The calculation of induction motors is based on the finite element analysis of the magnetic field. The field is assumed to be two-dimensional, and the time-dependence of the field and the motion of the rotor are modelled by the Crank-Nicholson time-stepping method. The non-sinusoidal voltage supplied by the frequency converter is imposed on the formulation through the circuit equations of the winding. The method is applied to the analysis of a cage induction motor supplied by a PWM inverter. The results are compared with the measured results, and the benefits and failings of the method are discussed. © 1990, IEEE. All rights reserved.