If it is determined "Micro Cooling Fan" vibration caused by mass imbalance, so long as the measurement point of the horizontal or vertical direction in the vicinity of the bearing housing shell vibration, use of influence coefficient method, increase in the impeller, will be able to reduce fan vibration within the desired range. DC cooling fan impedance will have two functions, one is the impedance protection, thermal protection, respectively, one is described as follows:
     1. "Micro Cooling Fan" impedance protection to prevent motor burnout occurs when you shut down, the way the motor winding is set impedance (alternating current resistance), so that appreciation is maintained at a temperature below the burning temperature of the motor.
     2. The thermal protection to prevent the motor before burning occurs when you shut down, the motor temperature reaches appreciation burnout temperature, by way of cutting off the heating element
     Conventional "Micro Cooling Fan" is not overheating protection, the normal DC cooling fan can only lock machine 2H, the temperature slowly rising, a long time, the motor will burn, IC will burn, which is a thermal protection an important role.