Usage:
Introduction
NOTE: For Specifications with illustrations, make reference to Specifications for 3304B & 3306B Industrial & Marine Engine Attachments, SENR2570. If the Specifications in SENR2570 are not the same as in the Systems Operation and the Testing and Adjusting, look at the printing date on the back cover of each book. Use the Specifications given in the book with the latest date.
Instrument Panel
Wiring Diagram For Instrument Panel
(1) Light switch. (2) Panel lights. (3) Instrument panel. (4) Ammeter. (5) Oil pressure gauge. (6) Water temperature gauge. (7) Gear oil pressure gauge. (8) Terminal strip. (9) Wire to battery. (10) Oil pressure switch with time delay. (11) Sending unit for oil pressure. (12) Sending unit for water temperature. (13) Sending unit for gear oil pressure.
Gauges With Resistors For 32 Volt System
(1) Resistor. (2) Oil pressure gauge. (3) Resistor. (4) Water temperature gauge. (5) Resistor. (6) Gear oil pressure gauge.
Resistor For 32 Volt System (65Ohms)
Indicators And Sending Units
Sending Unit for Water Temperature
Sending Unit For Water Temperature
(1) Connection. (2) Bushing. (3) Bulb.
The sending unit for water temperature is an electrical resistance. It changes the value of its resistance according to the temperature which the bulb (3) feels.
The sending unit is in a series circuit with the electrical indicator. When the temperature is high, the resistance is high. This makes the indicator have a high reading.
The sending unit must be in contact with the coolant. If the coolant level is too low because of a sudden loss of coolant while the engine is running or because the level is too low before starting the engine, the sending unit will not work correctly.
Sending Unit for Oil Pressure
Sending Unit For Oil Pressure
(1) Connection. (2) Bushing.
The sending unit for oil pressure is an electrical resistance. It has a material which changes electrical resistance according to pressure which it feels.
The sending unit for oil pressure is in a series circuit with the electrical indicator. As the pressure on the sending unit changes, the reading on the indicator changes in the same way.
Electric Hour Meter
Hour Meter Wiring Diagram
(1) Electrical hour meter. (2) Pressure switch. (3) To alternator or battery.
Electric hour meter (1) measures the clock hours that the engine operates. The hour meter activates when pressure switch (2) closes. Pressure switch (2) closes the circuit from the positive terminal on the alternator or battery when the engine oil pressure is above approximately 6 psi (40 kPa).
Electric Tachometer Wiring
(1) Magnetic pickup. (2) Terminal connections - terminals 7 and 8 on standby governor control. (3) Tachometer. (4) Ground connection - governor control chassis ground. (5) Governor control terminal strip. (6) Wiring connections - for second tachometer circuit. (7) All wire must be 22AWG shielded cable or larger. (8) Dual speed switch terminal strip. (9) Ground connection - ground to engine.
Wiring Diagram
Starting And Charging System
(1) Off, start switch. (2) Ammeter. (3) Fuel shutoff solenoid. (4) Starter solenoid. (5) Alternator regulator. (6) Starter motor. (7) Pressure switch - normally open. (8) Alternator. (9) Battery. (10) Hourmeter.
Automatic Start/Stop System
Automatic Start/Stop System Schematic (Hydraulic Governor)
(1) Starter motor and solenoid). (2) Shutoff solenoid. (3) Fuel pressure switch. (4) Water temperature switch. (5) Oil pressure switch. (6) Overspeed contactor. (7) Battery. (8) Low lubricating oil pressure light (OPL). (9) Overcrank light (OCL). (10) Overspeed light (OSL). (11) High water temperature light (WTL). (12) Automatic control switch (ACS).
An automatic start/stop system is used when a standby electric set has to give power to a system if the normal (commercial) power supply has a failure. There are three main sections in the system. They are: the automatic transfer switch, the start/stop control panel (part of switch gear) and the electric set.
Automatic Transfer Switch
Automatic Transfer Switch (Typical Illustration)
The automatic transfer switch normally connects the 3-phase normal (commercial) power supply to the load. When the commercial power supply has a failure the switch will transfer the load to the standby electric set. The transfer switch will not transfer the load from commercial to emergency power until the emergency power gets to the rated voltage and frequency. The reason for this is, the solenoid that causes the transfer of power operates on the voltage from the standby electric set. When the normal power returns to the rated voltage and frequency and the time delay (if so equipped) is over, the transfer switch will return the load to the normal power supply.
Control Panel (Later)
Electronic Modular Control Panel (EMCP II)
(1) Optional panel lights. (2) Optional governor switch (shown) or speed potentionmeter. (3) Optional starting aid switch. (4) Engine control switch. (5) Optional alarm module (shown) or synchronizing lights module. (6) Voltage adjust rheostat. (7) Emergency stop push button. (8) Generator set control. (9) Optional panel light switch.
The main function of the control panel is to control the start and shutoff of the engine.
The engine control on the automatic start/stop control panel is an automatic engine control switch (ECS) with four positions. The positions of the engine control switch (4) are: OFF/RESET, AUTO, MAN./START, and COOLDOWN/STOP. Each light goes ON only when an abnormal condition in the engine stops the engine. The light for the condition in the engine that stopped the engine is ON even after the engine has stopped. Engine control switch (4) must be moved to the OFF/RESET position for the light to go OFF. Each light will go ON, for a light test, when the light is pushed in and held.
When the generator is to be used as a standby electric power unit, the automatic control switch is put in the AUTO position. Now, if the normal (commercial) electric power stops, the engine starts and the generator takes the electric load automatically. When the normal (commercial) electric power is ON again, or the electric load, the transfer switch opens its contacts to the generator, and closes its contacts to the normal (commercial) electric power. After the transfer switch for the generator opens, the engine automatically stops, usually after running for a cooldown time.
When the automatic engine control switch (ECS) is moved to the MAN./START position, the engine starts. It may now be necessary for the circuit breaker for the generator electric power to be closed manually to the load. If the generator is a standby electric power unit and the automatic engine control switch (ECS) is in the MAN./START position when normal (commercial) electric power stops, the automatic engine control switch (ECS) can be put into the AUTO position and the engine will stop automatically when the normal (commercial) electric power is ON again.
