Breakdown of Motor Losses

[dpc]

I'm trying to determine the approximate distribution of losses in a typical three-phase induction motor ( say 100 hp, 1800 rpm, running at rated conditions). The best approximation I have at this point is:

Stator (I2R) 35%
Rotor 20%
Core 20%
Friction & Windage 15%
Stray 10%

Does this look about right?

Thanks,

dpc

 

[Marke]

I assume that by Rotor 20% you are refering to I2R losses in the rotor? And core you are refering to the total iron losses in the stator and the rotor? Mark Empson

http://www.lmphotonics.com

 

[dpc]

I assumed the core losses are confined to the stator, so rotor losses are I2R.

 

[electricpete]

EPRI 5036V6 gives some "typical" data (in kw losses):

Motor 500hp/1200rpm 1000hp/3600rpm
core 4.4 5
stator 9.8 12.6
rotor 8.1 8.4
stray 3.5 8.2
friction/windage 1.2 6.8
total 27 41

The most evident trend (as expected) - low speed motors have higher fraction of core losses, high speed motors have higher fraction of friction/windage losses.