Stator faults diagnosis in induction machines under fixed speed

In this paper, authors proposes a new monitoring technique of inter turns short circuit windings under fixed speed. This method is based on introduction of sinusoidal extra-signals to input voltage delivered by power inverter. For diagnosis, we proposed model of squirrel cage induction motors under stator faults. This model takes into account the effects of inter turn faults resulting in the shorting of one or more circuits of stator phase winding. The stator asymmetries caused in the faulty case are explained by the introduction of the short-circuit elements in the conventional Park´s model. Each short-circuit element allows faults detection and localization in the three stator windings. The estimation technique is performed by taking into account prior information available on the safe system operating in nominal conditions. Experimental test results show the good agreement between the real faults and their estimations and demonstrate the detection and localization possibilities of this predictive failure detection technique