Woodward UG8 Governors

SCHEMATIC OF UG8 DIAL GOVERNOR

Woodward UG8 Dial Governor

The UG8 Dial Governor is a mechanical-hydraulic governor. A hydraulic activated power piston is used to turn the output terminal shaft of the governor. A lever on the terminal shaft is connected to the fuel rack by a linkage rod. The governor has a separate oil supply and oil pump. The governor oil pump and ballhead are driven from a shaft in the governor drive housing. The shaft is driven by the variable timing drive assembly.

The oil pump gives pressure oil to operate the power piston. The drive gear of the oil pump has a bushing in which the pilot valve plunger moves up and down. The driven gear of the oil pump is also the drive for the ballhead.

An accumulator is used to keep a constant oil pressure of approximately 120 psi (830 kPa) to the top of the power piston and to the pilot valve.

The power piston is connected by a lever to the output terminal shaft. There is oil pressure on both the top and bottom of the power piston. The bottom of the piston has a larger area than the top.

Less oil pressure is required on the bottom than on the top to keep the piston stationary. When the oil pressure is the same on the top and bottom of the piston, the piston will move up and cause the output terminal shaft to turn in the increase fuel direction. When the oil pressure on the bottom of the piston is directed to the sump, the piston will move down and cause the output terminal shaft to turn in the decrease fuel direction. Oil to or from the bottom of the power piston is controlled by the pilot valve.

The pilot valve has a pilot valve plunger and a bushing. The bushing is turned by the governor drive shaft. The rotation of the bushing helps reduce friction between the bushing and the plunger. The pilot valve plunger has a land that controls oil flow through the ports in the bushing. When the pilot valve plunger is moved down, high pressure oil goes to the bottom of the power piston and the power piston will move up. When the pilot valve plunger is moved up, the oil on the bottom of the power piston is released to the sump and the power piston moves down. When the pilot valve plunger is in the center (balance) position, the oil port to the bottom of the power piston is closed and the power piston will not move. The pilot valve plunger is moved by the ballhead assembly.

The ballhead assembly has a ballhead, flyweights, speeder spring, thrust bearing, speeder plug and speeder rod. The ballhead assembly is driven by a gear and shaft from the driven gear of the oil pump. The speeder rod is fastened to the thrust bearing which is on the toes of the flyweights. The speeder rod is connected to the pilot valve plunger with a lever. The speeder spring is held in position on the thrust bearing by the speeder plug.

As the ballhead turns, the flyweights move out due to centrifugal force. This will make the flyweight toes move up and cause compression of the speeder spring. When the force of the speeder spring and the force of the flyweights are equal the engine speed is constant. The speeder plug can be moved up or down manually to change the compression of the speeder spring and will change the speed of the engine.

The compensation system gives stability to engine speed changes. The compensation system has a needle valve and two pistons-an actuating piston and a receiving piston. The actuating piston is connected to the output terminal shaft by the compensation adjusting lever. A fulcrum that is adjustable is on the lever. When the position of the fulcrum is changed, the amount of movement possible of the actuating piston is change.

The receiving piston is connected to the pilot valve plunger and the speeder rod by a lever.

The needle valve makes a restriction to oil flow between the oil sump and the two pistons.

When the actuating piston moves down, the piston forces the oil under the receiving piston and moves it up. When the receiving piston moves up it raises the pilot valve plunger to stop the flow of oil to the bottom of the power piston.

When the engine is in operation at a steady speed the land on the pilot control valve is in the center of the control port of the bushing. A decrease in load will cause an increase in engine speed. With an increase in engine speed the flyweights move out and raise the speeder road and floating lever. This raises the pilot valve plunger and releases oil from the bottom of the power piston. As the power piston moves down the output terminal shaft moves in the decrease fuel direction. When the output terminal shaft moves, the actuating compensation piston moves up and causes a suction on the receiving piston which moves down. The floating lever is pulled down by the receiving piston and the lever moves the pilot control valve down to close the control port. The output terminal shaft and power piston movement is stopped. As the engine speed returns to normal, the flyweights move in and the speeder rod moves down. When the oil pressure in the compensation system and the sump oil become the same through the needle valve, the receiving compensation piston moves up at the same rate as the speeder rod moves down. This action keeps the pilot valve plunger in position to close the port.

An increase in load will cause a decrease in engine speed. When engine speed decreases, the flyweights move in and lower the speeder rod and floating lever. This lowers the pilot valve plunger and lets pressure oil go under the power piston. The power piston moves up and turns the output terminal shaft in the increase fuel direction. When the output terminal shaft moves, the actuting compensation piston moves down and causes a pressure on the receiving piston which moves up. The floating lever is pushed up by the receiving piston and the lever moves the pilot valve plunger up to close the control port. The output terminal shaft and power piston movement is stopped.

A change to the speed setting of the governor will give the same governor movements as incincrease or decrease in load.

The synchronizer is used to change engine speed. The speed setting motor on the top of the governor can also be used to change engine speed. Either control turns the speeder plug which moves up or down and changes the force of the speeder spring. The synchronizer indicator gives an indication of the number of turns the synchronizer has moved.

The load limit control is used to control the amount of travel of the output terminal shaft. The control can be used to stop the engine if the knob is turned to zero.

