Magnetic Saturation Impacts on Fault Analysis of Squirrel-Cage Induction Motors using Winding Function Approach

Multiple coupled circuit modeling of squirrel-cage induction motors, or winding function approach is the most detailed and complete analytical model used to analyze the performance of the faulty induction motors. This paper extends the above-mentioned model to a saturable model including variable degrees of the saturation effects using an appropriate air gap function and novel techniques for locating the angular position of the air gap flux density and for estimating the saturation factor. Comparing simulated and experimental magnetization characteristics and no-load current waveforms, accuracy of the new saturable model is verified. Using saturable and non-saturable models, various simulations are carried out on faulty induction motors, and then, by comparing the results, the impacts of the saturation on the performance of the faulty motor become evident. Also, comparisons are made with the experimental and/or finite elements results, which confirm the higher accuracy of the saturable model versus non-saturable model.