Comparative investigation of electrical diagnostic procedures in induction motors

This paper reports a comparative investigation of different diagnostic procedures that use input electric signals to detect different types of abnormalities in rotating machinery. Besides the traditional one phase current spectrum analysis, the diagnostic procedures based on spectrum analysis of the instantaneous partial powers, total power, and finally the current space vector modulus are considered. It is shown that the relationship between the angular displacements of the current side-bands components is directly related to the fault type. The amplitude increase of the fault characteristic frequencies is used as a fault detection criterion. This allows us to investigate the ability of each of the five diagnostic procedures to detect mechanical and electrical faults. As a result, the total instantaneous power diagnostic procedure was observed to exhibit the highest values of the detection criterion in case of mechanical faults while in case of electrical ones the most reliable diagnostic procedure is tightly related to the motor power factor angle