SR4 GENERATOR MOUNTED CONTROL PANEL Caterpillar

The automatic start/stop system is normally used for standby operation. That is, without an operator. The generator set must start, pick up the load, operate the 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) power has a failure, initiating contactor (IC) 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. Initiating contactor (IC) will open. This will begin the automatic stop sequence. The generator set will also stop automatically if the engine has a failure.

NOTE: For specifications on components located on the engine, make reference to the ENGINE SERVICE MANUAL.

The automatic start/stop panel will shutdown the generator set when an 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 either energized to shutoff (ETS) or energized to run (ETR).

D.C. SCHEMATIC - AUTOMATIC CONTROL PANEL ENERGIZE TO SHUTOFF (ETS) ENGINE SYSTEM [Joint Industrial Council (JIC)]

D.C. SCHEMATIC - AUTOMATIC CONTROL PANEL ENERGIZE TO SHUTOFF (ETS) ENGINE SYSTEM [International Electro-Technical Commission (IEC)]

Energize To Shutoff Engine System

AUTOMATIC START/STOP MODULE

1. Off/Reset position.

2. Stop position.

3. Manual position.

4. Auto position.

ESPB Emergency stop pushbutton.

ECS Engine control switch.

OCL Overcrank light.

OPL Low oil pressure light.

OSL Overspeed light.

WTL High water temperature light.

Engine Start-Up

The engine can be started (and shutdown) with the ECS (line 24) in the following positions:

1. In ECS auto position (4) where start-up and shutdown depends on the closing and opening respectively of a remote start initiating contact (IC) (line 25) (except in case of a fault where shutdown is automatic).

2. In manual position (3) where the operator has to turn the ECS to manual position (3). Likewise, the operator has to turn the ECS to position (2) to stop the engine (except in the case of a fault).

NOTE: The emergency stop pushbutton (ESPB) (lines 9, 33 and 34) located on the engine junction box must be in the reset (out) position for proper operation of the control panel.

Prior to Crank Termination

With ECS in either the auto position (4) (and the IC closed) or in the manual position (3), the run relay (RR) (line 23) energizes. This causes contacts across RR (8 and 5) (line 7), RR (6 and 9) (line 23), RR (7 and 4) (line 34) to close and across RR (3 and 9) (line 20) to open.

RR (8 and 5) (line 7) - Normally open (N.O.) contact across RR (8 and 5) closes to energize the starting motor magnetic switch (SMMS) (line 9). Switch (SMMS) closes its contact (line 3) to energize the pinion solenoid (PS) (line 3) which in turn closes its contact (line 2) to energize the starting motor (SM) (line 2). Also the overcrank timer (OCT) (line 8) energizes to start its timer. After the engine cranks for approximately 30 seconds without the engine starting, OCT will energize the overcrank fault relay (OCR) (line 8). Make reference to section, ENGINE DOES NOT START.

RR (3 and 9) (line 20) - Normally closed (N.C.) contact across RR (3 and 9) opens to disarm the fuel shut-off solenoid (FSOS) (line 43) circuit during normal generator set operation.

RR (6 and 9) (line 23) - N.O. contact across RR (6 and 9) closes to provide power to the optional 2301 governor (line 55).

After Crank Termination

Once the engine has started and reached approximately 400 RPM:

RR (7 and 4) (line 34) - N.O. contact across RR (7 and 4) closes after crank termination energizes the arming delay timer (ADT) (line 34) which is set for a 10 second delay before allowing the arming relay (AR) (line 34) to energize. The 10 second delay allows time for initial oil pressure to build-up causing the oil pressure switch (OPS 1) (line 15) to open at 140 kPa (20 psi). This prevents the oil pressure fault relay (OPR) (line 15) and light (OPL) (line 16) from energizing on normal start-up and shutdown. The optional second stage oil pressure switch (OPS 2) (line 17) is also part of the circuit that operates through contact AR (7 and 4). OPS 2 opens at an oil pressure of 280 kPa (40 psi). The electronic speed switch (ESS) has a 9 second delay after high rpm is reached to allow OPS 2 to open before the oil pressure step switch ESS (OPSS) (line 17) closes. Contact across AR (2 and 8) (line 31) is used in the ENERGIZE TO RUN system.

