High-accuracy iron-loss measurements on motor stator stacks

Abstract

Traditionally iron loss in motor stators is measured using loss separation, where overall loss is measured and then other losses like windage, bearings, copper, and rotor losses subtracted. This technique is unsatisfactory because the stator iron loss is typically smaller than the other losses subtracted and therefore a small error percentage wise in one of these other losses leads to a large error in the iron loss. A new technique is described that directly measures the stator iron loss and therefore offers much improved accuracy. This new technique is then applied to a series of known difficult measurements, like effect of temperature on iron loss, compression on iron loss, etc., to demonstrate its veracity and usefulness and to quantify these effects accurately for the first time.