The charging circuit is in operation when the engine is running. An alternator makes electricity for the charging circuit. A voltage regulator in the circuit controls the electrical output. The electrical output maintains the battery at full charge.
| NOTICE |
|---|
The disconnect switch, if so equipped, must be in the ON position for the electrical system to function properly. There will be damage to some of the charging circuit components if the engine runs with the disconnect switch in the OFF position. |
The starting circuit is in operation only when the start switch is activated.
The charging circuit is connected through the ammeter. The starting circuit is not connected through the ammeter.
Charging System Components
Alternator
 | |
| Illustration 1 | g00292313 |
Delco-Remy Alternator (1) Regulator. (2) Roller bearing. (3) Stator winding. (4) Ball bearing. (5) Rectifier bridge. (6) Field winding. (7) Rotor assembly. (8) Fan. | |
The alternator is driven by vee shaped belts from the crankshaft pulley. This alternator is a three-phase, self-rectifying charging unit, and the regulator is part of the alternator.
The rotor assembly has many magnetic poles. There is a space between the opposite magnetic poles. The poles have residual magnetism which produces a small amount of magnet-like lines of force between the poles. A small amount of alternating current is produced as the rotor assembly begins to turn between the field winding and the stator windings. This alternating current is produced from the small magnetic lines of force that are created by the residual magnetism. The alternating current changes to direct current. This happens as the alternating current passes through the diodes of the rectifier bridge. Most of the current charges the battery. Some of this current supplies the low amperage circuit, and the remainder of the current is sent to the field windings. The DC current flow through the field windings increases the strength of the magnetic lines of force. The stronger lines of force increase the amount of the alternator current that is produced in the stator windings. The increased speed of the rotor assembly also increases the current and voltage output of the alternator.
The voltage regulator is a solid-state electronic switch. This switch feels the voltage in the system. The switch turns on and off multiple times in a second. This controls the field current for the alternator which will produce the necessary voltage output.
Starting System Components
Solenoid
A solenoid is a magnetic switch that performs two basic operations:
- The solenoid closes the high current starter motor circuit with a low current start switch circuit.
- The solenoid engages the starter motor pinion with the ring gear.
 | |
| Illustration 2 | g00292316 |
Typical solenoid schematic | |
The solenoid switch is made of an electromagnet around a hollow cylinder. There is a spring loaded plunger inside the cylinder. This plunger can move forward and backward. When the start switch is closed and electricity is sent through the windings, a magnetic field is created. This magnetic field pulls the plunger forward in the cylinder. This causes the shift lever to engage the pinion drive gear with the ring gear. The front end of the plunger makes contact across the battery and motor terminals of the solenoid. The starter motor begins to turn the flywheel of the engine.
When the start switch is opened, current no longer flows through the windings. The spring pushes the plunger back to the original position. While the plunger moves back to the original position, the pinion gear moves away from the flywheel.
When two sets of windings in the solenoid are used, one set of windings is referred to as the hold-in winding, and the other set of windings is referred to as the pull-in winding. Both sets of windings have the same number of turns around the cylinder. This pull-in winding uses a wire with a larger diameter. A wire with a larger diameter produces a stronger magnetic field. When the start switch is closed, part of the current flows from the battery through the hold-in windings. The remainder of the current flows through the pull-in windings to the motor terminal. The current then flows through the motor to ground. When the solenoid is fully activated, the current is shut off through the pull-in windings. The smaller hold-in windings are in operation for an extended period of time when the engine is started. The solenoid will take less current away from the battery. Heat that is produced by the solenoid will be kept at an acceptable level.
Starter Motor
The starter motor is used to turn the engine flywheel. The flywheel must reach a certain speed in order to start the engine.
The starter motor has a solenoid. When the start switch is activated, the solenoid will move the starter pinion. The starter pinion will engage with the ring gear on the flywheel of the engine. This will happen before the electric contacts in the solenoid close the circuit between the battery and the starter motor. When the circuit between the battery and the starter motor is complete, the pinion will turn the engine flywheel. A clutch gives protection for the starter motor. The clutch prevents the engine from turning the starter motor too fast. When the start switch is released, the starter pinion will move away from the ring gear.
 | |
| Illustration 3 | g00292330 |
Starter motor cross section (1) Field. (2) Solenoid. (3) Clutch. (4) Pinion. (5) Commutator. (6) Brush assembly. (7) Armature. | |
Other Components
Circuit Breaker
 | |
| Illustration 4 | g00281837 |
Circuit Breaker Schematic (1) Reset button. (2) Disc in the open position. (3) Contacts. (4) Disc. (5) Battery circuit terminals. | |
The circuit breaker is a switch that opens the battery circuit if the current in the electrical system goes higher than the rating of the circuit breaker.