With ECS in the auto position, ECS contact across ECS (11 and 12) (line 26) is also closed to provide a path 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 by opening the crank termination switch contact across ESS (CT) (11 and 12) (line 9). At the same time, ESS (CT) contact across ESS (11 and 10) (line 13) closes to arm circuits containing the following components:

Oil pressure switch (OPS 1) (line 15)

Arming relay (AR) (line 34)

Low oil pressure auxiliary switch (LOPAS 1) (line 25)

Electronic speed switch-overspeed [ESS (OS)] (line 29)

Slave relay (SR2) (line 33)

Slave relay (SR1) (line 36)

Engine Normal Shutdown

With the engine control switch (ECS) in the auto position, shutdown occurs when the remote initiating contact (IC) (line 26) opens. With the ECS in the manual position, engine shutdown occurs when the operator turns the ECS to the stop position.

When either the IC opens (automatic) or ECS contact across (1 and 2) (line 24) opens (manual), run relay (RR) (line 23) de-energizes to open contacts across RR (8 and 5) (line 7), RR (6 and 9) (line 23) and RR (7 and 4) (line 34) and close the contact across RR (3 and 9) (line 20).

RR (8 and 5) (line 7) - N.O. contact across RR (8 and 5) opens so that the SMMS (line 9) does not again energize the starting circuit when the ESS (CT) switch closes on shutdown of the generator set.

RR (3 and 9) (line 20) - N.C. contact across RR (3 and 9) closes to complete the circuit through the engine time delay relay (TD) contact (line 36) to the slave relay (SR1) (line 36). The TD contact remains closed for (70) seconds after the ESS (CT) contact (11 and 10) (line 13) re-opens, to make sure there is complete engine shutdown. SR1 energizes to close across its contact SR1 (1 and 3) (line 43) and energize the fuel shutoff solenoid (FSOS) (line 43). The FSOS is de-energized by TD 70 seconds after the engine is shutdown.

RR (6 and 9) (line 23) - Functions only in the ENERGIZE TO RUN system and/or provides power to the optional 2301 Speed Sensing Governor.

RR (7 and 4) (line 34) - N.O. contact across RR (7 and 4) opens to de-energize the relay (AR) (line 34). With AR de-energized, the contact across AR (7 and 4) (line 15) opens to keep the oil pressure fault relay (OPR) (line 15) and fault light (OPL) (line 16) from indicating a fault on normal shutdown.

The system is now ready for immediate starting if called upon to do so.

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

At start-up (make reference to ENGINE START-UP), the run relay (RR) (line 23) is energized. Relay (RR) closes the contact across both RR (8 and 5) (line 7) in the starting motor circuit and RR (7 and 4) (line 34) in the arming relay (AR) (line 34) circuit. With the contact across RR (7 and 4) closed, the arming delay timer (ADT) (line 34) starts a 10 second delay before allowing the relay (AR) to energize and close across its contact (AR) (7 and 4) (line 15). Under normal conditions, the 10 second delay allows initial oil pressure to build-up to 140 kPa (20 psi) and open oil pressure switch (OPS 1) (line 15). However, if initial oil pressure does not build-up in the 10 second time delay, (OPS 1) will still be closed. The contact across AR (7 and 4) will now be closed to complete the circuit to the oil pressure fault relay (OPR) (line 15) and light (OPL) (line 16). Relay (OPR) closes its contact (line 16) to latch in OPR. Relay (OPR) also closes its contact (line 41) to allow the engine failure relay (ENFR) (line 43) to energize. Normally closed (N.C.) contact ENFR (8 and 2) (line 24) opens to de-energize relay (RR) (line 23). The contact across RR (8 and 5) (line 7) opens to prevent the starting motor magnetic switch (SMMS) (line 9) from energizing. The contact across RR (3 and 9) (line 20) closes to energize the slave relay (SR1) (line 36) through the TD contact (line 36). Relay (SR1) closes its contact across SR1 (1 and 3) (line 43) to energize the fuel shut-off solenoid (FSOS) (line 43) which shuts fuel off to the engine. Approximately 70 seconds after ESS (CT) contact (11 and 10) (line 13) has again opened and de-energized the TD terminal 1 (line 13), the TD contact (6 and 7) (line 36) will again open to de-energize SR1 and in turn FSOS.

