Impact of the load in the detection of bearing faults by using the stator current in PMSM's

Many mechanical faults in industrial processes are related to bearing damage, which can be detected by vibration analysis. This approach may be expensive due to the cost of sensors. Therefore, studies are performed in order to use the stator current to detect bearing damage. This study is to investigate the impact of the load in the bearing damage detection by using the stator current. A diagnostic index is developed and evaluated for vibration signals measured from a healthy and a damaged bearing. Afterwards, the validated index is applied to the stator current of a permanent magnet synchronous machine measured with a healthy and a damaged bearing at different loads. The results show that, the damaged bearing can be differentiated from the healthy bearing by using the proposed index with the signal of the vibration or the stator current. However, the detection by the stator current is strongly dependent on the radial force of the bearing.