D353 INDUSTRIAL & MARINE ENGINES Caterpillar


Systems Operation

Usage:



Woodward UG-8 Governor

Electric Set Application When Frequency Control is Important)

There is no direct mechanical link between the governor weights and fuel rack. Movement of the rack is done by a hydraulic piston which is operated by action of the governor weights and a compensating piston.


WOODWARD UG-8 GOVERNOR
1. Synchronizing motor. 2. Synchronizer knob. 3. Speed droop knob. 4. Compensating pointer. 5. Synchronizer indicator. 6. Load limit knob. 7. Plug.

Engine rpm is controlled by changing the compression of the governor spring. An A.C. motor (1) installed on the top of the governor permits remote control of the spring compression.

Synchronizer knob (2) on the governor permits control of the same function (engine rpm). The synchronizer indicator (5) below the synchronizer knob, gives an indication of the number of revolutions of the synchronizer knob and the amount of compression of the governor spring.

A speed droop knob (3) permits a means of changing the difference between FULL LOAD rpm and HIGH IDLE (without load) rpm. Any difference between HIGH IDLE rpm and FULL LOAD rpm is called "DROOP" and this difference in rpm divided by the FULL LOAD rpm is called "DROOP PERCENTAGE". At zero droop the rpm is the same, either with or without load. This droop control permits the use of two or more electric sets to operate a common load (in parallel). Only one of the electric sets (with zero droop) feels the difference in power needs and permits the increase or decrease in power. The electric set or sets with high droop governors control the constant load.

A load limit knob (6) is for the operator to manually control the engine rpm. This knob gives a positive stop to linkage movement and gives the operator a fast way to stop the engine. The load limit knob also can be used to make a gradual reduction in engine rpm.

Compensating pointer (4) gives the governor a fine degree of adjustment control. Detailed information about governor adjustment is in TESTING AND ADJUSTING.

Plug (7) covers an adjustment screw that permits the operator to release (bleed) air from the governor hydraulic system. Loosening the screw causes the hydraulic components to move rapidly and remove air from the system. Final adjustment of the needle valve controls governor action.

Automatic Start/Stop Systems


COMPONENT LOCATION FOR AUTOMATIC START/STOP SYSTEM; UG-8 GOVERNOR
1. Load. 2. Transfer switch with initiating contactor. 3. Rack shutoff solenoid. 4. Overspeed contactor. 5. Water temperature contactor. 6. Commercial power source. 7. Oil pressure contactor. 8. Emergency power. 9. Starting motor and solenoid. 10. Fuel pressure switch. 11. Battery. 12. Engine. 13. Control panel. 14. Overcrank timer. 15. ON/ OFF/STOP switch. 16. AUTOMATIC/MANUAL switch. 17. Shutdown relay. 18. Initiating relay. 19. Auxiliary relay. 20. Run relay.

Two arrangements of the automatic start/stop system are available. The first is the Woodward UG-8 Governor application. The second is the Woodward 2301 Electric Governor application.

These systems automatically start the engine and connect the load to the generator set when the commercial power source is stopped. These systems automatically disconnect the generator set from the load and stop the engine when the commercial power source is started again. The load is also disconnected and the engine stopped if the engine has high water temperature, low lube (oil) pressure or an overspeed condition.

The automatic start/stop systems have three main wiring circuits:

Commercial power source.

Generator set.

Control panel, starting motor and battery.

These three circuits connect at the automatic transfer switch. The automatic transfer switch is the device that changes the load from the commercial power source to the generator set when commercial power is stopped.

An initiating contactor in the transfer switch, activated by commercial power, closes when the commercial power source is stopped. The starting operation of the engine then starts.


COMPONENT LOCATION FOR AUTOMATIC START/STOP SYSTEM; 2301 ELECTRIC GOVERNOR
1. Load. 2. Transfer switch with initiating contactor. 3. EG-3P Actuator. 4. Overspeed contactor. 5. Water temperature contactor. 6. Commercial power source. 7. Magnetic pickup. 8. Oil pressure contactor OPS1. 9. Starting motor and solenoid. 10. Oil pressure switch OPS2. 11. Emergency power. 12. 2301 Governor. 13. Battery. 14. Engine. 15. Control panel. 16. Overcrank timer. 17. ON/OFF/STOP switch. 18. AUTOMATIC/MANUAL switch. 19. Initiating relay. 20. Cranking relay. 21. Shutdown relay. 22. Auxiliary relay.