The ENFR contacts (9 and 6) (line 44) also close and provide power to the optional shunt trip coil (SHTC) (line 44) of the generator output circuit breaker. This trips open the breaker.

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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 (11 and 12) (line 26). This allows the OPR (line 15) to de-energize. OPR contact (line 16) opens and shuts off the light (WTL). Also, OPR contact (line 41) opens to de-energize the relay (ENFR). The contact across ENFR (8 and 2) (line 24) now closes to allow restart.

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

Engine Shutdown Caused By Oil Pressure Fault (At Engine Speed Above ESS (OPSS) Speed Setting)

NOTE: Electronic speed switch (ESS) oil pressure step switch (OPSS) has an adjustable step speed setting which is set according to rated engine speed (Make reference to Service Manual Form No. SENR2985, Electric Protective System, Speed Specification Chart). When starting the engine and it accelerates past that step speed setting, the engine has 9 seconds to build oil pressure up to at least 280 kPa (40 psi) [setting at which optional oil pressure switch (OPS 2) (line 17) opens] before ESS (OPSS) closes across ESS (13 and 14) (line 17). From the open position, switch (OPS 2) will close at 240 kPa (35 psi). If the engine has not achieved oil pressure required to open across OPS 2 contacts (1 and 3) (line 17), the control panel will shut the engine down.

If, during generator set operation, the engine oil pressure drops below 240 kPa (35 psi), oil pressure switch (OPS 2) will again close contacts (1 and 3) (line 17). If the engine at this point is running at a speed above the step speed setting, there will be a complete circuit through the switch [ESS (OPSS)] (line 17), switch (OPS 2) and closed contact across AR (7 and 4) (line 17) to the oil pressure relay (OPR) (line 17) and fault light (OPL) (line 16). Relay (OPR) energizes and latches ON through its contact (line 16).

The OPR contact (line 41) also closes to allow current to energize the engine failure relay (ENFR) (line 43). Relay (ENFR) opens the contact across ENFR (8 and 2) (line 24) which de-energizes the run relay (RR). With relay (RR) de-energized, the contact across RR (3 and 9) (line 20) closes to allow current to flow through the TD contact (6 and 7) (line 36) to the slave relay (SR1) (line 36). Relay (SR1) closes its contact across SR1 (3 and 1) (line 43) to energize the fuel shut-off solenoid (FSOS). The engine is then shutting down. The contact across RR (8 and 5) (line 7) also opens preventing possible starting motor engagement.

The contact across RR (7 and 4) (line 34) opens to de-energize the arming relay (AR) (line 34). Relay (AR) opens its contact across AR (7 and 4), in preparation for the next start-up. However, until ECS is turned to OFF/RESET, relay (OPR) will remain energized through the circuit made up across terminals ECS (11 and 12) (auto position) or ECS (15 and 16) (manual position) and through the OPR contact (line 16).

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 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 (11 and 12) (line 26). This allows the OPR (line 15) to de-energize. OPR contact (line 16) opens and shuts off the light (OPS). Also, OPR contact (line 41) opens to de-energize the relay (ENFR). The contact across ENFR (8 and 2) (line 24) now closes to allow restart.

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

Engine Shutdown Caused By Water Temperature Fault

When engine coolant temperature becomes too high, the normally open water temperature switch (WTS) (line 18) closes. This, in turn, energizes the water temperature relay (WTR) (line 18) and water temperature fault light (WTL). The contact (line 19) closes to latch in the relay (WTR).

The normally open WTR control (line 42) closes to energize the engine failure relay (ENFR) (line 43). With ENFR energized, the contact across ENFR (8 and 2) (line 24) opens to de-energize run relay (RR) (line 23). ENFR contact (9 and 6) (line 45) also closes and trips the generator circuit breaker. With RR de-energized, the contact across RR (3 and 9) (line 20) closes to allow current to flow through the TD contact (6 and 7) (line 36) to the slave relay (SR1) (line 36). Relay (SR1) then closes its contact across SR2 (1 and 3) (line 43) to energize the fuel shut-off solenoid (FSOS). The engine then shuts down.

The contact across RR (8 and 5) (line 7) opens to prevent possible starter engagement again.

