when the rotor is displaced from the equilibrium position. For small systems, this is usually no more than a minor nuisance, but in systems with large numbers of high power steppers, the ripple currents can induce dangerous AC voltages on nearby signal lines and dangerous currents in nearby ground lines. To find the ripple amplitude, first recall that: </p> <p> </p> <p>Iripple / Toff = Voff / L </p> <p>Then solve for Iripple: </p> <p>Iripple = Toff Voff / L </p> <p>Thus, to reduce the ripple amplitude at any particular duty cycle, it is necessary to increase the chopper frequency. This cannot be done without limit because switching losses increase with frequency. Note that this change has no significant effect on AC losses; the decrease in such losses due to decreased amplitude in the ripple is generally offset by the effect of increasing frequency. </p> <p>The primary problem with use of a simple chopping or pulse-width modulation control scheme is that it is completely open loop. Design of good chopper based control systems requires knowledge of motor characteristics such as inductance that are frequently poorly documented, and as with dual-voltage supplies, when motor performance is marginal, it is very tempting to increase the duty-cycle without attention to the long-term effects of this on the motor. In the designs that follow, this weakness will be addressed by introducing feedback loops into the low level drive system to directly monitor the current and determine the duty cycle. </p> <p> </p> <p><strong>One-Shot Feedback Current Limiting</strong></p> <p><strong> </strong></p> <p>The most common approach to automatically adjusting the duty cycle of the switches in the stepper driver involves monitoring the current to the motor windings; when it rises too high, the winding is turned off for a fixed interval. This requires a current sensing system and a one-shot, as illustrated in Figure 4.7: </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p>Figure 4.7</p> <p>Figure 4.7 illustrates a unipolar drive system. As with the circuit given in Figure 4.3, R1 should be as small as possible, limited only by the requirement that the sense voltage provided to the comparator must be high enough to be within its operating range. Note that when the one-shot output (¬Q) is low, the voltage across R1 no-longer reflects the current through the motor winding. Therefore, the one-shot must be insensitive to the output of the comparator between the time it fires and the time it resets. Practical circuit designs using this approach involve some complexity to meet this constraint! Selecting the value of R2 for the circuit shown in Figure 4.7 poses problems. If R2 is large, the current through the motor windings will decay quickly when the higher level control system turns off this motor winding, but when the winding is turned on, the current ripple will be large and the power lost in R2 will be significant. If R2 is small, this circuit will be very energy efficient but the current through the motor winding will decay only slowly when this winding is turned off, and this will reduce the cutoff speed for the motor. </p> <p> </p> <p>The peak power dissipated in R2 will be I2R2 during Toff and zero during Ton; thus, the average power dissipated in R2 when the motor winding is on will be: </p> <p> </p> <p>P2 = I2R Toff / (Ton + Toff) </p> <p>Recall that the duty cycle D is defined as Ton/(Ton+Toff) and may be approximated as Vrunning/Vsupply. As a result, we can approximate the power dissipation as: </p> <p>P2 = I2R2 (1 - Vrunning/Vsupply). </p> <p>Given the usual safety margins used in selecting power resistor wattages, a better approximation is not necessary. </p> <p>When designing a control system based on pulse width modulation, note that the cutoff time for the one-shot determines Toff, and that this is fixed, determined by the timing network attached to the one-shot. Ideally, this should be set as follows: </p> <p> </p> <p>Toff = L Iripple / Voff </p> <p>This presumes that the inductance L of the motor winding is known, that the acceptable magnitude of Iripple is known, and that Voff, the total reverse voltage in the current recirculation path, is known and fixed. Note that this scheme leads to a variable chopping rate. As with the linear current limiters shown in Figure 4.3, the full supply voltage will be applied during the turn-on phase, and the chopping action only begins when the motor winding reaches the current limit set by Vref. This circuit will vary the chopping rate to compensate for changes in the back EMF of the motor winding, for example, those caused by rotor motion; in this regard, it offers the same quality of regulation as the linear current limiter. The one-shot current regulator shown in Figure 4.7 can also be applied to an H-bridge