Motor Bearings and High Horsepower Belt-Drive Fans
Over our years designing, developing and delivering custom centrifugal fans and blowers for industrial applications, we have learned that no detail is too small in the specification process. This holds true when we talk about motor bearings too. There’s a specific nuance to consider when selecting motors for high horsepower belt-driven fans.
Bearing Modification for Belt-Driven Motors
Motor failures are often caused by bearing problems within the motor. Torque measures a twisting force on the bearings and is a stressor on bearing life that should be considered. With belt-driven motors, there’s an additional stress to think about. The belts create a horizontal pull or stress against the drive-side (side closest to the belt) motor bearing. This stress has a critical effect on motor life, especially when the motor horsepower is above 100. In these cases, you want to ensure the drive-side motor bearing is a roller bearing instead of the more typical ball bearing. Without this adjustment, the bearing can fail prematurely, requiring early or more frequent motor repairs/replacement along with incidental fan rework.
In a lower horsepower belt-driven motor, the additional horizontal stress is lower and the extra load from the belts is minimal. In these cases, we typically recommend sticking with the usual ball bearings on both sides.
What about Direct-Driven Motors?
In direct-drive applications, there is no horizontal pull or stress to worry about, as your motor only has torque stress to act against. As a result, the motor can use ball bearings and the roller bearing modification is not necessary.
Hear it from the Application Engineer
Senior Application Engineer Chet White demonstrates motor selection considerations, including the torque and horizontal stress factors, for your belt-driven or direct-driven fan application in this 1½ minute video.
When you’re ready to start your project, reach out and connect with one of our application engineers to discuss the details of your specification.
Related Content on Industrial Fan Applications
There are many factors to consider in every industrial fan application. We’ve seen it all. Here are two more articles that might be of interest as you think about your application:
- MOTOR SPEEDS FOR BELT DRIVE FANS
- INDUSTRIAL FANS: BELT DRIVE OR DIRECT DRIVE?
- BRAKE HORSEPOWER: SIZE MATTERS WHEN SELECTING FAN MOTORS