When the motor or mechanical leakage or partial static electricity generates current, the general bearing needs to use grease. In the bearing, the grease can produce oil film between the inner ring, the outer ring and the rolling element of the bearing (very thin about 0.005mm). The current can penetrate the grease (oil film) inside the bearing, causing direct contact between the inner ring, the outer ring and the rolling element of the bearing, causing electric shock on the contact surface, causing damage to the channel of the bearing, causing early failure of the bearing. Is the basic situation of electrocorrosion， so you can choose Anti-Electrocorrosion Bearings.