TRANSFER SWITCH

When the engine starts, the generator set gives emergency power while the commercial power is off. When the commercial power is started again the initiating contactor opens, to change the load from the generator set back to the commercial power source.

Safety shutoff switches on the engine, will also operate to stop the engine for high water temperature, low lube (oil) pressure or an overspeed condition.

Components on engines with automatic start/stop systems:

An explanation of the engine shutoff components is given in separate topics.

The standard control panel has an ON/OFF/ STOP switch, AUTOMATIC/MANUAL switch and a single red alarm light (lockout) to show the cause of a safety shutdown.


CONTROL PANEL (Typical Illustration)
1. Alarm light. 2. Automatic/Manual switch. 3. On/Off/ Stop switch.

Components in the remote control panel:

Woodward UG-8 Governor Application

The following illustrations for the UG-8 Governor are basic schematics. DO NOT use them as complete wiring diagrams.


CONTROL PANEL CONTROLS IN AUTOMATIC POSITION; STANDBY CONDITION


CONTROL PANEL CONTROLS IN AUTOMATIC POSITION STANDBY CONDITION (EARLY STARTING MOTOR)

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.


CONTROL PANEL CONTROLS IN AUTOMATIC POSITION; ENGINE STARTING


CONTROL PANEL CONTROLS IN AUTOMATIC POSITION; ENGINE STARTS

When the oil pressure is normal, the contactor switch for oil pressure closes. This energizes the auxiliary relay, which stops current flow to the magnetic switch and the pinion solenoid. The starting operation then 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 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.


CONTROL PANEL CONTROLS IN AUTOMATIC POSITION: ENGINE DOES NOT START

Automatic Stopping Operations


CONTROL PANEL CONTROLS IN AUTOMATIC POSITION; SAFETY SHUTDOWN

When the contacts for any of the safety 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 parallel 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.


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, 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.

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 times 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 as 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.

Application Of Woodward 2301 Electric Governor

This system is controlled by an electric governor in the remote control panel. The Electric 2301 Governor is used with a WOODWARD EG-3P Actuator and a magnetic pickup on the flywheel housing to give exact engine control. The electric governor can be used as an isochronous governor or as a speed droop governor. As an isochronous governor, it keeps the engine rpm constant for all loads in the capacity of the engine.

The 2301 Governor is an assembly of solid state components. It changes an input of 12,24 or 32 volts D.C. to a constant voltage for the amplifier section. The governor will feel changes in engine rpm and send a voltage signal to the EG-3P Actuator to correct the fuel setting. Only two adjustments to the gain and reset rheostats are needed for exact control.


2301 ELECTRIC GOVERNOR CONNECTIONS TO ENGINE CONTROLS
1. Junction box on engine. 2. OPS2 Oil pressure switch. 3. Wire. 4. EG-3P Governor actuator. 5. Terminal strip on electric governor. 6. Terminal strip on engine. 7. Magnetic pickup. 8. Negative D.C. supply from battery of either 32V, 24V or 12V. NOTE: Connect shielded cables to governor grounding stud. *Earlier controls with internal connections at posts 3 and 4 needed 32V + supply connected at 4, 24V + supply is connected at 3 and 12V + is connected at 1. **Earlier installations used unshielded cable between OPS2 and engine junction box through TS1-11 and 12.


MULTIPLE UNIT CONNECTIONS TO ENGINE CONTROLS
1. Terminal strip on electric governor. 2. Positive D.C. supply for 32V system. 3. Magnetic pickup. 4. Terminal strip on engine. 5. Positive D.C. supply for 24V system. 6. Negative D.C. supply from battery of either 24V or 32V. 7. OPS2 Oil pressure switch. 8. EG-3P Governor Actuator. 9. Wire. NOTE: Connect shielded cables to governor grounding stud.

The EG-3P Actuator has a gear pump in its base which is driven by the engine. The oil for the pump is common to the engine lubrication system. The pump also has an oil sump in the supply line so a ready supply of oil is available when the engine is started. The gear pump sends pressure oil to the pilot valve plunger in the actuator. The position of the valve plunger is controlled by the voltage signal from the 2301 Governor to the solenoid coils.

