Castle Holdings LLC -- our motor production facility

[A RC Dude]

Originally Posted by lincpimp

Geared for the same speed the 2 motors should "see" the same load. I just wondered why the 14xl ran cooler. I just figured the amp draw thru the motor (if there is such a thing) was around half as much with the 14xl than the 7xl, and that accounted for the addl heat created. Higher amp draw seems to produce more heat as the wires and such have to transmit it.

I may be completely wrong on this, so that is why I asked!

Thanks for the replys.

If you took the time to write out all the many many equations to get to the bottom of the question, i bet you'll find that the the efficiency is not dependent on the size or turn count. I bet the difference in heat comes from nothing more then the size of the motor.

The 14xl has two things keeping it cooler:
1. The more surface area allows it to cool off better, especially over time.
This is why larger, more powerful ESC's require heat sinks with more surface area (typically larger or finer fins)
2. More mass requires more heat (energy loss) to get it up to the same temperature (especially in a short amount of time).
Looking into specific heat, the equation is:
heat added = specific heat x mass x change in temperature
In this case, the specific heat should be equal for both motors (same materials), canceling out. Same heat added and greater mass = lower temperature.

Edit: Sorry for awakening a dead thread, I just now saw the dates