Quantitative study on harmonic flux densities of squirrel-cage induction motors

A novel method for the precise calculation of harmonic flux densities of induction motors and its verification by experiment are presented. The concept of `harmonic permanence´ is introduced for precise determination of air gap permeance pulsation caused by slot openings, which are calculated using a finite-element field solution. It is found that the same harmonic flux has distinctively different magnitudes on the stator inner and rotor outer peripheries, and it is necessary to fully take the differences into account in order to obtain good results. The calculated values of harmonic flux densities agreed adequately with experimental results