ARMY TM 9-6115-604-12NAVY NAVFAC P-8-633-12(3)Arming the start circuit activates several circuits before the engine is started.(a)Cabinet C door engine panel lights DS26 through DS29 will light if PANEL LT SW S1 Is set to ON.(b)OPEN indicator DS33 will light to indicate the condition of load circuit breaker CB101 CLOSEDindicator DS34. will be off when the engine is not running since the trip coil of load circuit breakerCB101 is energized through the normally closed contacts of engine run relay K15D. This preventsCB101 from closing.(c)PARALLEL indicator DS35 or SINGLE SET indicator DS36 will light to Indicate the setting ofPARALLEL SWITCH S6. If S6 is at SINGLE SET, SINGLE SET indicator DS36 will light throughthe normally closed contacts of parallel relay K4A If S6 is set at PARALLEL and LOCAL REMOTEswitch S2 is set to LOCAL, parallel self-latching relay K4A will be energized, effecting contacttransfers so that SINGLE SET indicator DS36 is off, and PARALLEL indicator DS35 is illuminated.(d)The fuel transfer system will operate if the generator set has been connected to an external source ofAC utility power and If FUEL PUMP switch S8 has been set to AUTO or HAND If set to HAND, fueltransfer pump slave relay K12 will energize if float switch FL2 is closed FL2 is normally closedunless the fuel level in the generator set fuel tank is too high to merit bringing in additional fuel IfFUEL 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 fueltransfer 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 positivethrough Its self-latching contacts and diode CR2. When the tank is full, FL2 will open, and relayK12 will deenergize. Diode CR1 prevents back-EMF from developing across the FL1 contacts whenrelay K12 deenergizes. Diode CR2 prevents relay K13 from receiving battery positive through FL1Note that If a high-fuel fault condition occurs, high fuel level fault relay K5 will be energized breakingthe NC contact. Relay K13, the fuel transfer pump contactor, is then cut off from battery positiveunder all conditions until the high fuel annunciator circuit is reset via ANNUNCIATOR RESETpushbutton S12 on the upper door of cabinet A in the control room.(e)If LOCAL REMOTE Switch S2 is set to LOCAL, START AID switch S10 will be connected to batterypositive 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 L5can 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 intakemanifold. Note that START AID switch S10 should be used only when the engine is cranking.(f)ANNUNCIATOR RESET pushbutton S12, ALARM SILENCE pushbutton S16, and ANNUNCIATORTEST pushbutton S15 will all be operable. After a generator set fault shutdown occurs, the faultcircuits must be reset before the generator set can be restarted Pushing ANNUNCIATOR RESETpushbutton S12 will deenergize the latched fault relay (A10K1 through A10K9 or A11K1 throughA11K9) that tripped the alarm circuit. Additionally, annunciator horn LS1 will silence, annunciatordisplay panel A9 will go dark, and the engine start circuit will be reenabled. If ALARM SILENCEpushbutton S16 is pushed instead, annunciator horn LS1 will silence, the appropriate fault indicatoron annunciator display panel A9 will cease flashing (but remain lit), and the engine start circuit willstill be disabled. ANNUNCIATOR TEST pushbutton S15 can be used, once the system is reset, totest annunciator horn LS1 and the lights in annunciator display panel A9.(g)Prelube pump B3 is also operable once 24 V dc battery power is made available through theMAINTENANCE LOCKOUT switch S100. The prelube pump B3 provides initial lubrication to theengine prior to engine start and is manually operated using PRELUBE SYS switch S5 on enginecontrol 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 releasingPRELUBE SYS switch S5.b.InitializationofStartingCircuit. If LOCAL REMOTE Switch S2 is set to LOCAL and the engine starting circuit hasbeen armed, the generator set can be started (unless it is in a fault shutdown condition). Setting MASTER SWITCHS9 to START and releasing it to RUN applies battery positive to the generator set DC control circuits. The followingevents occur Immediately and simultaneously.4-66
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