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Developing a Motor Bearing Regreasing Strategy
Steve Bay, Manufacturing Engineer, JDS Uniphase
I would first ask about their "history" of not greasing the motors,
and to try to better understand their thinking. Is it based on
facts meticulously and scientifically collected, or on someones'
beliefs?
Obviously, if they have data to prove there was more harm then
good, you then have to ask about HOW they greased the motors,
what grease, and how often. If the conclusion they came to was
due to the type of grease they were using, or the frequency of
greasing (schedule), "change" would be welcome and desirable.
I'm saying if they can somehow scientifically prove that the
previous non-greasing plan has merit, my approach would be to
examine their plan in detail first. To establish a new plan I
would begin by developing a map/matrix of the count of motors,
and where they are in house by location. Mark up and use the plant
floor plan as a location guide. On this matrix the type of bearing
would be included.
Also, the motor usage application (24/7, or intermittent). Additionally,
whether this is a newer motor, or if it is nearer the 10 year
old mark. Another condition that would have to be considered is
how close to max. power rating are these motors being run. This
would effect loading, and effect the current grease life. It was
stated that certain of these motors had sealed or shielded bearings.
These would be set up for a periodic (3 mo. or 6 mo. intervals)monitoring
check.
Perhaps a baseline IR (Infra red)measurement could be recorded
to ascertain "nominal" expected values. These could be used for
future checks, looking for deltas from the nominal. The open bearing
motors would be in two categories. The first being, the motors
recently placed into service, and the second being the ones nearer
the ten year mark. The period for greasing would depend on the
frequency of usage for the motor.
The 24/7 motors would require attention on a regular schedule.
All of these motors could be placed on a regular schedule. Down
time is money for manufacturing. If it is necessary to "stop the
line" to access the motors for lubrication, the cost of the down
time must be traded off against the time lost replacing a motor
that was not maintained when it fails.
Also, the increased life gained by regular lubing must be weighed
against the cost (man/hours) to perform the lubing. These costs
must be known before a "plan", backed by data, can be presented.
Performing PM has to be "sold" to management, otherwise it is
viewed as a "pesky" expense.
See other responses
to this Readers Challenge.
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