SR4 GENERATOR MOUNTED CONTROL PANEL FOR SPARK IGNITED (SI) E Caterpillar

Introduction

This control panel (part number 4P4780) is being produced to provide an SI control panel for SI generator set packages.

This panel (4P4780) provides the capability of changing from a manual start/stop panel to an automatic start/stop panel by simply switching modules and reconnecting some wiring at the control panel terminal strip. Also the panel can be equipped with the 2301 governor, the Caterpillar Inc. Digital Electronic SI Fuel System, or 1724/8290 governor mounted inside of the panel. The panel can be used on energize to run systems only.

The uses of the generator mounted control panel are:

To help control the electric power made by the generator set.

To monitor the operation of the generator set.

To help protect the generator set engine from damage caused by low oil pressure, high coolant temperature, overspeed and overcrank.

To help with the transfer of electrical load to and from the generator set.

To help manually parallel two or more units onto the same bus.

Automatic Start/Stop Control Panel

For abbreviations list, and schematics and wiring diagrams refer to the section Schematic And Wiring Diagrams in this manual.

The automatic start/stop system is normally used for standby operation. The generator set must start, pick up the load, operate at load, and stop after the load is removed. An automatic transfer switch controls the transfer of load to and from the generator set. When normal (commercial or utility supplied) power has a failure, initiating contactor (IC) which is part of the automatic transfer switch, closes. This will begin the automatic start sequence. When the engine starts, the control panel instruments will show voltage and frequency. The automatic transfer switch will transfer the load to the generator set when voltage and frequency reach approximately rated value. When normal power returns, the automatic transfer switch will transfer the load back to normal power and the initiating contactor (IC) will open. This will begin the automatic stop sequence. The generator set will also stop automatically if the engine has a monitored failure.

NOTE: For specifications on components located on the engine, make reference to the Engine Service Manual.

The automatic start/stop panel will shut down the generator set when a monitored engine fault occurs. At the same time, it will indicate by a fault lamp whether the fault is due to high water temperature, low oil pressure, overcrank or overspeed.

The automatic start/stop panel can be used on engine systems that are energized to run (ETR) only.

(1) Emergency stop pushbutton (ESPB). (2) Overcrank light (OCL). (3) Overspeed light (OSL). (4) High water temperature light (WTL). (5) Engine control switch (ECS). (6) Low oil pressure light (OPL).

Engine Start-Up

The engine can be started (and shut down) with the engine control switch (ECS) in the following positions:

1. In the AUTO position, start-up and shut down depends on the closing and opening respectively of a remote start initiating contact (IC) (line 27) (except in the case of a fault where shut down is automatic).

2. In the MAN position, start-up depends on the operator turning the engine control switch (ECS); likewise, the operator must turn the engine control switch (ECS) to the STOP position to shut the engine down (except in the case of a fault where shut down is automatic).

NOTE: The emergency stop pushbutton (ESPB) located on the engine junction box [as well as on the control panel (line 23)] must be in the RESET position for proper operation of the panel.

Prior To Crank Termination

With the engine control switch (ECS) in the MAN position or AUTO (IC closed) position, the circuit is complete to run relay (RR) (line 25). Relay RR energizes to close contacts across RR (8 and 5) (line 8), RR (6 and 9) (line 25) and RR (7 and 4) (line 36) and open the contact across RR (3 and 9) (line 22).

RR (8 and 5) - Normally open (N.O.) contact across RR (8 and 5) (line 8) closes to complete the starting circuit through the electronic speed switch-crank termination ESS (CT); through the engine junction box mounted emergency stop pushbutton (ESPB) to starting motor magnetic switch (SMMS). Switch SMMS energizes to close its contact and energize the pinion solenoid (PS). Solenoid PS closes its contact to engage the starting motor. When the contact across RR (8 and 5) closes, it also energizes the overcrank timer (OCT) (line 9). After the engine cranks for approximately 30 seconds (90 seconds with cycle cranking) without the engine starting, OCT will energize the overcrank fault relay (OCR) (line 9). Make reference to the section, Engine Does Not Start.

RR (6 and 9) - Normally open (N.O.) contact across RR (6 and 9) (line 25) closes to complete a circuit through ESS (CT) (11 and 12); through diode (D3); through the engine mounted ESPB; through the water temperature switch (WTS); across RR (6 and 9) (line 25); and through the control panel ESPB contacts (8 and 7) (line 25). At this point in the start-up, the current flows through arming relay contacts (2 and 8) (line 33) to slave relay (SR1). SR1 energizes and closes its contacts (1 and 3) to energize the fuel solenoid (FS). This provides fuel for start-up.

