Influence of magnetic slot wedges on the effective magnetic air-gap and the slot leakage

Contents In order to reduce the magnetizing current and no-load losses of h igh voltage induction motors with open slots, the use of magnetic slot wedg es is very common. Simultaneously, the slot leakage is increased. The non l inear permeability of the material of the magnetic slot wedges results in a dependency on the motor current. As the starting current is limited mainly by the leakage reactance and the power factor is influenced by leakage and magnetizing current, the appropriate determination of the slot wedges beha viour is very important. The influence of magnetic slot wedges on the radia l component of the field in the air-gap and the slot quadrature field is in vestigated by means of field calculations for eleven motors. The numericall y obtained results are compared with analytical approaches.