FINITE-ELEMENT CALCULATION OF UNBALANCED MAGNETIC PULL AND CIRCULATING CURRENT BETWEEN PARALLEL WINDINGS IN INDUCTION MOTOR WITH NON-UNIFORM ECCENTRIC ROTOR

Abstract

Abstract- In induction machines, an eccentrically positioned rotor experienced a strong unbalanced pull toward the short side of the air gap. The non-symmetric flux distribution due to the eccentricity induces circulating currents in the rotor cage and parallel branches of the stator winding. These currents equalise the flux distribution and reduce the unbalanced magnetic pull. In this paper, the effects of the rotor eccentricity and equalising currents on the unbalanced magnetic pull are studied by multi-slice, time-stepping, finite element model. The modelling is done for the cases in which the rotor is parallel or diagonal with respect to the stator. The results of series and parallel connected motors are then compared. I.