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Manual for Induction Motors and Generators
70 -
Maintenance
3BFP 000 050 R0101 REV E
7.5.2.2 Control of the lubricant
During the first year of operation, it is advisable to take samples of the lubricating oil after about
1000, 2000 and 4000 operating hours. The sample should be sent to the oil supplier for analysis.
Based on the results it is possible to determine a suitable oil change interval.
After the first oil change, the oil may be analyzed at about the middle and the end of the oil
change interval.
7.5.2.3 Recommended control values for the lubricating oil
The lubricating oil should be verified regarding the following aspects:
•
Check the oil visually with respect to color, turbidity and deposits in a test bottle. The oil
should be clear or negligibly turbid. The turbidity may not be caused by water
•
The water content must not exceed 0.2%
•
The original viscosity must be maintained within a tolerance of ±15%
•
The oil should be free from debris, and its cleanliness according to ISO 4406 class 18/15,
or NAS 1638 class 9
•
The quantity of metal impurities should be less than 100 PPM. An increasing trend of the
value means that the bearing is wearing
•
The total acid number (TAN) should not exceed 1 mg KOH per gram of oil. Please note
that the TAN value is not the same as the TBN (total base number) value
•
Smell the oil. Strong acid or burnt smell is not acceptable.
An oil check should be performed a few days after the first test run of the machine, just before
the first oil change, and subsequently as required. If the oil is changed just after the
commissioning, it can be used again after removing wear particles by filtering or centrifuging.
In doubtful cases, an oil sample may be sent to the laboratory to determine viscosity, acid
number, foaming tendency, etc.
7.5.2.4 Oil qualities
The bearings are designed for one of the oil qualities listed below.
The oils listed below include the following additives:
•
Oxidation and rust inhibitor
•
Anti-foaming agent
•
Anti-wear additive.
NOTE: Verify the correct oil quality from the bearing plate and the dimension drawing.