but buy-in and support were obtained
from management.
One of the gearcases was new and just
put into service. After two weeks of opera-
tion, the maintenance crew sampled the
gearcase. When the oil analysis report was
received, a resample was ordered immedi-
ately because the additive levels of the used
oil did not appear correct. The resample
confirmed that the new oil's additive
package had been lost. This is not
uncommon for new oil in new machinery.
In layman's terms, what happened was
that the additives had attached themselves
to the machinery's components and were
no longer suspended in the oil.
An oil change was ordered on the
gearbox, which had been in service only
one month. The cost of the oil change was
$3,000-$4,000, but the cost of a new
gearbox was $400,000. Traditional
wisdom for maintaining this machinery
was to change the oil approximately every
six months. In actuality, it was more like
once a year.
As monitoring continued on a
bi-monthly basis, the in-service oil was
good for three to four months before addi-
tives started dropping out and oxidation
levels increased. With custom test slates
and close monitoring, used oil analysis was
able to determine the proper oil change
intervals, and the planetary gearbox fail-
ures stopped completely.
COST SAVINGS
Effective maintenance should be viewed
in terms of the profits generated. The base-
line case for this example involved a
gearbox failure every six months, with a
cost of $800,000 per year in parts alone.
Assuming a gearbox lifespan of five years,
the replacement costs amounted to
$320,000 annually for the four units in
service. The oil change costs included two
changes per year per gearcase at a cost of
$3,500 per oil change, for a total of
$28,000 annually for the fleet. This was
increased to three changes per year per
gearcase, for a total cost of $42,000. The
cost of the used oil analysis was negligible.
So for a $14,000 increase in lubrication
costs, a profit of $466,000 per year was
generated. The savings could be even
10
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March - April 2017
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www.machinerylubrication.com
COVER STORY
