Early Fault Detection using A Novel Spectrum Enhancement Method for Motor Current Signature Analysis

-This paper develops a novel spectrum enhancement method to simplify the spectrum representation. It uses a forward synchronous transform to convert three phase current signals into the two current signals in the synchronous reference frame. The spectrum obtained by applying Fast Fourier Transform (FFT) to one of the transformed current signals is then maximized by varying the initial phase in the synchronous transform. The enhanced spectrum is a much concise representation of the fault signal because it not only eliminates the supply frequency but also enlarges the magnitudes of fault components. The capabilities in enhancing the fault signals and controlling the noise are highlighted through both theoretical analysis and numerical simulation. In addition, two common motor fault cases: a broken rotor bar and a small rotor eccentricity are also tested to evaluate the performance of the enhanced spectrum in detecting these incipient motor faults. Key-Words: Induction motor, motor current signature analysis, broken rotor bar, fault detection, synchronous reference frame.