ARMY TM 9-6115-645-10
AIR FORCE TO 35C2-3-444-11
MARINE CORPS TM 09244A/09M5A-10/l
1-10
SECTION III. TECHNICAL
INTRODUCTION.
This section contains func-
tional descriptions of the generator set and explains
how the controls and indicators interact with the sys-
tem.
PRINCIPLES OF OPERATION
1-11 ENGINE STARTING SYSTEM.
The Engine Starting System (Figure 1-3), consists of two
12-volt batteries connected in series, a starter, 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 tie starter motor through the
starter solenoid which in turn is controlled by the cranking
relay. The starter then engages the engine flywheel caus-
ing the engine to turnover. 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 posi-
tion, 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
1-12 Change 1