The speed droop control is used to adjust the amount of speed drop from zero to one hundred percent. Speed droop is the difference between no load high idle rpm and full load rpm. This difference in rpm divided by the full load rpm and multiplied by 100 is the percent of speed droop.

UG8 DIAL GOVERNOR
1. Speed droop knob. 2. Synchronizer knob. 3. Load limit knob. 4. Synchronizer indicator.

Zero speed drop is used on a single system engine, such as a standby generator set. Speed droop higher than zero permits a load to be divided between two or more engines connected to the same load.

Governor Air Actuators

The governor air actuator gives remote control of variable speed for the engine. The actuator operates on air pressure. Air pressure on the cup in the actuator moves the plunger, spring and rod. This motion controls the governor through the linkage.

2N6006 AIR ACTUATOR (Typical Example)
1. Linkage.

Two types of actuators are available. The 2N6006 Air Actuator connects directly to the governor control shaft through linkage (1). Inspection or replacement of the diaphragm without changing the adjustment of the high or low idle speeds or the spring preload is possible. See REMOVE AND INSTALL DIAPHRAGM in DISASSEMBLY AND ASSEMBLY. The 1N9318 Actuator controls the governor through the hand control lever (2) and cross shaft linkage. This actuator has an adjustment for spring preload only.

1N9318 AIR ACTUATORS
2. Hand control lever for the governor.

Prelubrication System

In the prelubrication system, (air start) an air driven prelubrication pump (1) fills the lubrication system to prevent possible damage when the engine is started. When the balanced whistle valve (7) is open, air from the auxiliary air compressor is sent from air valve (3) through line (2) to the prelubrication pump. When the oil pressure is 2.5 psi (17 kPa), oil from a connection in the passage cover at the top of the flywheel housing activates air valve (4) which stops air flow at air valve (3) to the prelubrication pump. The valve (3) then sends air to the starting motor. Air pressure for valve (4) is taken from a connection (6) through line (5).

PRELUBRICATION SYSTEM
1. Prelubrication pump. 2. Air line. 3. Air valve. 4. Air valve. 5. Airline. 6. Connection. 7. Balanced whistle valve.

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) to the right. The collar assembly is connected to four link assemblies (3). The action of the link assemblies will hold the faces of drive 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 driven discs 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 link assemblies released there will not be enough friction between the faces of the clutch assembly to permit a flow of torque.

2301 Nonparallel Control System

NONPARALLEL CONTROL BOX

The 2301 Nonparallel Control gives exact engine speed control. The system measures engine speed constantly and makes necessary corrections to the engine fuel setting through an actuator connected to the fuel system.

The engine speed is felt by a magnetic pickup. As the teeth of the flywheel go through the magnetic lines of force around the pickup an AC voltage is made. The ratio between the frequency of this voltage and the speed of the engine is directly proportional. An electric circuit inside the control box feels the AC voltage. In response it sends a DC control voltage, inversely proportional to engine speed, to the actuator.

The actuator is connected to the fuel system by linkage. It changes the electrical input from the control box to mechanical output that changes the engine fuel setting. For example, if the engine speed was more than the speed setting, the control box will decrease its output and the actuator will decrease fuel to the engine.

The rated and low idle engine speeds are set with speed setting potentiometers. An optional remote speed trim potentiometer will give ± 6% speed setting adjustment. A capacitor can be used between terminals 15 and 16 to control the amount of time it takes the engine to go from low idle to rated speed. An oil pressure switch is connected between terminals 9 and 10. This switch is normally open. When the engine oil pressure increases to 6.4 ± 2.7 psi (44 ± 19 kPa) the switch closes. This permits the control to accelerate the engine to rated speed. If the oil pressure decreases to 3.9 ± 3.3 psi (27 ± 23 kPa) the control will return the engine to low idle.

ACTUATOR

MAGNETIC PICKUP

The gain and stability protentiometers control the response of the engine to a change in load. The gain potentiometer is used to decrease response time to a minimum. The stability potentiometer is used to get the best speed stability for the gain setting that is used.

A droop potentiometer can be connected between terminals 13, 14 and 15 to control the amount of speed droop. Droop is necessary when paralleling with a utility bus or a unit with a hydra/mechanical governor.

The speed failsafe circuit will return the voltage output of the control to zero if the magnetic pickup signal has a failure. This will cause the actuator to move to the FUEL OFF position. Also the engine will not start if the magnetic pickup signal has a failure.

NOTE: On the 7N182 Control Box the jumper between terminals 3 and 4 must be removed to deactivate the speed failsafe circuit for test purposes. On the 8N408 Control Box a jumper must be added between terminals 3 and 4 to deactivate the failsafe circuit for test purposes.

WIRING DIAGRAM FOR 2301 NONPARALLEL CONTROL BOX

For more information, make reference to Special Instruction Form No. SEHS7367.

2301 Parallel Control System

2301 PARALLEL CONTROL BOX

The 2301 Parallel Control has two functions: exact engine speed control and kilowatt load sharing. The system measures engine speed constantly and makes necessary corrections to the engine fuel setting through an actuator connected to the fuel system.

The engine speed is felt by a magnetic pickup. As the teeth of the flywheel go through the magnetic lines of force around the pickup an AC voltage is made. The ratio between the frequency of this voltage and the speed of the engine is directly proportional. An electric circuit inside the control box feels this AC voltage. In response it sends a DC control voltage, inversely proportional to engine speed, to the actuator.

