A Novel Bearing Condition Monitoring Method in Induction Motors Based on Instantaneous Frequency of Motor Voltage

Bearing failures are the most frequent faults in induction motors. By utilizing an efficient bearing condition monitoring (BCM) method, unscheduled breakdowns and unnecessary costs caused by bearing failures can be eliminated. The methods proposed in the literature for this purpose are mainly based on measuring and analyzing vibration and current. This paper proposes a novel BCM method based on "instantaneous frequency of motor voltage." Simulation and experimental results show that defective bearings cause to increase the amount of non-Gaussianity in this signal. In this paper, it is shown the global kurtosis of the proposed signal is able to detect bearing defects at an early stage. In contrast, for both vibration and current signals, it is preferable to applying the kurtosis locally in different frequency bands. The electrical signals are acquired from the motor terminals and motor control center of an oil pump station. Results approve the merits and effectiveness of the proposed method for industrial applications.