WÄRTSILÄ PAAE051728, Инструкция по эксплуатации

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22.5 Electro-pneumatic overspeed trip device
22.5.1 Description (Fig 22-2)
The overspeed trip device is electronically controlled. Air of max.
30 bar is used as operating medium. The tripping speed is 15 %
above the nominal speed.
The three-way solenoid valve (44), Fig 21-4, gets the stop signal
for overspeed from the engine automation system.
When the solenoid valve opens, air is fed to the three-way valve,
which conveys pressure air to the cylinders (42, Fig 21-4), one for
each injection pump. The piston of the air cylinder actuates on
the fuel rack moving it to stop position.
The stop signal is energized long enough to stop the engine
completely. When de-energized, the air is evacuated through the
three-way valve.
The solenoid valve (44) can also be operated manually.
22.5.2 Check and adjustment of stop position
a) Check of stop position
·
Set the stop lever in the work position and the terminal shaft
lever in the max. fuel position.
·
Press the STOP-button on the engine. (Stop sequence is
activated approximately 1 min.) Note! The starting air
supply should be open.
·
Check that the fuel rack positions is less than 5 mm.
b) Adjustment of stop position
·
The electro-pneumatic overspeed trip device requires no adjust-
ment.
·
If a fuel rack position of less than 5 mm cannot be obtained,
check for wear.
22.5.3 Check of tripping speed
The tripping speed can be checked in two different methods,
simulating the engine speed signal by using a signal generator or
by running the engine and increasing the engine speed. The
recommended method is to use a signal generator, see chapter
23., section 23.3.
Increasing engine speed
Check the tripping speed at idle by increasing the engine speed
above the nominal speed by slowly bending the lever (12) with a
suitable wrench in direction from the engine. When the nominal
speed is reached and exceeded, the governor begins to decrease
the fuel setting, i.e. the control shaft must be bended against the
governor force.
32-200636-01 Control Mechanism 22
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