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Developing a Motor Bearing Regreasing Strategy
Craig Schutte, Predictive Maintenance Senior
Supervisor, Nan Ya Plastics Corp
First, we have to convince the company and its employees that
fresh grease added to open motor bearings extends the life of
the bearings, and thus the motor, if done correctly. Several options
include:
1. Share bearing and motor manufacturer information recommending
regreasing.
2. Look at damaged bearings from a motor that have been replaced
and inspect the grease. Aged grease or signs of contamination
will indicate the bearing life could have been extended by adding
fresh grease and purging the old.
3. Find records or talk to employees. Prove that the problem
hasn't been the regreasing, but IMPROPER regreasing.
4. Use vibration analysis to show that proper regreasing lowers
the vibration levels.
Second, for all of our motors, we will need to gather and organize
information, including...
1. motor speed? (higher speeds require more frequent regreasing)
2. motor horsepower? (larger motors/bearings require more frequent
regreasing)
3. open, sealed, or shielded motor bearings? (only open bearings
should be regreased - according to SKF tests)
4. grease fittings and purges available for proper regreasing
of open bearings?
5. time motor has been in service? (if available)
6. average motor operation time per month
7. current grease used in the motor bearings (to prevent improper
mixing of greases)
Third, using motor manufacturer information (acquired by paperwork,
phone, or internet), determine the recommended regreasing interval
for each motor using the above information. Create preventive
maintenance schedules and work orders in the computer system.
(These can be adjusted later based on experience, but the manufacturer's
recommendation is a great place to start.)
Fourth, perform training for all maintenance or other necessary
personnel. Training should include general grease information
(such as types, benefits, consequences of mixing different grease,
etc.) and proper greasing methods (such as using the grease gun,
using grease purge lines, cleanliness, etc.). VERY IMPORTANT!!!
Fifth, to prevent confusion, create some form of motor greasing
information system, such as tagging the motors with the regreasing
interval, type of grease, and proper amount OR a chart system
with similar information for all motors.
Finally, track and document MTBF and maintenance costs associated
with the motors. Show the company that proper regreasing DOES
improve the lifetime of motors, and thus reduces costs and downtime!
See other responses
to this Readers Challenge.
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