1)dia 200mm blades,220V/120v,50/60Hz,540-910rpm 2)single phase,UL,CE approval,ball bearings 3)dehumifier,air cooler,heater 1. An overview of axial fans with external rotor motor1. YWF series axial fans are external rotor motors. These motors have characteristics of compact structure, convenient installation and high efficiency.2. YWF series external rotor motors have two kinds, single phase ...