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TM 10-4320-343-14
1.14.2.3.2. Electrical System with Regulator Model ADC 1500. The electrical system with regulator (figure 1-4)
*functions as described in paragraph 1.14.2.3.1, except that regulator circuits are connected to the system and controls
engine starting. When the engine is to be started, a control switch on the CONTROL BOX is set to START. This applies
12 V dc from S2 to regulator pin B. Since Control Box switch is set to the START position, pin B is connected to pin A.
This applies 12 Vdc to K3 through closed contacts of K1. This allows the engine to start. After the engine has started, the
engine speed is controlled by the regulator.
1.14.2.3.3. Electrical System with Regulator Model 350 PAFN. The major electrical difference between the two
regulated models is that Model 350 PAFN does not use a shutdown solenoid. Major differences between Model 350
PAFN and other models is that Model 350 PAFN uses an electromechanical cold start system (other models use a strictly
mechanical system) and Model 350 PAFN uses four panel lights controlled by a rheostat. Other models have one light
that can only be shut off when the unit is shut down. In the following discussion of the start, stop, charging, lighting and
indicator circuits all references apply to Figure 1-4.1.
1.14.2.3.3.1.
Start Circuits.
a.
When the emergency start switch, S1 is energized (pulled out), power is transferred through its contacts (1 and 4)
and applied to the upper contact of the start switch, S2, and to contact 1 of the oil pressure bypass switch, S3 through the
closed contacts (4 and 2) of the V-belt switch,S4.
b.
When the operator turns the mode switch in the pressure control unit to START, presses both the start switch, S2
and the oil pressure bypass switch, S3 (normal start sequence), power is applied through S2 to contact 6 of K1 where it
stops; and to the coil of relay K2 through the closed contacts (1 and 2) of the oil pressure bypass switch, S3. This causes
relay K2 to become energized, its contacts (4 and 6), and (3 and 5) close and power is applied to the pressure control
module on the red and blue wires.
c.
This causes the pressure control module to provide a voltage to the control box of the actuator, and the actuator
retracts enough to position the actuator arm of the fuel shutofff valve to the idle position. It also delivers 12 Vdc to the coil
of relay K1 on the yellow wire.
d.
With power applied to the coil of relay K1, K1 becomes energized and its normally open contacts (6 and 8) close,
allowing for transfer of voltage to the coil of starter relay K3, and energizing that relay which, in turn, results in the closing
the contacts of the starter relay.
e.
This brings power to the starter motor, B1 through the contacts of relay K3, and to the cold start solenoid L1
through the cold start switch S6 if the ambient temperature is below 40 degrees F. With power available at the starter, the
starter cranks the engine and, if S6 is closed, the cold start solenoid L1 opens to allow the flow of starting fluid into the
intake manifold of the engine.
f.
When the engine has started and S3 is released (oil pressure bypass switch, S3 is not released until after
pressure is above 4 psi), power is interrupted to B1 to stop the starter, and to the cold start solenoid L1 to stop the flow of
starting fluid.
g.
When oil pressure is above 4 psi and S3 is released, an alternate path through the oil pressure switch,S5 is
provided to keep K2 energized and the engine running.
1.14.2.3.3.2. Stop Circuits. The engine is stopped by pushing in the emergency stop switch (S1). When this is done the
following events occur:
a.
Power, which is delivered to the coil of K2 through S1, S4, S5 and contacts (1 and 3) of K1 while the engine is
operating, is interrupted and K2 becomes de-energized.
b.
Because K2 is de-energized, delivery of power to the pressure control model is interrupted at contacts (6 and 4)
and (5 and 3) of K2.
c.
Because there is no power in the pressure control box, power is also lost to the control box of the actuator. And
because the control lever on the shutdown control valve of the engine is spring loaded to the off position, the valve closes,
stops fuel from reaching the engine and the engine stops.
c.
K2 will become de-energized and the engine will be stopped in the same manner if either S4 or S5 opens. S4 will
open if the V-belt breaks and S5 will open if engine oil pressure goes below 4 psi.
Change 1 1-14.1
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