The actuator is connected to the fuel system by linkage. It changes the electrical input from the control box to mechanical output that changes the engine fuel setting. For example, if the engine speed was more than the speed setting, the control box will decrease fuel to the engine.

Kilowatt load sharing between a group of engine driven generator sets is made possible by electric circuits in the control box. The load on each generator in the system is measured constantly by its control box. Loads are compared between control boxes through paralleling wires between all the units on the same bus. From the input of the paralleling wires the load sharing circuits make constant corrections to the control voltages sent to the actuators. This gives kilowatt load sharing.

The rated and low idle engine speeds are set with speed setting potentiometers. An optional remote speed trim potentiometer will give ± 4% speed setting adjustment. The ramp time potentiometer controls the amount of time it takes the engine to go from low idle to rated speed. An oil pressure switch is connected between terminals 14 and 15. This switch is normally open. When the engine oil pressure increases to 6.4 ± 2.7 psi (44 ± 19 kPa) the switch closes. This permits the control to accelerate to rated speed. If the oil pressure decreases to 3.9 ± 3.3 psi (27 ± 23 kPa) the control will return the engine to low idle.

WIRING DIAGRAM FOR 2301 PARALLEL CONTROL BOX

ACTUATOR

MAGNETIC PICKUP

A minimum fuel switch can be connected between terminals 22 and 23. This gives an optional method for shutdown. When this switch is closed the voltage output to the actuator is zero.

The gain and stability potentiometers control the response of the engine to a change in load. The gain potentiometer is used to decrease response time to a minimum. The stability potentiometer is used to get the best speed stability for the gain setting that is used.

The speed droop potentiometer controls the amount of speed droop. It can be set between 0 and 13%. Droop is necessary when paralleling with a utility bus or a unit with a hydra/mechanical governor.

NOTE: Potential Transformer and current transformers must be connected for speed droop to function.

The de-droop potentiometer gives compensation during isochronous operation for droop caused by component tolerances and outside electrical noise. Make adjustments after equipment installation is complete.

The load gain potentiometer is set so that the ratio between the actual kilowatt output and the rated kilowatt output of each unit in the system is the same.

The speed failsafe circuit will return the voltage output of the control to zero if the magnetic pickup signal has a failure. This will cause the actuator to move to the FUEL OFF position. Also the engine will not start if the magnetic pickup signal has a failure.

NOTE: On 7N183 and 7N5581 Control Boxes terminals 12 and 13 are used when the power supply is 24VDC. When the power supply is 32 VDC terminals 13 and 25 are used.

On the 8N409 Control Box terminals 12 and 13 are used for either 24V or 32 VDC. Terminals 25 of all the units in parallel, are connected together in series. This gives a high voltage selection of all battery voltages. Selection of the high voltage as the common supply to all units prevents small speed changes caused by different battery supply voltages.

For more information, make reference to Special Instruction Form No. SEHS7368.

Automatic Start/Stop System - (Non-Package Generator Sets)

AUTOMATIC START/STOP SYSTEM SCHEMATIC (Hydraulic Governor)
1. Magnetic pickup. 2. Starter motor and solenoid. 3. Shutoff solenoid. 4. Oil pressure switch. 5. Water temperature switch. 6. Oil pressure time delay switch. 7. Electronic overspeed switch. 8. Battery. 9. Initiating relay (IR). 10. Shutdown relay (SR). 11. Auxiliary relay (AR). 12. Overcrank timer (OCT). 13. Time delay relay (TD). 14. ON/OFF/STOP switch (SW2). 15. AUTOMATIC/MANUAL switch (SW1). 16. Terminal board (TS1).

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 cranking panel and the electric set.

Automatic Transfer Switch

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.

AUTOMATIC TRANSFER SWITCH

AUTOMATIC START/STOP SYSTEM SCHEMATIC (2301 Control System)
1. Magnetic pickup. 2. Starter motor and solenoid. 4. Oil pressure switch 1 (OPS1). 5. Water temperature switch. 7. Electronic overspeed switch. 8. Battery. 9. Initiating relay (IR). 10. Shutdown relay (SR1). 11. Auxiliary relay (AR). 12. Overcrank timer (OCT). 13. Time delay relay (TD). 14. ON/OFF/STOP switch (SW2). 15. AUTOMATIC/MANUAL switch (SW1). 16. Terminal board (TS1). 17. EG-3P Actuator. 18. Oil pressure switch 2 (OPS2). 19. 2301 Control box.

Cranking Panel

The main function of the cranking panel is to control the start and shutoff of the electric set.

BASIC CRANKING PANEL
1. Indicator light. 2. Manual-Automatic switch. 3. ON-OFF-STOP switch.

LOCKOUT indicator light (1) will activate if, the engine does not start, or if a protection device gives the signal to shutoff during operation.

Switch (2) gives either AUTOMATIC or MANUAL starting. In the diagrams shown later this switch is called SW1. Switch (3) has three positions "ON", "OFF" and "STOP". This switch is called SW2 in the diagrams. Move SW2 (3) to ON and SW1 (2) to MAN to start the engine immediately. Move SW2 (3) to OFF on an electric set in operation to start the shutoff sequence. If the system is equipped with a time delay the engine will not stop immediately. When SW2 (3) is moved to STOP position the engine stops immediately. The switch must be held in the STOP position until the engine stops. When the switch is released a spring returns it to the OFF position. With SW2 (3) in the ON position and SW1 (2) in the AUTO position the control is ready for standby operation.