RR (7 and 4) - N.O. contact across RR (7 and 4) (line 36) closes to arm the arming delay timer (ADT).

After Crank Termination

Once the engine has started and reached approximately 400 rpm, the ESS (CT) contacts (11 and 12) will open to terminate cranking. Contacts ESS (CT) (10 and 11) will close to energize the arming delay timer (ADT) (line 36) which begins timing. In addition, another current path is now provided through ESS (CT) contacts (11 and 10), diode (D2), ESS (OS) contacts (8 and 9), engine ESPB contacts (1 and 2), water temperature switch (WTS) and through to RR contacts (6 and 9) (line 25) to the oil pressure switch (OPS1).

Assuming the engine has adequate oil pressure, the current flow will continue through OPS1 contacts (1 and 2), through ESS (OPSS) contacts (14 and 15) down to SR1. Approximately 10 seconds after crank termination, the ADT (line 36) will time out and energize arming relay (AR) (line 36). Relay (AR) then opens its contacts (2 and 8) (line 33) and closes AR contacts (7 and 4) (line 17). At this point, the panel is armed for an oil pressure fault shutdown and all current flow to keep the fuel turned on is through the (OPS1).

However, 9 seconds after the engine speed has increased beyond the electronic speed switch (ESS) oil pressure step switch (OPSS) set point, the ESS (OPSS) contact (14 and 15) will open and (14 and 13) will close. At this point, the engine oil pressure must be high enough to close the optional oil pressure switch (OPS2) contacts (1 and 2) to keep SR1 and fuel solenoid (FS) energized or the engine will shutdown on a low oil pressure fault.

If the optional OPS2 was not supplied, a jumper will be provided in place of OPS2. This will also complete the circuit to SR1 to keep the FS energized and the engine running.

With ECS in the AUTO or MAN positions, the ECS contact across ECS (6 and 5) (line 28), ECS (8 and 5) (line 30) or ECS (7 and 5) (line 29) respectively provides a path for current to latch in one of the fault relays (OCR, OPR, WTR or OSR) should a fault occur.

As the engine starts and ESS senses a speed of 400 rpm through the magnetic speed pickup (MPU), the ESS opens the starting motor circuit through the opening of crank termination switch contact across ESS (CT) (11 and 12). At the same time, ESS (CT) contact across ESS (11 and 10) closes to arm circuits containing the following components:

Oil pressure switch (OPS1)ESPBArming relay (AR)Low oil pressure alarm switch (LOPAS 1)Electronic speed switch - overspeed [ESS (OS)]Slave relay (SR2)Slave relay (SR1)

Engine Shutdown

With the engine control switch (ECS) in the AUTO position, shutdown occurs when the remote initiating contact (IC) (line 28) opens. With the ECS in the MAN position, engine shutdown occurs when the operator turns the ECS to the STOP position.

When either the IC opens (automatic) or ECS contact across (9 and 11) (line 26) opens (manual), run relay (RR) (line 25) de-energizes to open contacts across RR (8 and 5), RR (6 and 9) and RR (7 and 4) and close the contact across RR (3 and 9).

RR (8 and 5) - N.O. contact across RR (8 and 5) (line 8) opens so that the SMMS does not energize the starting circuit when the ESS (CT) switch closes on shutdown of the generator set.

RR (6 and 9) - N.O. contact across RR (6 and 9) (line 25) opens to de-energize the slave relay (SR1), which in turn opens its contact across SR1 (1 and 3), to de-energize the fuel solenoid (FS). Also, the contact across RR (6 and 9) opens to de-energize the oil pressure fault circuit through OPS1, ESS (OPSS) and OPS2.

RR (7 and 4) - N.O. contact across RR (7 and 4) (line 36) opens to de-energize the arming relay (AR) (line 36) and reset the arming delay timer (ADT) (line 36). Relay AR (line 36) opens its contact across AR (7 and 4) (line 17) to keep the oil pressure fault relay (OPR) (line 17) and fault light (OPL) (line 18) from indicating a fault on normal start-up.

Fault Circuit Operation

Oil Pressure Fault (At Engine Speeds Below Oil Step Speed Setting)

For normal system operation, make reference to section Engine Start-Up.

During a normal start-up when initial engine oil pressure is at least 140 kPa (20 psi) and engine speed is below that of the ESS (OPSS) speed step setting, the contacts RR (6 and 9) (line 25) close to complete two current paths to energize slave relay (SR1) and the fuel solenoid (FS). One path is through contacts AR (2 and 8) (line 33). The other path is through oil pressure switch (OPS1) terminals (1 and 2) and electronic speed switch (ESS) oil pressure step switch (OPSS) terminals (14 and 15).

