Cooling Tower Adventures

The OJT portion of a recent XA alignment training class led us to a two-cell cooling tower that had a run of bad luck–motor bearing failures, internal supports broken, visibly shook when it ran, etc.

A cursory visual inspection revealed no shims under the 25 HP motor and a horizontal gap difference of ~3/8″ between the gearbox hub to the spacer shaft. That 3/8″ gap over the 8″ coupling works out to 47 mils/in of angular misalignment! No wonder it was falling apart!

Cooling TowerThe motor/spacer/gearbox were ‘roughed in’ pretty quick using the handy line lasers and 30 mm detectors on the XA sensors. The XA was setup to take readings in Tripoint mode and a first set of results were obtained. The vertical results showed the motor to be too high by ~75 mils. Remember–there were no shims under the motor. So now we’re base-bound. No problem. The FeetLock™ function was activated and the optimal move was calculated. A tiny 10 mils under the front feet of the gearbox and 45 mils under the front feet of the motor was all it took. Since the motor was also bolt-bound, FeetLock™ was used again to find the optimal move. After re-measuring, a slight additional horizontal correction was made and then re-measured one last time to verify the results.

An hour and 45 minutes is all it took to rough it in and align it  within spec for it’s operating speed. After start-up the shake was gone and the customer was smiling.

About the Author

Brad Case

Brad Case has been associated with VibrAlign since 1990, first as a manufacturer's representative, then joining the company as a direct employee in 2005. He has 25 years experience in aligning industrial machinery. Brad began his career in the automotive industry providing technical training, sales, and service for Murray Goldseal an aftermarket air conditioning component manufacturer. His background includes 25 plus years experience in sales, service and training for centralized lubrication systems (including large scale oil mist applications in petrochemical facilities), couplings, gearing, and gear reducers. Brad and his wife currently live in Allen, TX.
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