Modelling of rotorbars with skin effect for dynamic simulation of induction machines

A mathematical model of a squirrel-cage induction motor is presented. It considers skin effect in rotor bars for frequencies up to about 1500 Hz. The main idea is to represent the rotor bars as a lumped network of resistances and inductances. The model is part of a complete simulation program for a full-power main line locomotive. It is used for a more accurate investigation of copper losses and torque pulsations in the motor. Theoretical results are compared to data calculated with a finite-element-method (FEM) program in order to get the parameters for the special shape of the motor which is applied in a locomotive. The limitations of the derived formulas and the advantages of FEM calculations are shown.<
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