"Cooling Fan Manufacturer" Every leaf area after a stall would be a exciting force, thereby allowing the blade to resonate. In this case, the dynamic stress increases blade may cause blade breakage, so from the absolute reference frame outside the impeller, the stall area or rotated in the direction of rotation of the impeller, causing the mechanism of rotating stall "Cooling Fan Manufacturer", rotating stall pressure fluctuations generated by the impeller rotor excitation occurs is abnormal vibration excitation force, the excitation force size and the size of the gas molecular weight, they are proportional to the relationship, the greater the molecular weight, the greater the incentive force. To prevent the "Cooling Fan Manufacturer" unexpected failure resulting in unnecessary losses, we must make improvements from the design. Thus fundamental to dispel criticism, to change nature.