Improved methods for determining the equivalent circuit parameters for single-phase induction motor models

The traditional model of a single-phase induction motor is a poor performance predictor, especially when the motor is heavily loaded. Including core loss components improves the accuracy of this model considerably. Three possible equivalent circuits are developed which provide more accurate results. Using no-load and locked rotor test results, two equations can be solved simultaneously to determine appropriate values for the model parameters. The proposed models are then compared to measured data and found to give much better agreement than the traditional model. The nonlinearities of the model are explored by using an iterative technique to empirically refine the rotor resistance. This method yields predictions that are very close to measured values over a wide range of speeds, often within 5%. The best results were obtained by including a core loss resistor in parallel with the forward and backward field circuit magnetizing reactances.