Evaluation of the Detectability of Bearing Faults at Different Load Levels through the Analysis of Stator Currents

Bearing faults are among the most relevant electrical machines failures. Their early and reliable detection can imply significant economic savings for the industry. This paper discusses the effects of bearing faults in the stator current, performing steady state analysis, under different load levels. A motor-generator test bench has been built in order to simulate real working conditions. Motor current signature analysis (MCSA) is used to study steady-state regime. It is a well-known and widespread technique for detecting rotor-related faults but not so commonly used in bearing diagnosis. The objective is to study the evolution of the harmonic components in different cases of use, taking into account several types of progressive faults. Tests were carried out with healthy and damaged induction motors under different fault severities and confirm the potential of the technique for detecting such faults. Moreover, the results show the variation of the harmonics amplitudes with the load; the paper specifies the most suitable load levels for the application of the technique.