At start-up when oil pressure is less than 140 kPa (20 psi), (OPS1) remains closed across terminals (1 and 3). Arming delay timer (ADT) (line 36) keeps the arming relay (AR) (line 36) from energizing for 10 seconds after crank termination. After the 10 second delay, relay (AR) closes its contacts AR (7 and 4) (line 17) which completes the circuit to the oil pressure fault relay (OPR) (line 17) and the fault light (OPL). Also, the contacts AR (2 and 8) (line 33) open to de-energize the relay (SR1). This de-energizes the fuel solenoid (FS) shutting off fuel to the engine.

When relay (OPR) (line 17) energizes, its contacts OPR (line 18) close to latch in the relay (OPR). Also, its contacts OPR (line 43) close to energize engine fault relay (ENFR) (line 46). Relay (ENFR) opens the normally closed contacts ENFR (8 and 2) (line 26) which de-energizes relay (RR). With relay (RR) de-energized, its contacts open to provide another circuit to shut the engine down.

The normally closed contacts (RR) (6 and 9) (line 25) open to maintain the open circuit to relay (SR1).

The contacts RR (8 and 5) (line 8) open to keep the starting motor circuit from energizing when the ESS crank termination switch (CT) closes across terminals ESS (11 and 12) (after the engine stops).

The contacts RR (7 and 4) (line 36) open to de-energize the arming relay (AR) (line 36). With relay (AR) de-energized, the contacts AR (7 and 4) (line 17) open to make possible another start-up. The contacts AR (2 and 8) (line 33) close so relay (SR1) can be energized at engine restart.

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To prevent personal injury due to accidental starting of the engine, disconnect the batteries before doing maintenance or repair work.

To again start the engine, do the following steps:

1. Turn engine control switch (ECS) to STOP.

2. Correct the low oil pressure fault (see the engine service manual).

4. Rotate the ECS to OFF/RESET position which opens the circuit across ECS terminals (6 and 5) (line 28), (7 and 5) (line 29) and (8 and 5) (line 30). This allows relay (OPR) (line 17) to de-energize. The contacts OPR (line 18) open shutting off the light (OPL). Also, contacts OPR (line 44) open to de-energize the relay (ENFR). The contacts ENFR (8 and 2) (line 26) now close to allow restart.

4. The system is ready to start if the engine control switch (ECS) is turned to MAN or AUTO.

Oil Pressure Fault (At Engine Speeds Above Oil Step Speed Setting)

For normal system operation, make reference to section Engine Start-Up.

Under the fault condition of the engine operating above the ESS (OPSS) engine step speed setting without the required oil pressure, current flows as follows:

Through ESS crank termination terminals (CT) (11 and 10); through ESS overspeed terminals (OS) (8 and 9); through emergency stop pushbutton terminals (ESPB) (1 and 2) and through water temperature switch (WTS) to contacts RR (6 and 9) (line 25) of the control panel. From the contacts RR (6 and 9), current can flow one or two directions. Through the contacts AR (2 and 8) (line 33) to relay (SR1) [if the 10 second time delay has not elapsed from the arming relay delay (ADT) (line 36)] and/or through oil pressure switch (OPS1). In this fault, oil pressure is sufficient to close switch (OPS1), but is not enough to close the optional oil pressure switch (OPS2). Once the step speed setting of ESS (OPSS) has been passed and the speed remains above this setting, switch (OPS2) has 9 seconds to close before ESS (OPSS) closes its contacts (14 and 13) to complete the circuit through the now closed contacts AR (7 and 4) (line 17) to the oil pressure fault relay (OPR) (line 17) and fault light (OPL) (line 18). In addition, once ESS (OPSS) opens its contacts (14 and 15), it will immediately open the circuit that keeps relay (SR1) energized.

When relay (OPR) energizes, its contacts (line 18) close to latch in relay (OPR).

Also, the contacts OPR (line 44) close to energize engine fault relay (ENFR) (line 46). The contacts ENFR (8 and 2) (line 26) open which de-energizes relay (RR). With relay (RR) de-energized, its contacts open to maintain the engine shutdown.

The contacts RR (6 and 9) (line 25) open to maintain the open circuit to relay (SR1).

The contacts RR (8 and 5) (line 8) open to keep the starting motor circuit from energizing when the ESS crank termination switch (CT) closes across ESS terminals (11 and 12) (after the engine stops).

