Maintenance; Inspection And Maintenance Intervals; Maintenance Of Bearings; Dismantling Operations - MarelliMotori M8B 315 Instructions And Safety Information

Before first starting up, check:
- If fixing bolts are securely fixed
- that the alignment and coupling is correct
- that the ventilation air is sufficient
- that the protection grids are in place
- for single bearing generators, that the bolts of the disks are fixed with the correct torque.
Electrical checks
Verify that
- the plant is provided with the correct electrical protection devices, according to applicable standards
- that the connection to the terminal block is correctly performed (bolts of terminals properly tightened).

4. MAINTENANCE

For safety purposes it is necessary that any testing or maintenance carried out on electrical machine are performed by
qualified and authorised personnel, and all operation must be performed when the machine is stopped, at ambient temperature and
disconnected from any supply source (including the auxiliary circuits such as the anti-condensation heaters). Furthermore all
measures must be taken to avoid restarting of gen-set during maintenance.

4.1 Inspection and maintenance intervals

Inspection and maintenance should take into account the importance of the plant ambient conditions (dust etc.) and operating
conditions.
As a general rule, the machine should be subjected to a first inspection after approx. 500 operating hours (in any case not more than 1
year) and subsequent inspections when performing maintenance on prime mover.
When performing inspection check that:
- The generator operates smoothly, without noise or irregular vibrations due to bearing deterioration
- The operating data complies with that detailed on the rating plate
- The air inlet openings are not obstructed
- The supply cables show no signs of deterioration and connections are firmly tight
- The electrical connections are in perfect condition (undamaged)
- Screws and nuts are firmly tightened.

4.2. Maintenance of bearings

For M8B 315 and M8B 400 generators:
the D.End bearing is of regreasing type. The regreasing devices are according to UNI 7662.
Lubrication interval is 4.000 hours with 50 grams of grease.
The N.D.End bearing is prelubricated; the first filling of grease is sufficient for 10.000 hours of operation in normal conditions.
For M8B 500 generators both bearings are of regreasing type. The regreasing devices are according to UNI 7662.
Lubrication interval is 4.000 hours with 50 grams of grease.
We recommend the following types of grease:
MOBIL OIL - MOBILUX 3 / SHELL - ALVANIA 3 / AGIP - GR MU 3 / ESSO BEACON 3
Mixing of different greases (thickeners, basic oil) reduce the quality of grease and therefore has to be avoided.
An excessive lubrication or wrong quantity of grease may cause overheating of bearings.
In occasion of complete overhaul of the gen-set, remove the used grease and wash the bearings with solvent before regreasing.
In case of complete overhaul of gen-set, the bearing of the generator should be changed.

4.3. Dismantling operations

Before dismantling the machine, examine the views in cross-section.
Check that the lifting means available are suitable for the movement of all parts which have to be handled.
Check also that all the working conditions are suitable to operate without dangers for safety of personnel.
Then uncouple the generator from the prime mover, removing the bolts securing the flange and feet; remove the bolts fixing the
coupling and disconnect the terminals of the power leads on the terminal board.
Next, remove the generator from the prime mover.
Disconnect the leads red (+) and blue (-) connecting the exciter stator to the voltage regulator.
Remove the guard protecting the generator (45).
For M8B 315 and M8B 400 generators:
For two bearing generators:
- remove the half coupling from shaft extension and remove the key (223)
- remove the bolts fixing the shields (4-5) to the frame, then remove the shields having care to sustain the rotor in order it will not
fall heavily on the stator
- using proper lifting means, remove the rotor (3) from the main stator, through the D.E. side, taking special care to avoid any
damage to the windings.
For single bearing generators:
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