regulator. The encoded H-bridge shown in Figure 3.13 is an excellent candidate for this application, as shown in Figure 4.8: </p> <p> </p> <p>Figure 4.8</p> <p>Unlike the circuit in Figure 4.7, this circuit does not provide design tradeoffs in the selection of the resistance in the current decay path; instead, it offers the same selection of decay paths as was available in the original circuit from Figure 3.13. If the X and Y control inputs are held in a running mode (01 or 10), the current limiter will alternate between that running and slow decay modes, maximizing energy efficiency. When the time comes to turn off the current through the motor winding, the X and Y inputs may be set to 00, using fast decay mode to maximize the cutoff speed, while if the damping effect of dynamic braking is needed to control resonance, X and Y may be set to 11. </p> <p>Note that the current recirculation path during dynamic braking does not pass through R1, and as a result, if the motor generates a large amount of power, burnt out components in the motor or controller are likely. This is unlikely to cause problems with stepping motors, but when dynamic braking is used with DC motors, the current limiter should be arranged to remain engaged while in braking mode! </p> <p> </p> <p> </p> <p><strong>Practical Examples</strong></p> <p>SGS-Thompson (and others) L293 (1A) and L298 (2A) dual H-bridges are designed for easy use with partial feedback current limiters. These chips have enable inputs for each H-bridge that can be directly connected to the output of the one-shot, and they have ground connections for motor-power that are isolated from their logic ground connections; this allows sense resistors to be easily incorporated into the circuit. The 3952 H-bridge from Allegro Microsystems can handle up to 2-amps at 50 volts and incorporates all of the logic necessary for current control, including comparators and one-shot. This chip is available in many package styles; Figure 4.9 illustrates the DIP configuration wired for a constant current limit: </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p> </p> <p>Figure 4.9</p> <p>If Rt is 20 Kohm, and Ct is 1000pF, Toff for the pulse-width modulation will be fixed at 20 (±2) microseconds. The 3952 chip incorporates a 10 to 1 voltage divider on the Vref input, so attaching Vref to the 5 volt logic supply sets the actual reference voltage to 0.5 V. Thus, if the sense resistor Rs is 0.5 ohms, this arrangement will attempt to maintain a regulated current through the load of 1 A. </p> <p>Note that all power switching chips are potentially serious sources of electromagnetic interfence! The 47µF capacitor shown between the motor power and ground should be as close to the chip as possible, and the path from the SENSE pin through Rs to ground and back to a ground pin of the chip should be very short and with a very low resistance. </p> <p> </p> <p>On the 5 volt side, because Vref is taken from Vcc, a small decoupling capacitor should be placed very close to the chip. It may even be appropriate to isolate the Vref input from Vcc with a small series resistor and a separate decoupling capacitor. If this is done, note that the resistance from the Vref pin to ground through the chip's internal voltage divider is around 50 Kohms. </p> <p> </p> <p>One of the more dismaying features of the 3952 chip, as well as many of its competitors, is the large number of control inputs. These are summarized in the following table: </p> <p> </p> <p><strong>BRAKE ENABLE PHASE MODE OUTa OUTb Notes </strong></p> <p> </p> <p>0 - - 0 0 0 Brake </p> <p>0 - - 1 0 0 Limited Brake </p> <p> </p> <p>1 1 - 0 - - Standby </p> <p>1 1 - 1 - - Sleep </p> <p> </p> <p>1 0 0 0 0 1 Reverse, Slow </p> <p>1 0 0 1 0 1 Reverse, Fast </p> <p>1 0 1 0 1 0 Forward, Slow </p> <p>1 0 1 1 1 0 Forward, Fast </p> <p> </p> <p>In the forward and reverse running modes, the mode input determines whether fast or slow decay modes are used during Toff. In the dynamic braking modes, the mode input determines whether the current limiter is enabled. This is of limited value with stepping motors, but use of dynamic braking without a current limiter can be dangerous with DC motors. In sleep mode, the power consumption of the chip is minimized. From the perspective of the load, sleep and standby modes put the load into fast decay mode (all switches off) but in sleep mode, the chip draws considerably less power, both from the logic supply and the motor supply. </p> <p> </p> <p> </p> <p><strong>Hysteresis Feedback Current Limiting</strong></p> <p>In many cases, motor control systems are expected to operate acceptably with a number of different stepping motors. The one-shot based current regulators illustrated in Figures 4.7 to 4.9 have an accuracy that depends on the inductance of the