TM 9-6115-730-24
0003
DC POWER DISTRIBUTION (FIGURE FO-1, SHEETS 2 AND 3) - Continued
Engine Control Switch (ECS)
The ECS consists of two sections. One section consists of pins 1, 2, 3, 4, and 5; the other section consists of pins
6, 7, 8, 9 and 10 of the switch. There is a legend on the schematic that describes which contacts are closed in
which positions of the switch. Pins 6 thru 10 apply power to the GSC, Overload and Short Circuit (OL/SC) module,
and DVR whenever the switch is not in OFF. This allows the OFF position of this switch to reset any alarms that
have occurred. Shorting pins RM 1 and RM 2 on the GSC does this. Note the internal relay connections in the
GSC between pins RM 1 and RM 2. This is to ensure that power can not be removed from the GSC when the
Fuel Control Relay (FCR) A1 K7 is energized (signifying the engine is running) or the Crank Termination Relay
(CTR) A1 K3 is active (signifying that the engine is running and the starter can be released). Pins 1 thru 5 ground a
different input line to the GSC for each position of the switch, telling the GSC what to do.
Power to ECM, DVR, OL/SC, Fuel Gauge, Panel Lights, Winterization Kit
Fuse F10 shown between RM 1 and RM 10 is A1 F10 on the back of the GSC. This connects +24 Vdc to pin RM
39 whenever the ENGINE CONTROL switch is in any position other than OFF. Slave Relay (SRY) is connected to
RM 39 and is powered up any time the ECS is not in OFF. The contacts of SRY apply +24 Vdc from the battery to
ECM A8. Power to DVR A3 module also comes from RM 39. Power to the OL/SC module comes from RM 1
through a set of normally closed contacts on relay AR. AR is energized when the LAMP TEST button is pressed
on Alarm Module A2. The fuel gauge (FLG) is connected to RM 39 for power. The signal comes from the fuel
sending unit (FLSU) in the fuel tank. The panel lights get their power from RM2, which has power whenever the
DEAD CRANK SWITCH is set to NORMAL. Closing the PANEL LIGHT switch (PLS) applies power to the lights.
Power to the optional winterization system is applied whenever the DEAD CRANK SWITCH is set to NORMAL. If
the winterization kit is turned on at its control panel, +24 Vdc is output to TB5-15. This applies power to the two
resistor heaters used to keep the LCD displays in the GSC and the DVR from freezing. There is also a thermally
operated switch in the control panel that closes when the temperature falls below -20F 10F (-28.9C 5.6C).
This switch applies +24 Vdc from TB4-17 to the resistors used to keep the LCD displays in the GSC and the DVR
from freezing. Note that this power is only available when the ECS is not in OFF.
Coolant Low Sensor Interface
Pins P7-7, 8, 9, 13, 14, 24, 30, and 31 are connected between the GSC and connector J37. P7-9 is +8 Vdc power
for the Coolant Low sensor. P7-31 is power return. P7-13 is the Coolant Low signal from the sensor. This sensor
detects presence or absence of coolant in the engine and provides an output indicating that the coolant level is
dangerously low to allow an operator to add coolant before a forced shutdown occurs.
Load Sharing Module (LSM) A4
The LSM gets an input from the Speed Setting Potentiometer (SSP) (labeled FREQUENCY on the front panel).
This signal allows the generator frequency to be adjusted 10% of nominal. There is a SYNC input on pins 24 and
25 from the GSC. This signal is output on LSM Pins 10 and 11 if this generator is connected to a dead load bus
and in AUTO or SEMI-AUTO sync mode. Otherwise, pins 10 and 11 are an input. Pins 10 and 11 are connected
to J32 and J33 through contacts on the paralleling relay (PAR). J32 and J33 are the paralleling cable connectors
on the rear of the generator set near the control panel. In parallel operation, cables interconnect all of the
paralleled generators and these ports are all in parallel. Pins 19 and 20 are a serial communication port to the
ECM via J37. Pins 15 and 16 are power and ground respectively.
0003-16