The engine will be stopped with the automatic engine control switch (ECS) in either the AUTO or MAN./START positions if there is a fault (not normal) condition in the engine. The fault conditions in the engine that can stop the engine are low lubricating oil pressure, high engine coolant (water) temperature or engine overspeed (too much rpm). When any of these conditions stop the engine, the light for the fault condition will stay ON after the engine is stopped. A fourth fault condition light is ON only when the starting motor runs the amount of seconds for the overcrank timer (engine does not start).
Move the automatic engine control switch (ECS) to the OFF/RESET position and the fault condition lights go OFF if the fault condition has been removed.
Control Panel (Earlier)
The main function of the control panel is to control the start and shutoff of the engine.
Automatic Start/Stop Control Panel
(1) Overcrank light (OCL). (2) Low lubricating oil pressure light (OPL). (3) Overspeed light (OSL). (4) Automatic control switch (ACS). (5) High water temperature light (WTL).
The engine control on the automatic start/stop control panel is an automatic control switch (ACS) with four positions. The positions of the automatic control switch (4) are: OFF/RESET, AUTO, MAN and STOP. Each light (1), (2), (3) and (5) goes ON only when a not normal condition in the engine stops the engine. The light for the condition in the engine that stopped the engine is ON even after the engine has stopped. The automatic control switch (4) must be moved to the OFF/RESET position for the light to go OFF. Each light will go ON, for a light test, when the light is pushed in and held in.
When the generator is to be used as a standby electric power unit, the automatic control switch is put in the AUTO position. Now, if the normal (commercial) electric power stops, the engine starts and the generator takes the electric load automatically. When the normal (commercial) electric power is ON again, for the electric load, the circuit breaker for the generator electric power automatically opens and the generator goes off the electric load. After the circuit breaker for the generator opens, the engine automatically stops.
When the automatic control switch (ACS) is moved to the MAN position, the engine starts. It is now necessary for the circuit breaker for the generator electric power to be closed manually. If the generator is a standby electric power unit and the automatic control switch (ACS) is in the MAN position when normal (commercial) electric power is ON again, the generator circuit breaker opens. This causes the engine to stop automatically, the same as when the switch (ACS) is in the AUTO position.
The engine will stop with the automatic control switch (ACS) in either the AUTO or MAN positions if there is a not normal condition in the engine. The not normal condition in the engine that can stop the engine is either low lubricating oil pressure, high engine coolant (water) temperature or engine overspeed (too much rpm). When any of these conditions stops the engine, the light for the not normal condition will stay ON after the engine is stopped. The fourth not normal condition light is ON only when the starter motor runs the amount of seconds for the overcrank timer (engine does not start).
Move the automatic control switch (ACS) to the OFF/RESET position and the not normal condition lights go OFF.
Electric Set
The components of an electric set are: the engine, generator, starter motor, battery, shutoff solenoid and signal switches. The electric set gives emergency power to drive the load.
An explanation of each of the signal components is given in separate topics.
Wiring Diagrams
The following wiring diagrams are complete to show the connections of the automatic start/stop components with the engine terminal strip (TS1). The diagrams show all available options for both the hydraulic governor application or the PSG Governor application.
Automatic Start/Stop Wiring For Non-Package Generator Set (Used With HydraMechanical Or Woodward PSG Governors)
Starting System With One Starter Motor
(1) Magnetic switch. (2) Circuit breaker. (3) Starter motor. (4) Battery. (5) Circuit breaker. (6) Terminal strip (on engine).
NOTE: For wire sizes and color codes see the chart at the front of Wiring Diagrams section.
NOTE: Wires and cables shown in dotted lines are customer supplied wiring.
Dual Speed Switch
(7) Magnetic pickup. (8) Dual speed switch. (9) Time delay relay. (10) Oil pressure switch. (11) Governor synchronizing motor. (12) Water temperature switch.
Shutoff Solenoid
(13) Circuit breaker. (14) Rack shutoff solenoid. (15) Diode.
Automatic Start/Stop System Schematic
Electric Shutoff And Alarm System
Introduction
The are three types of electrical protection systems available for the 3300 Marine Engines.
- 1. Oil Pressure and Water Temperature Protection.
- 2. Oil Pressure, Water Temperature and Overspeed Protection.
- 3. Automatic Start Stop Systems.
- a. Package Generator Set.
- b. Non-Package Generator Set.
- 2. Oil Pressure, Water Temperature and Overspeed Protection.
This manual has information for No. 1 and 2. Make reference to the generator manual and the switch gear manual for information for No. 3.
The electric shutoff system is designed to give protection to the engine if there is a problem or a failure in any of the different engine systems. The engine systems that are monitored are: engine overspeed, starter motor crank terminate, engine oil pressure and engine coolant temperature.
The electric protection system consists of the electronic speed switch and time delay relay. This system monitors the engine from starting through rated speed.
Dual Speed Switch (DSS)
The speed switch has controls (in a single unit) to monitor engine overspeed and crank terminate speed.
Engine Overspeed
An adjustable engine speed setting (normally 118% of rated speed) that gives protection to the engine from damage if the engine runs too fast. This condition will cause a switch to close that shuts off the fuel to the engine.
Crank Terminate (Starter Motor)
An adjustable engine speed setting that gives protection to the starter motor from damage by overspeed. This condition will cause a switch to open that stops current flow to starter motor circuit, and the starter motor pinion gear will then disengage from engine flywheel ring gear. The crank terminate can also be used to activate the time delay relay.
Time Delay Relay
This relay has special ON/OFF switches with two controls that will either make the relay activate immediately, or after a 9 second delay. The time delay relay is used to arm the shutdown system. The time delay relay has a 70 second delay to be sure of complete engine shutdown and to prevent damage to the shutoff solenoids.
Water Temperature Contactor Switch
This contactor switch is a separate unit (mounted in the water manifold) that is wired into the shutdown circuit. It has an element that feels the temperature of the coolant (it must be in contact with the coolant). When the engine coolant temperature becomes too high, the switch closes to cause the fuel to be shut off to the engine.
Engine Oil Pressure Switch
This switch is mounted at the rear of the engine and feels the pressure of the oil in the oil manifold. The oil pressure switch is used to determine low engine oil pressure and to activate the time delay relay.
Wiring Diagrams
Abbreviations, wire codes and recommended wire sizes, used with the wiring diagrams that follow, can be found at the front of the Wiring Diagram section.
