Rotor cage fault diagnosis in three-phase induction motors by the total instantaneous power spectral analysis

This paper deals with the use of the total instantaneous power spectral analysis for diagnosing the occurrence of rotor cage faults in operating three-phase induction motors. The theoretical principles directly related to the application of this diagnostic technique are described, emphasizing the role of parameters such as the magnetizing current, motor-load inertia, motor rating and load level, in the diagnostic process. Both simulation and laboratory tests results demonstrate the effectiveness of the total instantaneous power spectral analysis for diagnosing the presence of rotor cage faults. The development of a severity factor, in order to evaluate the extension of the fault, is reported, and it is shown how this severity factor is almost independent of parameters such as the magnetizing current, motor rating and motor-load inertia