motor windings. Therefore, if fixed accuracy is required, any motor substation must be balanced by changes to the RC network that determines the off-time of the one-shot. </p> <p> </p> <p>This section deals with alternative designs that eliminate the need for this tuning. These alternative designs offer fixed precision current regulation over a wide range of load inductances. The key to this approach is arrange the recirculation paths so that the current-sense resistor R1 is always in the circuit, and then turn the switches on or off depending only on the current. </p> <p> </p> <p>The usually way to build this type of controller is to use a comparator with a degree of hysteresis, for example, by feeding the output of the comparator back into one of its inputs through a resistor network, as illustrated in Figure 4.10: </p> <p> </p> <p> </p> <p>Figure 4.10</p> <p>To compute the desired values of R2 and R3, we note that: </p> <p>Vripple > Vhysteresis </p> <p>Where: </p> <p>Vripple = Iripple R1 </p> <p>Iripple -- the maximum ripple allowed in the current </p> <p>and: </p> <p>Vhysteresis = Vswing R2 / (R2 + R3) </p> <p>Vswing -- the voltage swing at the output of the comparator </p> <p>We can solve this for the ratio of the resistances: </p> <p>R2 / (R2 + R3) <> </p><p>For example, if R1 is 0.5 ohms and we wish to regulate the current to within 10 milliamps, using a comparator with TTL compatable outputs and a voltage swing of 4 volts, the ratio must be no greater than .00125. </p> <p>Note that the sum R2 + R3 determines the loading on Vref, assuming that the input resistance of the comparator is effectively infinite. Typically, therefore, this sum is made quite large. </p> <p> </p> <p>One problem with the circuit given in Figure 4.10 is that it does not limit the current through the motor in dynamic braking or slow decay modes. Even if the current through the sense resistor vastly exceeds the desired current, switches B and D will remain closed in dynamic braking mode, and if the reference voltage is variable, rapid drops in the reference voltage will not be enforced by this control system. </p> <p> </p> <p>The designers of the Allegro 3952 chip faced this problem, and passed the solution back to the user, providing a MODE input to determine whether the chopper alternated between running and fast decay mode or running and slow decay mode. Note that this chip uses a fixed off-time set by a one-shot, and therefore, switching between the two decay modes will change the precision of the current regulator. Given that such a change in precision is acceptable, we can modify the circuit from Figure 4.10 to automatically thrown the system into fast-decay mode if the running or dynamic braking current exceeds the set-point of the comparator by too great a margin. Figure 4.11 illustrates how this can be done using a second comparator: </p> <p> </p> <p>Figure 4.11</p> <p>As shown in Figure 4.11, the lower comparator directly senses the voltage across R1, while the upper comparator senses a higher voltage, determined by a resistor network. This network should hold the negative inputs of the two comparators just far enough apart to guarantee that, as the voltage across R1 rises, the top comparator will always open the top switches before the bottom comparator opens the bottom switches, and as the voltage across R1 falls, the bottom comparator will always close the bottom switches before the top comparator closes the top switches. </p> <p>As a result, this system has two basic steady-state running modes. If the motor winding is drawing power, one of the bottom switches will remain closed while the opposite switch on the top is used to chop the power to the motor winding, alternating the state of the system between running and slow-decay mode. </p> <p> </p> <p>If the motor winding is generating power, the top switches will remain open and the bottom switches will do the chopping, alternating between fast-decay and slow-decay modes as needed to keep the current within limits. If the two comparators have accuracies on the order of a millivolt with hysteresis on the order of 5 millivolts, it is reasonable to use a 5 millivolt difference between the top and bottom comparator. If we use the 5 volt logic supply as the pull-up supply for the resistor network, and we assume a nominal operating threshold of around 0.5 volts, the resistor network should have a ratio of 1:900; for example, a 90k resistor from +5 and a 100 ohm resistor between the two comparator inputs. </p> <p> </p> <p> </p> <p><strong>Practical Examples</strong></p> <p> </p> <p>The basic idea described in this section is also applicable to unipolar stepping motor controllers, although in this context, it is somewhat easier to apply if the reference voltage is measured with respect to the unregulated