The notes that follow are used with the wiring diagrams shown in this section.
NOTE: Customer to furnish battery and all wires shown dotted.
Water Temperature And Oil Pressure Shutoff System (With Time Delay Relay)
Wiring Diagram (Fuel Shutoff Solenoid Energized To Shutoff)
(1) Time delay relay. (2) Oil pressure switch. (3) Water temperature switch. (4) Switch (N.O.). (5) Circuit breaker. (6) Shutdown relay. (7) Battery. (8) Diode assembly. (9) Shutdown solenoid. (10) Starter motor.
When the engine starts, engine oil pressure will close the N.O. switch and open the N.C. switch in oil pressure switch (2). This completes the circuit to time delay relay (1). Normally open (N.O.) switch (4) in the time delay relay now closes and completes the circuit between shutdown relay (6) and terminal TD-7 of the time delay relay.
If the engine coolant temperature goes above the setting of water temperature switch (3), the N.O. contacts will close. This lets current flow through water temperature switch (3) and through switch (4) to activate shutdown relay (6) which in turn activates fuel shutoff solenoid (9). When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N.O. switch will open and stop the flow of current to the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (4) will open to stop current flow through shutdown relay (6). Now, fuel shutoff solenoid (9) will no longer be activated.
If engine oil pressure gets less than the setting of the oil pressure switch, the N.C. switch will close. This will let current flow through switch (4) to activate shutdown relay (6) which in turn activates fuel shutoff solenoid (9). The N.O. switch will open and start the time delay relay timer. After 70 seconds, switch (4) will open to stop current flow through shutdown relay (6). Now, fuel shutoff solenoid (9) will no longer be activated.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to shutdown before the engine is started again. |
Water Temperature, Oil Pressure And Electronic Overspeed Shutoff System (With Time Delay Relay)
Wiring Diagram (Fuel Shutoff Solenoid Energized To Shutoff)
(1) Magnetic pickup. (2) Dual speed switch. (3) Overspeed switch. (4) Crank terminate switch. (5) Water temperature switch. (6) Oil pressure switch. (7) Time delay relay. (8) Normally open (N.O.) (9) Shutdown relay. (10) Battery. (11) Diode assembly. (12) Shutoff solenoid. (13) Starter motor.
The engine speed is felt by magnetic pickup (1). As the teeth of the flywheel go through the magnetic lines of force around the pickup, an AC voltage is made. Dual speed switch (2) measures engine speed from the frequency of the voltage.
Time delay relay (7) controls the operation of shut-down relay (9), which in turn, controls the operation of fuel shutoff solenoid (12). Time delay relay (7) will keep the fuel shutoff solenoid energized for 70 seconds after a fault condition. This prevents the engine from being started again before the flywheel has stopped rotation.
When the engine starts and gets to a speed just above cranking speed, the normally open contacts of crank terminate switch (4) [which is part of dual speed switch (2)] will close. This will complete the circuit to time delay relay (7) through terminal TD-2. In approximately 9 seconds N.O. switch (8) in time delay relay (7) will close and complete the circuit between shutdown relay (9) and terminal TD-7 of the time delay relay. If the engine oil pressure has not activated oil pressure switch (6) by 9 seconds, current will flow through the N.C. switch in the oil pressure switch and through the now closed N.O. switch (8) to activate shutdown relay (9) which in turn activates fuel shutoff solenoid (12). If engine oil pressure activates oil pressure switch (6), the N.O. switch will close and the N.C. switch will open. This will let current flow to terminal TD-1 of the time delay relay and immediately close N.O. switch (8). At the same time the N.C. switch in the oil pressure switch will open and prevent current flow to switch (8).
If the engine speed increases above the overspeed setting (118% of rated speed) of the dual speed switch, the overspeed switch (part of the dual speed switch) will close across terminals DSS-7 and DSS-8. This completes the circuit to shutdown relay (6) through the now closed switch (8) at terminal TD-7. Shutdown relay (9) is activated and in turn activates fuel shutoff solenoid (12) to cause the engine to shutdown.
When the engine speed gets less than the cranking speed setting, switch (4) opens. This stops the flow of current to terminal TD-2 of the time delay relay. When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N.O. switch will open and stop the flow of current to terminal TD-1 of the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (8) will open and stop current flow to shutdown relay (9) and fuel shutoff solenoid (12) will no longer be activated.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to overspeed before the engine is started again. |
After an overspeed shutdown, a button on the dual speed switch must be pushed to open the overspeed switch before the engine will run.
When the engine has been started and is running, the time delay relay will close switch (8). If the engine coolant temperature goes above the setting of water temperature switch (5), the N.O. contacts will close. This lets current flow through the water temperature switch and through switch (8) to activate shutdown relay (9) and in turn activates fuel shutoff solenoid (12).
When the engine speed gets less than the cranking speed setting, switch (4) opens. This stops the flow of current to terminal TD-2 of the time delay relay. When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N.O. switch will open and stop the flow of current to terminal TD-1 of the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (8) will open and stop current flow to shutdown relay (9) and fuel shutoff solenoid (12) will no longer be activated.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to get too hot before the engine is started again. |
When the engine has been started and is running, the time delay relay will close switch (8). If the engine oil pressure gets less than the setting of oil pressure switch (6), the N.C. switch will close. This will let current flow through switch (8) to activate shutdown relay (9) and in turn activates fuel shutoff solenoid (12). The N.O. switch will also open and stop current flow to terminal TD-1 of the time delay relay. When the engine speed gets less than the cranking speed setting, switch (4) opens. This stops the flow of current to terminal TD-2 of the time delay relay and starts the time delay relay timer. After 70 seconds, switch (8) will open and stop current flow to shutdown relay (9) and fuel shutoff solenoid (12) will no longer be activated.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the cause for low engine oil pressure before the engine is started again. |
Electronic Overspeed Shutoff System (With Time Delay Relay)
Wiring Diagram (Fuel Shutoff Solenoid Energized To Shutoff)
(1) Magnetic pickup. (2) Crank terminate switch. (3) Dual speed switch. (4) Time delay relay. (5) Normally open (N.O.) switch. (6) Shutdown relay. (7) Battery. (8) diode assembly. (9) Shutoff solenoid. (10) Starter motor.
