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Sometimes called the air-handler unit or the , the fan is the device which drives the treated air throughout the building. Usually driven by a single-phase AC motor in smaller applications, and a three-phase motor in larger commercial or industrial applications.
There are two main categories of fans, each with their own advantages and applications: the , which draws air parallel to the rotating axis and the , which draws air at a right angle to its rotating axis.
A motor that drives air in force-air systems.
Axial fans drive low volumes of air under low static pressure conditions in parallel with their axis of rotation. Mainly used for cooling of coils.
A centrifugal fan drives lager volumes of air under high static pressure conditions at a right angle to its axis of rotation. Mainly used for the moving air through ductwork.