Service manual

2. Overhauling
2-13
2.3.6 Changing the bearings in the generator main unit
 Use guide bolts to avoid the danger of dropping the bearing shield and to prevent the
rotor and stator from rubbing against each other. (Use the guide bolts used to mount
the generator main unit.)
 Do not hit the bearing outer race when installing or the bearing may be damaged.
The generator main unit is quipped with fully sealed bearing. It is not necessary to supply
grease. But the machine life (4 years or 15,000 ~ 20,000 hours of operation) may change,
depending upon the conditions such as vibration, ambient temperature and humidity. So always
make sure to check for any abnormal noise of the bearings and also to check for any abnormal
rise of temperature. Should it become necessary to replace the bearings, follow the under
mentioned procedures.
Replacement of bearings
1. Remove bearing shield (end cover).
2. Pull out the bearing from the shaft, using bearing removing tools (gear puller).
3. Clean the surface of the shaft and check for any damages.
4. Prepare a new bearing, and check it by turning it by hand before installing it.
5. Heat the bearing in the oil bath at average 100 to 118℃ (Never heat it over 120℃ or
partially.) and then install the bearing using a bearing installer (Heated bearing can be
installed to the shaft.)
6. Set guide bolts to the generator main unit frame.
7. Push in the bearing shield (end cover), hitting it with a plastic hammer evenly.
SG06061 SG06062