1, "Small Cooling Fan" shaft section is to ensure that there is oil, otherwise the blades will not drag in the above motivations. If it is your own home, you can choose to turn off the power, then toggle blades, rotating stiff if so, is basically a no lubricant.
2, with a long time due to wear and tear. If a fan with a long time, the motor will be losses, after the motor bushings wear can easily burn.
3, due to overheating fan does not turn. In a device where there is a fan motor, the motor will have a overheating circuit breakers, if local coil winding short circuit, heat will increase short time, under such circumstances the motor will "strike" does not move up.
4, start capacitance becomes smaller. When "Small Cooling Fan" with a long time, the capacitance is reduced, resulting in motor starting torque is smaller, does not bring the load.
5, often caused by reasons not turn the fan blades, are poor maintenance issues. If the power is turned off manually rotating blades struck stiff, you should use some lubricant drops shaft, it can be lubricated, it will not affect the motivation to drag blades.
6, for a fan does not rotate due to wear, simple or replacement parts, in particular the sleeve, if worn easily burned.
7, if the capacitance is small due to the fan does not turn, you can remove the capacitor capacitance change with a new model, the proposed 20% larger than the original choice of capacitor, there will be a better rotation effect.
8, "Small Cooling Fan" shaft axial clearance much of a problem, you can choose to adjust the pads after disassembling the motor. But I remember back when the motor is installed, you must pay attention to the rotor and bearing concentric, lubrication with screws diagonally slowly tightening, and finally with wood to knock the shaft, make sure it is concentric.
9, if it is due to an electrical fault, you can check the wiring of the lines, sometimes damaged cord can repair the problem.