Induction motor fault diagnosis using an improved combination of Hilbert and Park transforms

In this work we propose an original failure signature based on an improved combination of Hilbert and Park transforms. Starting from this combination we can release two failure signatures: Hilbert modulus current space vector (HMCSV) and Hilbert phase current space vector (HPCSV). These two signatures are subsequently analysed using the classical fast Fourier transform (FFT). The effects of HMCSV and HPCSV spectrums are described and the related frequencies determined. This analysis offers an easy interpretation to conclude on the induction motor condition and its voltage supply state. The proposed signature shows its effectiveness and its robustness in both electrical and mechanical fault detection. This approach was applied to a 1.1 kw induction motor under normal operation and with the following fault: voltage unbalanced, broken rotor bar, air-gap eccentricity and ball bearing defect.