motor power supply. Figure 4.12 illustrates a practical example, using the forward voltage drop across an ordinary silicon diode as the reference voltage. </p> <p> </p> <p> </p> <p>Figure 4.12</p> <p>The circuit shown in Figure 4.12 uses a 2.4K resistor to provide a bias current of 10ma to the reference diode. A small capacitor should be added across the reference diode if the motor power supply is minimally regulated. </p> <p> </p> <p>The 0.6 ohm value used for the current sensing resistor sets the regulator to 1 amp, assuming that the reference voltage is 0.6 volts. The 1000 to 1 ratio on the feedback network around the comparator sets the allowed ripple in the regulated current to around 8 ma. </p> <p> </p> <p>The comparator shown in Figure 4.12 can be powered from the minimally regulated motor power supply, but only if it is able to operate with the inputs very close to its positive supply voltage. Although I have not tried it, the Mitsubishi M5249L comparator appears to be ideally suited to this job; it can work from a positive supply of up to 40 volts, and the input voltages are allowed to slightly exceed the positive supply voltage! The output of this comparator is open collector, so the hysteresis network shown in the figure also acts as a pull-up network, providing a pull-up current of a few milliamps. The diode to +5 shown in the figure clamps the comparator output to the logic supply voltage, protecting the and gate inputs from overvoltage. </p> <p> </p> <p> </p> <p><strong>Other Current Sensing Technologies</strong></p> <p> </p> <p>The feedback loops of all of the current limiters given above use the voltage drop across a small resistor to measure the current. This is an excellent choice for small motors, but it poses difficulties for large high-current motors! There are other current sensing technologies appropriate for such settings, most notably those that deliver only a fraction of the motor current to the sensing resistor, and those that measure the current by sensing the magnetic field around the conductor. </p> <p> </p> <p>National Semiconductor had incorporated a very clever current sensor into a number of their H-bridges. This delivers a current to the sense resistor that is proportional to the current through the motor winding, but far lower. For example, on the LMD18200 H-bridge, the sense resistor receives exactly 377 micro amps per ampere flowing through the motor winding. </p> <p> </p> <p>The key to the current sensing technology used in the National Semiconductor line of H-bridges is found in the internal structure of the DMOS power switching transistors they use. These transistors are composed of thousands of small MOSFET transistor cells wired in parallel. A small but representative fraction of these cells, typically 1 in 4000, is used to extract the sense current while the remainder of the cells controls the motor current. The data sheet for the National LMD18245 H-bridge contains an excellent write-up on how this is done. </p> <p> </p> <p>When very high currents are involved, precluding use of an integrated H-bridge, an appealing and well established current sensing technology involves the use of a split ferrite core and a hall effect sensor, as illustrated in Figure 4.13: </p> <p> </p> <p>Figure 4.13</p> <p>Simple linear Hall effect sensors require a small regulated bias current between two of their terminals, and they generate a DC voltage proportional to the magnetic field on a third terminal. The magnetic field across the gap sawed in the ferrite core is proportional to the current through the wire, and therefore, the voltage reported by the Hall effect sensor will be proportional to the current. </p> <p>Allegro Microsystems and others make a full lines of Hall effect sensors, but pre-calibrated hall effect current sensors are available; these include the split core, the hall effect sensor, and auxiliary components, all mounted on a small PC board or potted as a unit. Newark Electronics lists a few sources of these, including Honeywell, F. W. Bell and LEM Instruments. </p> <p> </p> <p>An intriguing new current sensor is just becoming available, as of 1998, based on a thin-film magneto resistive sensor; the sensitivity of this technology eliminates the need for the ferrite core and the result is a very compact current sensor. The NT series sensors made by F. W. Bell use this technology.</p> <p> </p><strong>About the Author:</strong><br /><p>Assistant professor in lord venkateswara engineering college.I am doing phd in sathyabama university, Tamil Nadu,India.