A. dust in the air due to the operation "Micro Cooling Fan" was inhaled motor of the motor core, and storage of lubricating bearings around the sludge in the mixed, and made noise operation, even card refuses to turn;
B. bearing bore easy to wear, life is short;
C. can not be used in portable "Micro Cooling Fan" on;
D. bearing clearance and shaft core of the small, poor motor Activate the effect of the operation;
E. motor running hot gas core and the shaft bearing friction generated by the oil due to the two ends of the bearing rings, washers obstacles, can not rule out the formation of nitrides, easy blockage in the gap between the shaft and the bearing of the core, impede "Micro Cooling Fan"the smooth operation of the motor.