Finite Element Model for the Study of Inter-Turn Short Circuits in Induction Motors

This paper presents a finite element model for the study of the behavior of induction motors under inter-turn short circuit conditions. The main advantages of this model are its simplicity and the possibility of simulating different types of short circuits, involving different number of shorted turns located in different positions. This is achieved by means of the combination of a peculiar coil definition in the bi-dimensional finite element model with an external circuit coupled with it. The proposed model has been applied to a low-voltage random-wound induction motor, especially rewound for this study in order to allow the authors to introduce inter-turn short-circuits in any specific place of the windings. Experimental tests were performed on this machine in healthy and short-circuit conditions and, in both cases, measurements of supply currents and electromagnetic torque were taken. The spectral analysis of these magnitudes showed a good agreement between simulation and experimental results, validating the model for this kind of study.