The actuator, through linkage from its terminal shaft, will move the fuel rack to the fuel OFF position.

The actuator will move its terminal shaft from the maximum to the minimum fuel position in direct relation to the size of the input voltage signal. Temperature does not change the accuracy of the actuator. The actuator will move to the minimum fuel position on loss of power supply to the 2301 Governor or loss of signal to the EG-3P Actuator. Opening either of these circuits can stop the engine.

NOTE: Earlier arrangements will go to maximum fuel position on loss of power to the governor or loss of signal to the actuator.

The magnetic pickup is connected to the flywheel housing at an angle of 90° to the teeth of the flywheel ring gear. As the teeth of the ring gear move by the permanent magnetic and coil in the magnetic pickup, an alternating current voltage is generated (to make electricity) in the pickup. This voltage is in direct relation to engine rpm.


WOODWARD EG-3P ACTUATOR (Maximum Fuel Position)


MAGNETIC PICKUP

This voltage is sent to the 2301 Governor. In this manner the electrical governor has an input voltage signal which gives the exact engine rpm.

The following illustrations for the 2301 Electric Governor are basic schematics. DO NOT use them as complete wiring diagrams.


CONTROL PANEL CONTROLS IN AUTOMATIC POSITION; STANDBY CONDITION


CONTROL PANEL CONTROLS IN AUTOMATIC POSITION; STANDBY CONDITION (EARLY STARTING MOTOR)

Automatic Starting Operations

When emergency power is needed, the initiating contactor closes. This energizes the initiating relay. The current flow through the initiating relay contacts then energizes 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

When the oil pressure is normal, the contactor switch (OPS1) for oil pressure closes. Oil pressure switch (OPS2) also opens at this time. As OPS1 closes, the auxiliary relay is energized, which stops current flow to the cranking relay. This de-energizes the magnetic switch and the pinion solenoid. The starting operation stops.


CONTROL PANEL CONTROLS IN AUTOMATIC POSITION; ENGINE STARTS

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 Governor. 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 DOES NOT START

Automatic Stopping Operations

When the contacts for any of the safety 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 Governor 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; SAFETY SHUTDOWN


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 Governor 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 Governor. 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 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 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 Governor 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 Control Panel


SEPARATE ALARM LIGHTS

Separate Alarm Lights

In control panels with separate alarm lights, the exact cause of a safety shutdown is shown.

Cycle Cranking Timer

A diaphragm return solenoid in the overcrank timer gives five starting cycles of ten seconds, with a ten second delay between cycles. The standard control panel gives only one 30 second starting cycle.

Time Delay Relay

This relay lets the engine run for two minutes after the load is removed from the generator set to slow cooling. This action will also let the generator set take the load again if commercial power is starting and stopping every few seconds. The standard control panel stops the engine immediately after the load is removed from the generator set.

Wiring Diagrams


WIRING DIAGRAM FOR D353 ENGINE CONTROLS AUTOMATIC START/STOP WITH WOODWARD 2301 GOVERNOR
1. Magnetic switch. 2. Circuit breaker. 3. EG-3P Governor actuator. 4. Contactor switch for water temperature. 5. Pinion solenoid. 6. Contactor switch for oil pressure (OPS1). 7. Starting motor. 8. Contactor switch for overspeed. 9. Battery. 10. Terminal strip.
NOTE: No. 14 wire is used where wire size is not given.


WIRING DIAGRAM FOR D353 ENGINE CONTROLS AUTOMATIC START/STOP WITH UG-8 GOVERNOR
1. Magnetic switch. 2. Circuit breaker. 3. Rack solenoid. 4. Contactor switch for water temperature. 5. Pinion solenoid. 6. Contactor switch for oil pressure. 7. Starting motor. 8. Contactor switch for overspeed. 9. Battery. 10. Fuel pressure switch. 11. Governor synchronizing motor. 12. Terminal strip.
NOTE: No. 14 Wire is used where wire size is not given.


WIRING DIAGRAM FOR D353 ENGINE CONTROLS; OIL PRESSURE & WATER TEMPERATURE
1. Contactor switch for oil pressure. 2. Contactor switch for water temperature. 3. Fuel pressure switch (normally open). 4. Rack solenoid. 5. Terminal block (if so equipped). 6. Pinion solenoid. 7. Starting motor. 8. Battery.
* Grounded systems only.


