TM 9-6115-729-24
0003
ENGINE STARTING SYSTEM
The engine starting system (Figure 1) consists of two 12-volt batteries connected in series, a 24 Vdc starter, a 24
Vdc battery charging alternator, a magnetic pickup (for sensing engine speed) and the related switches and relays
required for control of the starting system. The PUSH TO STOP EMERGENCY STOP pushbutton on the EMCP
will automatically disable the starting system and shut down the TQG if it is pushed in. For engine cranking,
battery power is supplied to the starter motor through the starter solenoid that in turn is controlled by the EMCP.
The starter engages the engine flywheel causing the engine to turn over. As the engine accelerates to above idle
speed (sensed by the magnetic pickup), the EMCP disengages the starter. Moving the ENGINE CONTROL
switch to COOL DOWN/STOP may also stop the starting sequence. The engine may be cranked without starting
by engaging the DEAD CRANK SWITCH. The DEAD CRANK SWITCH is a three-position switch. Up position is
CRANK, the center position is OFF, and the lower position is NORMAL (operation). With the DEAD CRANK
SWITCH in CRANK position, the starter motor is energized without activating any other starting or control
function. With the switch in the OFF center position, the system is off. With the switch in NORMAL (operation)
position, the TQG may be cranked and started. The belt-driven engine alternator charges the batteries. The
battery charging alternator also supplies GSC power. Normal operating indication depends on the state of charge
in the batteries. A low charge, such as exists immediately after engine starting, will cause a high reading. Cold
outside temperatures make starting the engine difficult. To improve engine starting in cold weather the engine
contains a 78A intake air preheater. This heater is described in the discussion of the Air Inlet and Exhaust
System. If the batteries are dead or inoperable, external +24 Vdc power can be supplied to the TQG via the 24
Vdc NATO slave receptacle to start the generator set engine.
