Faults diagnosis for electrical machines based on analysis of motor current

This paper introduce faults diagnosis based on current analysis. The current spectrum of a three phases and single phase induction motor and also of a DC motor, are analyzed in order to achieve information for the detection of different faults. In order to perform the diagnosis we analyzed signals of current from the ampere sensor. The Fast Fourier Transform is applied to the signals acquired. We observe significant current spectrum differences between healthy motors and motors with faults. The high-frequency spectral analysis of current provides a method to detect bearing faults, broken rotor bars faults and commutator short circuit and presence of a displaced permanent magnet out of poles in polar axe. The system developed is scalable to different power ratings and it has been successfully tested with data from 0.75kW three phases induction motor, 0.65kW single phase induction motor and DC motor with permanent magnet.