"AC Fan" in order to better roof fans have a good grasp of, we need to look at the roof fans the most important several components, roof fan in general plant used mainly by the motor housing, impeller row gas housing, motor, drive shaft and centrifugal impeller, motor housing and the impeller housing vertically adjacent exhaust connection, the motor to be mounted within the motor housing, and other types of fans this is a different place, we are on the roof fan installation must pay extra attention to this.