... fan have advantage: 1.air flow 44000m3/h,motor 1100w 2.mirror designed balde 3.galvanized layer 180g ... external rotor motors are single or 3 phase,with permanent split capacitor,2,4 or 6 poles.The voltage of single phase motor ... ,50Hz/60Hz.The voltage of three phases motor is 380V,50Hz,or according to client's ... is more than 40,000 hours.Most of external rotor motors have passed CE,ROHS,UL and approval ...