Mase Generators I.S. 12 Manual Uso Y Mantenimento página 32

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6.7 V-belt tension check
A V-belt is used to transmit the rotary motion from the
drive shaft pulley to that of the seawater pump [Fig. 9 Ref.
1].
Excessive belt tension accelerates wear, while a slack
belt makes the pulleys idle and does not allow sufficient
water circulation.
Adjust the belt tension as follows:
Loosen the two adjusting screws [Fig. 9, Ref. 2] and
move the seawater pump outwards to increase the
tension or inwards to decrease it. Lock the screws and
check the tension.
The correct belt tension is such as to allow a yield of
about 5 mm [Fig. 9] under a thrust force of 8 kg.
A second belt is used to transmit the rotary motion from
the drive shaft pulley to that of the closed-circuit coolant
pump and the battery charger DC alternator [Fig. 9 Ref.
3].
Adjust the belt tension as follows:
Loosen the adjusting screw [Fig. 9 Ref. 4] and move the
battery charger DC alternator [Fig. 9, Ref. 5] outwards to
increase the tension and inwards to decrease it.
The correct belt tension is such as to allow a yield of
about 10 mm [Fig. 9] under a thrust force of 8 kg.
To prevent the belt from slipping,
do not dirty it with oil. Clean the belt with petrol if any
oil is spilled.
Keep hands away from the V-belt
or the pulleys when the engine is running.
6.8 Emptying the cooling system
To carry out maintenance on the water/air exchanger or
on the cooling system the seawater must be drained
from the intake circuit. This operation is carried out as
follows:
- Close the sea intake cock [Fig. 6, Ref. 2]
- Open the drain tap [Fig. 6, Ref. 3] until all the water
has run out
- Close the drain tap.
Reopen the seawater intake cock
before starting the generator.
6.9 Coolant replacement
Annually replace the coolant in the closed cooling circuit
as follows:
- Remove the lower door (Fig.10, Ref.2) by unscrewing
the retaining screws (Fig.10, Ref.3).
- Take a rubber hose of about 50 cm long with an inside
GB
diameter of 30-40 mm.
- Insert the hose through the lower slit, position it under
the cap (Fig.10, Ref.1) and connect it to the inside of a
container of about 10 litre capacity.
- Open the cap and completely drain the closed cooling
circuit.
When the operation has been completed, close the cap
and fill the circuit with new coolant.
Dispose of the used coolant in an
appropriate manner as it is a polluting product.
Take the used coolant to special collection centres
responsible for disposal.
6.10 Zinc anode replacement
To protect the water/air heat exchanger [Fig. 11, Ref. 1]
and the water/coolant heat exchanger [Fig. 11, Ref. 2]
against galvanic current, two sacrificial zinc anodes [Fig.
11, Ref. 4] have been inserted inside them. Periodically
check their state of wear and, if necessary, replace them
in order to prevent that the galvanic current irreparably
corrodes the heat exchanger. It is recommended to
check the zinc anodes at least once a month when the
generator is new to check how fast consumption is, to
then be able to act accordingly.
It is, however, opportune to replace the zinc anodes at
least once a year.
Fig. 11 shows the points where the zinc anodes are
positioned.
6.11 Seawater pump maintenance
At least once a year check the integrity of the rubber rotor
of the seawater pump [Fig. 12, Ref. 1].
Before opening the seawater pump to inspect the rotor,
drain the seawater from the cooling system as described
in Paragraph 6.8.
To access the rotor, remove the cover [Fig. 12, Ref. 2]
and with the aid of a pair of pliers extract the rotor pulling
it out with force.
To remount a new rotor, repeat the operations described
above in reverse order.
6.12 Alternator maintenance
The alternator used on this model of generator is type
synchronous, self-energised, with electronic voltage
regulation. This model alternator, without manifold and
brushes, does not require particular maintenance
operations. The periodic checks and maintenance are
limited to removing any traces of damp and oxidation
which might damage it.
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IS 12-14-16-19