hp rating of Dc motor
hp rating of Dc motor
(OP)
I've got some variable speed dc motors from treadmills that I'd like to use in some projects. I've been told that the hp ratings on treadmill motors was not the same as ratings on regular motors. Is this true? If so why? What is the conversion factor if one exists? Thanks for your help.
Ben Englund
Ben Englund





RE: hp rating of Dc motor
Ben Englund
RE: hp rating of Dc motor
RE: hp rating of Dc motor
Here is what I would do.
Measure the resistance.
Take a power drill and back drive the motor, measure the voltage generated at speed (probably 500 rpm for a cordless drill) then convert this to what it would be at 1000 rpm. The torque constant can be calculated from the voltage constant. Take the amount of volts generated at 1000 rpm and multiply it by .085, the result is the torque constant in lb-in/amp.
With the rated current from the name plate and the above info you know almost everything about this motor.
Do not exceed an rms current of more than the continuous rating. And I would limit the peak current to about 2X the continuous (so the copper won't burn up). Keep in mind that if you are at 2X (that is 4X heating losses) you would not be able to do for long and still have the rms current equal the continuous value. Put enough voltage to overcome the would be generated voltage at the speed you want to run (stay within 2x the rated nameplate speed for mechanical reasons).
good luck, hope this helps.
RE: hp rating of Dc motor
Rmastro,
Thanks for your information, I'll definately use it. I would be using the variable speed drivers originally for the motors. I was just wondering about the horsepower numbers. I guess I should have thought about the load on the motor. It makes sense to me now. Thanks again
Ben Englund