ARMY TM 9-6115-643-24
AIR FORCE TO 35C2-3-445-22
1.12.1.5
Electrical protection devices will cause two events to occur. The AC circuit interrupter relay will open, and a
fault indicator lamp will illuminate to indicate which fault occurred.
1.12.1.5.1
Short Circuit Relay. This device will activate when the set output current in any phase exceeds 425 percent
of the rated value.
1.12.1.5.2
Overload Relay. This device will operate when the load current in any phase exceeds 110 percent of rated
value.
1.12.1.5.3
Undervoltage Relay. This device will activate instantaneously when the 120 volt generator coil winding has
dropped to 48 volts and will trip after time delay when the coil voltage drops below 99 volts.
1.12.1.5.4
Reverse Power Relay. This device will operate if power flow into the generator set exceeds 20 percent of
rated value.
1.12.1.6
Although it is possible for more than one fault to occur at one time during operation, only the first fault to occur
will be displayed by the malfunction indicator. The activated indicator lamp circuit remains illuminated until the malfunction
indicator is reset. The lamp will be off with the MASTER SWITCH in the OFF position and will be reilluminated when the
MASTER SWITCH is turned to one of the RUN positions. Resetting a fault indication is done in two steps. First push the
PUSH TEST & RESET LAMPS switch located on the malfunction indicator. Then move the MASTER SWITCH to the OFF
position. After a shutdown due to engine overspeed, the OVERSPEED RESET switch must be actuated to reset the en-
gine electrical control circuit before the engine can be restarted.
1.12.1.7
After the generator set engine has been started, the BATTLE SHORT switch can be used to override all of
the potential faults except engine overspeed and short circuit.
1.12.2 Fuel System.
1.12.2.1
The Fuel System (FIGURE 1-3) includes a primary subsystem and an auxiliary subsystem.
1.12.2.2
The primary subsystem consists of fuel lines, fittings, fuel tank, low fuel level float switch, fuel float switch
module, fuel level sender, FUEL LEVEL indicator, transfer pump, fuel filter/water separator, injection pump, and injectors.
1.12.2.3
The injection pump output is controlled by the electronic governor control and governor actuator. When the
electronic governor control is deenergized, electrical power is removed from the governor actuator which is spring loaded
to the fuel shutoff position. The electronic governor control is energized by turning the MASTER SWITCH to the START
position or either of the two RUN positions. With the engine cranking or running, fuel is drawn from the fuel tank by the
transfer pump, After reaching the transfer pump, fuel passes through a fuel filter/water separator where water and small
impurities are removed. The fuel then goes to the injection pump. With the governor system energized, the fuel is metered,
pressurized, and pushed through the injectors by the injection pump. Fuel is sprayed by the injectors into the diesel engine
combustion chambers where it is mixed with air and ignited. The fuel that is not used by the injectors is returned to the
fuel tank by an excess fuel return line. power is removed from the electronic governor control, and the fuel is shut off when-
ever the MASTER SWITCH is turned to the OFF position. The electronic governor control is also deenergized by the Fault
System (refer to Paragraph 1.12.1 .3). The FUEL LEVEL indicator displays the fuel level of the fuel tank from E (empty)
to F (full) in quarter tank increments.
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