Practicing Oil Analysis Magazine. July 2001.
If the motor is offset misaligned by 10 percent of the coupling manufacturer's allowable offset, then one can expect a 10 percent reduction
in inboard bearing life.
Wesley Hines et al, Maintenance Technology, URL: http://www.mt-online.com/articles/04-99ma.cfm
Author: Jim Wardhaugh
Location: 2.2.2Large Complex Oil Refinery in the Far East
A recent benchmarking study and follow-up review revealed that our reliability was poor. The overall Mean Time Between Failure (MTBF) of rotating equipment in our refinery was about ten or eleven months. Locations with high reliability were getting an MTBF of about four or five years, so we had a long way to go. The Engineering Manager tried to address this issue, but previous attempts ended in failure. This time he was determined to succeed, so he gave me the job of identifying the issues and putting together a strategy to bring top performance.
I chatted with a number of people in the location as I don't find formal interviews very effective. These chats threw up a number of interesting comments:
- • We had about 3000 pieces of rotating equipment. Most were centrifugal pumps so the problem could immediately be refined to "Poor reliability of centrifugal pumps."
- • The rotating equipment advisory group was competent, felt a responsibility for pump reliability, but had little influence on events.
- • They felt that bunches of incompetents operated and maintained pumps.
- • A set of silos was in existence, typified by:
- • Production and maintenance had unclear roles in operating, maintaining and lubricating pumps
- • Little knowledge of best practices or consequences of bad practices
- • No coherent drive for improved reliability
- • Repair service rather than failure elimination
- • Facts (as opposed to opinions) were difficult to retrieve on reasons for failure, and actions taken.
Based on these findings we agreed on a multi-pronged approach to pump reliability improvement and a framework for action. What we wanted to achieve is well captured in Ron Moore's words, "Fixed forever as opposed to fixing forever."