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Questions about friction losses in an electric motor

  1. Aug 11, 2017 #1
    1) What is friction loss / are friction losses?

    2) How can it be determined / measured / calculated / figured out?

    3) How does it affect the power output (force * speed) of an electric motor when an electric motor is moving / lifting objects? Why does it have such affects?
  2. jcsd
  3. Aug 11, 2017 #2

    jim hardy

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    What effort did you make to answer these basic questions for yourself before asking others to invest their effort ?
  4. Aug 11, 2017 #3


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    In short, two sources to consider are parts rubbing against each other, and interaction of air with the moving parts.
    Steve Mould has a nice video about sources of friction losses in a fidget spinner.
  5. Aug 11, 2017 #4
    As ScottDave mentioned, windage is always present unless the motor runs in a vacuum. The other big friction source is the bearings. Even the very best bearings always have some friction.

    As to how to see/measure the effect of friction, assuming we are talking about an induction motor, measure the no-load speed. With no external load, and in the absence of friction, the no-load speed would be synchronous speed. Since friction is always present, the speed difference between synchronous speed and no-load speed is the evidence of friction losses.
  6. Aug 12, 2017 #5


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    This article, Wind 'em Up and Let 'em Go, from ecmweb.com give three things concerning bearing friction losses.
    Ditto. But for the other readers, I invested a little effort. :redface:
    Last edited: Aug 12, 2017
  7. Aug 17, 2017 #6
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