Inter-bar currents in induction machines

The paper presents a simple but effective model for predicting the effects of inter-bar rotor current on the performance of a 3-phase squirrel-cage induction motor. The model takes the form of a matrix that is solved in order to obtain values for the rotor resistance and reactance parameters in the standard per-phase equivalent circuit. The model is verified by tests on an induction motor with modified rotors (either one or two missing end-rings). The inter-bar resistance is also measured for the test-motor rotor and the results put forward with a discussion of the procedure. Good correlation is found between the predicted and experimental results.