Fault Diagnosis Way Based on RELAX Algorithms in Frequency Domain for the Squirrel Cage Induction Motors

The traditional method of spectrum analysis on the current signal via FFT is hard to diagnose the fault of the broken rotor bars. This paper presents a fault diagnosis method using the RELAX algorithm in frequency domain. It can estimate the amplitude and phase values of various frequency components using coarse and fine estimation according to the criterion of minimum energy. Finally the fundamental component can be eliminated in frequency domain after the expressions of the above frequency components are constructed. Compared with the method of eliminating the fundamental component in time domain, this method has the advantage of computing faster although less accurate. However, it has been proved that the algorithm can highlight the fault characteristic and value a lot early in the motor fault diagnosis.