New Method for Estimation of Stray-Load Loss

The high-frequency stray load losses (LL(r)), at rated current, are a result of increase motor current from no-load value (I(0)) to rated value I=I(N). They can be estimating by high frequency no-load losses due to MMF higher harmonics (P(HF,f0)). The basic idea is to divide the stray no-load losses in two components: first component, high frequency stray no-load losses due to the slot permeance harmonics (P(HF,xi 0)), is proportionate to the squared motor no-load voltage value; and component of high frequency no-load losses due to MMF higher harmonics (P(HF,f0)) is proportionate to the squared motor no-load current value. Also, it is shown that the high frequency no-load losses due to MMF higher harmonics (P(HF,f0n)) can be determined only by no-load test with slip measurement by stroboscope method. Synchronous speed measurement test can be omitted. Copyright (C) 2010 Praise Worthy Prize S.r.l. - All rights reserved.