Anything wrong with driving a motor using a switchmode PSU?

Thread Starter


Joined Oct 17, 2006
Please move this post to the General Electronics Chat forum, sorry!

Looking at power supply units offered by motor and motor servo manufacturers I was left wondering why none seem to offer switchmode PSU. Look at AMC offering for instance.

I understand that switchmode PSU are costly compared to linear one but let's say you need an efficient system? Is there anything wrong with driving an inductive load with a switchmode PSU? When the motor is stopped would you need to still have some sort of minimal load?

Old ATX PSU are basically given away... most have at least 8A on the 12V rail which would be quite enough to move some load with a DC motor. Plus you've got the 5V line to power your motor servo and other electronics!

Any clue?



Joined Feb 24, 2006
My recollection from that era of my career is that switching power supplies have difficulty with load transients. In applications like magnetic tape drives, the switching power supplies would collapse when the capstan motor was turned on. In order to prevent that from happening the speed of the loop response needs to increase, then the problem is noise and stability. Things may have improved with higher switching speeds, it has been awhile since I had deal with this problem.