The electric current through the circuit breaker is completed with a metal disc. This metal disc is activated by heat. The metal disc will become hot if there is too much current in the electrical system. This heat causes a distortion of the metal disc. This distortion of the metal disc opens the contacts. When the contacts open, the circuit breaks. An open circuit breaker can be reset after the temperature has dropped. The contacts must be closed in order to reset the circuit breaker. Push the reset button in order to reset the circuit breaker.
Wiring Diagrams
Engine Protection Systems, Starting, Charging, and Tachometer Circuits
This section contains point-to-point wiring diagrams for the engine protection systems, and for the following circuits:
- starting circuit
- charging circuit
- tachometer circuit
These diagrams can be helpful to a person that is not familiar with the electrical schematic type format. These diagrams may also be useful to a person that is interested in the component position layout for replacement purposes.
NOTES
A: The cable should only be grounded at the tachometer if the tachometer is used without an electric speed switch. Ground the cable at the speed switch if a speed switch is used.
B: This grounded system is required for the proper operation of the shutoff system.
C: If the 2301A Governor is used, only one magnetic pickup is required. Use the magnetic pickup from the speed switch. Connect the magnetic pickup to the speed switch. Connect the speed switch to the 2301A Governor Control. Do not use multiple grounds on any length of the shielded cable.
D: If the electric starting motor is not used, connect the battery cables to the studs for the power input. These studs are located on the bottom of the power distribution box. In some cases, the electric starting motor may not be used. In some cases, the charging alternator arrangement may not be used. If these parts are not used, connect the positive lead from a power source to the terminal TS1. This positive lead must be 24 volts from a DC power source. Terminal TS1 is located on the junction box terminal strip. Connect the negative lead to terminal TS28.
E: The diagrams and the schematics for the wiring of the junction box are provided with the junction box.
F: Attach the ground wire to the ground strap bolt. The ground strap bolt is on the mounting bracket for the junction box.
G: The jumper on the junction box terminal strip between point TS-30 and point TS-31 must be removed. This must be done when a right hand mounted start/stop switch is used on an engine that has no external power source.
H: The bypass switch must be held in the upward position during engine start-up. Hold the bypass switch in the upward position until the correct oil pressure is reached in the engine. If this is not done, the engine will stop.
J: Attach the ground wire to the bolt for the mounting bracket on the start/stop switch.
K: This start/stop switch is only required on a magneto that has variable timing.
L: A start/stop switch is required with oil pressure, water temperature, and the overspeed protection system. This is required in an application that is not an automatic application.
M: The jumper wire that is on the terminal strip between points TS-4 and TS-5 must be removed when a remote normal stop switch is used.
N: Location of the contactors on the magneto
Location of shutoff contactors for Altronic magneto ... G
Location of shutoff contactors for Fairbanks-Morse magneto ... H
P: Remove the jumper wire. The jumper wire is located between the TS-31 terminal and the TS-32 terminal. This should be done when the gas shutoff valve is used.
 | |
| Illustration 5 | g00607718 |
Abbreviations
- ALT (Alternator)
- ASSV (Air Start Solenoid Valve)
- AWG (American Wire Gauge)
- BATT (Battery)
- BT (Combustion Burn Time)
- BTU (British Thermal Unit content/cu ft)
- CAS (Crank Angle Sensor)
- CCM (Customer Communication Module)
- CCW (Counterclockwise)
- CMS (Computerized Monitoring System)
- CTR (Crank Termination Relay)
- CW (Clockwise)
- DDT (Digital Diagnostic Tool)
- DDTC (Digital Diagnostic Tool Connector)
- ECM (Engine Control Module)
- EFR (Engine Failure Relay)
- EFRX (Engine Failure Relay External)
- ESS (Engine Supervisory System)
- FCR (Fuel Control Relay)
- GSOV (Gas Shutoff Valve)
- LHDS (Left Hand Detonation Sensor)
- MAN (Manual)
- PLPSR (Prelube Pressure Switch Relay)
- PLR (Post Lube Relay)
- PWM (Pulse Width Modulation)
- RHDS (Right Hand Detonation Sensor)
- RR (Run Relay)
- SCM (Status Control Module)
- SEC (Second)
- SIG (Signal)
- SMR (Starting Motor Relay)
- SR1 (Slave Relay 1)
- SR2 (Slave Relay 2)
- TCM (Timing Control Module)
- TCMPU (Timing Control Module Speed Pickup)
- XDUCER (Transducer)
 | |
| Illustration 6 | g00607732 |
 | |
| Illustration 7 | g00607748 |
Junction Box Wiring Diagrams
This section contains point-to-point junction box wiring diagrams. These diagrams can be helpful to a user that is not familiar with an electrical schematic format. These diagrams are also helpful to a user that is interested in the component position layout for replacement purposes.
