New improvements in the computation of the polyphase induction-motor magnetic circuit

The present paper introduces a method of determining the airgap-flux-density waveshape in a polyphase induction motor operating under saturation conditions. It proposes to characterise the magnetic-circuit saturation by means of two independent factors, considering both the tooth and core saturation - and it produces new computative curves required to determine the magnetising current. The paper also proposes a new method of determining the field distribution in magnetic cores, considering the variable permeability, as well as curves for the computation of the core m.m.f. Comparison with other computative curves cited in the literature, as well as experimental results, has shown good correlation.