The engine speed is felt by magnetic pickup (1). As the teeth of the flywheel go through the magnetic lines of force around the pickup, an AC voltage is made. Dual speed switch (3) measures engine speed from the frequency of this AC voltage.
Time delay relay (4) controls the operation of shutdown relay (6), which in turn, controls the operation of fuel shutoff solenoid (9). Time delay relay (4) will keep the fuel shutoff solenoid energized for 70 seconds after a fault condition. This prevents the engine from being started again before the flywheel has stopped rotation.
When the engine starts and gets to a speed just above cranking speed, the normally open contacts of crank terminate switch (2) [which is part of dual speed switch (3)] will close. This will complete the circuit to time delay relay (4) through terminal TD-1. Normally open switch (5) in time delay relay (4) now closes and completes the circuit between shutdown relay (6) and terminal TD-7.
If the engine speed increases above the overspeed setting (118% of rated speed) of the dual speed switch, the overspeed switch (part of the dual speed switch) will close across terminals DSS-7 and DSS-8. This completes the circuit to shutdown relay (6) through the now closed switch (5) at terminal TD-7. Shutdown relay (6) is activated and in turn activates fuel shutoff solenoid (9) to cause the engine to shutdown.
When the engine stops, crank terminate switch (2) will open the circuit across terminals DSS-10 and DSS-11. This stops current flow to time delay relay (4). Now, the time delay relay timer is started and 70 seconds later, switch (5) will open the circuit at terminal TD-7. Current flow is then stopped through shutdown relay (6) and fuel shutoff solenoid (9) will no longer be activated.
A reset button on the dual speed switch must be pushed to open the overspeed switch before the engine will run.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to overspeed, before the engine is started again. |
Water Temperature And Oil Pressure Shutoff With Time Delay Relay (Fuel Shutoff Solenoid Energized To Run)
Wiring Diagram
(1) Time delay relay. (2) Water temperature switch. (3) Oil pressure switch. (4) Switch (N.C.). (5) Fuel shutoff solenoid.
When the electrical current is turned on to the time delay relay terminal four, the current will flow to oil pressure switch (3) and to terminal six of time delay relay (1). From terminal six the current flows through N.C. switch (4) to energize fuel shutoff solenoid (5) so the engine will start.
When the engine starts, engine oil pressure will close the N.O. switch in oil pressure switch (3). This completes the circuit to time delay relay (1), water temperature switch (2) and fuel shutoff solenoid (5). N.C. switch (4) in the time delay relay now opens and breaks the circuit between fuel shutoff solenoid (5) and terminal six of the time delay relay.
If the engine coolant temperature goes above the setting of water temperature switch (2), the N.C. contacts will open. This stops current flow through water temperature switch (2) and through switch (4) to the fuel shutoff solenoid. When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N.O. switch will open and stop the flow of current to the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (4) will close and current will again flow to the fuel shutoff solenoid.
Wiring Schematic (Water Temperature And Oil Pressure Shutoff)
(BAT) Battery. (CB) Circuit breaker. (OPS) Oil pressure switch. (PS) Pinion solenoid. (SM) Starter motor. (SPB) Start push button. (SS) Shutoff solenoid. (TDR) Time delay relay. (VTS) Voltage transient suppressor. (WTS) Water temperature switch.
If engine oil pressure gets less than the setting of the oil pressure switch, the N.O. switch will open. This will stop current flow through switch (4) to the fuel shutoff solenoid. The current flow will stop to the time delay relay and start the time delay relay timer. After 70 seconds, switch (4) will close and current will again flow through the fuel shutoff solenoid.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to shut off before the engine is restarted. |
NOTE: To help prevent discharge of the batteries when the engine is shut off, a switch can be installed to turn off the current to the shutoff solenoid.
Water Temperature, Oil Pressure And Electronic Overspeed Shutoff With Time Delay Relay (Fuel Shutoff Solenoid Energized To Run)
Wiring Diagram
(1) Magnetic pickup. (2) Dual speed switch. (3) Overspeed switch (N.C.). (4) Cranking speed switch (N.O.). (5) Water temperature switch. (6) Oil pressure switch. (7) Time delay relay. (8) Switch (N.C.). (9) Fuel shutoff solenoid.
The engine speed is felt by magnetic pickup (1). As the teeth of the flywheel go through the magnetic lines of force around the pickup, an AC voltage is made. Dual speed switch (2) determines engine speed from the frequency of the voltage.
Time delay relay (7) controls the operation of fuel shutoff solenoid (9). To prevent the engine from restarting, the time delay relay turns off the current to the fuel shutoff solenoid for approximately 70 seconds after the engine stops.
When the electrical current is turned on to the time delay relay terminal four, the current then goes to terminals six and eleven of the dual speed switch and to terminal one of oil pressure switch (6). Current also flows to terminal six of the time delay relay and through N.C. switch (8) to energize fuel shutoff solenoid (9) so the engine will start.
When the engine starts, N.O. cranking speed switch (4) in the cranking circuit of the dual speed switch closes at a speed just above cranking speed. This completes the circuit to terminal two of the time delay relay. In approximately 9 seconds N.C. switch (8) in the time delay relay will open and break the circuit between the fuel shutoff solenoid and terminal six of the time delay relay. If engine oil pressure has not closed oil pressure switch (6) by 9 seconds, N.C. switch (8) will open and break the circuit to fuel shutoff solenoid (9) causing engine shutdown. However, if engine oil pressure closes the N.O. switch in oil pressure switch (6), current will flow through water temperature switch (5), overspeed switch (3) and terminal five of time delay relay to the shutoff solenoid. Current also flows to terminal one of the time delay relay. This will immediately open N.C. switch (8).
If the speed of the engine gets more than the setting of the overspeed switch, N.C. switch (3) opens. This stops current flow to the fuel shutoff solenoid and will cause the engine to shutdown.
When the engine speed gets less than the cranking speed setting, cranking speed switch (4) opens. This stops the flow of current to terminal two of the time delay relay. When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N.O. switch will open and stop the flow of current to terminal one of the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (8) will close and again let current flow to the fuel shutoff solenoid.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to overspeed before the engine is restarted. |
After an overspeed shutdown, the overspeed switch must be reset.