Note: The independent ETR junction boxes are used on a variety of engines. The ETR junction boxes that have an automatic protection system are used on a variety of different engines. The parts in the junction box wiring diagram are not in every engine.
 | |
| Illustration 8 | g00607769 |
Electrical System
Three electrical systems are available to provide engine protection. In each case, engine shutoff is achieved by grounding the magneto or CDIS system. Each system is capable of activating the gas shutoff valve.
- For the self-powered protection system, oil pressure protection and water temperature protection are provided. If these components are combined with a mechanical overspeed contactor switch, full protection is obtained. A gas valve is available. This valve will shut off if the valve is energized. This valve is activated by magneto voltage.
- An ETR system that is not an automatic start/stop system provides protection for the following items.
- oil pressure
- water temperature
- engine overspeed
An electronic speed switch (ESS) is used for overspeed (OS) protection. This system is a fully independent system. An external power source of 24 volts is required for this system. A gas shutoff valve is also required for this system.
- oil pressure
- An ETR system that is an automatic start/stop system is similar to the system that does not have an automatic start/stop system. There is a significant difference between the two systems. The second system is an independent system. A cranking panel must be wired into an automatic start/stop system. This will provide the logic input for starting and stopping.
Electrical Schematics And Wiring Diagrams
Electrical schematic foldouts are provided in this section with the text for each protection system. Use the electrical schematics to follow the circuit operations of the protection systems.
Point-to-point wiring diagrams for the protection systems, and for the circuits are located in the Wiring Diagrams Section of this module. Use the diagrams in order to find the layout of the components.
Components
There are three protection systems that are available on 3408 and 3412 spark ignited engines. The following components may be used on one or more of the protection systems.
Water Temperature Sending Unit (WTSU)
 | |
| Illustration 9 | g00601099 |
Sending Unit For Water Temperature (1) Bulb. (2) Bushing. (3) Connection. | |
The sending unit for water temperature is an electrical resistance. The sending unit changes the value of resistance. The bulb (1) senses the temperature. This temperature will change the resistance.
The sending unit is in a series circuit with the electrical gauge. When the temperature is high, the resistance is high. When the resistance is high, the gauge will have a high reading.
The sending unit must be in contact with the coolant. If the coolant level is too low, the sending unit will not work correctly. The coolant level may be too low because of a sudden loss of coolant. The coolant level may be too low if the amount of coolant in the engine before engine start-up was not sufficient.
This sending unit requires twenty-four volts. The sending unit is only used with protection systems that are energized to run.
Oil Pressure Sending Unit (OPSU)
 | |
| Illustration 10 | g00601233 |
Typical Example (1) Oil Pressure Sending Unit. | |
Electrical resistance is the sending unit for oil pressure. This sending unit has a material that changes electrical resistance according to the pressure that is sensed.
The sending unit for oil pressure is in a series circuit with the electrical gauge. As the pressure on the sending unit changes, the reading on the gauge changes in the same way.
This sending unit requires twenty four volts DC. This unit is only used with protection systems that are energized to run.
Electric Service Meter
The electric service meter is self-powered. A magnetic pickup that is mounted on the flywheel housing will provide the voltage that is needed to power the electric service meter. This magnetic pickup will provide voltage at a minimum of 200 engine rpm. The electric service meter records clock hours with quartz accuracy. A separate magnetic pickup must be used for each service meter. The electric service meter cannot be shared with any of the following components.
- digital tachometer
- electronic speed switch
- electronic governor magnetic pickup
Water Temperature Contactor Switch (WTS)
A water temperature contactor switch is located in the cooling system. The unit is nonadjustable. Thermal expansion of the element operates a microswitch that signals the shutoff solenoid which causes engine shutdown. The water temperature element must be in contact with the coolant. If overheating occurs, the unit will not function. Overheating may be caused by a low coolant level or having no coolant.
