MM-13- rev 01-EN
27
If an automatic re-lubrication system is used, the quantities of grease mentioned on the plate should
be doubled.
The maximum permitted temperature for the bearings is 120°C
The maximum operating temperature for grease and for bearings must not be
exceeded.
The following directions are of general nature. It is advisable to look at the assembly drawing
normally belonging to the generator monograph.
Changing the grease
Generator re-greasing can also be performed while the generator is in operation.
CAUTION
Pay particular attention to the rotary moving parts.
To lubricate generators during operation:
Remove the grease drain plug, if available.
Insert new grease into the bearing until the existing grease is completely discharged.
Let the generator run for 1-2 hours to make sure that all excess grease is forced out of the
bearings.
Reinstall the drain plug, if available.
If possible, lubrication can be performed with generator at a standstill.
In this case, only use half of the required grease quantity, then let the generator run for a few minutes
at rated speed.
Stop the generator, add the remaining grease quantity until the old grease is completely replaced.
After 1-2 hours operation, reinstall the grease drain plug.
In case of automatic lubrication remove the grease drain plug permanently.
Cleaning the bearings
The rolling bearing lubrication method tends to release the used grease from the collection chamber
and therefore the grease does not require frequent total replacement.
However, every time the generator is disassembled for general cleaning, it is advisable to wash the
bearings with a solvent. (e.g. petrol).
Disassembly of the bearings
Bearings are one of the most important points for the correct operation of an electric machine. The
bearings installed in the generator are of the best quality available on the market and are carefully
fitted and with accurate machinings. However, sometimes it is necessary to remove them for
maintenance or to replace them.
An extractor must be used to remove the bearings, after having disassembled covers and shields.
If the same bearings are to be re-used, proceed carefully to prevent damages on the ball or roller
tracks.
If the generator must be disassembled, it is advised to replace the bearings as it is often very difficult
to evaluate the state of the disassembled bearings and therefore it is not generally worth re-mounting
the same bearings and risk having to disassemble the generator for the replacement of damaged
bearings.
Mounting the bearings
Before mounting a bearing it is necessary to clean it carefully with a suitable solvent (e.g. petrol).
