Why is pulley alignment important and how is it checked?

• A. Misalignment causes belt wear and vibration; check with straightedge or laser alignment tools and correct offset, angular, or parallel misalignment.
• B. Alignment only affects color matching.
• C. Alignment is only needed for new belts.
• D. Alignment has no effect on belt life.

Answer: (A)

Pulley alignment matters because when the pulleys aren’t lined up, the belt won’t track true. Misalignment causes edge wear, belt glazing, increased vibration, and uneven loading of bearings, all of which shorten belt life and can lead to premature failures.

To check alignment, use tools that compare the pulley faces and shaft centers against each other. A straightedge can be laid across the pulley faces to verify parallelism and planarity, and a laser alignment tool can project a reference line between pulleys to measure offset and angle. You’re looking for proper offset, angular misalignment, and parallelism so the belt can sit flat on both pulleys as it runs. If misalignment is found, adjust motor or driven-pulley mounts (and add shims if needed) until the centerlines are coplanar and parallel, then recheck and set the correct belt tension.