Evaluation of interlaminar eddy currents in induction machines

A novel three-dimensional eddy current model to account for the additional losses caused by interlaminar short circuits is presented and applied to the loss estimation of an induction machine. The method is based on a single sheet model with appropriate boundary conditions on the interlaminar contact surface avoiding cumbersome full three-dimensional models with multiple short circuited laminations. The interlaminar model is validated by means of full models comprising several interconnected sheets and used for the quantification of extra losses caused by conductive joints and shearing burrs. It has been found that particularly burrs occurring on the tooth edges lead to a significant loss increase.