Estimation of Parameters of Induction Motor with Broken Rotor Bars

This paper describes the evaluation of parameters of a three-phase induction motor with broken rotor bars. Such fault causes electric and magnetic asymmetry in the machine. Using standard d-q model of induction motor this asymmetry can be expressed through differently modified rotor parameters in both axes. In pursuing the goal to establish accurate motor parameters, a non-standard, one-phase measuring method was employed. In this way angle dependence of rotor parameters following a sinusoidal shape was determined. Additionally to measurements an extensive finite element analysis has been performed for two purposes. Firstly, to assess the measurement results of the method and, secondly, to predict various situations which can not be easily achieved by measurements due to hardware limitations (e.g. different numbers of broken bars). Finite element analysis evidences the correctness of the machine parameters obtained from proposed measurement method.