Many "Waterproof Cooling Fan" will happen one way or another corporate failure in the course of production equipment, most of the reason may be due to the heat caused by, the following stall during rotation judge raised the possibility of the corresponding analysis. Rotor rotating stall frequency: When "Waterproof Cooling Fan" cooling fan normal operation, with the direction of the impeller rotor is in the same direction, an exception occurs when the fluid direction, the rotor is abnormal vibration. So this is the reason causing the fan rotating stall. To prevent "Waterproof Cooling Fan" unexpected failure resulting in unnecessary losses, we must make improvements from the design. Thus fundamental to dispel criticism, to change nature.