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Old 10-27-2013, 11:49 PM   #253 (permalink)
thingstodo
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Revs versus efficiency

Quote:
Originally Posted by mechman600 View Post
My understanding is that staying in a higher RPM range for a given load means that the voltage at the motor will be higher and the current lower (since Watts = Volts*Amps), and since higher current (amp) levels = generated heat/inefficiency, this is better.
Hmmm...

For a given motor resistance, the power lost in the windings is I*I*R. So less current should be WAY LESS losses. That makes sense.

Reducing the motor current by increasing the applied voltage will drop the winding losses. Check.

What about the brush-to-commutator interface? Does higher voltage increase the losses there, even without arcing? I don't see why it should ...

So is there a down side to running the motor at (relatively) higher rpm?

If you confirm the sweet spot, it would interesting to find out WHY it's a sweet spot.
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