Author Options:

A power supply hooked up to a DC motor starts to run and speeds up. Then it slows down and stops. Why? Answered

I constructed a power supply that can be adjusted for different voltage settings. When I set it to 9.6 volts and hook up a DC motor from an old RC car it starts to run and gradually speeds up. Then it just as gradually starts to slow down until it stops. Anybody have an idea why this happens?


Yeah, it's probably feedback from the motor. You can probably fix that with a diode.

I want to run a 24v dc 5amp elecric motor and I was thinking of using a regular LED power supply unit. I was told that the feedback could stop the unit from working so your answer above could be useful to me. Any suggesations?

The motor could be drawing too much power, not really sure of you power supply's construction but for example I have a damaged wifi stick that will let my computer run fine for a minute or so before it ticks and shuts off, instantly firing back up and cycling like so. Though it could be feedback from the motor I'd be more inclined to say the motor's too much for the power supply...

Need to know how you've constructed this power supply I think. L

Maybe the motor sucks out too much current, and your PSU sets itself in short-protection mode?

maybe the back emf from the motor is crapping on your power supply's parade. Really I've never heard of that phenomenon - does it happen with different motors, different loads (leds with resistor etc). I'm curious to find out!