A Simple Method for Identifying Mass Unbalance Using Vibration Measurement in Permanent Magnet Synchronous Motors

There has been active research in fault diagnosis of permanent magnet synchronous motors (PMSMs) with the recent increase in reliability-critical PMSM applications. Most of the research efforts are focused on the motor current signature analysis (MCSA), as it allows remote online detection of the rotor and load defects using the current measurement available in the drive. A critical limitation of MCSA or vibration analysis is their inability to distinguish the type of rotor or load defect. It is crucial for the maintenance engineer to identify the type of defect since the course of action for continued operation differs depending on the fault. In this letter, a simple automated test method for identifying mass unbalance using vibration measurement commonly available in motor drive systems is proposed. The effectiveness of the proposed method is verified on a PMSM under emulated PM demagnetization, dynamic eccentricity, and mass unbalance conditions.