Vibration analysis, with proper mechanical inspections, can make the difference between making the same ineffective repairs over and over again, or determining the precise nature of a problem and applying the proper solution once.

HVAC air handling equipment is a good example because the bearings fit to the shaft in rotating machinery can degrade over many years. We had a recent repair job in a retail building in which the HVAC system had become very noisy and begun vibrating. The customer had previously replaced the bearings several times, hoping that would solve the problem, but the noise and vibration never went away..

We performed a vibration analysis on the system and a dial indicator reading revealed a .010 run-out on the shaft, suggesting shaft wear. That conclusion was supported by a red residue in the area that seemed to indicate iron powder wearing off the shaft (fretting).

Since the system was over 60 years old, new shafts were not available. Even if one could be fabricated, it would be very difficult, time-consuming, and expensive to replace a shaft on a system that old.

Instead, we took very careful measurements, fabricated a precision sleeve to fit over the worn area and a new bearing arrangement to accommodate a larger bearing to fit over the now-larger shaft sleeve. As a result, we were able to make the repair in just five hours, instead of days, saving the customer thousands of dollars.

Hi-Tek Balancing, Inc. provides industrial balancing and vibration analysis to companies around the world.