The Importance of Spare Rotation
On a routine monthly inspection of pumps on a cold rolling
steel mill, the vibration analyst had noticed an increase in vibration
at four times the running speed of the unit.
The pump with the increased vibration
was one of two pumps used to supply oil to the back-up roll bearings.
One pump supplied oil to the back-ups and one pump was a spare. 
An increase in vibration at four times the running speed
of the unit indicated a probable coupling problem with the gear-type
coupling.
The vibration analyst
recommended taking the coupling apart and inspecting the coupling.
The coupling was not inspected in time to avoid coupling
failure. When the coupling failed on the primary pump, the spare pump would
not start.
The
mill was
down for at least an hour until the spare pump could be put into
operation. The spare pump had not been run in some time and the importance
of
checking the coupling on the primary pump probably didn’t seem that great because
there was a spare. Even when you have spares you need to rotate them and
know their condition to avoid downtime.
Submitted by Thurman Speece, Vibration Analyst, Allegheny
Energy Supply.
Lean Tools for Maintenance and Reliability Conference
Learn how lean strategies are being applied to improve production
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2005: Lean Tools for Maintenance and Reliability, 4-5 October in Cleveland.
Hear case studies from experts
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