</p><p>Article Source: <a href="http://www.articlesbase.com/electronics-articles/open-loop-solutions-and-current-limiting-for-stepping-motors-590070.html" title="Open Loop Solutions and Current Limiting for Stepping Motors">http://www.articlesbase.com/electronics-articles/open-loop-solutions-and-current-limiting-for-stepping-motors-590070.html</a></p>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-53612775079647608792009-06-30T06:01:00.000-07:002010-01-18T20:38:15.289-08:00Dc Motor Speed Control Lecture Video<span style="font-family: arial;font-size:130%;" ><span style="font-weight: bold; color: rgb(51, 204, 0);">DC MOTOR DRIVE FUNDAMENTALS</span></span><br /><span style="font-weight: bold; font-family: arial;">UNDERSTANDING DC MOTOR DRIVES</span><br /><span style="font-family: arial;">DC motors have been available for nearly 100 years. In fact the first electric motors were designed and built for operation from direct current power. </span><br /><span style="font-family: arial;">AC motors are Now and will of course remain the basic prime movers for the fixed speed requirements of industry. Their basic simplicity, dependability and ruggedness make AC motors the natural choice for the vast majority of industrial drive applications. </span><br /><br /><span style="font-family: arial;">Then where do DC drives fit into the industrial drive picture of the future? </span><br /><span style="font-family: arial;">In order to supply the answer, it is necessary to examine some of the basic characteristics obtainable from DC motors and their associated solid state controls. </span><a style="font-family: arial;" href="http://www.joliettech.com/dc_drive_fundamentals.htm" target="_blank" rel="nofollow">more</a><br /><br /><span style="font-family: arial;font-size:130%;" ><span style="font-weight: bold; color: rgb(51, 204, 0);">Precision DC motor speed controller</span></span><br /><span style="font-family: arial;">Optical tachometers that produce a frequency proportional to RPM are popular feedback sources for precision analog motor speed control. This usually involves a frequency-to-voltage converter (FVC) to convert the tachometer output to a voltage that’s then input to a conventional servo. Though it typically works fine, it’s unnecessarily complicated and requires a tachometer with a relatively high pulse/revolution characteristic to allow for both a reasonably fast loop response and adequate ripple filtering in the</span> FVC. <a href="http://electronicdesign.com/content.aspx?topic=precision-dc-motor-speed-controller6417&catpath=components" target="_blank" rel="nofollow">more</a><br /><br /><br /><span style="font-family: arial;font-size:130%;" ><span style="font-weight: bold; color: rgb(51, 204, 0);">DC Motor Speed Control PWM</span></span><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7WrpLfETJZRSoVFx6nxl0-tgfKFDyoq15IxCIsuq466AnQTGLycb8AWQMS9NltVlzYTcm0317-_cOhKazcYnpD2vIKcenjJyOYYDMOhm-LCSSK_RaRBD5oZUiSngQ8Kb2v_vXdFoEQ3E/s1600-h/basic+dc+motor+speed.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 320px; height: 234px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7WrpLfETJZRSoVFx6nxl0-tgfKFDyoq15IxCIsuq466AnQTGLycb8AWQMS9NltVlzYTcm0317-_cOhKazcYnpD2vIKcenjJyOYYDMOhm-LCSSK_RaRBD5oZUiSngQ8Kb2v_vXdFoEQ3E/s320/basic+dc+motor+speed.JPG" alt="" id="BLOGGER_PHOTO_ID_5428304944803432434" border="0" /></a><br /><br /><span style="font-family: arial;">The user may feel that the RC PWM signal may be an awesome resource to control the speed of a DC motor. And this is of course true, except that the RC PWM signal itself is pretty much useless as a direct means of controlling the DC motor speed. What needs to be done is to have an intermediate circuit to decode the position information (RC Pulse width) and generate a speed magnitude signal. In other words, if the input pulse is 1 ms, move the DC motor on reverse at maximum speed, if 1.5 ms wide stop the DC motor and if 2.0 ms, move the DC motor forward at maximum speed. Any other pulse width is then decoded to partial speed on the corresponding direction.</span> <a href="http://robot.avayanex.com/?p=48" target="_blank" rel="nofollow">more</a><br /><br /><br /><span style="font-weight: bold;font-family:arial;font-size:130%;" >Dc Motor Speed Control - Introduction</span><span style="font-size:130%;"><span style="font-weight: bold;font-family:arial;" > Lecture Video</span><br /><br /><object style="font-family: arial; font-weight: bold;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/VoN0e3n6EGA&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/VoN0e3n6EGA&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-weight: bold;font-family:arial;" >Dc Motor Speed Control - Block Diagram Lecture Video</span><br /><br /><object style="font-family: arial; font-weight: bold;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/AC8YRAxyZ7Q&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/AC8YRAxyZ7Q&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-weight: bold;font-family:arial;" >Dc Motor Speed Control Current Control & S C