There are several attachments that can be ordered for this panel. A description of how each one works and the effect it has on the operation of the standard system is given after the explanations of the standard system.

Electric Set

The components of the electric set are: the engine, the generator, the starting motor, the battery, the shutoff solenoid and signal switches on the engine. The electric set gives emergency power to drive the load.

An explanation of each of the signal components is given in separate topics.

Hydraulic Governor Application

The circuit illustrations that follow are basic schematics. DO NOT use them as complete wiring diagrams.

Components of the automatic start/stop system:

Automatic Starting Operations

When emergency power is needed, the initiating contactor closes. This energizes the initiating relay and the run relay. The current flow through the initiating relay contacts then energizes the magnetic switch, which energizes the pinion solenoid. The starting motor is now connected to the battery. The starting operation starts. At the same time the overcrank timer is energized and starts to run.

At 600 rpm the cranking terminate relay closes. Oil pressure causes oil pressure shutdown switch (OPS) to activate. The normally closed contacts open and the normally open contacts close. When oil pressure shutdown switch (OPS) activates, the auxiliary relay is energized and current flow to the magnetic switch and pinion solenoid is stopped. The starting operation then stops.

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION: ENGINE STARTING

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION: ENGINE STARTS

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION: ENGINE DOES NOT START

If the engine does not start in 30 seconds, the overcrank timer contact closes. This energizes the shutdown relay and the alarm light. The shutdown relay stops current flow to the initiating relay and the run relay. De-energizing the run relay also stops current flow to the auxiliary relay. When the shutdown relay is energized, the magnetic switch and the pinion solenoid are de-energized. The starting operation then stops. The shutdown relay also energizes the rack solenoid to move the fuel rack to the fuel OFF position. The shutdown relay is energized until switch (SW2) is manually turned to the OFF position.

Automatic Stopping Operations

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION: SHUTDOWN BY PROTECTION COMPONENT

When the contacts for any of the shutdown switches close, the shutdown relay and the alarm light are energized. This de-energizes the initiating relay, run relay and auxiliary relay. The rack solenoid is energized to move the fuel rack to the fuel OFF position. A parellel circuit through the fuel pressure switch and the normally closed contact of the run relay is also completed to the rack solenoid. The shutdown relay is energized until switch (SW2) is manually turned to the OFF position.

When commercial power is started again, the initiating contactor opens. This de-energizes the initiating relay, the run relay and the auxiliary relay. Current then goes through the normally closed contact of the run relay to the rack solenoid. The rack solenoid is energized to move the fuel rack to the FUEL OFF position.

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION: EMERGENCY POWER NOT NEEDED

Manual Starting Operation

CONTROL PANEL CONTROLS IN MANUAL POSITION: ENGINE STARTING

Switch (SW1), in the MANUAL position, removes the initiating contactor from the circuit. In the MANUAL Position the initiating relay and the run relay are energized. This energizes the magnetic switch and the pinion solenoid. The starting motor is now connected to the battery. The starting operation starts. The overcrank timer is not in this circuit, so if the engine does not start, either switch (SW1) or (SW2) must be turned to another position to stop the starting operation. When the engine starts, the magnetic switch and the pinion solenoid are de-energized in the same way they are de-energized when the engine starts in the AUTOMATIC position.

Manual Stopping Operation

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION: MANUAL SHUTDOWN

When switch (SW2) is moved to the STOP position, current flow is directly to the rack solenoid. The rack solenoid moves the fuel rack to the fuel OFF position. The initiating relay, run relay and auxiliary relay are de-energized. Switch (SW2) must be held in the STOP position until the engine stops.

2301 Control System Application

The circuit illustrations that follow are basic schematics. DO NOT use them as complete wiring diagrams.

Components of the automatic start/stop system:

Components on the 2301 Control System:

Automatic Starting Operations

When emergency power is needed, the initiating contactor closes. This energizes the initiating relay, the cranking relay and connects the 2301 Governor to the battery. The cranking relay energizes the magnetic switch and the pinion solenoid. The starting motor is now connected to the battery. The starting operation starts. At the same time the overcrank timer is energized and starts to run.

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION: ENGINE STARTING

At 600 rpm the cranking terminate relay closes. Oil pressure switch (OPS2) closes at approximately 6.4 psi (44 kPa). This lets the 2301 control signal the actuator to move from low idle to the desired rpm. Oil pressure also causes oil pressure shutdown switch (OPS1) to activate. The normally closed contacts open and the normally open contacts close. When oil pressure shutdown switch (OPS1) activates, the auxiliary relay is energized and current flow to the cranking relay stops. This de-energizes the magnetic switch and the pinion solenoid. The starting operation stops.

If the engine does not start in 30 seconds, the overcrank timer contact closes. This energizes the shutdown relay and the alarm light. The shutdown relay stops current flow to the initiating relay. The current flow is then stopped to the 2301 Control. The EG-3P Actuator moves the fuel rack to the FUEL OFF position. This also de-energizes the magnetic switch and the pinion solenoid. The starting operation stops. The shutdown relay is energized until switch (SW2) is manually turned to the OFF position.