WIRING DIAGRAM FOR D353 ENGINE CONTROLS; OIL PRESSURE, WATER TEMPERATURE & OVERSPEED
1. Contactor switch for oil pressure. 2. Contactor switch for water temperature. 3. Fuel pressure switch (normally open). 4. Rack solenoid. 5. Contactor switch for overspeed. 6. Terminal block (if so equipped). 7. Pinion solenoid. 8. Starting motor. 9. Battery.
* Grounded systems only.


WIRING DIAGRAM FOR ALARM SYSTEM
1. Contactor switch for oil pressure. 2. Contactor switch for water temperature. 3. Horn. 4. A.C. or D.C. power source. 5. Alarm light. 6. Toggle switch.


WIRING DIAGRAM FOR WOODWARD SYNCHRONIZING MOTOR
1. Two-way switch. 2. Red wire (R). 3. Motor, 110 V, AC or DC., 4. Blue wire (C), connected to 110 V AC or DC supply (14 gauge wire). 5. Black wire (L).

Safety Controls

Mechanical Safety Shutoff

A mechanical safety shutoff for overspeed (engine running too fast) and low oil pressure is available for industrial engines.

The safety shutoff (1) is installed on the side of the housing for the fuel injection pumps and is driven by the camshaft for the fuel injection pumps.

Oil pressure from the engine lubrication system is used to activate the safety shutoff. Line (3) sends oil to the shutoff valve for water temperature. Line (4) gives engine oil pressure to the safety shutoff.


MECHANICAL SAFETY SHUTOFF
1. Safety shutoff. 2. Shutoff lever for fuel rack. 3. Line (pressure oil connection to water temperature shutoff). 4. Line (pressure oil to safety shutoff). 5. Linkage to shutoff lever. 6. Oil drain line. 7. Release rod. 8. Reset plunger. 9. Manual shutoff button for emergency.

The overspeed shutoff part of the safety shutoff stops the engine mechanically, if for some reason the engine runs too fast.

The manual shutoff button (9) works with the overspeed shutoff and can be used to activate the shutoff in an emergency. Release rod (7) for the safety shutoff activates linkage (5) to move shutoff lever (2) for the fuel rack to the fuel OFF position.

Reset plunger (8) is used to put the safety shutoff in the normal operation position, after the engine has been stopped by the shutoff.

NOTE: It is not necessary to use reset plunger (8) after the engine has been stopped in a normal way.

The parts of the safety shutoff get lubrication from oil leakage around the oil pressure shutoff piston. Return oil goes through line (6).

NOTE: It is important that line (6) be kept open. If the housing gets too much oil in it, the overspeed will not operate correctly. Too much oil in the housing will cause an increase in the rpm necessary to activate the overspeed control.

Operation of Controls

Low Oil Pressure and Water Temperature Shutoff

The oil pressure control will stop the engine if the pressure of the lubrication oil becomes lower than the pressure for safe operation. If the temperature of the water gets too high, it will open a shutoff valve for water temperature and give an indication of low oil pressure. This activates the safety shutoff to stop the engine.

In normal engine operation, engine lubrication oil goes through cover (4) and against control piston (6).


SAFETY SHUTOFF (Cross Section, Front View; Normal Operation)
1. Worn shaft. 2. Slide follower. 3. Slide follower shaft. 4. Cover. 5. Guide. 6. Piston. 7. Spring. 8. Release rod.

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

Worm shaft (1) is turned by the drive for the safety shutoff. The safety shutoff will function any time the engine is running.

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

When the pressure of the engine oil becomes lower than the pressure for safe operation, the pressure of oil on piston (6) is less and spring (7) will force guide (5) and piston (6) to the stop position. Slide follower (2) will turn on shaft (3) and contact worm shaft (1).


SAFETY SHUTOFF (Cross Section, Side View; Normal Operation)
1. Worm shaft. 2. Slide follower. 3. Slide follower shaft. 5. Guide. 8. Release rod. 9. Pin. 10. Release latch. 11. Spring.

With slide follower (2) engaged with worm shaft (1), the slide follower will move the length of worm shaft (1). As the slide follower comes to the end of its movement, pin (9) on the follower will make contact with release latch (10). The release latch (10) will move and permit release rod (8) to be moved out by force of spring (11).

