Impeller material generally for aluminium alloy or engineering plastics. Aluminum alloy impeller highly strength, light weight, high temperature resistant, can keep long smooth operation and deformation; plastic impeller by mold injection, again by ultrasonic welding , rotational speed is low occasions, larger diameter. Air duct general for sheet metal stamping forming, can also become plastic or aluminum alloy casting. The body is made of streamline design, which can effectively reduce the loss of the air, make the fan work efficiency greatly improve. Motor is transverse flow fan power part, can communication power supply, also can supply DC power . Ac power supplyment are mainly shaded pole motor and capacitor start motor, DC power supplyment for the brushless DC