Finite-element investigation on zig-zag flux in squirrel cage induction machines

摘要

The stray load losses represent a non-negligible contribution to the total losses in electrical machines. This paper investigates a contribution to these losses in the case of a non-skewed squirrel cage induction motor, namely the zig-zag flux. The study is performed at no-load, locked-rotor and load conditions for an induction machine with different rotor slot openings, using a time stepping 3-D finite element modeling approach. The discrete Fourier transform is used to analyze the magnetic flux density waveforms in the air gap and deduce the main harmonics related to the zig-zag flux. The influence of the rotor slot opening on the zig-zag flux and core losses, in both rotor and stator, are discussed.