When the engine has been started and is running, the time delay relay will open switch (8). If the engine coolant temperature goes above the setting of water temperature switch (5), the N.C. contacts will open. This stops current flow through the water temperature switch and through overspeed switch (3) to the fuel shutoff solenoid causing engine shutdown.
When the engine speed gets less than the cranking speed setting, cranking speed switch (4) opens. This stops the flow of current to terminal two of the time delay relay. When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N.O. switch will open and stop the flow of current to terminal one of the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (8) will close and again let current flow to the fuel shutoff solenoid.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to get too hot before the engine is restarted. |
When the engine has been started and is running, the time delay relay will close switch (8). If the engine oil pressure gets less than the setting of oil pressure switch (6), the N.O. switch will open. This will stop current flow through overspeed switch (3) to the fuel shutoff solenoid causing engine shutdown. The current flow will also stop to terminal one of the time delay relay. When the engine speed gets less than the cranking speed setting, cranking speed switch (4) opens. This stops the flow of current to terminal two of the time delay relay and starts the time delay relay timer. After 70 seconds, switch (8) will close and again let current flow to the fuel shutoff solenoid.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the cause for low engine oil pressure before the engine is restarted. |
NOTE: To help prevent discharge of the batteries when the engine is shut off, a switch can be installed to turn off the current to the shutoff solenoid.
Wiring Schematic
(BAT) Battery. (CB) Circuit breaker. (CT) Crank terminate. (D) Diode. (DSS) Dual speed switch. (MAG.PU) Magnetic pickup. (OPS) Oil pressure switch. (OSS) Overspeed switch. (PS) Pinion solenoid. (SM) Starter motor. (SPB) Start push button. (SS) Shutoff solenoid. (TDR) Time delay relay. (VTS) Voltage transient suppressor. (WTS) Water temperature switch.
Alarm Contactor System
Wiring Diagram
(1) Oil pressure switch. (2) Water temperature contactor. (3) Source voltage. (4) Toggle switch (optional). (5) Alarm. (6) Signal lights.
If the oil pressure is too low or the water temperature is too high this system will activate alarm (5) and signal lights (6).
| NOTICE |
|---|
When the alarm and signal lights activate, stop the engine immediately. This will help prevent damage to the engine from heat or not enough lubrication. Find and correct the problem that caused the alarm and signal lights to activate. |
Before the engine is started it will be necessary to override oil pressure switch (1) or the alarm will activate. This is done by either a manual override button on the (earlier) oil pressure switch or toggle switch (4). Oil pressure will return the manual override button to the run position. The toggle switch must be manually closed when the engine has oil pressure.
Wiring Diagram
(1) Oil pressure switch. (2) Water temperature contactor. (3) Source voltage. (4) Toggle switch (optional). (6) Signal lights (three). (7) Air temperature contactor.
If the oil pressure is too low or the water temperature is too high this system will activate signal lights (6).
| NOTICE |
|---|
When the signal lights activate, stop the engine immediately. This will prevent damage to the engine from heat or not enough lubrication. Find and correct the problem that caused the signal lights to activate. |
Before the engine is started it will be necessary to override oil pressure switch (1) or the signal lights will activate. This is done by either a manual override button on the (earlier) oil pressure switch or toggle switch (4). Oil pressure will return the manual override button to the run position. The toggle switch must be manually closed when the engine has oil pressure.
Wiring Diagram
(1) Oil pressure switch. (2) Water temperature contactor. (3) Source voltage. (4) Toggle switch (optional). (5) Alarm. (7) Air temperature contactor.
If the oil pressure is too low or the water temperature is too high this system will activate alarm (5).
| NOTICE |
|---|
When the alarm activates, stop the engine immediately. This will help prevent damage to the engine from heat or not enough lubrication. Find and correct the problem that caused the alarm to activate. |
Before the engine is started it will be necessary to override oil pressure switch (1) or the alarm will activate. This is done by either a manual override button on the (earlier) oil pressure switch or toggle switch (4). Oil pressure will return the manual override button to the run position. The toggle switch must be manually closed when the engine has oil pressure.
Water Temperature And Oil Pressure Shutoff System (With Oil Pressure Delay Or Fuel Pressure Switch)
Wiring Diagram
(1) Oil pressure switch. (2) Water temperature contactor. (3) Oil pressure (time delay) or fuel pressure switch. (4) Rack solenoid. (5) Diode assembly. (6) Starter. (7) Battery.
If the oil pressure is too low or the coolant temperature is too high this system will activate rack solenoid (4) The solenoid is connected to the fuel rack by linkage. When it is activated it will move to stop the flow of fuel to the engine. The engine will stop.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to shutdown before the engine is started again. |
Before the engine can be started it will be necessary to push the manual override button on (earlier) oil pressure switch (1). Oil pressure will return the manual override button to the run position.
Diode assembly (5) is used to stop arcing, for protection of the system.
Oil pressure or fuel pressure switch (3) is used to prevent discharge of battery (7) through the solenoid when the engine is stopped.
Electronic Overspeed Shutoff System (With Oil Pressure Delay Or Fuel Pressure Switch)
Wiring Diagram
(1) Rack solenoid. (2) Oil pressure (time delay) or fuel pressure switch. (3) Dual speed switch. (4) Magnetic pickup. (5) Diode assembly. (6) Starter. (7) Battery.
The engine speed is felt by magnetic pickup (4). As the teeth of the flywheel go through the magnetic lines of force around the pickup, an AC voltage is made. Dual speed switch (3) measures engine speed from the frequency of this AC voltage.
Rack solenoid (1) is connected to the fuel rack by linkage. When it is activated, it will move to stop the flow of fuel to the engine.
If the engine speed increases above the overspeed setting (118 percent of rated speed) of the dual speed switch, the overspeed switch [which is part of dual speed switch (3)] will close across terminals DSS-7 and DSS-8. This completes the circuit to rack solenoid (1) through the now closed oil pressure or fuel pressure switch (2) and activates the solenoid to shutdown the engine.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to overspeed, before the engine is started again. |
After an overspeed shutdown, a button on the dual speed switch must be pushed to open the overspeed switch before the engine will run.
Diode assembly (5) is used to stop arcing, for protection of the system.
An oil pressure or fuel pressure switch (2) is used to prevent discharge of battery (7) through the solenoid when the engine is stopped. The dual speed switch can be connected to the battery constantly because it uses less than 20 MA of current when the engine is stopped.