L Lecture Video</span><br /><br /><object style="font-family: arial; font-weight: bold;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/9-6Fn7HJ-T8&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/9-6Fn7HJ-T8&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-weight: bold;font-family:arial;" ><br />Dc-Motor Speed Control Controller Design-1 Lecture Video</span><br /><br /><object style="font-family: arial; font-weight: bold;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/A7SUJ669TEI&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/A7SUJ669TEI&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-weight: bold;font-family:arial;" >Dc Motor Speed Control Controller Design-2 Lecture Video</span><br /><br /><object style="font-family: arial; font-weight: bold;" width="425" height="344"><param name="movie" value="http://www.youtube.com/v/ra7REkBA9kI&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/ra7REkBA9kI&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /></span>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-6845759602783917622009-06-22T06:00:00.000-07:002010-01-18T20:14:48.884-08:00Dc Motor Lecture Video<span style="font-family: arial;font-size:130%;" ><span style="font-weight: bold; color: rgb(51, 204, 0);">Basic DC Motor theory</span></span><br /><span style="font-family: arial;">The DC motor has two basic parts: the rotating part that is called the armature and the stationary part that includes coils of wire called the field coils. The stationary part is also called the stator. The armature is made of coils of wire wrapped around the core, and the core has an extended shaft that rotates on bearings. You should also notice that the ends of each coil of wire on the armature are terminated at one end of the armature. The termination points are called the commutator, and this is where the brushes make electrical contact to bring</span><span style="font-family: arial;"> electrical current from the stationary part to the rotating part of the machine.</span><br /><br /><span style="font-family: arial;">The coils that are mounted inside the stator are called field coils and they may be connected in series or parallel with each other to create changes of torque in the motor. You will find the size of wire in these coils and the number of turns of wire in the coil will depend on the effect that is trying to be achieved.</span><br /><a href="http://59.163.61.3:8080/GRATEST/SHOWTEXFILE.do?page_id=user_image&user_image_id=2529" target="_blank" rel="nofollow">more</a><br /><br /><span style="font-size:130%;"><br /></span><span style="font-weight: bold; font-family: arial;"><span style="font-size:130%;"><span style="color: rgb(51, 204, 0);">Basic DC Motor</span><span style="color: rgb(51, 204, 0);">s </span></span></span><br /><span style="font-weight: bold; font-family: arial;">Principles of operation</span><br /><span style="font-family: arial;">In any electric motor, operation is based on simple electromagnetism. A current-carrying conductor generates a magnetic field; when this is then placed in an external magnetic field, it will experience a force proportional to the current in the conductor, and to the strength of the external magnetic field. As you are well aware of from playing with magnets as a kid, opposite (North and South) polarities attract, while like polarities (North and North, South and South) repel. The internal configuration of a DC motor is designed to harness the magnetic interaction between a current-carrying conductor and an external magnetic field to generate rotational motion.</span><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDteQ4ZNpNUs7Y9AuGLb9hJV1ttCULf9qnkb9JHmVtyW36i0QLymqQjaq3gSB2cMjdELzVjjqpbOTBIeaz5xefhJT8PwCISlK7hpE_JkICGw6iW0YFigTIqJTMig8UNAe1XlF48q4O2yE/s1600-h/basic+dc+motor.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 204px; height: 159px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjDteQ4ZNpNUs7Y9AuGLb9hJV1ttCULf9qnkb9JHmVtyW36i0QLymqQjaq3gSB2cMjdELzVjjqpbOTBIeaz5xefhJT8PwCISlK7hpE_JkICGw6iW0YFigTIqJTMig8UNAe1XlF48q4O2yE/s320/basic+dc+motor.JPG" alt="" id="BLOGGER_PHOTO_ID_5428299035487323378" border="0" /></a><br /><br /><a href="http://www.solarbotics.net/starting/200111_dcmotor/200111_dcmotor2.html" target="_blank" rel="nofollow">more</a><br /><br /><br /><br /><span style="font-size:130%;"><span style="font-weight: bold;font-family:arial;" >D C Motors</span></span> <span style="font-size:130%;"><span style="font-weight: bold;font-family:arial;" >Lecture Video</span></span><br /><object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/1OfLgpFq6Rc&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/1OfLgpFq6Rc&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><span style="font-size:130%;"><span style="font-weight: bold;font-family:arial;" ><br />DC Motor 2</span></span> <span style="font-size:130%;"><span style="font-weight: bold;font-family:arial;" >Lecture Video</span></span><br /><object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/Fqn7od-Z5Ww&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/Fqn7od-Z5Ww&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object><br /><br /><span style="font-size:130%;"><span style="font-weight: bold;font-family:arial;" >DC Motor 3</span></span> <span style="font-size:130%;"><span style="font-weight: bold;font-family:arial;" >Lecture Video</span></span><br /><object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/Z9W0F9I6R2k&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/Z9W0F9I6R2k&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.comtag:blogger.com,1999:blog-3897093515559291014.post-41677656982444918692009-06-13T22:18:00.000-07:002010-01-19T21:14:32.770-08:00Induction Motor Drives and Speed Control Lecture Video<span style="font-size:130%;"><span style="font-weight: bold;font-family:arial;" >Lecture - Induction Motor Drives Video</span></span><br /><br /><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/96hvtQ8Qlvo&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/96hvtQ8Qlvo&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" height="344" width="425"></embed></object><br /><br /><span style="font-weight: bold;font-size:130%;" ><span style="font-family:arial;">Lecture - Speed Control of Induction Motor Part - 1 Video</span></span><br /><br /><object height="265" width="320"><param name="movie" value="http://www.youtube.com/v/K3jUTnhzA-Q&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/K3jUTnhzA-Q&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" height="265" width="320"></embed></object><br /><br /><span style="font-size:130%;"><span style="font-weight: bold;font-family:arial;" >Lecture - Speed Control of Induction Motor Part-2 Video</span></span><br /><br /><object height="344" width="425"><param name="movie" value="http://www.youtube.com/v/6Pg2l8nILSU&hl=en&fs=1&rel=0"><param name="allowFullScreen" value="true"><param name="allowscriptaccess" value="always"><embed src="http://www.youtube.com/v/6Pg2l8nILSU&hl=en&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" height="344" width="425"></embed></object><br /><br /><span style="font-family: arial;font-size:130%;" ><span style="font-weight: bold; color: rgb(51, 204, 0);">Implementing Embedded Speed Control for AC Induction Motors</span></span><br /><br /><span style="font-family: arial; font-weight: bold;">Topices</span><br /><span style="font-family: arial;"> •Induction Motor principles</span><br /><span style="font-family: arial;"> –Physics of induction motors</span><br /><span style="font-family: arial;"> –Induction motor construction </span><br /><span style="font-family: arial;"> •Control hardware –typical layout</span><br /><span style="font-family: arial;"> •Modulation techniques</span><br /><span style="font-family: arial;"> –Sinusoidal, Quasi-sinusoidal & Space Vector</span><br /><span style="font-family: arial;"> •Control methods </span><br /><span style="font-family: arial;"> –Open loop algorithms</span><br /><span style="font-family: arial;"> –Closed loop algorithms</span><br /><span style="font-family: arial;"> •MCU performance benchmark</span><br /><span style="font-family: arial;"> •Summary</span><br /><br /><a onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_7Rfu2WiViagHZ28yD05iNgZ1Jkk3SA5ejsuHnkXB8YfhPJsXIlwOxPlryJPA2fo42qYOhpBtRHoGLYlCv8tHwI4ndF6p3Y6jGr9xNjHFWWNniVlesCF9NBBxYRny0ua7k8CFUISueAg/s1600-h/AC+Induction+Motor+control.JPG"><img style="margin: 0px auto 10px; display: block; text-align: center; cursor: pointer; width: 320px; height: 239px;" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_7Rfu2WiViagHZ28yD05iNgZ1Jkk3SA5ejsuHnkXB8YfhPJsXIlwOxPlryJPA2fo42qYOhpBtRHoGLYlCv8tHwI4ndF6p3Y6jGr9xNjHFWWNniVlesCF9NBBxYRny0ua7k8CFUISueAg/s320/AC+Induction+Motor+control.JPG" alt="" id="BLOGGER_PHOTO_ID_5428685265990284722" border="0" /></a><br /><br /><span style="font-family: arial; font-weight: bold;">Induction Motors</span><br /><span style="font-family: arial;">•Motors operate on principle of Induction and hence the name “Induction Motors”is used</span><br /><span style="font-family: arial;">•Motors also known as AC motors because Alternating Current (AC) is required </span><br /><span style="font-family: arial;">•All AC motors are “brushless”</span><br /><span style="font-family: arial;">–No mechanical contacts to wear</span><br /><span style="font-family: arial;">–Requires AC source</span><br /><span style="font-family: arial;">–If used, inverter creates desired freq and magnitude of AC</span><br /><span style="font-family: arial;">•AC induction motors for lower cost applications</span><br /><span