MMF and permeance harmonic torques and losses in cage induction motors-the effects of skew, bar-to-bar impedance and saturation

The overall machine analysis technique described has been based on an equivalent circuit representation of the induction motor. Methods of determining each additional component of loss have been outlined and the most useful approach has been found to be that based upon the solution of a series of harmonic equivalent circuits. In some cases simplified finite-element models have been found to be particularly useful in the determination of equivalent circuit parameters. The major sources of additional loss in inverter-fed machines have been identified as: additional stator winding loss arising from skin and proximity effects at high frequency; additional rotor winding loss arising from deep bar effects at high frequency; additional core loss due to the existence of harmonic fluxes; and additional stray loss