The contacts RR (7 and 4) (line 36) open to de-energize the arming relay (AR) (line 36). With relay (AR) de-energized, the contacts AR (7 and 4) (line 17) open so that the engine control switch (ECS) can clear the fault indicators (OPR) and (OPL) at restart. The contacts AR (2 and 8) (line 33) close so relay (SRI) can be energized engine restart.

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To prevent personal injury due to accidental starting of the engine, disconnect the batteries before doing maintenance or repair work.

To again start the engine, do the following steps:

1. Turn engine control switch (ECS) to STOP.

2. Correct the low oil pressure fault (see the engine service manual).

3. Rotate the ECS to OFF/RESET position which opens the circuit across ECS terminals (6 and 5) (line 28), (7 and 5) (line 29) and (8 and 5) (line 30). This allows relay (OPR) (line 17) to de-energize. Contacts OPR (line 18) open shutting off the light (OPL). Contacts OPR (line 44) also open to de-energize relay (ENFR). Contacts ENFR (8 and 2) (line 26) now close to allow restart.

4. The system is ready to start if engine control switch (ECS) is turned to MAN or AUTO.

Water Temperature Fault

For normal system operation, make reference to section, Engine Start-Up.

When engine coolant temperature becomes too high, the normally open water temperature switch (WTS) closes. This results in engine shutdown as follows:

1. The open side of the switch (WTS) cuts off current through the contact across RR (6 and 9) (line 25); through switch (OPS1); through switch ESS (OPSS); through a jumper (or optional oil pressure switch OPS2) and diode (D4) to de-energize slave relay (SR1). SR1 opens its normally open contact to de-energize the fuel solenoid (FS) and shut the engine down. No current at switches (OPS1) and (OPS2) also prevents the oil pressure fault relay (OPR) from energizing when switches (OPS1) and (OPS2) close during engine shutdown.

2. On the close side of the water temperature switch (WTS), current flows to and energizes the water temperature relay (WTR) (line 20) and water temperature fault light (WTL). WTL contact (line 21) closes to lock in WTR. The normally open (N.O.) WTR contact (line 45) closes to energize the engine failure relay (ENFR) (line 46). With ENFR energized. the contact across ENFR (8 and 2) (line 26) opens to de-energize run relay (RR) (line 25). With RR de-energized, the contact across RR (8 and 5) (line 8) opens to keep the starting motor circuit from energizing when the electronic speed switch (ESS) crank termination (CT) closes across terminals (11 and 12) (after engine stops).

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To prevent personal injury due to accidental starting of the engine, disconnect the batteries before doing maintenance or repair work.

To clear the fault and ready the system for starting, do the following:

1. Turn engine control switch (ECS) to STOP position.

2. Determine the cause of the high water temperature problem and repair. Allow engine temperature to cool so WTS will reset.

3. Make sure red ESPB has been reset (button out) on both the engine junction box and generator control panel.

4. Turn ECS to OFF/RESET position to de-energize the fault relay (WTR) and fault light (WTL).

5. The system is ready to start if engine control switch (ECS) is turned to MAN or AUTO.

Engine Overspeed Fault

For normal system operation, make reference to section Engine Start-Up.

When engine speed increases above the overspeed setting (118% of rated speed) of the electronic speed switch (ESS), the overspeed switch contact ESS (OS) will close across terminals ESS (7 and 8) and open across terminals ESS (8 and 9). When ESS (OS) closes across terminals ESS (7 and 8), the following occurs:

1. ESS (OS) latches itself in the closed position.

2. Current flows through diode (D12) to energize the engine failure relay (ENFR) (line 46). ENFR opens normally closed contact across ENFR (8 and 2) (line 26) which de-energizes run relay (RR) (line 25). With RR de-energized, the contact across RR (8 and 5) (line 8) opens to keep the starting motor circuit from energizing when the ESS crank termination (CT) closes across terminals ESS (11 and 12) (after engine stops).

3. Current flows to the overspeed fault relay (OSR) (line 31) and to the fault light (OSL) (line 32). OSR energizes to close the OSR contact (line 32) which latches in OSR. The OSR contact (line 46) closes to also energize ENFR. This is necessary because as soon as the engine stops, ESS (CT) closes across terminals ESS (11 and 12) and cuts off current through ESS (OS). This in turn cuts off current to ENFR (line 46).

When ESS (OS) opens across terminals ESS (8 and 9) the following occurs:

1. Current is stopped from flowing through emergency stop pushbutton (ESPB) terminals (1 and 2); through the water temperature switch (WTS); through contact RR (6 and 9) (line 25); through oil pressure switch (OPS1); through ESS oil pressure step switch (OPSS); through a jumper or (OPS2) and through diode (D4) to de-energize slave relay (SR1). With SR1 de-energized, the normally open contact across SR1 (1 and 3) opens to de-energize the fuel solenoid (FS).

