Speaking of "220V AC Cooling Fan", we have to mention that the fan works and its core "bearing" Often "220V AC Cooling Fan" is mainly composed of two parts, a stator and a rotor, the stator comprising main circuit, bearings, coils. The main rotor blades containing magnets and the shaft. Currently in the "220V AC Cooling Fan" piece bearings are mainly divided into two categories: oil shafts, ball. Both bearings will have a very good representative of the product, of course, each have their own shortcomings, it can not be denied. The use of oil-bearing sliding friction sleeve bearings, use of lubricants as a lubricant and DRA. Use over time, due to the oil seal, oil will gradually volatile, and the dust will enter the bearing, causing the fan speed slows down, the noise increases and other issues. Many manufacturers are the basis of a number of improvements in order to achieve better results.