Water Temperature, Oil Pressure And Electronic Overspeed Shutoff System (With Oil Pressure Delay Or Fuel Pressure Switch)
Wiring Diagram
(1) Oil pressure switch. (2) Oil pressure (time delay) or fuel pressure switch. (3) Water temperature contactor. (4) Dual speed switch. (5) Magnetic pickup. (6) Rack solenoid. (7) Diode assembly. (8) Starter motor. (9) Battery.
This system gives high water temperature, low oil pressure and overspeed protection to the engine.
Rack solenoid (6) is connected to the fuel rack by linkage. When it is activated it will move to stop the flow of fuel to the engine. The rack solenoid can be activated by oil pressure switch (1), water temperature contactor (3) or the overspeed switch that is part of dual speed switch (4).
If the oil pressure is too low or the coolant temperature is too high, oil pressure switch (1) or water temperature contactor (3) will close to complete the circuit and activate rack solenoid (6).
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to shutdown before the engine is started again. |
The engine speed is felt by magnetic pickup (5). As the teeth of the flywheel go through the magnetic lines of force around the pickup, an AC voltage is made. Dual speed switch (4) measures engine speed from the frequency of this AC voltage.
If the engine speed increases above the overspeed setting (118% of rated speed) of the dual speed switch, the overspeed switch [which is part of dual speed switch (4)] will close across terminals DSS-7 and DSS-8. This completes the circuit to rack solenoid (6) through oil pressure or fuel pressure switch (2) and water temperature contactor (3) to activate the solenoid and shutdown the engine.
| NOTICE |
|---|
To help prevent damage to the engine find and correct the problem that caused the engine to overspeed, before the engine is started again. |
After an overspeed shutdown, a button on the dual speed switch must be pushed to open the overspeed switch before the engine will run.
Diode assembly (7) is used to stop arcing, for protection of the system.
An oil pressure (time delay) or fuel pressure switch (2) is used to prevent discharge of battery (9) through the solenoid when the engine is stopped. The dual speed switch can be connected to the battery constantly because it uses less than 20 MA of current when the engine is stopped.
NOTE: On systems that use an earlier type oil pressure switch, it will be necessary to push the manual override button before the engine can be started. Oil pressure will return the manual override button to the run position.
Mechanical Overspeed Shutoff (Fuel Shutoff Solenoid Energized To Run)
Wiring Diagram
(1) Overspeed switch. (2) Shutoff solenoid.
The mechanical overspeed switch (1) is mounted to the tachometer drive on the engine. If there is an engine overspeed the N.C. switch in overspeed switch (1) will open and brake the electrical circuit to shutoff solenoid (2) causing engine shutdown.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to overspeed before the engine is restarted. |
After an overspeed shutdown, the overspeed switch must be reset.
Wiring Schematic
(BAT) Battery. (CB) Circuit breaker. (OSS) Overspeed switch. (PS) Pinion solenoid. (SPB) Start push button. (SM) Starter motor. (SS) Shutoff solenoid. (VTS) Voltage transient suppressor.
Mechanical Overspeed Shutoff (Fuel Shutoff Solenoid Energized To Shutoff)
Wiring Diagram
(1) Time delay relay. (2) Overspeed switch. (3) Oil pressure switch. (4) Switch (N.O.). (5) Fuel shutoff solenoid.
When the engine starts, engine oil pressure will close the N.O. switch in oil pressure switch (3). This completes the circuit to time delay relay (1). N.O. switch (4) in the time delay relay now closes and completes the circuit between fuel shutoff solenoid (5) and terminal seven of the time delay relay.
When mechanical overspeed switch (2), mounted to the tachometer drive, senses an engine overspeed the N.O. contacts will close. This lets current flow through overspeed switch (2) and through switch (4) to activate the fuel shutoff solenoid. When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N.O. switch will open and stop the flow of current to the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (4) will open and stop current flow through the fuel shutoff solenoid.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to overspeed before the engine is restarted. |
After an overspeed shutdown, the overspeed switch must be reset.
Wiring Schematic
(BAT) Battery. (CB) Circuit breaker. (OSS) Overspeed switch. (PS) Pinion solenoid. (RNS) Remote normal shutdown switch. (SM) Starter motor. (SPB) Start push button. (SS) Shutoff solenoid. (TDR) Time delay relay. (VTS) Voltage transient suppressor.
Water Temperature, Oil Pressure And Mechanical Overspeed Shutoff With Time Delay Relay (Fuel Shutoff solenoid Energized To Run)
Wiring Diagram
(1) Overspeed switch (N.C.). (2) Water temperature switch. (3) Oil pressure switch. (4) Time delay relay. 5 Switch (N.C.) (6) Fuel shutoff solenoid.
The engine speed is monitored by the mechanical overspeed switch (1).
Time delay relay (4) controls the operation of fuel shutoff solenoid (6). To prevent the engine from restarting, the time delay relay turns off the current to the fuel shutoff solenoid for approximately 70 seconds after the engine stops.
When the electrical current is turned on to the time delay relay terminal four, the current goes to terminal one of oil pressure switch (3). Current also flows to terminal six of the time delay relay and through N.C. switch (5) to energize fuel shutoff solenoid (6) so the engine will start.
After the engine is started, engine oil pressure closes the N.O. switch in oil pressure switch (3), current will flow through water temperature switch (2), overspeed switch (1) and terminal five of time delay relay to the shutoff solenoid. Current also flows to terminal one of the time delay relay. This will immediately open N.C. switch (5).
If the speed of the engine gets more than the setting of the overspeed switch, the N.C. switch opens. This stops current flow to the fuel shutoff solenoid and will cause the engine to shutdown.
When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N.O. switch will open and stop the flow of current to terminal one of the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (5) will close and again let current flow to the fuel shutoff solenoid.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to overspeed before the engine is restarted. |
After an overspeed shutdown, the overspeed switch must be reset.
