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Old Nov 01, 2012, 01:52 PM
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grain valley mo, or about 25 minutes east of kansas city
Joined Jan 2004
600 Posts
Originally Posted by Skylar View Post
I can't agree with your statements above. It IS amps that causes a motor to heat up and burn the windings.
Look carefully at this formula: R x IČ = copper loss.
R (or Rm) is the resistance in one phase of an outrunner motor. So, amps squared times the Rm is what causes the primary loss in a motor, i.e. the main source of heat.
In outrunners, iron loss is usually much smaller than copper loss and can also be calculated: Io x volts, where Io is the no-load current.

most people around here can't use formulas, it's easier to remember what the max watts recomended by the manufacturer is, and most have a max wattage, not max amps since if they rated it at x amps for say, 2 cells someone would try to run it at the same amps on 4 cells and very quickly burn it up. it's all in the watts. lol.

either way you look at it though, I still recomend a meter if you are going to experiment. a good way to measure the temp of the stator is a good idea too if you are really going to push it.

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