Release rod (8) moving out will cause the linkage to the shutoff lever for the rack to move down. As the shutoff lever moves, a rod connected to the lever assembly makes contact with the linkage for the rack and moves the rack to the fuel OFF position.


SAFETY SHUTOFF (Cross Section, Front View; Shutoff Operation Position)
1. Worm shaft. 2. Slide follower. 3. Slide follower shaft. 5. Guide. 6. Piston. 7. Spring. 8. Release rod.


SAFETY SHUTOFF (Cross Section, Side View; Shutoff Operation Position)
1. Worm shaft. 2. Slide follower. 8. Release rod. 9. Pin. 10. Release latch. 11. Spring.

Overspeed Shutoff

In case of an overspeed (engine running too fast) condition, the overspeed shutoff control will activate the release rod and move the rack to the fuel OFF position.

Overspeed carrier assembly (1) is driven by gears and the drive for the safety shutoff. The overspeed shutoff will function any time the engine is running. A rotating weight (2) in the carrier flange is held toward the center of the carrier shaft by an adjustment screw, spring and nut.


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

When the engine rpm becomes faster, the force of the weight will have an increase. The weight moves out of the carrier flange. The weight will move out until the spring force (restriction of weight movement out) is the same as 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.

Manual Shutoff Button for Emergency


EMERGENCY SHUTOFF
1. 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 shutdown 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 engine is stopped.

In an emergency where the engine must be stopped immediately, push the emergency shutoff button in and hold it until the rack has been moved to the fuel OFF position.

When you push button (5) 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 overspeed (engine running too fast) condition.

Setting The Control

If the engine has been stopped by the safety shutoff, the cause of the engine shutoff must be found and corrected. After the problem has been corrected, put the controls in the normal operation position.

Setting After Overspeed and Emergency Manual Shutoff

To put the release rod in the normal operation position, pull the rack shutoff lever on the governor housing up. The engine will now start.

Setting After Low Oil Pressure or Water Temperature Shutoff

Push reset plunger (4). This will move the piston (3) and pin against guide (1). The movement of the guide will turn slide follower (2) away from the end of the worm shaft. This will permit the spring to move the slide follower to the start of the threads on the worm shaft.

To put the release rod in the normal operation position, pull the rack shutoff lever on the governor housing up. The engine will now start.

NOTE: In cold weather operation, it can be necessary to push the reset plunger (4) when starting the engine to keep the shutoff control from activating. This is necessary because the oil pressure does not get to the operating range fast enough during the longer starting period needed in these conditions.

In normal weather operation, the pressure of the oil will get to the operating range before the slide follower (2) has moved the length of the worm shaft and activated the release lever and rod.


SHUTOFF SETTING CONTROL
1. Guide. 2. Slide follower. 3. Piston. 4. Reset plunger. 5. Release rod.

Rack Shutoff Solenoid With Hydraulic Boost

An electric solenoid which operates to move the fuel rack to the fuel OFF position is available. The contactor switches for water temperature, overspeed and oil pressure activate the rack solenoid (2).


RACK SHUTOFF SOLENOID
1. Linkage. 2. Rack solenoid. 3. Outer lever. 4. Cover on governor drive housing. 5. Rod to move fuel rack. 6. Shaft. 7. Piston valve assembly for hydraulic boost. 8. Lever inside of governor drive housing.

Linkage (1) is connected to lever (8) through lever (3) and shaft (6). Lever (8) is connected to valve (12) of piston valve assembly (7). Rod (5) is held against piston (11) by its spring. Engine oil pressure in passage (9) goes around piston (11) and is stopped from going behind the piston by the position of valve (12).


PISTON VALVE ASSEMBLY
9. Passage in governor drive housing for engine oil pressure. 10. Pin to control movement of valve and piston. 11. Piston. 12. Valve.

When the solenoid (2) is activated, the force of the plunger in the solenoid moves linkage (1). The initial movement of the solenoid, through the levers, moves valve (12) out of piston (11). Valve (12) moves by itself until it makes contact with pin (10). This opens a passage for the oil to get behind piston (11). The pressure of the oil behind the piston then moves the piston with valve (12). Since rod (5) is held against the piston, the force of the solenoid on the valve and the pressure of the oil behind the piston move rod (5). Rod (5) then pushes the fuel rack to the fuel OFF position to stop the engine.