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To prevent personal injury due to accidental starting of the engine, disconnect the batteries before doing maintenance or repair work.

To clear the fault and ready the system for starting, do the following:

1. Turn the engine control switch (ECS) to the STOP position.

2. Determine the cause of the overspeed problem and repair.

3. Manually reset the air shut-off lever (at top of air inlet housing).

4. Push the reset on the ESS (located in engine junction box) to open the overspeed switch ESS (OS).

5. Make sure red ESPB has been reset (button out) on both the engine junction box and generator control panel.

6. Turn ECS to OFF/RESET position to de-energize the fault relay (OSR) and fault light (OSL).

7. Turn ECS to AUTO or MAN for start up.

Engine Does Not Start

If the engine does not start in approximately 30 seconds, overcrank timer (OCT) (line 8 will let current flow to the overcrank relay (OCR) (line 8) and the overcrank light (OCL) (line 9). OCR will close its contact (line 9) to lock in the OCR. At the same time OCR closes its contact (line 43) which allows the engine failure relay (ENFR) (line 46) to energize. ENFR opens its contact across ENFR (8 and 2) (line 26) which de-energizes the run relay (RR) (line 25). RR then opens its contact across RR (8 and 5) (line 8) which causes the starting motor magnetic switch (SMMS) to de-energize. SMMS opens its contact causing the pinion solenoid (PS) to de-energize. PS opens its contact causing the starting motor to shutdown.

Show/hide table

To prevent personal injury due to accidental starting of the engine, disconnect the batteries before doing maintenance or repair work.

To again start the engine, do the following steps:

1. Turn the engine control switch (ECS) to the STOP position.

2. Correct the overcrank fault (see engine service manual).

3. Rotate the ECS to OFF/RESET position which opens the circuit across ECS terminals (16 and 5) (line 28). This allows the OCR (line 8) to de-energize. OCR contact (line 9) opens and shuts off the light OCL. Also, OCR contact (line 43) opens to de-energize the relay ENFR. The contact across ENFR (8 and 2) (line 26) now closes to allow restart.

4. Turn ECS to AUTO or MAN for start-up.

Emergency Stop Pushbutton

The emergency stop pushbutton (ESPB) is a red, mushroom shaped button which is located on both the engine junction box and the generator control panel. Either button will shut the engine down or prevent it from starting when pushed in.

The ESPB on the junction box shuts the engine down as follows:

When pushed in, ESPB creates an open circuit across terminals (1 and 2) to open the starting motor circuit. Another open circuit across terminals (1 and 2), de-energizes slave relay (SR1) which opens its normally open contact to de-energize the fuel solenoid (FS). This shuts-off fuel to the engine.

ESPB contacts (3 and 4) also provide a current path to energize OSR (line 31) and turn ON the OSL (line 32) in the control panel. Another set of ESPB contacts (3 and 4) prevent OSL from being reset by the ECS until ESPB is reset.

The ESPB on the generator panel shuts down the engine as follows:

When pushed in, ESPB creates an open circuit across ESPB contacts (7 and 8) (line 25) to de-energize SR1 and shut-off fuel to the engine. There is also an open across ESPB terminals (1 and 2) (line 26) which de-energizes run relay (RR) (line 25). RR opens normally open contact across RR (8 and 5) (line 8) to open the starting motor circuit.

ESPB contacts (6 and 5) (line 33) also provide a current path to energize OSR (line 31) and turn on the OSL (line 32) in the control panel. Another set of ESPB contacts (3 and 4) (line 30) prevent OSL from being reset by the ECS until ESPB is reset.

Show/hide table

To prevent personal injury due to accidental starting of the engine, disconnect the batteries before doing maintenance or repair work.

Before starting the system, do the following:

1. Turn the engine control switch (ECS) to the STOP position.

2. Correct any faults that may have been the cause of the emergency shutdown.

3. Manually reset the air shut-off lever (at the top of the air inlet housing).

4. Make sure red ESPB has been reset (button out) on both the engine junction box and generator control panel. Turn the button the direction shown to reset.

5. Turn ECS to OFF/RESET position to de-energize the OSR and OSL.

6. Turn ECS to AUTO or MAN for start-up.

Manual Start/Stop Control Panel

(1) Emergency stop pushbutton (ESPB). (2) Engine control switch (ECS). (3) Engine failure light (EFL).

For abbreviations list, and schematics and wiring diagrams refer to the section Schematic And Wiring Diagrams in this manual.

