Dynamic model of induction machine with faulty cage in rotor reference frame

This paper presents a simplified model of an induction machine with broken rotor bars. The model is founded on the fact that broken bars cause asymmetries in the normally homogeneous cage´s resistance and inductance. Thus, the rotor becomes pseudo-salient. This effect could be best comprised through the rotor time constants that differ in the orthogonal axes of a rotor reference frame. A method for their evaluation is also presented. Consequently, a choice of rotor co-ordinates for the model of a faulty machine to be developed in, is obvious. Experiments show good agreement with simulation results obtained from the developed model.