TM 9-6115-729-24
0003
DC POWER DISTRIBUTION (FIGURE FO-1, SHEETS 2 AND 3) - Continued
BATTLE SHORT Switch (BSS) Input to ECM
One set of contacts on the BSS is connected to the ECM. This is to notify the ECM when the system is in the
Battle Short Mode. In this mode, shutdown conditions are locked out except for Short Circuit Over Speed.
Auxiliary Fuel Pump Circuit
The AUX FUEL switch on the control panel is labeled AFPS (Auxiliary Fuel Pump Switch) on the schematic. The
ON position is when terminal 1 and 2 are connected together. The OFF position is when terminals 2 and 3 are
connected together. When the AUX FUEL switch is ON, fuel level sensors FL2A and FL2B in the fuel tank control
the Auxiliary Fuel Pump Relay (AFPR). When the fuel level in the tank gets low, FL2A and FL2B will be closed,
applying power to relay AFPR. One set of contacts on AFPR latch, keeping AFPR energized. Another set of
contacts on AFPR apply 24 Vdc to the auxiliary fuel pump. The auxiliary fuel pump will transfer fuel from an
external tank to fill the internal tank in the generator set. As the fuel level raises in the tank, FL2B will open. The
pump will continue transferring fuel since a set of contacts on AFPR latches the relay to the ON condition. When
the fuel level gets to FL2A, those contacts will open. AFPR will drop out and the transfer pump will stop.
SYNC MODE Switch (SMS)
The SYNC MODE switch has three sections and four positions for the four sync modes: OFF, SEMI-AUTO,
AUTO, and PERMISSIVE. OFF is used when not paralleling generator sets, the other modes are for paralleling.
The first section controls the AUTO SYNC input to the GSC. The AUTO SYNC input to the GSC is grounded in
AUTO and PERMISSIVE modes. When grounded, this input enables the automatic synchronization of Generator
G1 with the load bus. The second section controls the SYNC CHECK input to the GSC. The SYNC CHECK
input to the GSC is grounded in SEMI-AUTO and PERMISSIVE. When grounded, this input enables the
synchroscope function on the GSC. The third section is integrated with the opening and closing of the load
contactor K1 and is discussed more fully with K1 operation. Note that SEMI-AUTO and PERMISSIVE are wired
together.
Load Contactor K1, K1 Relay (KR), and Contactor Control Switch (CCS) aka AC CIRCUIT INTERRUPTER
Switch
Load contactor K1 is controlled by K1 Relay (KR), GSC Run Relay (RR) A1 K5, and GSC Programmable Spare
Relay (PSR) A1 K8. GSC PSR (A1 K8) is programmed to close whenever there are no alarm conditions sensed
by the GSC. When the ENGINE CONTROL switch (ECS) is placed in START (or in AUTO and a remote start
command is received), the GSC closes RR (A1 K5). The fuse labeled F7GSC is actually A1 F6. Note that the
GSC checks to be sure there are no faults present prior to closing RR and verifies that all previous faults have
been reset, otherwise RR will not be closed. As long as no faults are detected, PSR will also be closed. The cool
down relay (CDR) is normally closed and opens at the start of Cool-down Mode. Under these conditions, +24 Vdc
is connected to relay KR. The SC contacts will be closed unless the OL/SC module detects a short circuit
condition. These contacts are reset to closed by turning the ENGINE CONTROL switch to OFF/RESET or
pushing the LAMP TEST button on Alarm Module A2. The battle short switch shorts across the next two contacts
to disable them in Battle Short Mode. The Generator Fault Relay contacts are normally closed and open when
the GSC detects a generator fault condition. The OL contacts will be closed unless the OL/SC module detects an
overload condition. These contacts are reset to closed by turning the engine control switch to OFF or pushing the
LAMP TEST button on Alarm Module A2.
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