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION: ENGINE STARTS

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION: ENGINE DOES NOT START

Automatic Stopping Operations

When the contacts for any of the shutdown switches close, the shutdown relay and the alarm light are energized. This de-energizes the initiating relay and the auxiliary relay. Current flow to the 2301 Control is stopped. The EG-3P Actuator will then move the fuel rack to the FUEL OFF position. The shutdown relay is energized until switch (SW2) is manually turned to the OFF position.

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION: SHUTDOWN BY PROTECTION COMPONENT

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION: EMERGENCY POWER NOT NEEDED

When commercial power is started again, the initiating contactor opens. This de-energizes the initiating relay and the auxiliary relay. Current flow to the 2301 Control is stopped. The EG-3P Actuator will then move the fuel rack to the fuel OFF position.

Manual Starting Operation

Switch (SW1), in the MANUAL position, removes the initiating contactor from the circuit. In the MANUAL position the initiating relay is energized and current goes to the 2301 Control. The current flow through the initiating relay contacts also energizes the cranking relay. The cranking relay energizes the magnetic switch which in turn energizes the pinion solenoid. The starting motor is now connected to the battery. The starting operation starts. The overcrank timer is not in this circuit, so if the engine does not start, either switch (SW1) or (SW2) must be moved to another position to stop the starting operation. When the engine starts, the magnetic switch and the pinion solenoid are de-energized in the same way as they are de-energized when the engine starts in the Automatic Starting Operation.

CONTROL PANEL CONTROLS IN MANUAL POSITION: ENGINE STARTING

Manual Stopping Operation

When switch (SW2) is moved to the STOP position, current flow to the 2301 Control is stopped. The EG-3P Actuator will then move the fuel rack to the FUEL OFF position. The initiating relay and auxiliary relay are also de-energized. Switch (SW2) must be held in the STOP position until the engine stops.

CONTROL PANEL CONTROLS IN AUTOMATIC POSITION: MANUAL SHUTDOWN

Attachments For Cranking Panel

Separate Alarm Lights

SEPARATE ALARM LIGHTS

This attachment shows the reason for shutdown.

Cycle Cranking Timer

The cycle cranking timer has a cycle crank module (CC). It permits adjustment of the amount of time that the starting motor operates. It can be set for 30 seconds of constant operation to 5 cycles of 10 seconds of operation with a 10 second delay between each cycle of operation. When the cranking cycles set in the timer are completed, cycle crank module (CC) closes the circuit to the overcrank relay (OCT).

Time Delay Relay

This attachment causes a 2 minute delay in the activation of the shutoff solenoid (RS) when the engine is automatically being stopped because of the return of (commercial) normal power.

The purpose of this time delay is to let the engine cool more slowly after running.

When the (commercial) normal power starts again, the initiating contactor (I) opens. This opens the circuit to the run relay (RR) and initiating relay (IR). The run relay (RR) has normally closed contacts which connect the oil pressure time delay switch (OPTD) with the time delay relay (TD). The oil pressure time delay switch (OPTD) is closed at this time. The time delay relay (TD) starts to measure time. After 2 or more minutes of engine operation, the time delay relay (TD) activates. It closes its normally open contacts in the circuit between the oil pressure time delay switch (OPTD) and the shutoff solenoid (RS). Because the oil pressure time delay switch (OPTD) is closed, the circuit is now closed to the shutoff solenoid (RS). The shutoff solenoid (RS) activates. It moves the fuel rack to the FUEL OFF position. This makes the engine stop running.

If the (commercial) normal power stops before the engine stops turning, the engine can start running again immediately. This is because the initiating contactor (I) closes again. This closses the circuit to run relay (RR) and initiating relay (IR). The run relay (RR) activates and opens its normally closed contacts in the circuit with the time delay relay (TD). The time delay relay (TD) is now disconnected so it opens its normally open contacts in the circuit with the shutoff solenoid (RS). The shutoff solenoid (RS) releases the fuel in the fuel injection pump. The governor now controls the fuel supply to the engine. The governor gives the engine more fuel to make the speed increase to the correct speed for the engine.

If the initiating contactor (I) closes just as the engine stops running, the starting motor can activate almost immediately. This is because the oil pressure switch (OPS) is activated by engine oil pressure. When the engine stops running, the oil pressure decreases faster than the engine stops its motion. If the engine does not start running again because of the force of rotation of the flywheel, the engine oil pressure does not increase to activate the oil pressure switch (OPS). If the oil pressure switch (OPS) does not activate, the starting motor (SM) activates when the initiating relay (IR) closes its contacts.

SCHEMATIC OF CONTROL PANEL (SHOWS ALL STANDARD ATTACHMENTS) (ALL COMPONENTS ARE SHOWN IN NORMAL CONDITIONS)

The components are:

NOTE: Dotted lines show components outside the cranking panel.

Shutoff And Alarm Systems

Alarm Contactor System

WIRING SCHEMATIC (Typical Example)
1. Oil pressure switch (switch with manual override shown). 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).

Before the engine is started it will be necessary to override the oil pressure switch (1) or the alarm will activate. This is done by either a manual override button on the 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

WIRING SCHEMATIC (Typical example)
1. Oil pressure switch (switch with manual override shown). 2. Water temperature contactor. 3. Oil pressure (time delay) or fuel pressure switch. 4. Rack solenoid. 5. Terminal block. 6. Diode assembly. 7. Starter. 8. Battery.