After the engine has stopped and the rack solenoid (2) is no longer activated, the return spring, connected to lever (3), moves valve (12) back into piston (11). Since the engine is stopped, no oil is in passage (9) and the position of the valve lets the oil behind the piston go through a passage in the valve. The force of the return spring will then move the piston and the valve back to their original position.

In case of a low oil pressure failure, the force of rack solenoid (2) is enough to pull the valve (12) and piston (11) out of the housing. This moves rod (5) and the rack to the fuel OFF position.

Rack Shutoff Solenoid

Some engines with UG-8 governors have a rack shutoff solenoid which is connected to the lower lever (1) of the governor linkage. When activated, the rack solenoid (3) will move the fuel rack to the fuel OFF position.


RACK SHUTOFF SOLENOID
1. Lower lever of governor linkage. 2. Rack solenoid linkage. 3. Rack solenoid.

Contactor Switch For Water Temperature

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.


CONTACTOR SWITCH FOR WATER TEMPERATURE

Contactor Switch For Overspeed

The contactor switch for overspeed is installed on the tachometer drive on the side 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.

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.


PRESSURE SWITCH

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

Contactor Switch For Oil Pressure

Micro Switch Type

The contactor switch for oil pressure is 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 contactor switch closes to remove the starting system from the circuit when the engine is running with normal oil pressure.

This contactor 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.


CONTACTOR SWITCH FOR THE OIL PRESSURE (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 contactor switches have a "Set For Start" button. Pushing in the button, puts the micro switch in the RUN position. This is done because latch plate (7) holds arm (9) against button (8) of the micro switch and the switch operates as if oil pressure is normal. When the engine is running, oil pressure is in bellows (6) and arm (4) moves to make the arm come in contact with latch plate (7). The "Set For Start" button is released by spring (5). This puts the contactor switch in a ready to operate condition to stop the engine when the oil pressure is low.

Earlier Type Switch

Early contactor 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. The knob moves to the RUN position when the oil pressure is normal.


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

Shutoff Valve For Water Temperature

The shutoff valve for water temperature is connected in an oil line from the mechanical safety 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 safety 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 safety shutoff go back to the engine oil sump through outlet port (6). The low oil pressure causes the safety 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.

Circuit Breaker

The circuit breaker in the later automatic start/stop systems is a safety switch that opens the battery circuit whenever the current in the starting system is higher than the rating of the circuit breaker.

A metal disc with a contact point completes the electric circuit through the circuit breaker. High current in the electric starting system will cause heat in the metal disc. Heat will cause distortion of the disc, causing the contacts to open. An open circuit breaker will close (reset) automatically after it becomes cooler.


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

Air Starting System

The air starting motor is used to turn the engine flywheel fast enough to get the engine running.


AIR STARTING SYSTEM (TYPICAL EXAMPLE)
1. Starter control valve. 2. Oiler. 3. Relay valve. 4. Air starting motor.

The air starting motor can be mounted on either side of the engine. Air is normally contained in a storage tank and the volume of the tank will determine turning time of engine. The storage tank must hold this volume of air at 250 psi (1720 kPa) when filled.

For engines which do not have heavy loads when starting, the regulator setting is approximately 100 psi (690 kPa). This setting gives a good relationship between cranking speeds fast enough for easy starting and the length of time the air starting motor can turn the engine before the air supply is gone.

If the engine has a heavy load which can not be disconnected during starting, the setting of the air pressure regulating valve needs to be higher in order to get high enough speed for easy starting.

The air consumption is directly related to speed. The air pressure is related to the effort necessary to turn the engine flywheel. The setting of the air pressure regulator can be up to 150 psi (1030 kPa) if necessary to get the correct cranking speed for a heavily loaded engine. With the correct setting, the air starting motor can turn the heavily loaded engine as fast as it can turn a lightly loaded engine.

Other air supplies can be used if they have the correct pressure and volume. For good life of the air starting motor, the supply should be free of dirt and water. The maximum pressure for use in the air starting motor is 150 psi (1030 kPa). Higher pressures can cause safety problems.

The 1L5011 Regulating and Pressure Reducing Valve Group has the correct characteristics for use with the air starting motor. Most other types of regulators do not have the correct characteristics. Do not use a different style of valve in its place.