The contact across RR (7 and 4) (line 34) opens to de-energize the arming relay (AR) (line 34). With (AR) de-energized, the contact across AR (7 and 4) opens to keep the oil pressure relay (OPR) (line 15) from possibly energizing and giving a fault indication as the oil pressure decreases at engine shutdown.

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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 start the engine, do the following steps:

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

2. Correct the high water temperature problem. Allow the engine temperature to cool so WTS will reset.

3. Rotate the ECS to OFF/RESET position which opens the circuit across ECS terminals (11-12) (line 26). This allows the WTR (line 18) to de-energize. WTR contact (line 19) opens and shuts off the light (WTL). Also, WTR contact (line 42) opens to de-energize the relay (ENFR). The contact across ENFR (8 and 2) (line 24) now closes to allow restart.

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

Engine Shutdown Caused By Engine Overspeed

When engine speed increases above the overspeed setting (118% of rated speed) of the electronic speed switch (ESS), the overspeed switch contact ESS (OS) (line 29) will close across ESS (7 and 8) (line 29). This completes the circuit to the following:

1. The overspeed fault relay (OSR) (line 29) and fault light (OSL) (line 30) causing them to energize. The contact (line 30) then closes to latch relay (ENFR) (line 43) which opens its contact across ENFR (8 and 2) (line 24). The open contact across ENFR (8 and 2) causes run relay (RR) (line 23) to de-energize which in turn:

a. Opens the contact across RR (7 and 4) (line 34) which opens the starting motor circuit at starting motor magnetic switch (SMMS) (line 9).

b. Closes the contact across RR (3 and 9) (line 20) which energizes slave relay (SR1) (line 36); which causes fuel shut-off solenoid (FSOS) (line 43) to energize by way of SR1 contacts (1 and 3) (line 43).

c. Open the contact across RR (7 and 4) (line 34) which de-energizes arming relay (AR) (line 34); which opens the control across AR (7 and 4) (line 15) to prevent oil pressure fault relay (OPR) (line 15) from energizing at engine shut-down.

2. The slave relay (SR2) (line 47) which causes the normally open (N.O.) SR2 contact (line 47) to close. This completes the circuit to the air shut-off solenoid (ASOS) (line 47) which closes off the combustion air to the engine.

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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 start the engine again after overspeed shutdown, do the following steps:

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

2. Correct the overspeed problem.

3. Push the reset button on the ESS located in the engine junction box. This opens the ESS (OS) contact (line 29).

4. Manually reset the air shut-off lever located at the top of the air inlet housing.

5. Rotate the ECS to OFF/RESET position which opens the circuit across ECS terminals (11-12) (line 26). This allows OSR (line 29) to de-energize. OSR contact (line 30) opens and shuts off the light (OSL). Also, OSR contact (line 43) opens to de-energize the relay (ENFR). The contact across ENFR (8 and 2) (line 24) now closes to allow restart.

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

Engine Does Not Start (Overcrank Indicator Lights)

If the engine does not start in approximately 30 seconds for single crank (90 seconds for cycle crank auto start-stop), 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. OCR at the same time closes its contact (line 40) which allows the engine failure relay (ENFR) (line 43) to energize. ENFR opens its contact across ENFR (8 and 2) (line 24) which de-energizes the run relay (RR) (line 23). RR then opens its contact across RR (8 and 5) (line 7) which causes the starting motor magnetic switch (SMMS) (line 9) to de-energize. (SMMS) opens its contact (line 3) causing the pinion solenoid (PS) (line 3) to de-energize. (PS) opens its contact (line 2) 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 engine control switch (ECS) to STOP.

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

3. Rotate the ECS to OFF/RESET position which opens the circuit across ECS terminals (11 and 12) (line 26). This allows the OCR (line 8) to de-energize. OCR contact (line 9) opens and shuts off the light (OCL). Also, OCR contact (line 40) opens to de-energize the relay (ENFR). The contact across ENFR (8 and 2) (line 24) now closes to allow restart.

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

Operation of Emergency Stop Pushbutton (ESPB) (Energize to Shutoff Engine System)

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) (line 9) to open the starting motor circuit.

When pushed in, ESPB creates a closed circuit across terminals (3 and 4) (lines 33 and 34) to energize both slave relays (SR1) (line 36) and (SR2) (line 33). Relay (SR2) closes its normally open contact (line 47) to energize the air shut-off solenoid (ASOS). This effectively shuts-off air to the engine. ASOS remains energized until ECS (CT) contacts (10 and 11) (line 17) re-open after the engine stops.

