Belt Drives – Episode One

belt drive

Premature belt failures are caused by improper installation practices.

There, we said it. It needed to be said, and we said it.

We know what you’re thinking:

“How could this be, everyone knows how to install a belt…I know how to install a belt!”

It’s ok…read on…we’ll help you through the trauma of becoming belt aware. 

In upcoming weeks, we’ll make you one with the belt drive.

Episode One: Terminology!


Let’s start with a review of terminology.

Drive Assembly

Components that transmit power from the motor shaft to the fan shaft.   


Pulley with grooves for V belts (pulleys are for flat belts)                                                                                                                     

Drive Sheave

AKA motor sheave; mounts on the motor shaft.

Driven Sheave

AKA blower sheave; mounts to the fan shaft.                                                                                                          

Split Taper Bushing

Secures sheave to a shaft via friction.

Shaft key

Square metal stock used to engage the sheave with the shaft.


Groove machined into shaft and sheave to accommodate shaft key.                                                                                                                                         

V Belt

Flexible belt with angled contact surfaces.                                                                                                                                                         

Adjustment Base

Movable motor mount that allows for belt adjustment.                                                    

Motor base

Base attached to the motor, used for alignment and adjustments.

Patrick is Zen HVAC’s diagnostic and training guy. Patrick started in the trade the day he left technical school and never looked back. He's served in various technical and training roles in the HVAC industry but specializes in system troubleshooting and diagnostics, retro commissioning, and technical training. His moto: If I can understand it, anybody can. Patrick uses the Zen common sense approach to teach Patrick’s Likes- His Wife, kids and dog. Old pickup trucks. Hiking. The industrial Revolution. Patrick’s Dislikes- Taking work too seriously. Anything unintuitive. Emoticons :( Patrick’s Favorite famous person- Theodore Roosevelt “I am only an average man, But I work harder at it than the average man" Famous Patrick Quote- “Well, that was stupid of me”

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