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Breakdown of Motor Losses

Breakdown of Motor Losses

Breakdown of Motor Losses

(OP)
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

RE: Breakdown of Motor Losses

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

RE: Breakdown of Motor Losses

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

RE: Breakdown of Motor Losses

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.

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