Broken Rotor Bar Fault Detection Working at a Low Slip Using Harmonic Order Tracking Analysis Based on Motor Current Signature Analysis

Abstract

Induction motor is one of the standouts amongst the most generally utilized prime driver component in industry. However, they are subjected to various faults due to harsh working conditions. Exact and convenient diagnosis of these faults will help to maintain its operation, efficiency and performance under ideal status and avoid excessive energy utilization thereby reducing severe harm to these motors. Broken rotor bar is one of the commonly encountered induction motor faults that may cause serious motor damage and if not detected on time, can caused serious damage and this surely cannot be over emphasize. However, the condition monitoring and diagnosis relies solely on tracking the frequency signature. Hence, this fault signatures rely on the fundamental frequency and motor’s slip. This study therefore aims to solve these problems by tracking this fault signature produced in series of multiple harmonics in the current’s spectrum; whose frequencies are a feature of the main fault frequency. The tracking analysis of the fault components using the harmonic order is defined as the frequencies in per unit of the fundamental fault frequency as it helps in the presentation of the fault information by directly locating the harmonic fault in its integer order in a clear and simple way. Furthermore, this fault signatures can be gathered in a very small set of values in integer harmonic order. This proposed methodology is presented hypothetically and justified by carried out tests from the lab.