The water temperature sending unit can be wired into an alarm system or to a light. This will signal a high water temperature. After an overheated engine is allowed to cool, the contactor will automatically reset.
 | |
| Illustration 11 | g00580098 |
Magnetic Pickup (MPU)
 | |
| Illustration 12 | g00608052 |
The magnetic pickup is a permanent magnet generator that is made with one pole. The magnetic pickup is made of wire coils that are turned around a permanent magnet pole piece. As the teeth of the flywheel ring gear go through the magnetic lines of force around the magnetic pickup, an AC voltage is created. A positive voltage is made when each gear tooth passes by the pole piece. As the spaces between the teeth pass by the pole piece, a negative voltage is created. Engine speed is determined by the frequency of these signals.
Overspeed Contactor Switch
The overspeed contactor is used in a self-powered protection system to protect the engine from damage due to overspeeding. This switch contains a microswitch that is activated by high engine speeds. The overspeed switch is mounted on the tachometer drive. If the engine overspeeds, the contacts of the switch will close. This action connects the magneto to ground in order to shut down the engine. When the engine shuts down due to overspeeding, the overspeed contactor switch must be reset. This switch is reset by pushing the reset button (1). The overspeed contactor switch is adjustable.
 | |
| Illustration 13 | g00580699 |
Overspeed Contactor (1) Reset button. | |
Oil Pressure Switch (OPS)
 | |
| Illustration 14 | g00580111 |
The oil pressure switch uses a spring loaded piston to activate a microswitch for a specific pressure rating. This type of switch has better accuracy over the operating temperature range. A much higher electrical contact rating is used to improve reliability.
Slave Relay (SR)
This is a standard type of relay. When this relay is energized, the contacts open across one circuit. The contacts close across another circuit. The circuits are wired in a specific manner. When the relay is energized, voltage is allowed to flow from the magneto to the spark plugs. When the relay is not energized, the voltage from the magneto will go to ground. This relay is not used on the self-powered protection system.
Electronic Speed Switch (ESS)
 | |
| Illustration 15 | g00580167 |
Electronic Speed Switch (ESS) (1) Verify button. (2) Reset button. (3) LED Overspeed light. (4) Seal screw plug (overspeed). (5) Seal screw plug. | |
The Electronic Speed Switch (ESS) is designed with controls that are built into a single unit. These controls monitor several functions at the same time. The functions that are monitored by the ESS are listed below.
Engine Overspeed (OS)
This is an adjustable engine speed setting. The normal engine speed setting is 128 percent of the rated speed for the engine. This will prevent the engine from running at a speed that could cause damage. The engine overspeed setting will cause a switch to close. The switch will shut off the fuel to the engine. The magneto will connect to ground in order to stop the current flow to the spark plugs.
Crank Termination (CT)
This is an adjustable engine speed setting that signals the starter motor that the engine is firing and cranking must be terminated. When the speed setting is reached, a switch will open in order to stop the current flow to the starter motor circuit. The starter motor pinion gear will now disengage from the engine flywheel ring gear.
Junction Box
 | |
| Illustration 16 | g00580701 |
Junction Box (1) Terminal strips (TS). (2) Location for the electric speed switch (ESS). (3) Emergency stop switch (ES). (4) Location for the slave relay (SR). (5) Bypass for the stop switch. (6) Location for circuit breakers. | |
The junction box contains the terminal strips (TS) and the emergency stop switch (ESS). An oil pressure switch (OPS) is located at the back of the junction box. The junction box may contain some other items according to the type of protection system that is used. The following items may be in the junction box: electric speed switch (ESS), slave relay (SR), circuit breakers (CB), bypass switch for starting (SBS) and start/stop switch (SSS).
Self-Powered Protection System
This system requires no external power for electrical protection. When the engine is started by a separate system, the engine has some protection. The following items protect the engine: low oil pressure fault (OP) and high water temperature fault (WT). Overspeed protection is provided if a mechanical overspeed contactor switch is wired into the system. There is a valve that is available as an option for the engine. This valve is a gas valve (GSOV) that will shut off when the valve is energized.
The following components are contained in the junction box: bypass switch for starting (SBS), emergency stop switch (ES) and an oil pressure switch (OPS).
