The Current Eigenfrequencies for Bearing Fault of Mixed Eccentric Motor Based on Amplitude Modulation

Abstract

The current feature for motor carried with natural mixed eccentric and bearing fault is merely focused even though it is very important for motor online diagnosis. Based on the amplitude modulation, this theme researched on periodic change of the air-gap length caused by not only bearing fault but also mixed eccentric. Based on the relationship between the motor inductance and the magnetic permeability, the inductance expression was deduced for motor with bearing fault, motor with mixed eccentric and motor with not only bearing fault but also mixed eccentric. A new current eigenfrequencies expression was introduced by employing proposed inductance expression. Finally, a series of simulation studies were conducted, the results show that the new current eigenfrequencies expression is valid and useful for online diagnosis of those motor in service.