ESPB contacts (3 and 4) (line 33) also provide a current path to turn on the OSL (line 30) in the control panel. Another set of ESPB contacts (3 and 4) (line 34) prevent OSL from being reset by the ECS until ESPB is reset.

Relay (SR1) (line 36) closes its contact SR1 (1 and 3) (line 43) to energize the fuel shutoff (FSOS). This shuts off fuel to the engine.

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

When pushed in, ESPB closes across terminals (10 and 9) (line 21) to energize slave relay (SR1). Relay (SR1) closes its contact SR1 (1 and 3) (line 43) to energize the fuel shutoff solenoid (FSOS) (line 43).

When pushed in, ESPB opens across terminals (1 and 2) (line 24) which de-energizes relay (RR) (line 23). Relay (RR) opens normally open contact across RR (8 and 5) (line 7) to open the starting motor circuit.

When pushed in, ESPB closes across terminals (6 and 5) (line 31) to energize relay (SR2). Relay (SR2) closes its contact SR2 (1 and 3) to energize the air shutoff solenoid (ASOS) (line 47). Solenoid (ASOS) effectively shuts off air to the engine. ASOS remains energized until the engine stops and ESS (CT) contacts (11 and 10) (line 13) opens. ESPB contact across terminals (6 and 5) also provides a current path to turn on the overspeed light (OSL) (line 30) in the control panel. Another set of ESPB contacts (3 and 4) (line 28) prevent OSL from being reset by the ECS until ESPB is reset.

Show/hide table

To prevent personal injury during repair or maintenance operations, disconnect the batteries to prevent the engine from starting.

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 clear the OSR and OSL.

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

Energize To Run Engine System

AUTOMATIC START/STOP MODULE

1. Off/Reset position.

2. Stop position.

3. Manual position.

4. Auto position.

ESPB Emergency stop pushbutton.

ECS Engine control switch.

OCL Overcrank light.

OPL Low oil pressure light.

OSL Overspeed light.

WTL High water temperature light.

Engine Start-Up

The engine can be started (and shutdown) with the engine control switch (ECS) (line 24) in the following positions:

1. In auto position (4) where start-up and shutdown depends on the closing and opening respectively of a remote start initiating contact (IC) (line 26) (except in the case of a fault where shutdown is automatic).

2. In manual position (3) where start-up depends on the operator turning the ECS; likewise, the operator turns the ECS to position (2) to stop the engine (except in the case of a fault where shutdown is automatic).

NOTE: The emergency stop pushbutton (ESPB) located on the engine junction box (line 9) [as well as on the control panel (line 21)] must be in the reset (out) position for proper operation of the control panel.

Prior to Crank Termination

With the engine control switch (ECS) in the manual position (3) or automatic (IC closed) position (4), the circuit is complete to run relay (RR) (line 23). Relay (RR) energizes to close contacts across RR (8 and 5) (line 7), RR (6 and 9) (line 23) and RR (7 and 4) (line 34) and open the contact across RR (3 and 9) (line 20).

RR (8 and 5) - Normally open (N.O.) contact across RR (8 and 5) (line 7) closes to complete the starting circuit through the electronic speed switch-crank termination ESS (CT) terminals ESS (11 and 12) (line 17); through the engine junction box mounted emergency stop pushbutton (ESPB) to starting motor magnetic switch (SMMS) (line 9). Switch (SMMS) energizes to close its contact (line 3) and energize the pinion solenoid (PS) (line 3). Solenoid (PS) closes its contact (line 2) to engage the starting motor. When the contact across RR (8 and 5) closes, it also energizes the overcrank timer (OCT) (line 8). 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 8). Make reference to the section, ENGINE DOES NOT START.

RR (3 and 9) - Normally closed (N.C.) contact across RR (3 and 9) (line 20) does not have a function in the energize to run (ETR) system.

RR (6 and 9) - N.O. contact across RR (6 and 9) (line 23) closes to complete a circuit through ESS (CT) (11 and 12) (line 17); through diode (D3) (line 18); through the engine mounted (ESPB) (line 18); through the water temperature switch (WTS) (line 18); across RR (6 and 9) (line 23); and through the control panel ESPB contacts (8 and 7) (line 23). At this point in the start-up, the current flows through arming relay contacts (2 and 8) (line 31) to slave relay (SR1) (line 36) energizes and closes its contacts (1 and 3) (line 43) to energize the fuel solenoid (FS) (line 43). This provides fuel for start-up.

