"220V Cooling Fan" fan blades of the same if other parts remain unchanged, only the leaf blade consists of five to seven blades, wind changes may not add much. But on the fan speed, the fan's speed will be lower than seven five blades, the opposing fan blades if seven, bearing wear, oil spills less frequently, "220V Cooling Fan" longer life expectancy. If the five-speed fan blades and seven identical, ventilation seven blades will be even greater. The higher fan speed, the shorter the life of the corresponding noise is greater. In addition, the thicker the fan blades, the greater the blade bevel, the pressure is greater. Inlet angle of the blades is an important factor in the decision "220V Cooling Fan" ventilation rate. If you start from the design, the best airflow also a small increase in the inlet and outlet of the rotary groove to assist air flow design uses some fans do not like the ideal launch.