Modelling of the closed rotor slot effects in the induction motor equivalent circuit

In induction motors with closed rotor slots the enclosure upper part of the rotor slot saturates during the machine operations, involving an additional non-linearity in the machines behavior. A simple locked rotor test gives prominence to this phenomenon. In fact, in this test the supply voltage versus adsorbed current characteristics are not linear. In the paper a single-phase induction motor equivalent circuit suitable to take into account the effects due to the rotor wedge saturation is proposed. Complete theoretical details about the new equivalent circuit are reported together with experimental validation.