RR (7 and 4) - N.O. contact across RR (7 and 4) 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) (line 17) will open to terminate cranking. Contacts ESS (CT) (10 and 11) (line 17) will close to energize the arming delay timer (ADT) (line 34) which begins timing. In addition, another current path is now provided through ESS (CT) contacts (11 and 10), diode (D2) (line 29), ESS (OS) contacts (8 and 9) (line 29), engine ESPB contacts (1 and 2) (line 18), water temperature switch (WTS) (line 18) and through to RR contacts (6 and 9) (line 23) to the oil pressure switch (OPS1) (line 13).

Assuming the engine has adequate oil pressure, the current flow will continue through OPS1 contacts (1 and 2) (line 13), through ESS (OPSS) contacts (14 and 15) (line 13) down to SR1 (line 36). Approximately 10 seconds after crank termination, the ADT (line 34) will time out and energize arming relay (AR) (line 34). Relay (AR) then opens its contacts (2 and 8) (line 31) and closes AR contacts (7 and 4) (line 15). 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) setpoint, the ESS (OPSS) contact (14 and 15) (line 13) will open and (14 and 13) (line 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) (line 13) 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 (line 36) to keep the FS (line 43) energized and the engine running.

With ECS in the auto or manual positions, the ECS contact across ECS (11 and 12) (line 26) or ECS (15 and 16) (line 27) 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) (line 58), the ESS opens the starting motor circuit through the opening of crank termination switch contact across ESS (CT) (11 and 12) (line 17). At the same time, ESS (CT) contact across ESS (11 and 10) (line 17) 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 26) opens. With the ECS in the manual position, engine shutdown occurs when the operator turns the ECS to the stop position.

When either the IC opens (automatic) or ECS contact across (1 and 2) (line 24) opens (manual), run relay (RR) (line 23) 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 7) 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 23) opens to de-energize the slave relay (SR1), which in turn opens its contact across SR1 (1 and 3) (line 43), to de-energize the fuel solenoid (FS) (line 43). Also, the contact across RR (6 and 9) opens to de-energize the oil pressure fault circuit through OPS1, (line 13), ESS (OPSS) (line 13) and OPS2 (line 13).

RR (7 and 4) - N.O. contact across RR (7 and 4) (line 34) opens to de-energize the arming relay (AR) (line 34) and reset the arming delay timer (ADT) (line 34). Relay (AR) (line 34) opens its contact across AR (7 and 4) (line 15) to keep the oil pressure fault relay (OPR) (line 15) and fault light (OPL) (line 16) from indicating a fault on normal start-up.

Engine Shutdown Caused By 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 contact across RR (6 and 9) (line 23) is closed to complete two current paths to energize slave relay (SR1) (line 36) and in turn the fuel solenoid (FS) (line 43). One path is through contact AR (2 and 8) (line 31). The other path is through oil pressure switch (OPS1) (line 13) terminals (1 and 2) and through electronic speed switch (ESS) oil pressure step switch (OPSS) terminals (14 and 15) (line 13).

At start-up when oil pressure is less than 140 kPa (20 psi), (OPS1) remains closed across terminals (1 and 3) (line 13). Arming delay timer (ADT) (line 34) keeps the arming relay (AR) (line 34) from energizing for 10 seconds after crank termination. After the 10 second delay, relay (AR) closes its contact across AR (7 and 4) (line 15) which completes the circuit to the oil pressure fault relay (OPR) (line 15) and the fault light (OPL). Also, the contact across AR (2 and 8) (line 31) opens to de-energize the relay (SR1). This de-energizes the FS and shuts off fuel to the engine.

When relay (OPR) (line 15) energizes, its contact (line 16) closes to latch in OPR. Also, its contact (line 41) closes to energize engine fault relay (ENFR) (line 43). Relay (ENFR) opens the contact across ENFR (8 and 2) (line 24) which de-energizes RR. With relay (RR) de-energized, its contacts open to provide another circuit to shut the engine down.

