"220V Cooling Fan" depends primarily on the diameter of the fan blades, the axial length of the blades of the fan speed and the shape and other factors. Cooling fan blades are usually between 6-12. In general, less likely to have a greater number of blades of wind pressure, but also large operating noise; and a larger number of "220V Cooling Fan" leaves the opposite. Design Excellence blades, can produce output larger air volume and pressure at the fan speed is not high, but it will not have much wind noise. In addition to the shape, "220V Cooling Fan" blade pitch angle is also important to meet the needs of the motor characteristics and heat sink design. Otherwise, the simple pursuit of big leaf inclination may appear large wind wind noise is small.