Engine Start-Up

Engine Control Switch Turned And Held In START Position

NOTE: In the Manual Start/Stop control panel, the Engine Control Switch (ECS) has a spring return from START position to RUN position.

In the START position, the engine control switch (ECS) contact closes across ECS (3 and 4) (line 9). The starting motor circuit is then energized through electronic start switch-crank termination ESS (CT) terminals (11 and 12); through emergency stop pushbutton (ESPB) (engine mounted) contacts (1 and 2); through ECS contacts (3 and 4) (line 9); through ESPB (panel mounted) contacts (1 and 2) (line 9) to starting motor magnetic switch (SMMS). SMMS energizes to close its contact and energizes the pinion solenoid (PS). PS closes its contact to energize the starting motor (SM).

In the START position, ECS also closes across contacts (5 and 6) (line 15) to arm the engine failure relay (ENFR) circuit.

In the START position ECS also closes across contacts (1 and 2) (line 25) and (11 and 12) (line 26). The fuel solenoid circuit is energized starting at ESS (CT) (11 and 12); through diode (D3); through ESPB (engine mounted junction box) contacts (1 and 2); through water temperature switch (WTS) contact; through engine failure relay (ENFR) contact (2 and 8) (line 25) and through ECS contacts (1 and 2) (line 25) to ESPB (panel mounted) contacts (8 and 7). At this point. current initially flows through ECS contacts (11 and 12) to slave relay (SR1). SR1 then closes its contacts (1 and 3) to energize the fuel solenoid (FS). This allows fuel for engine combustion.

As soon as engine low idle oil pressure comes up (check oil pressure gauge), current also flows in a parallel path from ESPB contacts (7 and 8) (line 25) through oil pressure switch (OPS1) contacts (1 and 2) and through ESS oil pressure step switch (OPSS) contacts (14 and 15) to SR1 (which should be already energized).

When the engine reaches approximately 400 rpm. ESS (CT) closes across contacts (11 and 10) (line 17). Besides opening the starting circuit, current flows through the ESS overspeed switch (OS) contacts (8 and 9); through ESPB contacts (1 and 2) and on through the paths described above. Also, through ESS (CT) contacts (11 and 10), the oil pressure relay (OPR) circuit is armed.

ECS Released To RUN Position

When ECS switch is released from the START position to the RUN position, ECS contacts across (3 and 4) (line 9) open to de-arm the starting motor circuit.

In the RUN position, ECS remains closed across contacts (1 and 2) (line 25) to keep the SR1 energized and in turn the fuel solenoid (FS) as described in the above section. ECS Turned And Held In Start Position.

NOTE: The electronic speed switch-oil pressure step switch ESS (OPSS) is a switch which starts a 9 second delay [after reaching a step speed while accelerating to rated engine speed] before closing one set and opening another set of contacts. The step speed setting is adjusted according to the rated engine speed. For example, an engine rated at 1800 rpm has its ESS (OPSS) adjusted to 1125 rpm. When the engine accelerates past 1125 rpm, the ESS (OPSS) starts a 9 second delay before it opens across terminals ESS (14 and 15) and closes across terminals ESS (14 and 13).

Once the engine speed reaches the ESS (OPSS) step speed, ESS (OPSS) will delay 9 seconds before closing across contacts (14 and 13) and opening across (14 and 15). Current then flows through a jumper or across an optional high idle oil pressure switch (OPS2) to keep SR1 energized and in turn the fuel solenoid (FS).

In the RUN position, ECS contacts (11 and 12) are open to remove this parallel circuit to SR1, used during START.

In the RUN position, ECS contacts (9 and 10) (line 17) close to arm the oil pressure fault relay (OPR) circuit. If OPS2 fails to close across its contacts (1 and 2) within 9 seconds after the step speed setting is passed and/or OPS1 fails to close before the ECS is released from START to RUN, then OPR (line 17) will energize to initiate engine shutdown. (Make reference to the following fault sections for further information).

Engine Normal Stop

The operator stops the engine by turning the engine control switch (ECS) to the OFF/RESET position from the RUN position.

When turned to OFF/RESET from the RUN position, ECS contacts across (1 and 2) (line 25) open to stop the flow of current through ESPB (8 and 7); through OPS1 (1 and 2): through ESS (OPSS) (14 and 13) and through OPS2 (1 and 2) to SRI which de-energizes. When SRI de-energizes, it opens its contact (1 and 3) to de-energize the fuel solenoid (FS) which shuts off fuel to the engine.

After the engine shuts down, the switch ESS (CT) opens across (11 and 10) and closes across (11 and 12) to allow for restart.