AIR STARTING MOTOR (Ingersoll-Rand Motor Shown)
5. Vanes. 6. Rotor. 7. Air inlet. 8. Pinion. 9. Gears. 10. Piston. 11. Piston spring.

The air from the supply goes to relay valve (3). The starter control valve (1) is connected to the line before the relay valve (3). The flow of air is stopped by the relay valve (3) until the starter control valve (1) is activated. Then air from the starter control valve (1) goes to the piston (10) behind the pinion (8) for the starter. The air pressure on the piston (10) puts the spring (11) in compression and puts the pinion (8) in engagement with the flywheel gear. When the pinion is in engagement, air can go out through another line to the relay valve (3). The air activates the relay valve (3) which opens the supply line to the air starting motor.

The flow of air goes through the oiler (2) where it picks up lubrication oil for the air starting motor.

The air with lubrication oil goes into the air motor. The pressure of the air pushes against the vanes (5) in the rotor (6). This turns the rotor which is connected by gears (9) to the starter pinion (8) which turns the engine flywheel.

When the engine starts running the flywheel will start to turn faster than the starter pinion (8). The pinion (8) retracts under this condition. This prevents damage to the motor, pinion (8) or flywheel gear.

When the starter control valve (1) is released, the air pressure and flow to the piston (10) behind the starter pinion (8) is stopped. The piston spring (11) pulls back the pinion (8). The relay valve (3) stops the flow of air to the air starting motor.

Hydraulic Starting System


HYDRAULIC STARTING SYSTEM DIAGRAM
1. Reservoir. 2. Hand pump. 3. Pressure gauge. 4. Hydraulic starting motor. 5. Starter control valve. 6. Hydraulic pump (driven by engine timing gears). 7. Unloading valve. 8. Filter. 9. Accumulator.

The hydraulic starting motor (4) is used to turn the engine flywheel fast enough to get the engine started. When the engine is running, the hydraulic pump (6) pushes oil through the filter (8) into the accumulator (9). The accumulator (9) is a thick wall cylinder. It has a piston which is free to move axially in the cylinder. A charge of nitrogen gas (N2) is sealed in one end of the cylinder by the piston. The other end of the cylinder is connected to the hydraulic pump (6) and the hydraulic starting motor (4). The oil from the hydraulic pump (6) pushes on the piston which puts more compression on the nitrogen gas (N2) in the cylinder. When the oil pressure gets to 3000 psi (20 700 kPa), the accumulator (9) has a full charge. At this point the piston is approximately in the middle of the cylinder.

The unloading valve (7) feels the pressure in the accumulator (9). When the pressure is 3000 psi (20 700 kPa) the unloading valve (7) sends the hydraulic pump (6) output back to the reservoir (1). At the same time it stops the flow of oil from the accumulator (9) back to hydraulic pump (6). At this time there is 3000 psi (20 700 kPa) pressure on the oil in the accumulator (9), in the line to the unloading valve (7), in the lines to the hand pump (2) and to the hydraulic starting motor (4).

Before starting the engine, the pressure on the pressure gauge (3) should be 3000 psi (20 700 kPa). When the starter control valve (5) is activated, the oil is pushed from the accumulator (9) by the nitrogen gas (N2). The oil flow is through the hydraulic starting motor (4), where the energy from the compression of the fluid is changed to mechanical energy for turning the engine flywheel.

Hydraulic Starting Motor


HYDRAULIC STARTING MOTOR
1. Rotor. 2. Piston. 3. Thrust bearing. 4. Starter pinion. A. Oil inlet. B. Oil outlet.

The hydraulic starting motor is an axial piston hydraulic motor. The lever for the starter control valve pushes the starter pinion (4) into engagement with the engine flywheel at the same time it opens the way for high pressure oil to get into the hydraulic starting motor.

When the high pressure oil goes into the hydraulic starting motor, it goes behind a series of pistons (2) in a rotor (1). The rotor (1) is a cylinder which is connected by splines to the drive shaft for the starter pinion (4). When the pistons (2) feel the force of the oil they move until they are against the thrust bearing (3). The thrust bearing (3) is at an angle to the axis of the rotor (1). This makes the pistons (2) slide around the thrust bearing (3). As they slide, they turn the rotor (1) which connects through the drive shaft and starter pinion (4) to the engine flywheel. The pressure of the oil makes the rotor (1) turn very fast. This turns the engine flywheel fast enough for quick starting.

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