When the engine has been started and is running, the time delay relay will open switch (5). If the engine coolant temperature goes above the setting of water temperature switch (2), the N.C. contacts will open. This stops current flow through the water temperature switch and through overspeed switch (1) to the fuel shutoff solenoid causing engine shutdown. When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N.O. switch will open and stop the flow of current to terminal one of the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (5) will close and again let current flow to the fuel shutoff solenoid.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to get too hot before the engine is restarted. |
When the engine has been started and is running, the time delay relay will close switch (5). If the engine oil pressure gets less than the setting of oil pressure switch (3), the N.O. switch will open. This will stop current flow through switch (1) to the fuel shutoff solenoid causing engine shutdown. When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N.O. switch will open and stop the flow of current to terminal one of the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (5) will close and again let current flow to the fuel shutoff solenoid.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the cause for low engine oil pressure before the engine is restarted. |
NOTE: To help prevent discharge of the batteries when the engine is shut off, a switch can be installed to turn off the current to the shutoff solenoid.
Wiring Schematic (Water Temperature, Oil Pressure And Overspeed Shutoff)
(BAT) Battery. (CB) Circuit breaker. (CT) Crank terminate. (D) Diode. (OPS) Oil pressure switch. (OSS) Overspeed switch. (PS) Pinion solenoid. (SPB) Start push button. (SS) Shutoff solenoid. (TDR) Time delay relay. (VTS) Voltage transient suppressor. (WTS) Water temperature switch.
Water Temperature, Oil Pressure And Mechanical Overspeed Shutoff With Time Delay Relay (Fuel Shutoff Solenoid Energized To Shutoff)
Wiring Diagram
(1) Time delay relay. (2) Overspeed switch (N.O.). (3) Water temperature switch. (4) Oil pressure switch. (5) Switch (N.O.). (6) Fuel shutoff solenoid.
The engine speed is monitored by the mechanical overspeed switch (2).
Time delay relay (1) controls the operation of fuel shutoff solenoid (6). To prevent damage to the fuel shutoff solenoid, the time delay relay turns off the current approximately 70 seconds after the engine stops.
After the engine is started, engine oil pressure activates oil pressure switch (4), the N.O. switch will close and the N.C. switch will open. This will let current flow to terminal one of the time delay relay and immediately close N.O. switch (5). At the same time the N.C. switch in the oil pressure switch will open and prevent current flow to switch (5).
If the speed of the engine gets more than the setting of the overspeed switch, the N.O. switch closes. This lets current flow through switch (5) to activate the fuel shutoff solenoid. When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N.O. switch will open and stop the flow of current to terminal one of the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (5) will open and stop current flow to the fuel shutoff solenoid.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to overspeed before the engine is restarted. |
After an overspeed shutdown, the overspeed switch must be reset.
When the engine has been started and is running, the time delay relay will close switch (5). If the engine coolant temperature goes above the setting of water temperature switch (3), the N.O. contacts will close. This lets current flow through the water temperature switch and through switch (5) to activate the fuel shutoff solenoid.
When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N.O. switch will open and stop the flow of current to terminal one of the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (5) will open and stop current flow to the fuel shutoff solenoid.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the problem that caused the engine to get too hot before the engine is restarted. |
When the engine has been started and is running, the time delay relay will close switch (5). If the engine oil pressure gets less than the setting of oil pressure switch (4), the N.C. switch will close. This will let current flow through switch (5) to activate the fuel shutoff solenoid.
When the engine stops, engine oil pressure will become less than the setting of the oil pressure switch. The N.O. switch will open and stop the flow of current to terminal one of the time delay relay. This will start the time delay relay timer. After 70 seconds, switch (5) will close and again let current flow to the fuel shutoff solenoid.
| NOTICE |
|---|
To help prevent damage to the engine, find and correct the cause for low engine oil pressure before the engine is restarted. |
Wiring Schematic (Water Temperature, Oil Pressure And Overspeed Shutoff)
(BAT) Battery. (CB) Circuit breaker. (CT) Crank terminate. (D) Diode. (OPS) Oil pressure switch. (OSS) Overspeed switch. (PS) Pinion solenoid. (SPB) Start push button. (SM) Starter motor. (SS) Shutoff solenoid. (TDR) Time delay relay. (VTS) Voltage transient suppressor. (WTS) Water temperature switch.
Oil Pressure Switch
Micro Switch Type
Oil Pressure Switch (Micro Switch Type)
(1) Locknut. (2) Adjustment screw. (3) Spring. (4) Arm. (5) Spring. (6) Bellows. (7) Latch plate. (8) Button (for micro switch). (9) Arm. (10) Projection (of arm).
The oil pressure switch is used to give protection to the engine from damage because of low oil pressure. When oil pressure lowers to the pressure specifications of the switch, the switch closes and activates the rack shutoff solenoid.
On automatic start/stop installations, this switch closes to remove the starting system from the circuit when the engine is running with normal oil pressure.
This switch for oil pressure can be connected in a warning system for indication of low oil pressure with a light or horn.
As pressure of the oil in bellows (6) becomes higher, arm (4) is moved against the force of spring (3). When projection (10) of arm (4) makes contact with arm (9), pressure in the bellows moves both arms. This also moves button (8) of the micro switch to activate the micro switch.
Some of these switches have a "Set For Start" button. When the button is pushed in, the micro switch is in the START position. This is done because latch plate (7) holds arm (9) against button (8) of the micro switch and the switch operates as if the oil pressure was normal. When the engine is started, pressure oil flows into bellows (6). The bellows move arm (4) into contact with latch plate (7). The latch plate releases the "Set For Start" button and spring (5) moves it to the RUN Position. This puts the switch in a ready to operate condition.
Pressure Switch
Pressure switches are used for several purposes and are available with different specifications. They are used in the oil system and in the fuel system. One use of the switch is to open the circuit between the battery and the rack shutoff solenoid after the oil pressure is below the pressure specifications of the switch. It also closes when the engine starts.
Another use of the switch is to close and activate the battery charging circuit when the pressure is above the pressure specification of the switch. It also disconnects the circuit when the engine is stopped.
Shutoff Solenoid
A shutoff solenoid changes electrical input into mechanical output. It is used to move the fuel injection pump rack to the off position.
The shutoff solenoid can be activated by any one of the many sources. The most usual are: water temperature contactor, oil pressure switch, overspeed switch and remote manual control switch.
The shutoff solenoid can be either the energized to run or the energized to shutoff type as provided with the engine shutoff control logic.
