ARMY TM 9-6115-671-14
AIR FORCE TO 35C2-3-446-32
MARINE CORPS TM 09249A/09246A-14A
1-32
1.16.12.8
Bearing. The generator rotor assembly is suspended on shielded, factory lubricated ball bearings.
They are greased for life and do not require lubrication.
1.16.12.9
Stator Assembly. The stator assembly consists of laminations of steel mounted in a rolled steel frame.
Random wound stator coils are fitted into the insulated slots.
1.16.13
Generator Set Controls.
1.16.13.1
Engine Starting System.
1.16.13.1.1 Engine starting is accomplished primarily with two 12 volt batteries, connected in series to provide 24
VDC power, and a starter (Figure 1-29). The starter includes a cranking motor and a 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 registered on the CIM display
screen must have been corrected by activating the FAULT RESET switch.
When the ENGINE CONTROL switch 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 DCS
speed control unit disconnects power from the starter.
1.16.13.1.2 When the ENGINE CONTROL switch is first moved to the START position, the control modules are
energized. The Engine Starting System includes three control circuits. One starting control circuit
energizes the K2 relay through closed switch contacts of the crank disconnect relay. The second
starting control circuit signals the I/O interface module. With the K2 relay energized, power passes
from the batteries through closed contacts of the K2 relay to energize the starter solenoid. With the
starter solenoid energized, power passes from the starter solenoid to the cranking motor. The cranking
motor then cranks the engine. Engine speed is sensed by the magnetic pickup which sends a signal to
the DCS speed control unit. As the engine accelerates to approximately 900 RPM, the signal from the
magnetic pickup causes the crank disconnect switch to open the crank disconnect relay. The open
contacts break the circuit to the cranking relay and stop engine cranking. The third control circuit
causes the field flash relay to be energized. When the ENGINE CONTROL switch is moved to one of
the two RUN positions, all starting control circuits are de-energized. The other generator set control
and instrument circuits remain energized.
1.16.13.1.3 The engine may be cranked without starting by use of the DEAD CRANK switch. With the DEAD
CRANK switch in the CRANK position, the K2 relay coil is energized to initiate engine cranking
without energizing any other starting or control functions.
1.16.13.1.4 The generator set can be started without batteries by connecting an external 24 VDC power source to
the NATO/SLAVE RECEPTACLE. The generator set can also supply power to another set through
the NATO/SLAVE RECEPTACLE.
1.16.13.1.5 The batteries are charged by the battery charging alternator which is belt driven by the engine. The
CIM display screen BATTERY CHARGE ammeter indicates the charge/discharge rate of the batteries,
from -60 amps to +60 amps. A sensor provides a DC voltage signal, which is directly proportional to
the actual battery current flow, to the BATTERY CHARGE ammeter. Normal operating indication on
the BATTERY CHARGE ammeter depends on the state of the charge in the batteries. A low charge,
which may exist immediately after engine starting, will cause a high reading (indication toward
CHARGE area). When the charge in the batteries has been restored, the indicator moves near zero.
The battery charging system is protected from reverse polarity in the battery connections by a diode.