Emergency Stop Pushbutton

The emergency stop pushbutton (ESPB) is a red, mushroom shaped button located on both the engine junction box and the generator control panel. Either button will shut the engine down or prevent it from starting when pushed in.

NOTE: The emergency stop pushbutton should not be used for normal shutdown.

The ESPB on the engine junction box shuts the engine down as follows:

When pushed in, ESPB opens across terminals (1 and 2) (line 9) to open the starting motor circuit. ESPB also opens across terminals (8 and 7) (line 25) to open the circuit from ESS (CT) (11 and 10) through ESS (OS) (8 and 9); WTS; ENFR (2 and 8) (line 25); ECS (1 and 2) (line 25); ESPB (panel mounted) contacts (8 and 7) (line 24); OPS1 (1 and 2); ESS (OPSS) (14 and 13) and through OPS2 (1 and 2) to SR1. SR1 then de-energizes to open its contacts and de-energize the fuel solenoid (FS). This shuts off the fuel to the engine.

When pushed in, ESPB closes across terminals (3 and 4) (line 23) to close the circuit from ESS (CT) (11 and 10) to slave relay (SR2). SR2 energizes to close its contacts (1 and 3) to energize the air shutoff solenoid (ASOS). ASOS shuts off air for combustion. At the same time, the circuit is completed from SR2 through diode (D11) to energize the engine failure relay (ENFR) (line 14) and turn ON the engine failure light (EFL) (line 15). ENFR closes across its contacts (7 and 4) (line 15) to complete a circuit through ECS contacts (5 and 6) (line 15) to latch relay (ENFR) and the light (EFL).

The ESPB on the generator mounted panel (when pushed in) shuts down the engine as follows:

When pushed in, ESPB opens across its terminals (1 and 2) (line 9) to open the starting motor circuit.

When pushed in, ESPB opens across its terminals (8 and 7) to open the circuit (as described in engine mounted ESPB) to SR1. SR1 de-energizes to open its contacts (1 and 3) and de-energize the fuel solenoid (FS).

When pushed in, ESPB closes across (5 and 6) (line 32) to complete a circuit from ESS (CT) (11 and 10) to SR2. SR2 energizes to close its contacts (1 and 3) and energize ASOS. This shuts off combustion air to the engine. With contacts ESPB (5 and 6) closed, current also flows through diode (D11) (line 28) to energize ENFR (line 14) and turn ON the engine failure light (EFL) (line 15). ENFR closes across its contacts (7 and 4) (line 15) to complete a circuit through ECS contacts (5 and 6) (line 15) to latch ENFR and EFL.

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To prevent personal injury due to accidental starting of the engine, disconnect the batteries before doing maintenance or repair work.

Before starting the engine, do the following:

1. Turn the engine control switch (ECS) to the OFF/RESET position.

2. Correct any faults that may have been the cause of an emergency shutdown.

3. Manually reset the air shut-off lever (at the top of the air inlet housing).

4. Make sure the ESPB has been reset (button out) on both the engine junction box and generator control panel. Turn the button in the direction shown to reset.

5. Turn and hold the ECS in the START position until normal oil pressure is seen on the oil pressure gauge.

Fault Circuit Operation

Low Oil Pressure Fault (OPS1)

For normal operation, make reference to the section, engine Start-Up.

Depending on engine speed during start-up, the electronic speed switch (ESS) - crank termination (CT) will be:

closed across contacts (11 and 12), providing a current path through diode (D3) to emergency stop pushbutton (ESPB) terminals (1 and 2) (1f engine speed is less than 400 rpm).

closed across contacts (11 and 10) providing a current path through ESS-overspeed switch (OS) contacts (8 and 9) to ESPB terminals (1 and 2) (If engine speed is equal to or greater than 400 rpm).

Regardless of initial oil pressure and engine speed (as long as engine control switch (ECS) is held in the START position) the engine will start and run. From ESPB terminals (1 and 2), current flows through the water temperature switch (WTS) through normally closed (N.C.) engine failure relay (ENFR) contacts (2 and 8) (line 25) through ECS contacts (1 and 2) (line 25) through ESPB (panel mounted) terminals (8 and 7) (line 25) through ECS contacts (12 and 11) (line 26) to slave relay (SR1). SR1 energizes to close its contacts (1 and 3) and energize the fuel solenoid (FS). This provides fuel to the engine.

If at this point the ECS is released from the START to RUN position and there is not enough initial oil pressure to close oil pressure switch (OPS1) across contacts (1 and 2), then the opening of ECS contacts (11 and 12) (line 26) will de-energize SR1 and FS. This shuts off fuel to the engine, resulting in engine shutdown.