Mechanical Oil Pressure And Water Temperature Shutoff
Mechanical Shutoff Group
(1) Oil pressure sensing valve. (2) Tee. (3) Water temperature sensing valve. (4) Shutdown cylinder.
The shutdown cylinder (4) is mounted to the rear of the governor housing. The plunger of the cylinder acts on a spring-loaded lever assembly inside the governor housing. When extended, the plunger rotates the lever assembly to allow full movement of the fuel rack. When the plunger is retracted, the lever assembly returns to its original position which moves and holds the fuel rack in the shutoff position.
When starting the engine, the knob on shutdown cylinder (4) must be held in to extend the plunger against the lever assembly inside the governor housing. This will rotate the lever assembly to allow full rack movement. After the engine starts and oil pressure is high enough to hold the plunger extended, the knob can be released. Oil pressure will hold the plunger in this position until there is a low oil pressure condition.
Under normal operating conditions, pressure oil from the engine oil manifold flows to tee (2). Part of the oil from the tee flows through water temperature sensing valve (3) into the pressure inlet end of oil pressure sensing valve (1) where the oil flow is blocked and the oil pressure is monitored. The other part of the oil flow from tee (2) flows to and through the drain end of the water temperature sensing valve (3) on to shutdown cylinder (4) where the oil flow is blocked and the pressure holds the cylinder plunger extended.
When the oil pressure gets too low then the drain end of the oil pressure sensing valve (1) will open causing the pressure oil at shutdown cylinder (4) to drain back to the engine block. With no oil pressure at the shutdown cylinder (4), the lever assembly in the governor returns to its original position pushing the cylinder plunger to the retracted position and moves the fuel rack to the shutoff position to stop the engine.
When the water temperature is too high, the pressure oil that flows through water temperature sensing valve (3) is diverted to drain within the valve body and flows back to the engine block. This causes the oil pressure to become too low and the engine will stop as described above.
| NOTICE |
|---|
Find and correct the problem that caused the engine to stop. This will help prevent damage to the engine from not enough lubrication or too much heat. |
Water Temperature Switch
Water Temperature Switch
The contactor switch for water temperature is installed in the water manifold. No adjustment to the temperature range of the contactor can be made. The element feels the temperature of the coolant and then operates the micro switch in the contact when the coolant temperature is too high, the element must be in contact with the coolant to operate correctly. If the cause for the engine being too hot is because of low coolant level or no coolant, the switch will not operate.
The switch is connected to the rack shutoff solenoid to stop the engine. The switch can also be connected to an alarm system. When the temperature of the coolant lowers to the operating range, the contactor switch opens automatically.
Circuit Breaker
Circuit Breaker Schematic (Typical Example)
(1) Disc in open position. (2) Contacts. (3) Disc. (4) Circuit terminals.
The circuit breaker gives protection to an electrical circuit. Circuit breakers are rated as to how much current they will permit to flow. If the current in a circuit gets too high it will cause heat in disc (3). Heat will cause distortion of the disc and contacts (2) will open. No current will flow in the circuit.
| NOTICE |
|---|
Find and correct the problem that caused the circuit breaker to open. This will help prevent damage to the circuit components from too much current. |
An open circuit breaker will close (reset) automatically when it becomes cooler.
Mechanical Overspeed Switch
Mechanical Overspeed switch
(1) Button. (2) Lock Screws.
The overspeed switch is installed on the tachometer drive shaft of the fuel injection pump. The switch activates when the engine speed is equal to the overspeed setting. When the overspeed switch has activated, the contacts do not automatically return to their normal positions. The reset button (1) must be pushed by the operator to make the switch contacts return to their normal positions. The usual setting for the overspeed switch is 18% higher than the rated speed of the engine.
Some overspeed switches also have under speed contacts. These contacts close at approximately 600 rpm as the engine speed increases. The under speed setting is not adjustable.
Electronic Speed Switch (ESS)
Electronic Speed Switch (ESS)
(1) Verify button. (2) Reset button. (3) "LED" overspeed light. (4) Seal screw plug (overspeed). (5) Seal screw plug (crank terminate).
The Electronic Speed Switch (ESS) is designed with controls built into a single unit to monitor several functions at the same time. The functions that the ESS monitors are:
Engine Overspeed (OS)
This is an adjustable engine speed setting (normally 118 percent of rated speed) that prevents the engine from running at a speed that could cause damage. This condition will cause a switch to close that shuts off the fuel to the engine and connects the magneto to ground to stop current flow to the spark plugs.
Crank Termination (CT)
This is an adjustable engine speed setting that signals the starting motor that the engine is firing and cranking must be terminated. When the speed setting is reached, a switch will open to stop current flow to the starting motor circuit. The starting motor pinion gear will now disengage from the engine flywheel ring gear.
Power Take-Off Clutches
Power Take-Off Clutch (Typical Illustration)
(1) Ring. (2) Driven discs. (3) Link assemblies. (4) Lever. (5) Key. (6) Collar assembly. (7) Nut. (8) Yoke assembly. (9) Hub. (10) Plates. (11) Output shaft.
Power take-off clutches (PTO's) are used to send power from the engine to accessory components. For example, a PTO can be used to drive an air compressor or a water pump.
The PTO is driven by a ring (1) that has spline teeth around the inside diameter. The ring can be connected to the front or rear of the engine crankshaft by an adapter.
NOTE: On some PTO's located at the rear of the engine, ring (1) is a part of the flywheel.
The spline teeth on the ring engage with the spline teeth on the outside diameter of driven discs (2). When lever (4) is moved to the ENGAGED position, yoke assembly (8) moves collar assembly (6) in the direction of the engine. The collar assembly is connected to four link assemblies (3). The action of the link assemblies will hold the faces of driven discs (2), drive plates (10) and hub (9) tight together. Friction between these faces permits the flow of torque from ring (1), through driven discs (2), to plates (10) and hub (9), Spline teeth on the inside diameter of the plates drive the hub. The hub is held in position on the output shaft (11) by a taper, nut (7) and key (5).
NOTE: A PTO can have from one to three driven discs (2) with a respective number of plates.
When lever (4) is moved to the NOT ENGAGED position, yoke assembly (8) moves collar assembly (6) to the left. The movement of the collar assembly will release link assemblies (3). With the link assemblies released there will not be enough friction between the faces of the clutch assembly to permit a flow of torque.