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2. Glow Plug Indicator
This coil is used as a visual aid to assist the operator in
determining when the glow plugs are fully energized.
While holding the glow plug switch in the UP (preheat)
position peer through the small holes on the face of the
indicator. When the coil inside illuminates to a bright
orange this indicates that the combustion chamber is at
the pre-heat stage for ignition.
c. Switches
1. Glow Plug Switch
The glow plug switch (momentary contact type), when
held in the UP position (pre-heat), permits battery
current (approximately 10 amps per plug at 12 vdc) to
flow to the glow plugs in the engine to pre-heat the
combustion chambers. The glow plugs are located under
the fuel injectors. When starting engine, it is necessary to
continue to hold the glow plug switch in the UP position
until the engine has developed sufficient oil pressure to
close the oil pressure safety switch.
2. Ignition Switch
The ignition switch (momentary contact type in the
start position), when held in the START (ignition)
position energizes the starter motor solenoid which in
turn allows the starter motor to crank.
3. Voltage Selector Switch (Optional)
This switch is used to select either 230 or 460 vac
output. When making a selection the unit must be OFF.
1.8.3 Protective Devices
a. Circuit Breakers
1. A-C Generator Circuit Breaker (CB-1)
This device is located on the control box panel. It
protects the A-C generator (main alternator) from
excessive current (amperage) draw. When the circuit
breaker trips, the generator power output to the
refrigeration unit ceases. The diesel engine will continue
to run (with normal engine operation), but a voltmeter
will indicate no output . The circuit breaker trips at 26
amps (460 vac) and must be manually reset.
2. Circuit Breaker (CB-2)
The circuit breaker is located in the control box. This
device prevents excessive current draw by the
components FS, FH, HR, S, SS and TT. The circuit
breaker opens at 20 amps and will automatically reset.
3. Circuit Breaker (CB-3)
The circuit breaker is located next to CB-2 in the
control box. This device prevents excessive current draw
by the glow plug and fuel pump circuitry. The circuit
breaker opens at 50 amps and will reset automatically.
4. Circuit Breaker (CB-4) (Optional)
This device is located next to CB-1 on the control box
panel. It protects the A-C generator (main alternator)
from excessive current (amperage) draw. When the
circuit breaker trips, the generator power output to the
refrigeration unit ceases. The diesel engine will continue
to run (with normal engine operation), but a voltmeter
will indicate no output . The circuit breaker trips at 48
amps (230 vac) and must be manually reset.
b. Switches
1. Fan Belt Switch (FBS)
This switch is activated by the fan belt breaking and
releasing the spring tension on the idler pully, which in
turn swings around to hit the fan belt switch. When this
happens a set of internal contacts open to de-energize the
fuel solenoid (FS); thus stopping the engine.
2. Low Oil Pressure Switch (LOP)
This switch, set to open below 26 psig (1.83 kg/cm@)
will automatically stop the engine upon loss of oil
pressure. This switch is located behind the oil pressure
gauge (see Figure 1-1). When the switch opens, the fuel
solenoid (FS) de-energizes; thus stopping the engine.
3. Oil Temperature Switch (OTS)
This switch, set to close above 266 _F (130 _C) will
automatically stop the engine when a high oil
temperature is reached. The switch is located at the top of
the engine block oil connection (see Figure 1-4). When
the switch closes, the safety relay (S) coil is energized and
the normally closed (N.C.) safety relay contacts open to
de-energize the fuel solenoid (FS); thus stopping the
engine.
1-7
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