Multidimensional Amplitude Demodulation Techniques for Diagnosis Broken Rotor Bars fault in an Induction Machine Operating at Low Load Condition

Improving the availability and reliability of the induction machine in industrial systems means reducing and expecting maintenance operations. The traditional Motor Current Signal Analysis MCSA method is incapable to diagnose and distinguish IM failures when the supply network polluted and even at small load operating conditions. This paper proposes multidimensional amplitude demodulation techniques to diagnosis rotor failure in an induction machine fed by an inverter under light load operating conditions. These methods are Concordia Transform (CT), Principal Component Analysis (PCA), the Maximum Likelihood Estimation Approach MLEA, The Envelope of Three-Phase Stator Current (TPCSE), and Square Roots method (SQ). The obtained stator current amplitude modulation signal of each method is analyzed in the time and frequency domain by using Fast Fourier transform FFT. The background of these techniques is presented theoretically then tested experimentally by using laboratory workbench results. Our findings show the robustness and the effectiveness of these techniques which can successfully detect an inverter-fed induction machine rotor failure at lightly load conditions compared to the conventional MCSA method.