df series centrifugal fan is mainly direct drive, single volute outlet and double volute outlet structure has the advantages of unique structure, body, beautiful, convenient installation. according to the principle of the air dynamics, the fan casing and impeller are designed with quality cord rolled steel, galvanized sheet, aluminum alloy plate, 304 stainless steel plate, which has the advantages of large air quantity, high pressure, low noise, stable operation, small volume, light weight and long service life. fan surface through advanced technology and surface treatment, pickling and pasivation anti fingerprint, electrophoressis and enhances the anti-rust and corrosion protection. fan driven by three-phase asynchronous motor, motor insulation class is f, protectiom grade ip56, the use of international brand maintenance free bearings, resistance to voltage and frequency transmission, etc. long tern use of low temperature, high temperature and high altitude. df series fan covers train air conditioning refrigeration capacity of 5.0kw to 53kw air conditioning units, widely used in emu, high-speed rail, subway, light rail, trolley buses and electric buses, etc