... Centrifugal fan and blower, external rotor axial fan,ventilation fan, Duct fan, shaded pole motor, external rotor fan motor,aluminum die casting ... efficiency production lines and scientific management, "low noise, high air volume, stable running and long life time" Fans has been ... : Asynchronous external rotor motor2. 68: Motor air gap diameter3: L15: Core length code4: P4 : Motor pole numbe, 2,4,6,8 ...