ARMY TM 9-6115-641-24
AIR FORCE TO 35C2-3-456-12
1-12-7-4. The GND (ground terminal) is connected to the generator set skid base. This terminal is also connected to
the ground rod for all generator set operation. The removable link provides a removable, low inductance connection be-
tween LO and GND terminals. This removable link must be in place for all generator set operation except when the load
instructions specifically require its removal.
1-12-8. Generator Set Control%
1-12-8-1. Engine Starting System.
1-12-8-1-1. Engine starting (Figure 1-9) is accomplished primarily with two 12-volt batteries, connected in series to
provide 24 VDC power, and a starter. The starter includes a cranking motor and solenoid. To permit engine starting, the
DC CONTROL POWER circuit breaker must be pushed in, the DEAD CRANK switch must be in the NORMAL position
and the BATTLE SHORT switch must be in the OFF position. In addition, any ENGINE SHUTDOWN fault previously regis-
tered on the malfunction indicator panel must have been corrected, and the malfunction indicator panel must have been
reset. When the MASTER SWlTCH is then placed in the START position, the starting circuits supply 24 VDC power to
the starter. As the engine accelerates to approximately 900 rpm, the starting circuits disconnect power from the starter
and energize the field flash relay. After the needle of the AC voltmeter (VOLTS AC) reaches rated voltage, indicating that
the generator is producing power, the MASTER SWITCH can be moved to one of the two RUN positions for generator
operation.
1-12-8-1-2. When the MASTER SWITCH is first moved to the START position, the various instrument and control cir-
cuits including two starting control circuits are energized. One starting control circuit supplies 24 VDC power directly to
the control function of the crankdisconnect switch and also energizes the coil of the crank disconnect relay through closed
contacts of BATTLE SHORT switch and crank disconnect switch. The other starting control circuit directly energizes the
coil of the field flash relay and also energizes the cranking relay coil through closed contacts of the engine fault relay and
crank disconnect relay. With the cranking relay energized, power passes from the batteries through closed contacts of
the cranking relay to energize the solenoid and the pulling coil of the fuel solenoid. With the solenoid energized, power
passes from the batteries through closed contacts of the solenoid to the cranking motor. The cranking motor then cranks
the engine. As the engine accelerates to approximately 900 rpm, the magnetic pickup, which senses engine speed,
causes the crank disconnect switch to break the circuit to the coil of the crank disconnect relay and dose the contacts
of the field flash relay. When the MASTER SWITCH is moved to one of the RUN positions, both starting control circuits
are de- energized while the instrument and other control circuits remain energized. The fuel solenoid holding coil remains
energized.
1-12-6-1-3. 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 coil is energized to initiate engine cranking without energizing any other
starting or control function.
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