TM 9-6115-729-24
0003
DC POWER DISTRIBUTION (FIGURE FO-1, SHEETS 2 AND 3) - Continued
Batteries
Batteries BT1 and BT2 are 12 Vdc batteries connected in series to supply 24 Vdc for this system. The DC power
distribution system operates on 24 Vdc. The Slave Receptacle (SR) is the NATO connector on the generator set.
This is useful for charging the batteries and jumping the generator set with another if the batteries become
discharged. The Battery Disconnect Switch disconnects the batteries from everything except the slave
receptacle. Battery power goes directly to the starter solenoid (Labeled PS (pinion solenoid) on the schematic)
for use when cranking or starting the engine. The batteries are connected to the alternator through shunt R4 and
circuit breaker CB-5. R4 generates a voltage for the ammeter, which displays the amperage from the alternator
when charging the batteries. Battery power is connected to ECM A8 through circuit breaker CB-4 and relay
contacts of slave relay (SRY). SRY is energized any time power is applied to the GSC. Battery power goes
through D1 to the common of the DEAD CRANK SWITCH. In OFF, battery power is removed from the GSC,
DVR, ECM, and Winterization Kit (if supplied). In NORMAL, battery power is applied to the relay module of the
GSC through circuit breaker CB1. Power is distributed to the other equipment by the ECS. In CRANK, +24 Vdc
is applied to the Starter Motor Magnetic Switch (SMMS) relay coil. SMMS connects battery voltage to the starter
solenoid through circuit breaker CB-2, causing the engine to crank. Since power is not supplied to the
electronics, the engine will not start.
Emergency Stop Push Button
The Emergency Stop Push Button (ESPB) (PUSH TO STOP EMERGENCY STOP on EMCP) is there to stop the
generator set in an emergency. When pushed, contacts 3 and 4 ground P7-38, tell the GSC that the switch is
pressed. Contacts 1A and 2A remove the ground from the output to the engine controller, which enables the
engine to run. This will stop the engine. Contacts 1 and 2 open the circuit between the GSC and relay SMMS so
that the GSC will not be able to attempt to crank the engine.