style="font-family: arial;">–Single speed applications: fan, blower, pump, compressor</span><br /><span style="font-family: arial;">–No control, just start the AC power source</span><br /><span style="font-family: arial;">–Relays are used for ON/OFF</span><br /><a href="http://america.renesas.com/media/products/mpumcu/child_folder/Renesas_Jani_Seminar.pdf" target="_blank" rel="nofollow">more</a><br /><br /><br /><span style="font-family: arial;font-size:130%;" ><span style="font-weight: bold; color: rgb(51, 204, 0);">Speed control of three phase AC induction motor using single phase supply along</span><span style="font-weight: bold; color: rgb(51, 204, 0);"> with active power factor correction</span></span><br /><span style="font-weight: bold; font-family: arial;">Abstract</span><br /><span style="font-family: arial;">Majority of industrial drives use electric motors, since</span><br /><span style="font-family: arial;">they are controllable and readily available. In practice,</span><br /><span style="font-family: arial;">most of these drives are based on ac induction motor</span><br /><span style="font-family: arial;">because these motors are rugged, reliable, and relatively</span><br /><span style="font-family: arial;">inexpensive. The proposed technique of single phase to</span><br /><span style="font-family: arial;">three phase conversion has a wide range of applications in</span><br /><span style="font-family: arial;">rural areas and also in industries where three phase</span><br /><span style="font-family: arial;">equipment or motors are to be operated from the easily</span><br /><span style="font-family: arial;">available single phase supply. These converters are</span><br /><span style="font-family: arial;">excellent choice for situations where three phase power</span><br /><span style="font-family: arial;">supply is not available. The added advantage is that the</span><br /><span style="font-family: arial;">three phase motor is more efficient and economical than</span><br /><span style="font-family: arial;">the single phase motor. Also the starting current in three</span><br /><span style="font-family: arial;">phase motor is less severe than in single phase motor.</span><br /><span style="font-family: arial;">This needs a strong, efficient cost effective and high</span><br /><span style="font-family: arial;">quality single phase to three phase conversion. Advanced</span><br /><span style="font-family: arial;">PWM techniques are employed to guarantee high quality</span><br /><span style="font-family: arial;">output voltage with reduced harmonics and sinusoidal</span><br /><span style="font-family: arial;">input current irrespective of the load. To obtain sinusoidal</span><br /><span style="font-family: arial;">input current at the terminal of single phase source a high</span><br /><span style="font-family: arial;">performance active input power factor correction</span><br /><span style="font-family: arial;">technique for single phase boost switch mode rectifier</span><br /><span style="font-family: arial;">operating with discontinuous current conduction is used.</span><br /><span style="font-family: arial;">The operation is based on variable turn-on time. Equal</span><br /><span style="font-family: arial;">Area Criteria (EAC) is applied to the discontinuous</span><br /><span style="font-family: arial;">current operation. To obtain high quality output voltage,</span><br /><span style="font-family: arial;">double edge modulated sine wave PWM technique is</span><br /><span style="font-family: arial;">implemented for three phase inverter. From experimental</span><br /><span style="font-family: arial;">results obtained on a laboratory prototype it can be</span><br /><span style="font-family: arial;">concluded that input power factor remains nearly unity for</span><br /><span style="font-family: arial;">any variations in the load or speed. Thus three phase ac</span><br /><span style="font-family: arial;">drives using single phase supply with improved power</span><br /><span style="font-family: arial;">factor is an approach to implement high frequency</span><br /><span style="font-family: arial;">induction boosting along with the three phase PWM</span><br /><span style="font-family: arial;">inverter for controlling the speed of three phase induction</span><br /><span style="font-family: arial;">motor by maintaining v/f ratio at constant value. This</span><br /><span style="font-family: arial;">scheme can be used in lathe machines, small cranes, lifts</span><br /><span style="font-family: arial;">etc, which are frequently switched ON and OFF1.</span><br /><a href="http://www.icgst.com/acse/Volume6/Issue3/P1110615003.pdf" target="_blank" rel="nofollow">more</a>smart_bloghttp://www.blogger.com/profile/03610848287930809726noreply@blogger.com