UNDERSTANDING DC MOTOR DRIVES
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.
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.
Then where do DC drives fit into the industrial drive picture of the future?
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. more
Precision DC motor speed controller
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 FVC. more
DC Motor Speed Control PWM
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. more
Dc Motor Speed Control - Introduction Lecture Video
Dc Motor Speed Control - Block Diagram Lecture Video
Dc Motor Speed Control Current Control & S C L Lecture Video
Dc-Motor Speed Control Controller Design-1 Lecture Video
Dc Motor Speed Control Controller Design-2 Lecture Video
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