If the oil pressure is too low or the water 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.

Before the engine can be started it will be necessary to push the manual override button on oil pressure switch (1). Oil pressure will return the manual override button to the run position.

Diode assembly (6) is used to stop arcing, for protection of the system.

Oil pressure delay or fuel pressure switch (3) is used to prevent discharge of battery (8) through the solenoid when the engine is stopped. The optional grounds to engine shown are used with grounded systems only.

Electronic Overspeed Shutoff System

WIRING SCHEMATIC (Typical example)
1. Rack solenoid. 2. Diode assembly. 3. Oil pressure (time delay) or fuel pressure switch. 4. Overspeed switch. 5. Magnetic pickup. 6. Terminal block. 7. Starter. 8. Battery.

Magnetic pickup (5) sends a voltage to overspeed switch (4). The frequency of this voltage tells the overspeed switch the speed of the engine. If the speed of the engine gets too high the overspeed switch sends a signal to activate rack solenoid (1).

The rack 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.

After an overspeed shutdown the overspeed switch must be reset before the engine can start.

Diode assembly (2) is used to stop arcing, for protection of the system.

If the Woodward 2301 Control System is used, only one magnetic pickup is needed. The magnetic pickup is wired to the overspeed switch and from the overspeed switch to the control box.

The optional grounds to the engine shown are used with grounded systems only.

An oil pressure (time delay) or fuel pressure switch (3) is used to prevent discharge of battery (8) through the solenoid when the engine is stopped. The electronic overspeed 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

WIRING SCHEMATIC (Typical Example)
1. Oil pressure switch (switch with manual override shown). 2. Water temperature contactor. 3. Oil pressure (time delay) or fuel pressure switch. 4. Overspeed switch. 5. Rack solenoid. 6. Diode assembly. 7. Magnetic pickup. 8. Terminal block. 9. Starter. 10. Battery.

The rack solenoid can be activated by oil pressure switch (1), water temperature contactor (2) or overspeed switch (4). See WATER TEMPERATURE AND OIL PRESSURE SHUTOFF SYSTEM and ELECTRONIC OVERSPEED SHUTOFF SYSTEM.

Mechanical Overspeed Shutoff System

WIRING SCHEMATIC (Typical Example)
1. Rack solenoid. 2. Diode assembly. 3. Oil pressure (time delay) or fuel pressure switch. 4. Overspeed switch. 5. Terminal block. 6. Starter. 7. Battery.

The mechanical overspeed switch (4) is fastened to the tachometer drive on the engine. Wires connect the switch to the rack shutoff solenoid. If the speed of the engine gets too high the overspeed switch sends a signal to activate rack solenoid (1).

The rack 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.

After an overspeed shutdown the overspeed switch must be reset before the engine can start.

Diode assembly (2) is used to stop arcing, for protection of the system.

The optional grounds to the engine shown are used with grounded systems only.

An oil pressure (time delay) or fuel pressure switch (3) is used to prevent discharge of battery (7) through the solenoid when the engine is stopped.

Water Temperature, Oil Pressure And Mechanical Overspeed Shutoff System

WIRING SCHEMATIC (Typical Example)
1. Oil pressure switch (switch with manual override shown). 2. Water temperature contactor. 3. Oil pressure (time delay) or fuel pressure switch. 4. Overspeed switch. 5. Rack solenoid. 6. Diode assembly. 7. Terminal block. 8. Starter. 9. Battery.

The rack solenoid can be activated by oil pressure switch (1), water temperature contactor (2) or overspeed switch (4). See WATER TEMPERATURE AND OIL PRESSURE SHUTOFF SYSTEM and MECHANICAL OVERSPEED SHUTOFF SYSTEM.

Shutoff And Alarm System Components

Oil Pressure Switch

Micro Switch Type

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.

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.

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.

Earlier Type Switch

Early type switches for oil pressure have a control knob (1). The knob must be turned (reset) every time the engine is stopped. Turn the knob counterclockwise to the OFF position before the engine is started. The knob will move to the RUN position when the oil pressure is normal

OIL PRESSURE SWITCH (Earlier Type)
1. Control knob.

Pressure Switch

These type 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.

Some switches of this type have three terminal connections. They are used to do two operations with one switch. They open one circuit and close another with the single switch.

PRESSURE SWITCH

Water Temperature Contactor 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 contactor 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 contactor switch will not operate.

The contactor 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.

WATER TEMPERATURE CONTACTOR SWITCH

Shutoff Solenoid

A shutoff solenoid changes electrical input into mechanical output. It is used to move the fuel rack to a no fuel position or to move a valve assembly in the air inlet pipe to a closed position. This stops the engine.

The shutoff solenoid can be activated by any one of many sources. The most usual are: water temperature contactor, oil pressure switch, overspeed switch (electronic or mechanical) and remote manual control switch.

RACK SHUTOFF SOLENOID (Typical Illustration)

Circuit Breaker

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.

An open circuit breaker will close (reset) automatically when it becomes cooler.

CIRCUIT BREAKER SCHEMATIC
1. Disc in open position. 2. Contacts. 3. Disc. 4. Circuit terminals.

Electronic Speed Switch

The electronic speed switch (dual speed switch) activates the shutoff solenoid when the engine speed gets approximately 18% higher than the rated full load speed of the engine. It also causes the starter motor pinion to move away from the flywheel.

