"220V Cooling Fan" is symmetrical double the number of leaf blades, in the injection molding, such as the mold flow analysis software to explore, we can see both sides of the elements, the fan, it is impossible to simultaneously emitted saturated. Based on this factor, To exit the completion of a fan, it will have one side of the blade is too saturated (ie the weight on both sides of the blade, not the same), so singular. The blade is not possible, but in accordance with the requirements to consider the amount of wind pressure, high volume leaves windy while, "220V Cooling Fan" noise will increase when the speed has reached the limit, to increase the amount of wind, only to change blades or increasing the blade angle, the fan is proportional to the amount of air flow relationship. From the energy point of view, three fans more cost-saving also relatively few. Because the three-piece "220V Cooling Fan" and form a reasonable mechanical power asymmetry, when a blade does not have the power potential, the other two in the potential state, two potential blades can easily drive a temporary nature does not have the potential of blade, you can save electricity and conserve energy.