The contact across RR (6 and 9) opens to maintain the open circuit to SR1.

The contact across RR (8 and 5) (line 7) opens to keep the starting motor circuit from energizing when the ESS crank termination switch (CT) closes across terminals ESS (11 and 12) (line 17) (after engine stops).

The contact across RR (7 and 4) (line 34) opens to de-energize the arming relay (AR) (line 34). With AR de-energized, the contact across AR (7 and 4) opens to make possible another start-up. The contact across AR (2 and 8) (line 31) closes 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).

3. Rotate the ECS to OFF/RESET position which opens the circuit across ECS terminals (11 and 12) (line 26). This allows the OPR (line 15) to de-energize. OPR contact (line 16) opens and shuts off the light (OPL). Also, OPR contact (line 41) opens to de-energize the relay (ENFR). The contact across ENFR (8 and 2) (line 24) now closes to allow restart.

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

Engine Shutdown Caused By 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) (line 13) engine step speed setting without the required oil pressure, current flows as follows:

Through ESS crank termination (CT) terminals (11 and 10) (line 17); through ESS overspeed (OS) terminals (8 and 9) (line 29); through emergency stop pushbutton (ESPB) terminals (1 and 2) (line 18) and through water temperature switch (WTS) (line 18) to the RR contact (6 and 9) (line 23) of the control panel. From the contact across RR (6 and 9), current can flow one or two directions. Through the contact across AR (2 and 8) (line 31) to relay (SR1) (line 36) [if the 10 second time delay has not elapsed from the arming relay delay (ADT) (line 34)] and/or through oil pressure switch (OPS1) (line 13). In this fault, oil pressure is sufficient to close (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, (OPS2) has 9 seconds to close before ESS (OPSS) closes across its contacts (14 and 13) (line 13) to complete the circuit through the now closed contact across AR (7 and 4) (line 15) to the oil pressure fault relay (OPR) (line 15) and fault light (OPL) (line 16). In addition, once ESS (OPSS) opens its contacts (14 and 15) (line 13), it will immediately open the circuit that keeps SR1 energized.

When relay (OPR) energizes, its contact (line 16) closes to latch in OPR.

Also, the OPR contact (line 41) closes to energize engine fault relay (ENFR) (line 43). Relay (ENFR) opens the contact across ENFR (8 and 2) (line 24) which de-energizes relay (RR). With relay (RR) de-energized, its contacts open to maintain the engine shutdown.

The contact across RR (6 and 9) (line 23) opens to maintain the open circuit to SR1 (line 36).

The contact across RR (8 and 5) (line 7) opens to keep the starting motor circuit from energizing when the ESS crank termination switch (CT) closes across terminals ESS (11 and 12) (line 17) (after engine stops).

The contact across RR (7 and 4) (line 34) opens to de-energize the arming relay (AR) (line 34). With AR de-energized, the contact across AR (7 and 4) (line 15) opens so that the engine control switch (ECS) can clear the fault indicators (OPR) and (OPL) at restart. The contact across AR (2 and 8) (line 31) closes 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).

3. Rotate the ECS to OFF/RESET position which opens the circuit across ECS terminals (11 and 12) (line 26). This allows the OPR (line 15) to de-energize. OPR contact (line 16) opens and shuts off the light (OPL). Also, OPR contact (line 41) opens to de-energize the relay (ENFR). The contact across ENFR (8 and 2) (line 24) now closes to allow restart.

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

Engine Shutdown Caused By Water Temperature

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) (line 18) 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 23); through switch (OPS1) (line 13); through switch ESS (OPSS) (line 13); through a jumper (or optional OPS2) (line 13) and diode (D4) (line 14) to de-energize slave relay (SR1) (line 36). Relay (SR1) opens its normally open contact (line 43) to de-energize the fuel solenoid (FS) (line 43) and shut the engine down. No current at (OPS1) and (OPS2) also prevents the oil pressure fault relay (OPR) (line 15) from energizing when switches (OPS1) and (OPS2) close during engine shutdown.

