... CE ----approvalsaaUL , VDE 60hz : Axial and centrifugal fans with AC motor sizes 094/110/138 Asynchronous external rotor ... from 500mm to 910mm , for backward curved centrifugal fans with impeller diameter 450mm to 630mm , and forward ... , fibre-reinforced plastic . For backward curved centrifugal fans up to 630mm in diameter , an impeller with ... of size 094,110,138. ebmpapst 500 mm AC axial fans-hyblade