Estimating Electric Motor Heat Production
Estimating Electric Motor Heat Production
(OP)
Does anyone have a quick calculation method for estimating the heat generated by an electric motor? I'm curious if I can provide sufficient heating from a pump motor to keep a pump house above freezing while the pump is running.





RE: Estimating Electric Motor Heat Production
RE: Estimating Electric Motor Heat Production
RE: Estimating Electric Motor Heat Production
If you have the motor efficiency, it is pretty safe to assume that the rest of the input power is lost to either friction or I^2R losses. Either one comes out in the form of heat.
Say you have a 10 hp motor with a full-load efficiency of 90%, and operating at full load. The heat generated would therefore be the remaining 10%. Converted to heat, that would be 2544 BTU/hr (1.0 Hp).
Regards,
speco
RE: Estimating Electric Motor Heat Production
Thanks for explaining. That's pretty simple. The complicated question then becomes how much heat is transferred to the water being pumped vs. the air around the pump.
Thanks!
Bekirk
RE: Estimating Electric Motor Heat Production
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RE: Estimating Electric Motor Heat Production
As far as I know, the centrifugal pump used in this case was designed to be air-cooled, and that heat transfer to the product being pumped (i.e. water) was intended to be minimized. So I was guessing that in this case heat transfer to water was much less than 90%, but to be honest, I really don't know.
RE: Estimating Electric Motor Heat Production
In your case, the heat rejection into the air should be at least 90% of the motor heat load.
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RE: Estimating Electric Motor Heat Production
Thanks,
Barton