... % controllable speedEnvironmental friendly, low emission level, freatly improved efficiency, longger motor life and competitive priceTechnical features of External ... rotor motor, centrifugal fan, centrifugal blower, axial fan in HVAC,Tele-communication, refrigeration, clean room, IT industry and air- ... duct fan, EC Gas blower, etc. High efficiency EC fan 24V brushless DC motor driver controllor