|
| |
TM 10-4320-343-14
1.14.2 Unit Maintenance Functional Description.
1.14.2.1 Exhaust System.
The exhaust system consists of the muffler, exhaust tubing,
and spark arrester.
The muffler is connected directly to the engine and provides a
noise reduction.
Exhaust tubing provides an enclosed path for the released gases
from the muffler to the spark arrester.
The spark arrester prevents sparks from
entering the atmosphere and rain from entering the exhaust.
1.14.2.2 Air Cleaner.
The air cleaner provides filtered air to the combustion
chambers of the engine.
It consists of two filters that filter the air before it
reaches the intake-manifold of the engine.
1.14.2.3 Electrical System.
There are two types of electrical systems used with the
350 GPM Pumping Assembly.
One type has no electrical feedback from the pump and
the other type-uses a regulator on the output of the pump.
The regulator provides
electrical feedback to control the speed of the engine.
Both types are explained
in the following paragraphs.
1.14.2.3.1 Electrical System Without Regulator.
The electrical system (figure 1-3)
provides electrical control signals and 12 V dc.
TWO 12 volt batteries are
connected in parallel.
The batteries supply the initial starting power.
The
electrical wiring harness connects the electrical components of the control panel
and engine.
When EMERGENCY-STOP (OFF-ON) switch (S1) is pulled out, S1 contacts
connect ammeter (M1), START switch (S2) and switch (S4) to positive side of
battery.
When cooling fan blower belt is installed on engine, S4 contacts 4 and 2
are closed connecting OIL PRESSURE BYPASS switch (S3) to positive side of battery.
When S3 is pressed, relay (K2) is energized and normally open contacts of K2 are
closed.
Since the contacts of K2 are closed, 12 V dc is applied to fuel shutoff
solenoid (L1).
L1 then connects ground to K1 via auxiliary tap (AUX) and K1
energizes.
Mechanical linkage is connected from L1 to the cut-off lever that
controls fuel flow into engine.
Since L1 retracted, fuel can be injected into
engine and K1 is energized.
When K1 is energized, normally open contacts 6 and 8
are closed.
Since S2 is pressed, 12 V dc is applied to starter relay (K3). K3
energizes and provides 12 V dc to starter (B1) .
This causes drive gear of B1 to
engage with engine flywheel and causes B1 to rotate.
Rotation of B1 cranks engine
until S2 is released.
After starting, S2 is released and 12 V dc is removed from
K3.
Since no voltage is applied to K3, 12 V dc is removed from B1.
When B1 has no
voltage, drive gear of B1 is disengaged from engine and B1 no longer rotates.
When
oil pressure reaches 4 psi (27.579 kPa), oil pressure switch (S5) closes and S3 is
now released.
The 12 V dc is still applied to K2 via closed contacts 1 and 3 of K1
which keeps L1 retracted.
Alternator (G1) is turned by engine drive pulley and
outputs approximately 14 V.
The 14 V then provides 12 V dc to keep K1 and K2
energized.
In addition, 14 V from G1 recharges 12 V dc batteries.
Since the engine can be damaged by overheating, V-belt switch (S4) is provided. If
the V-belt that turns the cooling fan breaks, S4 opens.
When S4 is open, 12 V dc
is removed from K1 and K2.
This causes L1 to extend (fuel closed) and shuts off
fuel flow to engine.
Since no fuel is provided to engine, 350 GPM pumping assembly
is stopped.
Since oil provides both lubrication and cooling to the engine, an oil pressure
switch (S5) is provided.
If engine oil pressure drops below 4 psi (27.579 kPa), S5
opens.
When S5 is open, 12 V dc for K1 and K2 is removed.
This causes L1 to
extend (fuel closed) and shuts off fuel flow to engine.
Since no fuel is provided
to engine the 350 GPM pumping assembly stops.
When operation is no longer required, S1 is pushed in and 12 V dc is removed from
K1 and K2.
This causes L1 to extend (fuel closed) and shuts off fuel flow to the
engine.
Since no fuel is provided to the engine, 350 GPM pumping assembly stops.
When an emergency occurs, S1, the emergency stop switch, provides rapid engine shut
down.
Pull position is normal operation, push position is shutdown.
1-13
|
