An Alternative Approach for the Detection of Broken Rotor Bars and Bearing Faults of Induction Motor Based on Vibration Signals

Induction motors are widely used in industrial facilities for the conversion of electrical energy to mechanical energy due to their simplicity, easy maintenance and robustness. The smooth operation of these motors may be interrupted due to broken rotor bars and/or bearing faults. In single fault detection, the fault characteristic harmonics can be successfully detected by applying conventional Motor Vibration Signal Analysis (MVSA) methods. The characteristic harmonics may appear hiding or overlapping with closely-located spectral components in the presence of multiple faults. This paper proposes an effective solution to overcome this difficulty. Hilbert envelope analysis is applied to the vibration signals of an induction motor with multiple faults (broken rotor bars and bearing faults). Two different fault cases were implemented. At the first case, the induction motor was tested with three broken rotor bars and outer-race bearing faults. At the second case, the induction motor was tested three broken rotor bars and inner-race bearing faults. The results indicate/show that the proposed method is capable of detecting all characteristic harmonics in both cases under four different loading levels (25%, 50%, 75% and 100%) of induction motor.