Bolts, nuts, flat washers, spring washers and stop plates are the most widely used components on motors, but they are often unsuitable during use. There are generally static and even imbalances in the rotor of the motor. This combination is called dynamic imbalance. Balancing is a process that improves the rotor mass distribution so that the rotor does not create excessive unbalanced centrifugal forces while rotating. This process is called the dynamic balance of the rotor. During the dynamic balancing process, it is necessary to balance the rotor end ring, the rotating shaft, the inner fan and other parts by weighting. If necessary, bolts and nuts will be used. In this case, the washer is involved, and the rotating part of the washer is recommended to use a retaining washer. To prevent loosening, some motor manufacturers use elastic pads to prevent loosening, and there are certain quality hazards.