ARMY TM 9-6115-643-10
AIR FORCE TO 35C2-3-445-21
SECTION Ill. TECHNICAL PRINCIPLES OF OPERATION
1-10 INTRODUCTION.
1-11 ENGINE STARTING SYSTEM.
The Engine Starting System (FIGURE 1-3), consists
This section contains functional descriptions of the
of two 12-volt batteries connected in series, a starter,
generator set and explains how the controls and
indicators interact with the system.
a 24 volt battery charging alternator, a magnetic
pickup (for sensing engine speed) and the related
switches and relays required for control of the starting
system. For engine cranking, battery power is
supplied to the starter motor through the starter
solenoid which in turn is controlled by the cranking
relay. The starter then engages the engine flywheel
causing the engine to turn over. For engine starting,
the DEAD CRANK switch must be in the NORMAL
position, the DC Control power circuit breaker must be
pushed in, the Emergency Stop Switch must be in the
Out position and the MASTER SWITCH is moved to
the START position. The cranking relay is then
controlled by a circuit consisting of the start relay and
crank disconnect switch. As the engine accelerates
to the preset speed (sensed by the magnetic pickup),
the crank disconnect switch opens and deenergizes
the cranking relay to stop and disengage the starter.
The starting sequence may also be stopped by
moving the MASTER SWITCH to OFF. The engine
may be cranked without starting by use of the DEAD
CRANK switch. With the DEAD CRANK switch in the
CRANK position, the cranking relay, starter solenoid
and starter motor are energized without activating any
other starting or control function.
Figure 1-3. Engine Starting System
