Time-stepping finite-element analysis of eddy currents in the form-wound stator winding of a cage induction motor supplied from a sinusoidal voltage source

The eddy-current effects of multi-conductor form-wound stator winding because of the fundamental and high-frequency magnetic flux in a cage induction motor are studied. The time dependence of the field and circuit variables and the motion of the rotor are modelled by the backward Euler time-stepping method. The motor was supplied from a sinusoidal voltage source. The series and parallel connected stator bars are strongly coupled with the circuit and field equations. The Newton-Raphson method is applied to solve the system of non-linear equations. The eddy-current loss distribution of the stator bars and the quantitative results of eddy-current losses are studied. The radial distance of the stator bars from the air gap has a remarkable effect on the losses and the hot spots. Methods to minimise the losses and to avoid the local hot spots are studied.