2. On the closed side of the switch (WTS), current flows to and energizes the water temperature relay (WTR) (line 18) and water temperature fault light (WTL). The WTL contact (line 19) closes to lock in the relay (WTR). The normally open (N.O.) WTR contact (line 42) closes to energize the engine failure relay (ENFR) (line 43). With ENFR energized, the contact across ENFR (8 and 2) (line 24) opens to de-energize run relay (RR) (line 23). With relay (RR) de-energized, the contact across RR (8 and 5) (line 7) 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 clear 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 Shutdown Caused By Engine Overspeed

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) (line 29) and open across terminals ESS (8 and 9) (line 29). When ESS (OS) closes across terminals ESS (7 and 8), the following occurs:

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

2. Energizes the slave relay (SR2) (line 33) which closes its normally open contact to energize the air shut-off solenoid (ASOS) (line 47). The (ASOS) assists the de-energized fuel solenoid (FS) (line 43) in engine shutdown by shutting off engine combustion air.

3. Current flows through diode (D12) (line 36) to energize the engine failure relay (ENFR) (line 43). Relay (ENFR) opens normally closed contact across ENFR (8 and 2) (line 24) which de-energizes run relay (RR) (line 23). With relay (RR) de-energized, the contact across RR (8 and 5) (line 7) 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).

4. Current flows to the overspeed fault relay (OSR) (line 29) and to the fault light (OSL) (line 30). Relay (OSR) energizes to close the OSR contact (line 30) which latches in OSR. The OSR contact (line 43) closes to also energize relay (ENFR). This is necessary because as soon as the engine stops, ESS (CT) (line 17) closes across terminals ESS (11 and 12) (line 17) and cuts off current through ESS (OS) (line 29). This in turn cuts off current to SR2 (line 33) and to ENFR (line 43).

When ESS (OS) opens across terminals ESS (8 and 9) (line 29) the following occurs:

1. Current is stopped from flowing through emergency stop pushbutton (ESPB) terminals (1 and 2) (line 18); through the water temperature switch (WTS) (line 18); through contact RR (6 and 9) (line 23); through oil pressure switch (OPS1) (line 13); through ESS oil pressure step switch (OPSS); through a jumper or (OPS2) and through diode (D4) (line 14) to de-energize slave relay (SR1) (line 36). With relay (SR1) de-energized, the normally open (SR1) contact across SR1 (1 and 3) (line 43) opens to de-energize the fuel solenoid (FS) (line 43) which assists the (ASOS) in engine shutdown by shutting off fuel.

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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 clear the fault relay (OSR) and fault light (OSL).

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

Engine Does Not Start

NOTE: Make reference to section, ENERGIZE TO SHUTOFF ENGINE SYSTEM, Engine Does Not Start.

Operation of Emergency Stop Pushbutton (ESPB) (Energize To Run System)

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 (line 9) on the junction box shuts the engine down as follows:

When pushed in, ESPB creates an open circuit across terminals (1 and 2) (line 9) to open the starting motor circuit. Another open circuit across terminals (1 and 2), de-energizes slave relay (SR1) (line 36) which opens its normally open contact to de-energize the fuel solenoid (FS) (line 43). This shuts-off fuel to the engine.

When pushed in, ESPB closes across terminals (3 and 4) to energize slave relay (SR2). Relay (SR2) closes its normally open contact to energize the air shut-off solenoid (ASOS). This effectively shuts-off air to the engine. ASOS remains energized until ECS (CT) contacts (10 and 11) (line 17) re-open after the engine stops.

ESPB contacts (3 and 4) (line 33) also provide a current path to turn on the OSL (line 30) in the control panel. Another set of ESPB contacts (3 and 4) (line 34) 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 23) to de-energize SR1 (line 36) and shut-off fuel to the engine. There is also an open across ESPB terminals (1 and 2) (line 24) which de-energizes run relay (RR) (line 23). Relay (RR) opens normally open contact across RR (8 and 5) (line 7) to open the starting motor circuit.

ESPB closes across terminals (6 and 5) (line 31) to energize relay (SR2)_(line 33) which in turn energizes the solenoid (ASOS) (line 47). Solenoid (ASOS) effectively shuts-off air to the engine. ASOS remains energized until the engine stops and ESS (CT) contacts (11 and 10) (line 17) re-open.

ESPB contacts (6 and 5) (line 31) also provide a current path to turn on the OSL (line 30) in the control panel. Another set of ESPB contacts (3 and 4) (line 28) prevent OSL from being reset by the ECS until ESPB is reset.

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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 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 clear the OSR and OSL.

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