ARMY TM 9-6115-604-12
NAVY NAVFAC P-8-633-12
Arming the start circuit activates several circuits before the engine is started.
Cabinet C door engine panel lights DS26 through DS29 will light if PANEL LT SW S1 Is set to ON.
OPEN indicator DS33 will light to indicate the condition of load circuit breaker CB101 CLOSED
indicator DS34. will be off when the engine is not running since the trip coil of load circuit breaker
CB101 is energized through the normally closed contacts of engine run relay K15D. This prevents
CB101 from closing.
PARALLEL indicator DS35 or SINGLE SET indicator DS36 will light to Indicate the setting of
PARALLEL SWITCH S6. If S6 is at SINGLE SET, SINGLE SET indicator DS36 will light through
the normally closed contacts of parallel relay K4A If S6 is set at PARALLEL and LOCAL REMOTE
switch S2 is set to LOCAL, parallel self-latching relay K4A will be energized, effecting contact
transfers so that SINGLE SET indicator DS36 is off, and PARALLEL indicator DS35 is illuminated.
The fuel transfer system will operate if the generator set has been connected to an external source of
AC utility power and If FUEL PUMP switch S8 has been set to AUTO or HAND If set to HAND, fuel
transfer pump slave relay K12 will energize if float switch FL2 is closed FL2 is normally closed
unless the fuel level in the generator set fuel tank is too high to merit bringing in additional fuel If
FUEL PUMP switch S8 is set to AUTO, relay K12 will be energized If both FL1 and FL2 are closed.
Thereafter, the relay will remain energized until both FL1 and FL2 are open Relay K13, the fuel
transfer pump contactor, will receive battery positive through the self-latching contacts of relay K12.
As the generator set fuel tank fills, FL1 will open, but relay K12 will still receive battery positive
through Its self-latching contacts and diode CR2. When the tank is full, FL2 will open, and relay
K12 will deenergize. Diode CR1 prevents back-EMF from developing across the FL1 contacts when
relay K12 deenergizes. Diode CR2 prevents relay K13 from receiving battery positive through FL1
Note that If a high-fuel fault condition occurs, high fuel level fault relay K5 will be energized breaking
the NC contact. Relay K13, the fuel transfer pump contactor, is then cut off from battery positive
under all conditions until the high fuel annunciator circuit is reset via ANNUNCIATOR RESET
pushbutton S12 on the upper door of cabinet A in the control room.
If LOCAL REMOTE Switch S2 is set to LOCAL, START AID switch S10 will be connected to battery
positive and the ether priming circuit will be enabled If the ambient engine temperature is below 40°F
(40C). Thermoswitch S17 is closed if the ambient temperature is low enough. Solenoid valve L5
can then be energized If the START AID switch S10 is set to ON. When the switch is released,
solenoid L5 is deenergized, causing a metered amount of ether to be injected into the engine intake
manifold. Note that START AID switch S10 should be used only when the engine is cranking.
ANNUNCIATOR RESET pushbutton S12, ALARM SILENCE pushbutton S16, and ANNUNCIATOR
TEST pushbutton S15 will all be operable. After a generator set fault shutdown occurs, the fault
circuits must be reset before the generator set can be restarted Pushing ANNUNCIATOR RESET
pushbutton S12 will deenergize the latched fault relay (A10K1 through A10K9 or A11K1 through
A11K9) that tripped the alarm circuit. Additionally, annunciator horn LS1 will silence, annunciator
display panel A9 will go dark, and the engine start circuit will be reenabled. If ALARM SILENCE
pushbutton S16 is pushed instead, annunciator horn LS1 will silence, the appropriate fault indicator
on annunciator display panel A9 will cease flashing (but remain lit), and the engine start circuit will
still be disabled. ANNUNCIATOR TEST pushbutton S15 can be used, once the system is reset, to
test annunciator horn LS1 and the lights in annunciator display panel A9.
Prelube pump B3 is also operable once 24 V dc battery power is made available through the
MAINTENANCE LOCKOUT switch S100. The prelube pump B3 provides initial lubrication to the
engine prior to engine start and is manually operated using PRELUBE SYS switch S5 on engine
control cabinet C. Once engine oil pressure, as monitored, on the LUBE OIL PRESSURE GAGE,
is stabilized and the engine is running, the prelube pump is manually deenergized by releasing
PRELUBE SYS switch S5.
Initialization of Starting Circuit. If LOCAL REMOTE Switch S2 is set to LOCAL and the engine starting circuit has
been armed, the generator set can be started (unless it is in a fault shutdown condition). Setting MASTER SWITCH
S9 to START and releasing it to RUN applies battery positive to the generator set DC control circuits. The following
events occur Immediately and simultaneously.