"220V AC Cooling Fan" rely on motor-driven fan to rotate, resulting in the wind. So called heart parts motor, blades are called wings, the fans use a significant role. See "220V AC Cooling Fan" fan blade diameter and blade twist angle size: the larger inner diameter blades, wind blades cutting the air to produce greater; the harder torsion angle increases cutting wind, the wind blowing out the hardness is large; the more the number of wind blades cut more intensive wind, wind effect softer, more stable wind, "220V AC Cooling Fan" Usually five blades of fan blades inner diameter than the big three, and the twist angle of the three blades of more than five big fan, so the air volume five blades, the wind effect and soft, three-blade wind speed, wind effect hard.