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PWM/DC motor torque

  1. Oct 30, 2007 #1
    I had posted this is in "Electrical Engineering" but no one has posted any thing so I am posting g my question here as well.

    I've done my best to find an answer to no avail. Can anyone offer some insight?
    Subject: DC brushed motor with PWM control
    If the motor has 10 units of torque @ full rated voltage in the spec sheet, what torque can be expected when operating at full voltage but a reduced duty cycle? Is there some predictable mathematical relationship? I'm hoping for 100% torque, but doubting the possibilities.
    I await enlightenment,

    Bill Black
    waiting for Noel in South Florida
  2. jcsd
  3. Oct 30, 2007 #2


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    Well, I guess the torque will go from 0 to 10 units as the duty cycle goes from 0 to 100%

    Have you looked at this: Pulse-width_modulation?
  4. Nov 3, 2007 #3
    Yes..I have researched this quite a bit past Wikipedia. I'd "guess" the same thing, but I was trying to avoid guessing.
    The torque specs on motors are most often given in reference to the voltage applied. If the PWM is supplying, for instance, 10 VDC @ 60% duty cycle, does the motor "see" that as a 6 VDC applied to the motor or as 10VDC applied 600 mSec per Sec? Is there any difference between the two conditions?
    Heck...maybe I am just analyzing this to death and @ 60% power means 60% power no matter how you name it.
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