Mono-Dimensional Demodulation Techniques for Diagnosing Broken Rotor Bars Faults Within Inverter-Fed Induction Machine at Low Load Operation Condition

This paper presents a comparative study of reliable offline methods to detect and diagnose the rotor fault of an inverter fed induction machine operating under low load conditions. These methods are based on the mono-dimensional stator current demodulation techniques to extract the amplitude modulation signal for one phase stator current. The investigated methods are: Hilbert transform, Synchronous demodulator, Teager Kaiser Energy Operator, and peaks detection method. These techniques are theoretically presented and experimentally validated by using a test bench that contains three industrial motors: one is healthy, the second has one broken bar, and the third has two broken bars. Each motor is tested with three supply frequencies and operates under low load conditions. The obtained results for different methods are compared with each other and with the Motor Current Signature Analysis (MCSA) method to show the robustness and effectiveness of the investigated methods, especially under low load conditions.