NOTE: Some earlier electronic speed switches do not have the crank disconnect.

The electronic speed switch makes a comparison between the output frequency of magnetic pickup (2) and the setting of the electronic speed switch. When they are equal, the normally open contacts in the electronic speed switch close. On earlier models handle (1) moves to the overspeed position. On later models lamp (4) will go on. The switch also has a fail safe circuit that will cause the engine to shutdown if there is an open in the magnetic pickup circuit.

When the engine is stopped by the earlier electronic speed switch it will be necessary to move handle (1) to the run position before the engine can be started. On later model switches push reset button (3).

ELECTRONIC SPEED SWITCH (EARLIER)
1. Handle. 2. Magnetic pickup.

ELECTRONIC SPEED SWITCH (LATER)
3. Reset button. 4. Lamp.

Contactor Switch For Overspeed

The contactor switch for overspeed is installed on the tachometer drive on the front of the engine. It gives protection to the engine from running too fast.

The switch is connected to the rack shutoff solenoid to stop the engine. After the engine is stopped because of an overspeed condition, push the button (1) to open the switch and permit the starting of the engine.

CONTACTOR SWITCH FOR OVERSPEED
1. Button.

Shutoff Control

A shutoff control for overspeed (engine running too fast) and low oil pressure is provided for industrial engines. An attachment is also available to provide protection for high coolant temperature and is used with the shutoff control.

Shutoff controls are available for marine engines that give protection against overspeed and reverse rotation. These controls do not give protection against low oil pressure when the direction of engine rotation is correct.

The shutoff control (1) is installed in the V of the engine in front of the injection pump housing. The control is driven by the injection pump camshaft.

Engine oil pressure is used to activate the low oil pressure shutoff control. The location of plug (5) is for the connection of a shutoff control valve for water temperature. The line (4) supplies engine oil pressure to the shutoff control.

SHUTOFF CONTROL
1. Shutoff control. 2. Emergency manual shutoff button. 3. Reset button. 4. Pressure oil line to shutoff control. 5. Plug (pressure oil connection to water temperature shutoff).

The overspeed shutoff part of the control stops the engine mechanically in the event of engine overspeeding.

Controls equipped with reversal protection are activated by low oil pressure only when the engine runs in reverse.

The emergency manual shutoff button (2) works with the overspeed shutoff and provides the operator with an emergency shutoff control.

NOTE: DO NOT use the emergency manual shutoff button to shut down the engine in normal operation. This will cause more than normal wear on the overspeed shutoff parts.

Reset button (3) is used to set the control after the engine has been stopped by the control because of low oil pressure. It is also used after the engine has been stopped because of high water temperature.

NOTE: It is not necessary to set the control after a normal engine stop.

The shutoff control parts get lubrication from leakage past the oil pressure shutoff piston. Return oil goes through two drilled holes in the bottom of the housing.

Shutoff Control Operation

Low Oil Pressure Shutoff and Water Temperature Shutoff

The oil pressure control will stop the engine when the lubrication oil pressure drops below 12 ± 3 psi (85 ± 20 kPa). It will also stop the engine when high water temperature opens a shutoff control valve which causes low oil pressure to the control.

SHUTOFF CONTROL (Cross Sectional Side View; Normal Operation)
1. Worm shaft. 2. Slide follower. 3. Slide follower shaft. 4. Cover. 5. Guide. 6. Piston. 7. Spring. 8. Release rod.

Under normal engine operation, engine lubrication oil goes through line (4). (See illustration of Shutoff control.) This oil goes to cover (4) and against control piston (6). (See illustration Shutoff Control, Cross Sectional Side View; Normal Operation.)

One end of slide follower (2) is engaged with guide (5). The follower is free to pivot about slide follower shaft (3) in the housing and is activated by the movement of guide (5).

Worm shaft (1) is turned by the shutoff drive which is turned by the fuel injection pump camshaft. Any time the engine is running the control is in operation.

When the pressure of the engine oil is normal, piston (6) is held against guide (5) putting spring (7) in compression and keeps slide follower (2) out of contact with worm shaft (1).

SHUTOFF CONTROL (Top View; Normal Operation Position)
1. Worm shaft. 2. Slide follower. 3. Slide follower shaft. 5. Guide. 8. Release rod. 9. Pin. 10. Release latch. 11. Spring.

When the pressure of the lubrication oil drops below normal operating range, the oil pressure on piston (6) will also drop and spring (7) will force guide (5) and piston (6) to the stop position and cause slide follower (2) to turn on shaft (3) and contact worm shaft (1).

The slide follower (2) will move the length of worm portion of shaft (1) when slide follower (2) is engaged with worm shaft (1). As the follower comes close to the end of its movement, pin (9) on the follower makes contact with release latch (10).

The release latch is then moved out of engaged position and releases rod (8) which moves outward by force of spring (11).

SHUTOFF CONTROL (Side View; Shutoff Operation Position)
1. Worm shaft. 2. Slide follower. 3. Slide follower shaft. 5. Guide. 6. Piston. 7. Spring. 8. Release rod.

SHUTOFF CONTROL (Top View; Shutoff Operation Position)
1. Worm shaft. 2. Slide follower. 8. Release rod. 9. Pin. 10. Release latch. 11. Spring.

