Effects of rotor eccentricity and parallel windings on induction machine behavior: a study using finite element analysis

Rotor eccentricity and the effect of parallel windings in an induction motor are investigated by means of a transient finite element model. Magnetic flux density and force distribution harmonics generated by the model are presented for the cases of static and dynamic rotor eccentricity, with various combinations of series and parallel stator winding connections. These results are compared with those obtained from a centered rotor case. Examples of the action of parallel-connected windings to reduce the effects of rotor eccentricity are given. The effect of circulating current between various combinations of parallel windings in an eccentric rotor induction machine is shown to reduce the unbalanced magnetic pull and to significantly reduce or eliminate other vibration-producing magnetic force harmonics generated by the eccentricity.<
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