April - Library

Technical Short Feature:
Machinery Troubleshooting - First Impressions
When troubleshooting a machinery problem, whether for an
unusual vibration problem or a component failure such as a bearing
or seal, first impressions from the initial machinery inspection are
very important. Any troubleshooting exercise should begin with
a thorough investigation of machine history - process, design,
operation, maintenance, and all available machine details. These
first impressions are necessary to make sure the troubleshooting
team is fully armed with important data and minimize the chances
of a misdiagnosis.
Many people new to the troubleshooting process have a
tendency to immediately pick up tools and start working. A better
approach is to put the tools down and collect first impressions.
While they might not immediately reveal the problem, they may
identify a number of issues that are impacting overall reliability.
Recommendations for these initial inspections include:
1. Overall cleanliness - Good housekeeping often reveals that machinery maintenance practices are held
to a higher standard. Look beyond dust to the condition of the base and foundation, piping supports, seal
leaks, etc., for evidence of maintenance practices or environmental factors that negatively impact reliability.
What are the expectations that a field repair can be conducted without introducing contaminants that will
shorten the life of the replacement parts?
2. More detailed machine inspection - Start with the machine base and look for obvious signs of decay
or improper anchoring. Move up to the feet and inspect the shims and hold-down bolts. Poor practices at
the base often reveal a lack of quality of other repairs. Move to the shaft and drive (i.e., couplings, belts,
etc.) and look for evidence of shaft damage, improper coupling assembly, and incorrect key length. While
issues with these areas may not be the cause of the current problem, improvements made with the required
repairs will improve machinery reliability.
3. If running, perform a basic vibration check - Use a simple tool such as a coin with serrated edges to obtain
an impression of relative machinery movement if the machine is still running. While vibration measurements
tend to focus on the bearings, with coin in hand, start at the base and work up to the bearing locations to feel
for unusual movement. Pay close attention to boundaries and connections such as the base-to-foundation,
machine feet-to-base, and all piping and conduit. A simple condition such as a loose base-bolt can have a
dramatic impact on the machine.
4. Keep detailed notes of the initial impressions – They will provide a comprehensive and professional report
on improvements that will impact the life and reliability of the machine. While at the machine site, inspect
other equipment in the area for similar issues and carefully present this information to the stakeholders.
While no one likes to have their flaws revealed, a good presentation of steps that can be followed to
positively impact machinery will be well received.
Motor Feet Outside Base - Poor Support
Content and pictures courtesy of SKF @ptitude Exchange
Base Not Flat
Vol 24 No 2