Can I use a PWM controller to control the speed of a motor?
Generally abrupt starts to Motors will draw up to 10x the rated current in the 1st cycle and then reduce to the stable value when acceleration reaches the final velocity.

If one considers the heat rise of over current and the application does not demand rapid changes in  speed then the current rating can be reduced from 10x the motor rating to much less. Spinning a magnet is not much of a load compared to abrupt turn on to max speed.

Speed control is done by changing the average duty cycle of the supplied pulsed voltage not by reducing the peak amplitude.

Therefore a 30A PWM is a good choice for a 1A motor with 10A worst case expected surges even if draws  &lt; 1 A at steady speed.  One might consider a smaller rating, but at this cost, reliability is improved by over-design as there is often little or no active cooling.


  Stable low speed settings should not be expected if the load changes.  This only controls average voltage and not power or RPM.