Release rod (8) moves cable assembly (12) which is connected to the governor drive housing. The cable assembly contacts the lever assembly in the governor drive housing to move the fuel rack to the fuel off position and stop the engine.

RACK SHUTOFF
12. Cable assembly.

Engine Reversal Protection Control

The shut off control for engine reversal protection is the same as the control for low oil pressure except the threads on worm shaft (1) go in the opposite direction. Low oil pressure will shut off the engine only if the engine runs in reverse. The oil pressure will be low because the engine oil pump will not give oil pressure in reverse.

Overspeed Shutoff

OVERSPEED CONTROL
1. Carrier assembly. 2. Rotating weight. 3. Release latch. 4. Release rod.

When an overspeed (engine running too fast) condition has happened, the overspeed shutoff control, located in the shutoff control housing, will activate the release rod. The release rod moves the fuel rack to the off position to stop the engine.

Overspeed carrier assembly (1) is driven by gears and the shutoff drive which is driven by the fuel injection pump camshaft. When the engine is running the overspeed carrier will turn. A rotating weight (2) in the carrier flange is held toward the center of the carrier shaft by an adjustment screw, spring and nut.

When the engine rpm increases, the centrifugal force acting on the wieght increases, and the weight moves out of the carrier flange. This movement of the weight continues until the spring force (restriction of weight movement outward) is equal to the force moving the weight out.

When the engine overspeeds, the weight will move out of the carrier flange and make contact with release latch (3). Release latch (3) will move and permit release rod (4) to move down which moves the shutoff lever and the fuel rack to the fuel OFF position.

Emergency Manual Shutoff Button

EMERGENCY SHUTOFF
1. Spring loaded weight. 2. Carrier assembly. 3. Pin. 4. Plunger. 5. Button.

Manual shutoff button (5) is used only to stop the engine in an emergency. DO NOT use the shutoff button to stop the engine in normal operation. In normal operation, remove all of the load from the engine and make a reduction in engine rpm to low idle before the engine is stopped.

If an emergency where the engine must be shut down immediately, push the emergency shutoff button and hold it in until the release rod has been released.

When button (5) is pushed, it will move plunger (4) against pin (3) which will force weight (1) out of carrier assembly (2). This makes the shutoff control operate the same as an overspeed (engine running too fast) condition.

Setting The Shutoff Control

When the engine has been shut-down by the shutoff control, the reason for the shut-down must be corrected and the control set again before the engine can be started.

Setting After Overspeed and Emergency Manual Shut-down

The release rod is set by moving the lever (1). The engine now can be started.

SHUTOFF SETTING CONTROL
1. Lever.

Setting After Low Oil Pressure or High Water Temperature Shut-down

Push reset button (4) on the top of the shutoff control housing. This moves control piston (3) and pin against slide follower guide (1). The movement of the guide turns slide follower (2) away from the end of the worm shaft. This permits the spring to move the slide follower to the start of the worm shaft threads.

Latch the release rod (5) by pulling on the shutoff setting control lever.

The engine can now be started.

SHUTOFF SETTING CONTROL
1. Slide follower guide. 2. Slide follower. 3. Control piston. 4. Reset button. 5. Release rod.

NOTE: In cold weather operation, it may be necessary to push the reset button (4) while cranking the diesel engine to prevent activating the shutoff control. This is necessary as the oil pressure will not increase to the operating range fast enough because of the longer cranking period needed under these conditions.

Under conditions of normal operation, pressure of the lubrication oil will increase to the operating range before the follower has moved to the limit of travel and activates the release latch and rod.

Oil Pressure And Water Temperature Shut-Off

Engine oil under pressure enters line (1) from the auxiliary oil manifold (2) and flows behind the control piston in the oil pressure and overspeed shut-off control (3). When a water temperature shut-off control valve is used, a line (5), connected to the oil pressure and overspeed shut-off, supplies pressure oil to the valve (6). When engine coolant temperatue is normal, valve (6) remains closed and no oil can flow through the valve and into the dump line (4).

Should the coolant temperature become excessive, the thermostatically controlled valve opens and oil flows through the dump line and into the engine crankcase. Thus, a low oil pressure condition is actually simulated and the oil pressure shut-off control then stops the engine.

After a shut down caused by excessively high water temperatures, depress reset button and reset the release rod.

OIL FLOW-SCHEMATIC
1. Oil inlet line. 2. Auxiliary oil manifold.^* 3. Shut-off control. 4. Dump line. 5. Oil line. 6. Water temperature shutoff control valve.
^*On later engines the oil inlet line connects to the junction block welded to the aftercooler.

Shutoff Valve For Water Temperature

The shutoff valve for water temperature is connected in an oil line from the mechanical shutoff. Thermostat assembly (4) is in contact with the engine coolant. When the water temperature is normal, spring (1) holds ball (5) on its seat which stops the flow of oil. This lets the oil pressure become normal in the shutoff. High water temperature above the setting of the valve will cause the thermostat assembly to move stem (3). This will move ball (5) off its seat to let the oil pressure in the shutoff go back to the engine oil sump through outlet port (6). The low oil pressure causes the shutoff to stop the engine.

SHUTOFF VALVE FOR WATER TEMPERATURE
1. Spring. 2. Inlet port. 3. Stem. 4. Thermostat assembly. 5. Ball. 6. Outlet port.