The Importance of PrecisePulley Alignment (Belt or Chain Driven Machines)

Updated: Nov 9, 2020

Do you have repeated belt failures or failure of drive end bearing for a motor ? Do you have rotor gap issues or repeated electrical failure motor driving a machine by belt? Pulley or sheave misalignment is a leading cause of failure for belt and chain driven machines!


Pieces of broken belt / powder on the floor



The traditional methods are not good enough!


+ Many maintenance personnel have misconception that precise pulley alignment is not necessary

+ Some think the alignment done using a thread or even a staright edge is good enough for the machine.

+ Others believe belts "can take" the misalignment.

+ The obove photo is from a site where the maintenance team did the pulley alignment using thread and straight edge after belt replacement. Luckily one of the cleaners found some black powder on the clean floor (something very rare in a plant) and notified the maintenance personnel.


The effect of non-precise pulley alignment


+ Repeated belt failures/ high belt wear casuing frequent belt replacement.

+ High wear of pulleys or sheaves. So pulleys cannot reach it's intended life period.

+ Repeated bearing failures, especially for the Drive End bearings in Motors.

+ Electrical issues such as change in rotor gap for motor, causing motor failure of reduced efficiency.

+ Machine downtime caused by above failures.

+ Increased maintenance cost.


The Solution - Pulley Laser Alignment

The below photo is from the same site where belt "powders" or pieces where found. We can clearly see the pulley is misaligned by a 3-5 mm. This was impossible to detect with thread or staright edge method!

Some recommendations:


+ High precision straight laser alignment tool can show even minor difference in the pulley alignment condition. Heliping you align the machine within tight tolerance!

+ Ensure that belts are not forced into the pulley. Always loosen the bolts and move the machine or move the pulley (if possible)

+ Ensure proper belt tension.

+ Repair or replace extemly worn out sheaves.

+ Stroboscope inspection on running machines can help diagnose belt wear/ some misalignment condition. Periodically monitor the machine.



  • Osborne Engineering can provide pulley alignment as a service or provide you with the product with training.

#belt #pulley #maintenance #alignment #motor #sheave #industrial

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