A. The fan does not turn first. The motor is not lubricated. When the fan is installed on the motor and the motor cannot be dragged, it will be found that the shaft can still operate normally.
B. After disconnecting the fan's power, you can find that the rotation is a bit stiff when you gently turn the fan blades, which means that the fan oil is gone. If the fan turns easily and freely, the fan is well lubricated.
C. And you have to consider how long the electric fan has been used, the electric motor of the electric fan will be worn out, and the motor's shaft sleeve is easy to burn off. If the motor is used for a long time, the internal resistance of the motor will also increase, and the load capacity will become low, which will cause the blades to be unable to rotate. There is also a large axial clearance of the motor's rotating shaft, which will cause it to be unable to drag the load.
D, most people may encounter the following phenomenon, the electric fan does not turn, you pull it by hand or wait for a long time to slowly turn it on, and after using it for a period of time, it is found that Will move. The possible cause of this phenomenon is that the starting capacitance in the fan has become smaller, which is not enough to make the motor rotate.