With oil pressure below the activation pressure of OPS1, contacts OPS1 (1 and 3) are closed. The current path will be through ECS contacts (9 and 10) (line 17) to oil pressure relay (OPR). OPR energizes to close its contact (5 and 8) (line 18). If ESS (CT) has closed across its contacts (11 and 10) to arm the circuit to OPR contacts (5 and 8) through diode (D13) (line 19) to engine failure relay (ENFR) (line 14) and engine failure light (EFL) (line 15). ENFR energizes to close its contacts (7 and 4) (line 15) which latches ENFR and EFL through ECS contacts (5 and 6) (line 15).

When the ECS is turned to the OFF/RESET position from the RUN position, ENFR and light EFL de-energize to allow restart.

Low Oil Pressure Fault (OPS2) (Optional)

For normal operation, make reference to the section, Engine Start-Up.

Once the engine is started and ECS has been released from the START to the RUN position, initial oil pressure is enough to close oil pressure switch (OPS1) across its contacts (1 and 2). This keeps slave relay (SR1) energized through electronic speed switch (ESS) oil pressure step switch (OPSS) contacts (14 and 15). However, as engine speed increases past the oil pressure step switch speed setting, ESS (OPSS) initiates a 9 second delay before closing across contacts (14 and 13) and opening across (14 and 15).

At the end of the 9 second delay, ESS (OPSS) closes across contacts (14 and 13) to complete the circuit to oil pressure switch (OPS2) and opens across ESS (OPSS) (14 and 15) to stop current flow to SR1. If at this point, the oil pressure is not at least 240 kPa (40 psi), OPS2 remains closed across contacts (1 and 3) to stop current now to SR1. SR1 then de-energizes to open across contacts (1 and 3) and de-energize the fuel solenoid (FS). This shuts off fuel to the engine and in turn the engine shuts down.

At the same time, current flows through OPS2 contacts (1 and 3) and ECS contacts (9 and 10) (line 17) to oil pressure relay (OPR). OPR energizes to close its contact (5 and 8) (line 18) and latch OPR; also current flows through diode (D13) (line 19) to engine failure relay (ENFR) (line 14) and engine failure light (EFL) (line l5). ENFR energizes to close its contacts (7 and 4) (line 15) which latches ENFR and EFL through ECS contacts (5 and 6) (line 15).

When the ECS is turned to the OFF/RESET position from the RUN position, ENFR and light (EFL) de-energize to allow restart.

Water Temperature Fault

When the engine coolant temperature becomes too high, the normally open water temperature switch (WTS) opens across its normally closed (N.C.) contact. This opens the circuit to slave relay (SR1). SR1 de-energizes to open its contacts (1 and 3) and de-energize the fuel solenoid (FS). This shuts off fuel to engine which in turn shuts down.

Also WTS closes across its normally open (N.O.) contact to energize the engine failure relay (ENFR) (line 14) and engine failure light (EFL) (line 15). ENFR energizes to close its contact (7 and 4) (line 15) which latches ENFR and EFL through ECS contacts (5 and 6) (line 15).

Turn the ECS to the OFF/RESET position from the RUN position. ENFR and light EFL will de-energize to allow restart after the engine cools down and the fault has been corrected.

Overspeed Fault - ESS

For normal operation. make reference to the section, engine Start-Up.

When engine speed increases above the overspeed setting (118% of rated speed) of the electronic speed switch (ESS), the overspeed switch ESS (OS) will close across contacts (8 and 7) and open across contacts (8 and 9).

When ESS (OS) opens across contacts (8 and 9), this opens the circuit to slave relay (SR1). SR1 de-energizes to open its contacts (1 and 3) to de-energize the fuel solenoid (FS). This shuts off fuel to the engine which in turn shuts down the engine.

At the same time, ESS (OS) closes across terminal (8 and 7) which energizes slave relay (SR2). SR2 in turn closes its contact to energize the air shutoff solenoid (ASOS). ASOS shuts off air for combustion. Also, current flows through diode (D11) (line 30) to engine failure relay (ENFR) (line 14) and engine failure light (EFL) (line 15). ENFR energizes to close its contact (7 and 4) (line 15) which latches ENFR and EFL through ECS contacts (5 and 6) (line 15).

Turn the ECS to the OFF/RESET position from the RUN position. ENFR and light EFL will de-energize to allow restart after the following:

1. overspeed fault has been corrected.

2. the air shut-off lever has been manually reset (at the top of the air inlet housing).

3. manually reset the overspeed button on the ESS module.