Diagnosis of induction motor faults using the motor current normalized residual harmonic analysis method

Abstract

Induction motors are susceptible to many types of faults that can become catastrophic and cause production stoppages. To predict emerging faults and avoid an unexpected failure, an induction motor can be diagnosed using the proposed motor current normalized residual harmonic analysis method. This method is simple and efficient. It is based on a more sensitive fault signature and a single frequency of the harmonic for the different faults. It is based also on the analysis of residual harmonics, which can be measured between the normalized linear fast Fourier transform spectrum of the healthy motor current and that of the faulty motor current. The proposed method can mitigate the task of the fault detection system by monitoring the occurrence of a residual harmonic fixed at a precise frequency. This study focuses on the rotor fault of broken bars and inter-turn short circuits in stator windings. In-depth experimental results demonstrate the rapid detection of different faults at the characteristic frequency of 50 Hz. It is not necessary to conduct a wide spectral sweep to search each time for different faults that have variable characteristic frequencies depending on the type of fault. This method can be useful for diagnosing other types of faults such as eccentricities, bearings and magnetic circuits.