To follow the circuit operations of this protection system, refer to Electrical Schematic For Self-Powered Protection. This is located at the end of this text.
The point-to-point wiring diagram for this protection system and the junction box are located in the Wiring Diagrams portion of this text.
No Fault Circuit Operation
Stopped Engine
With a stopped engine, no electrical power is available to the system. The water temperature switch (WTS) and the mechanical overspeed switch (MOS) are in the normally open positions. Oil pressure switch (OPS1) is in the normally closed position.
Engine Start-up
When the engine is started by a separate system the bypass switch must be held in the upward position. This is done between contacts SBS-2 & 3 and contacts SBS 5 & 6. Hold the switch in the upward position until the correct engine oil pressure is reached. The voltage from the magneto will travel to ground.
The magneto voltage will travel to ground if the correct oil pressure is not reached. This voltage will travel to ground through closed contacts SBS-2 & 3, and through the closed oil pressure switch (OPS1). The voltage that travels through the gas shutoff valve energizes the valve coil. This shuts off the gas to the engine. At the same time, the circuit between contacts GSOV-1 & 3 opens and the circuit between contacts GSOV-1 & 5 closes. This grounds the voltage from the magneto. This will prevent sparking to the cylinders.
Once oil pressure is achieved, oil pressure switch OPS1 will open. The bypass switch for starting can now return to the RUN position. This position will have closed contacts between SBS-2 & 3, and open contacts between SBS-4 & 5. The voltage from the magneto is not allowed to travel to ground.
Running Engine
When the engine is running without any problems, the voltage in the magneto is not grounded. The following items will be open: The oil pressure switch (OPS1), the mechanical overspeed switch, the water temperature switch (WTS) and (MOS), and the emergency stop switch (ESS). The voltage from the magneto is not felt by the valve coil of the gas shutoff valve (GSOV). Gas is allowed to flow to the engine.
Normally Stopped Engine
The engine is stopped by pressing downward on the bypass switch for starting. This is the stop position that closes contacts SBS-5 & 6. The stop position allows the voltage in the magneto to go to ground. This prevents sparks at the cylinders. The valve coil of the gas shutoff valve is energized by the voltage from the magneto. The gas supply is shut off. At the same time, the circuit between contacts GSOV-1 & 3 opens and the circuit between contacts GSOV-1 & 5 closes. This grounds the voltage from the magneto.
Emergency Stop Switch (ES)
The emergency stop switch is the red button that is mounted on the junction box door. This switch will shut down the engine. If this button is locked in the ON position, the engine will not restart.
The voltage from the magneto will flow through the contact ES-3 and the contact ES-4, if the switch is in the OFF position. The voltage flows to ground in order to prevent sparking at the cylinders. The valve coil of the gas shutoff valve is energized by the voltage from the magneto. This will shut off the gas supply. The circuit will open between the contact GSOV-1 and contact GSOV-3. The circuit between contact GSOV-1 and contact (5) will close. This will ground the voltage from the magneto.
 |
To prevent personal injury due to accidental starting of the engine, disconnect the batteries during maintenance or repair work. |
 |
Before starting the engine again, perform the steps that follow:
- Correct any faults that may have been the cause of the emergency shutdown.
- When a gas engine has been stopped by a grounded magneto, certain steps must be followed. Run the engine while the gas valve is turned off and the magneto is grounded. Run the engine for 10 seconds to 15 seconds. This will clear the unburned gas from the exhaust system.
|
Unburned gas can ignite when the engine is restarted. |
|
- Make sure that the ES has been reset on the engine junction box. The ES has been reset if the push button is out. Push the push button in the direction that is shown on the button face.
- Manually reset the gas shutoff valve.
- Start the engine and hold the bypass switch for starting SBS in the upward position. Hold this switch until the correct oil pressure is reached.
Fault Circuit Operation
Low Oil Pressure (OP), High Coolant Temperature (WT) and Optional Engine Overspeed (OS)
When the engine is running, any of the following faults will cause the magneto voltage to be grounded through the respective switch:
- Oil pressure drops below a certain setting of the oil pressure switch (OPS1). This will cause the switch to close.
- The coolant temperature exceeds the setting of the water temperature switch (WTS). This will cause the switch to close.
- Engine speed increases above the overspeed setting of the mechanical overspeed switch (MOS). This will cause the switch to close.
