A critical fan at an East Alabama insulation plant experienced reoccurring bearing failures that began deteriorating almost immediately and excessive 1x Turning Speed amplitude. After complying multiple databased and reviewing the historical data, it was found that prior to December 2019 the fan exhibited negligible amplitudes of vibration but after which saw a continuous upward trend well into the alarm levels. Looseness was suspected in the foundation around the Inboard Fan Bearing but was never inspected. While assisting with the December 2020 bearing installation cross-channel phase analysis was conducted across the fan bearings and found an inconsistent coherence.
We inspected the fan wheel and found that the set screw holding the wheel into place was missing and 1-2 inches of movement could be seen on the shaft. A set screw was reinstalled however the damage to the shaft was done and the movement could not be completely corrected. A new shaft and fan wheel were ordered and replaced which corrected the dominate 1x Turning Speed issues unfortunately during installation bearing alignment was not able to be completed due to production demands but was completed less than a week later. Vibration amplitude has returned to the historically low levels and the 1-2 week duration between bearing replacements was eliminated.
Our advanced analysis techniques corrected this issue during a planned shutdown and prevented costly unplanned down time. Here at Nelson Electric Motor Service, we strive to provide our customers with expert condition monitoring services as it:
About the Author
Christian A. Smith is a Mechanical Engineer, Vibration Specialist with Nelson Electric Motor Service tasked with developing and improving systems, practices, and programs. He holds a Bachelors of Science in Mechanical Engineering from Lamar University, ISO Category III Vibration Analysis Certification, Level I Infrared Thermography Certification, Optical Gas Imaging Certification, and a Failure Analysis Certification.