"Cooling Fan Manufacturer" motor is a fan having a hub and blades of the motor, the fan along the outer circumference of the hub and have a uniform distribution of grooves, the blade inserted in the groove, by welding, bonding or the like permanently coupled to the blade and a fan hub, the method become one. "Cooling Fan Manufacturer" testing general resistance with a multimeter to measure the resistance profile of the leads between the end of the fan motor, if the measured tissue is infinite or zero, it indicates the presence of an open or shorted windings. When "Cooling Fan Manufacturer" operation, if the speed decreased, first check the power supply voltage is normal, and then check the oil in the bearing adequacy obvious if the operation sound of the collision, check motor bending.