No spark is available for the cylinders if the magneto is grounded. Voltage from the magneto that flows to any of the closed switches will energize the gas shutoff valve. The energized GSOV then shuts off the gas supply. The circuit that is between contact GSOV-1 and contact GSOV-3 will open. The circuit that is between contact GSOV-1 and contact GSOV-5 will close. The voltage from the magneto will be grounded.
|
Unburned gas can ignite when the engine is restarted. |
|
When a gas engine has been stopped by a grounded magneto, certain steps must be followed. Run the engine while the gas valve is turned off and the magneto is grounded. Run the engine for 10 seconds to 15 seconds. This will clear the unburned gas from the exhaust system.
| NOTICE |
|---|
To avoid engine damage, repair or correct the problem that causes engine shutdown before restarting. |
Note: It is possible to add more modes for fault detection. This can be done by adding the appropriate switches between certain terminal strip points. These switches should be added between one of the following points, and terminal strip point TS-28: terminal strip point TS-1, terminal strip point TS-2 and terminal strip point TS-3.
Electrical Schematic Self-Powered Protection
NOTES
F: Attach a ground wire in order to ground the strap bolt on the mounting bracket for the junction box.
G: If a start/stop switch that is mounted on the right hand side is used on an engine, a jumper wire must be removed. The jumper wire that must be removed is on the junction box terminal strip between the point TS-30 and the point TS-31.
H: The bypass switch for stopping must be held in the upward position during engine start-up. This must be done until oil pressure is achieved. Failure to hold this switch in the upward position will result in engine shutdown.
N: Shutoff contactor for the magneto or CDIS
Altronic ... G
NOTE P: If a gas valve is used, a jumper wire must be removed. The jumper wire that must be removed is between the point TS-31 and the point TS-32.
 | |
| Illustration 17 | g00607954 |
ETR, Independent, Full Protection System
This fully independent system requires external DC voltage of 24 volts for electrical engine protection. The engine is monitored for the following items: engine overspeed OS, oil pressure OP and water temperature WT. The gas shutoff valve (GSOV) is energized to run (ETR).
The junction box contains an electric speed switch (ESS), slave relay (SR1), oil pressure switch (OPS1), circuit breaker (CB5), start/stop switch (SSS) and emergency stop switch (ES). With this system, the slave relay remains energized. This allows the engine to run.
To follow the circuit operations of this protection system, refer to the Electrical Schematic For ETR, Independent, Full Protection at the end of this text.
The point-to-point wiring diagram for this protection system and this junction box are located in the wiring diagrams section of this text.
No Fault Circuit Operation
Engine Stop
With a stopped engine, power is always available across terminal 5 and terminal 6 of the electronic speed switch (ESS). Terminal 5 and terminal 6 are located on line 54 of the schematic. All switches are in the normal positions of operation.
Engine Start-Up
Note: A spring loaded start/stop switch is located on the front of the junction box door. This switch will automatically return to the RUN position when the switch is released from the START position.
When the Start/Stop Switch (SSS) is moved to the START position, the circuit to the starter motor is closed across terminals SSS-2 and SSS-1. These terminals are located on line 9 in the schematic. The starter motor magnetic switch (SMMS) will energize. This will close the contact on the switch. This will energize the pinion solenoid PS. This solenoid is located on line 3 of the schematic. Solenoid PS will close the contact. This will energize the starter motor (SM). This contact is located on line 2 of the schematic.
The current flows across terminal SSS-11 and terminal SSS-10. These terminals are located on line 24. The current will arm slave relay (SR1), and the ETR gas shutoff valve (GSOV). The energized SR1 opens contacts across terminal SR1-1 and terminal SR1-2. This will close the contacts across terminal SR1-1 and terminal SR1-3. The magneto is prevented from being grounded.
When the engine starts to run, the setting for the crank termination speed will be reached. When this speed is reached, the switch for crank terminate ESS (CT) will open contacts. The contacts are located across terminal ESS-11 and terminal ESS-12. The contacts across terminal ESS-10 and terminal ESS-11 will close. These terminals are located on line 17.
The ESS (CT) contacts will open across terminal ESS-11 and terminal ESS-12. This will stop the current flow to the starter motor circuit. The starter motor (SM) will stop.
At this point, the engine has started to run. The setting for the crank termination is reached. The correct oil pressure is not yet achieved. The SSS is held in the START position. Current is flowing through terminal ESS-11 and terminal ESS-10. Current is also flowing through terminal ESS-8 and terminal ESS-9. These terminals are located on line 20. Current is also flowing through the following terminals: terminal ES-1, terminal ES-2, terminal WTS-2, terminal WTS-3, terminal SSS-11 and terminal SSS-10. Oil pressure switch OPS1 is bypassed due to low oil pressure. This switch is open at terminal OPS1-1 and terminal OPS1-2.
