Treadmill Motor, Simple One Speed Controller

Thread Starter


Joined Jul 22, 2011
I would like to re-purpose a treadmill motor, basic specs. 90 V DC and 2.5 HP.

I would like to run this motor from standard 120vac, I only require one speed at the nominal ratings, simple on/off.

I have an electronics education/background but am quite rusty as I have been out of the field for some time.

Any suggestions for a simple, low component count circuit. I was thinking a simple bridge rectifier circuit but not sure of the best way to control the DC down to 90 V DC. I am not sure how it is done in the treadmill motor controllers.



Joined Feb 5, 2010
I would suggest a 5 watt/ 90 volt zener clamping the output of a half wave rectifier(single diode), coming from a 3 amp 1:1 isolation transformer.

THAT's how I would do it CHEAP.

If you want to learn how to do it better, but at slightly higher cost and complexity, I'm sure more people will be along soon with other ideas.


Joined Feb 5, 2010
Judging by the voltage and horsepower rating I would guess it draws 15 amps or so at full load, perhaps a little more. 2 1/2 horsepower is a LOT of power. If the OP needs full power from the motor all the time, he would not be happy with my CHEAP suggestion. For one thing, the size of a transformer which can deliver 2 1/2 horsepower constantly spells MONEY in large amounts, and the 5 watt zener would be inadequate at such sustained power levels.