Characterising the Orthogonal Outputs of an On- Rotor Sensing Vibration Node for Efficient Condition Monitoring of Electric Motors

Condition monitoring (CM) of induction motors (IMs) is critical to keep IMs operating in a healthy status. With the development of the Internet of Things (IoT), wireless sensor nodes are widely used in industries for more efficient CM. However, the increasing amount of sensor nodes in service produces large volumes of data, leading to increases in the power consumption of the sensor networks and computing costs, so it is wise to reduce the data size and develop edge computing algorithms. This paper investigates the three orthogonal outputs of an on-rotor sensing vibration note with triaxial accelerometer in order to reduce the outputs without impairments of the CM performances. In particular, the output of each triaxial vibration is examined by analytic and experimental analysis to evaluate the performances of monitoring bearing defects and shaft misalignment which are of common faults in IM. Especially, the analysis considers the inherent deviations in sensor installation and motor manufacturing. It has been found that that each of the three channels can be used for IM monitoring but the output along axial direction gives better results in diagnosing bearing defects and misalignment. It means that it is possible to integrate an ORS node with a single sensitivity axis, which will be at low costs in both hardware and computing.