When the correct oil pressure is reached, terminal OPS1-1 and terminal OPS1-3 for the oil pressure switch will open. Terminal OPS1-1 and terminal OPS1-2 will close. The SSS switch can be released to the normal RUN position. This will close contacts across terminal SSS-11 and terminal SSS-12. OPS1 is now included in the circuit. Full protection for the engine is now provided from OP, WT, and OS.
Running Engine
In an engine that is operating properly, oil pressure switch OPS1 will be closed across contact OPS1-1 and contact OPS1-2. Current will continue to flow to energize the slave relay SR1 and the gas shutoff valve (GSOV). The engine will continue to run with these conditions.
Engine Stop
The operator stops the engine by pressing the start/stop switch (SSS). This switch is pressed from the RUN position to the STOP position.
When the SSS is moved to the STOP position, the SSS opens across contact SSS-5 and contact SSS-4. This will stop current flow through terminal OPS1-1 and terminal OPS1-2. With no current from OPS1, the gas shutoff valve (GSOV) will close. SR1 will be de-energized. Terminal SR1-1 and terminal SR1-3 will open. Terminal SR1-1 and terminal SR1-2 will close. This will ground the magneto. Sparks are now prevented from reaching the cylinders.
After complete engine shutdown is accomplished, the electronic speed switch ESS (CT) will close. This switch will close across terminal ESS-11 and terminal ESS-12. This allows the engine to be restarted immediately.
Emergency Stop Switch (ES)
The emergency stop switch ES is a red push button. This switch is located on the front of the junction box door. This push button will shut down the engine. The engine is also prevented from restarting because the switch locks in the OFF position.
When the ES is pushed in, an open circuit is created across contact ES-1 and contact ES-2. The flow of current to SR1 and GSOV is stopped. The ETR gas valve closes. At the same time, relay SR1 closes the contact between SR1-1 and SR1-2. This will connect the magneto to ground. The current flow to the spark plugs is stopped.
|
To prevent personal injury due to accidental starting of the engine, disconnect the batteries during maintenance or repair work. |
|
Before the engine is started again, perform the steps that follow:
- Correct any faults that may have been the cause of the emergency shutdown.
- When a gas engine has been stopped by a grounded magneto, certain steps must be followed. Run the engine while the gas valve is turned off and the magneto is grounded. Run the engine for 10 seconds to 15 seconds. This will clear the unburned gas from the exhaust system.
|
Unburned gas can ignite when the engine is restarted. |
|
- Make sure that the ES has been reset on the engine junction box. In order to reset the ES, turn the push button in the direction that is shown on the button face.
- Start the engine with the Start/Stop Switch (SSS).
Fault Circuit Operation
- Low Oil Pressure (OP)
- Overheating Coolant (WT)
- Engine Overspeed (OS)
In an engine that is operating properly, electric current for the gas shutoff valve (GSOV) and the slave relay SR1 travel through switches. These switches are the following switches: the overspeed (OS) switch, the water temperature switch (WTS) and the oil pressure switch (OPS1). Any one of the following faults will stop the current flow to the GSOV and the SR1. When the GSOV is de-energized, the GSOV will close in order to shut off the gas. SR1 will cause the magneto to be grounded. Sparks will be prevented from entering the cylinders.
- If the oil pressure drops below the rating of the OPS1, the contacts between terminal OPS1-1 and terminal OPS1-2 will open.
- If the coolant temperature exceeds the setting of the WTS, the contacts between terminal WTS-2 and terminal WTS-3 will open.
- If the engine speed increases above the overspeed setting of the ESS (OS), the contact between terminal ESS-8 and terminal ESS-9 will open.
Note: A reset button on the ESS must be pushed in order to open the overspeed switch ESS (OS). When this is done, the engine can be restarted.
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Unburned gas can ignite when the engine is restarted. |
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When a gas engine has been stopped by a grounded magneto, certain steps must be followed. Run the engine while the gas valve is turned off and the magneto is grounded. Run the engine for 10 seconds to 15 seconds. This will clear the unburned gas from the exhaust system.
