ARMY TM 9-6115-643-24
AIR FORCE TO 35C2-3-445-22
The auxiliary subsystem consists of an auxiliary fuel supply, fuel lines, fittings, auxiliary fuel filter, auxiliary
fuel pump, and auxiliary fuel pump float switch located in the fuel tank, and a fuel float switch module.
When the MASTER switch is set on PRIME & RUN AUX FUEL, it actuates the auxiliary fuel pump and trans-
fers fuel from the auxiliary fuel supply to the fuel tank The auxiliary fuel pump float switch shuts off the auxiliary fuel pump
when the fuel tank is full and reactivates the pump as the level drops. The fuel float switch module allows the current used
by the auxiliary fuel pump to bypass the float switch.
The 24 VDC control circuits provide control and power for indicators, float switches, fault system, governor
system, and auxiliary fuel pump.
Generator Set Cooling System.
The Generator Set Cooling System (FIGURE 1 -4) includes air intake and exhaust grilles, baffles and ducting
within the generator set housing and the engine driven radiator cooling fan. The air intake grilles are located in panels on
both sides of the generator set housing. The air exhaust grille is located in the housing top panel.
Air is drawn in through the air intake grilles and forced through the engine coolant radiator and out of the gener-
ator set through the exhaust grille by the radiator cooling fan. Most of the cooling airflows externally past the generator
assembly and engine. Some cooling air is circulated internally through the generator assembly by a generator fan which
is an integral part of the AC generator assembly. Baffles, ducting, and sound absorbing material are used to control the
air flow through the generator set and to reduce sound transmission through the grilles.
1.12.4 Engine Cooling System.
The Engine Cooling System (FIGURE 1-5) consists of a radiator, hoses, thermostat, temperature sender,
coolant high temperature switch, COOLANT TEMP indicator, water pump, a belt driven fan, and cooling jackets (part of
The water pump forces coolant through passages (cooling jackets) in the engine block and cylinder head
where the ooolant absorbs heat from the engine. When the engine reaches normal operating temperature, the thermostat
opens and the heated coolant flows through the upper radiator hose assembly into the radiator. The cooling fan circulates
air through the radiator where the coolant temperature is reduced.
A coolant high temperature switch in conjunction with the fault system provides automatic shutdown in the
event that coolant temperature exceeds 220 ± 3.5°F(104 ± 2°C). The COOLANT TEMP indicator indicates the engine
coolant temperature, from 120°F to 240°F (48°C to 115°C).
1-14 Change 1