... 0.1%, which greatly reduce the resonance of the fan. VFD has frequency-skipping function to avoid the ... fan, FD fan, Primary air fan, Second Air fan, Condensate exhausting pump, Boiler feed water pump, Slurry pump. Metal: Dust air fan, Primary air fan, ... Cement: Pre-heater fan, Coal mill fan, Cement mill fan, Bag house fan, Raw mill fan, Lignite Mill Filter Fan, By Pass Filter Fan, Kiln. Mining: ...