Direct Drive And Belt Driven Fans

The two bearings on direct drive fan motors which are 7 horsepower and larger are typically regreaseable.

Direct drive and belt driven fans.

Direct drive fans have no power transmission loss since the propeller is directly connected to the motor shaft. You have a fan a motor and maybe a coupling. On both direct drive and belt drive fans the motor has two bearings. Belt drive fans have two additional bearings.

In a direct drive configuration the fan motor that controls the movement of the fan blades is connected either to a shaft or fan axle. The second pulley is connected to a shaft that drives the fan propeller. Unlike the belt driven fans in case of a direct drive fan there is lesser energy loss. Thus the fan blades will rotate at the same speed as the motor rotates.

Where on a belt drive fan the fan motor shaft has a pulley connected by a belt to a second pulley. With the growing acceptance and affordability of vfd motor controllers direct drive fans are increasingly finding their way into mainstream industrial fan applications. This is because of the fact that the amount of friction is greatly reduced in case of this fan when the fan is operating. More often than not the maintenance cost of this kind of fan is also comparatively lower.

When compared to belt drive fans which require belts sheaves and bushings direct drive is just plain simpler and maintenance folks tend to lean toward direct drive for daily maintenance. On a direct drive fan as implied by the name the fan propeller is connected directly to the shaft of the motor. Direct drive fans should be designed for acceptable bearing life. While both belt and direct drive fans have been around for a long time the mainstay fan for most industrial fan applications under 250 hp has been the belt drive fan.