1-16. EQUIPMENT OPERATION (continued).
The APU and personnel heater receive fuel through the fuel inlet tee connection from the fuel distribution terminal. APU
pumps become operational when the MASTER switch located on the APU control panel is turned to ON. Fuel is routed
through the APU compartment wall-mounted filters to the APU. Excess fuel is routed through the fuel-return line to
the fuel tanks.
The personnel heater fuel pump becomes operational when the personnel heater MASTER switch is turned to ON.
Fuel is routed to the personnel heater filter and onto the personnel heater.
ELECTRICAL SUPPLY SYSTEMS AND COMPONENTS
Four 12-volt batteries, connected in series and parallel, deliver 24 Vdc to the master relay. The MASTER switch, when
turned to ON, draws 24 Vdc from the batteries and allows operation of vehicle electrical systems without the main
engine running. The engine-driven alternator supplies 24 Vdc to the rectifier when the engine is operating. The rectifier
converts the alternating current output to direct current voltage, which is supplied to the voltage regulator.
The voltage regulator controls the supply of 24 Vdc to vehicle electrical systems through the master relay. It also acts
as a charger for the batteries when the engine is operating, keeping the batteries fully charged. The APU electrical
generator supplies 24 Vdc through the APU voltage regulator to operate vehicle electrical systems and to recharge
batteries when the main engine is not in operation.