Consequences of motor not using insulated bearing:

1. Axial current will be generated

When the motor is running, the potential difference between the two ends of the rotating shaft or between the shaft and the bearing is called the shaft voltage. If the two ends of the shaft form a loop through the motor frame, the shaft voltage forms the shaft current. Shaft current is generated by shaft voltage through the motor shaft, bearing, stator frame or auxiliary device to form a closed loop.

2, axial current in normal conditions and the consequences of higher axial voltage

Under normal circumstances, the shaft voltage of the motor is low, and the lubricating oil film in the bearing can play the role of insulation, and will not produce shaft current. However, when the shaft voltage is high or the oil film is not formed stably at the beginning of the motor, the shaft voltage will make the oil film discharge breakdown into the circuit and generate shaft current. The high temperature generated by the energy release of shaft current partial discharge can melt many tiny areas on the inner ring, outer ring or ball bearing, and form grooves, resulting in noise and vibration. If not found and treated in time, it will lead to bearing failure, which has a great impact on production.