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To avoid engine damage, repair or correct the problem that causes engine shutdown before restarting. |
Electric Governor Control System
An Electric Governor Control EGC may be used on an engine. The operation of this governor is close to the operation of the nonelectric governor.
Electrical Schematic ETR, Independent, Full Protection
Refer to the notes for using the Electrical Schematic for ETR, Independent, Full Protection.
NOTES
D: If the electric starting motor is not used, connect the battery cables to the studs for the power input. These studs are located on the bottom of the power distribution box. In some cases, the electric starting motor may not be used. In some cases, the charging alternator arrangement may not be used. If these parts are not used, connect the positive lead from a power source to the terminal TS1. This positive lead must be 24 volts from a DC power source. Terminal TS1 is located on the junction box terminal strip. Connect the negative lead to terminal TS28.
M: If a remote normal stop switch is used, a jumper wire must be removed. Remove the jumper wire between terminal TS-4 and terminal TS-5.
N: Shutoff contactor for the magneto
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| Illustration 18 | g00607958 |
Automatic Start/Stop System
This system (full system without switchgear) is not an independent system. This system is made for a customer that owns a switchgear. The switchgear is wired into the junction box. The switchgear will monitor certain engine parameters. The following engine parameters will be monitored: engine overspeed, oil pressure, coolant temperature and starter motor overspeed. The gas shutoff valve is ETR.
This junction box contains an electronic speed switch ESS, slave relay SR1, oil pressure switch OPS1, circuit breaker CB5, and emergency stop switch ES. With this system, the slave relay remains energized in order for the engine to run.
To follow the circuit operations, refer to the Electrical Schematic Automatic Start/Stop at the end of this text.
There are point-to-point wiring diagrams for this protection system. These diagrams can be found in the Wiring Diagram section of this text.
Electrical Schematic For Full Protection, ETR Automatic Start/Stop
Refer to the notes for using the Electrical Schematic For Full Protection, ETR Automatic Start/Stop.
NOTES
D: If an electric starting motor is not used, connect battery cables to the studs for the power input. These studs are located on the bottom of the power distribution box. An electric starting motor may not be used, and a charging alternator arrangement may not be used. If this is the case, connect the positive lead of a DC power source to the junction TS-1 on the junction box. The power source must be 24 volts. Connect the negative lead to the junction TS-28.
N: Shutoff contactor for the magneto or CDIS
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Circuit Operation
The circuit operation of this system will function as the following systems: ETR, Independent and Full Protection. The start/stop switch (SSS) will function differently. To interface with the customer supplied switchgear, use the suggestions that follow for the start/stop switch:
- Connect the switch so that two open contacts in the START position are across the correct terminal on the junction box terminal strip. This switch should be across terminal TS-4 and terminal TS-14. This switch should also be across terminal TS-21 and terminal TS-26.
- Connect the switch so that the contacts in the RUN position are across the correct terminals of the junction box terminal strip. This switch should be across terminal TS-4 and terminal TS-5. Ensure that the contact will close when the switch is placed in the RUN position. Ensure that the contact will open when the switch is placed in the STOP position.
Note: To avoid premature engine shutdown, the switch must be held in the START position until oil pressure is seen on the oil pressure gauge.
Connections For Temporary Start-up
If an engine with this system needs to be started temporarily before installation in the plant, use the wiring suggestions that follow:
- Connect a start switch across the junction box terminal strip. One open contact should be between terminal TS-21 and terminal TS-26. The other open contact should be between terminal TS-4 and terminal TS-14. These contacts must act simultaneously when the start switch is activated.
- Connect the run/stop switch system arrangement to certain terminals on the junction box. Connect this switch so that contact is made between terminal TS-4 and terminal TS-5. This contact must be closed in the RUN position and open in the STOP position.
All fault circuits are now operational. There is a difference between these circuits and circuits that are in a final installation. During a final installation, the engine must have enough oil pressure to open OPS1 when the engine starts. If this oil pressure is not reached, this circuit will cause immediate shutdown of the engine.
NOTES
D: If the electric starting motor is not used, connect the battery cables to the studs for the power input. These studs are on the bottom of the power distribution box. The electric starting motor may not always be used. The alternator for charging may not always be used. If this is the case, obtain the positive lead of a DC power source. The DC power source should be 24 volts. Connect this positive lead to the terminal TS-1 on the junction box terminal strip. Connect the negative lead to the terminal TS-28.
N: Shutoff contactor for the magneto
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| Illustration 19 | g00607958 |