5.75" BORE SIX CYLINDER ENGINE ATTACHMENTS Caterpillar


Systems Operation

Usage:



Introduction

NOTE: For Specifications with illustrations, make reference to ATTACHMENT SPECIFICATIONS FOR 5.75" BORE, SIX CYLINDER ENGINES, Form No. REG01529. If the Specifications in Form No. REG01529 are not the same as in the Systems Operation and the Testing and Adjusting, look at the printing date on the back cover of each book. Use the Specifications given in the book with the latest date.

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 or carburetor. Movement of the rack or carburetor 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 the TESTING AND ADJUSTING section of this manual.

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.

Woodward PSG Governor

The Woodward PSG Governor is a hydraulic speed governor with a system for compensation of the small movements of the governor weights and spring which would cause a change in the engine rpm. The governor will cause the engine to keep the same speed when there is a change in the load on the engine.

The oil supply is from the engine lubrication system. This oil goes to the governor oil pump (7) which makes an increase in pressure to 175 psi (12.3 kg/cm2). Four check valves permit rotation of the governor in either direction. Oil from the relief valve goes back to the supply, so oil which is not used in pumped to the components inside the governor.


SCHEMATIC OF OIL FLOW IN GOVERNOR
1. Check valves. 2. Governor weights. 3. Linkage to fuel rack or carburetor throttle. 4. Return spring. 5. Terminal lever. 6. Power piston. 7. Pump. 8. Supply valve (pressure controlled). 9. Hydraulic valve bushing and governor drive shaft. 10. Drain. 11. Pilot valve plunger.

The governor drive shaft is the hydraulic valve bushing (9). The pilot valve plunger (11) in the center of the bushing is installed in the thrust bearing and spring seat (12). The rotation of the bushing causes governor weights (2) to turn. The toes of the weights are against the thrust bearing and the spring seat. One of the hydraulic pump gears is made as part of the bushing (9).

When there is an increase in the load on the engine, the rpm of the engine goes down and there is a reduction of the speed of rotation of the governor weights (2). The force of rotation (centrifugal force) of the governor weights (2) is less and the spring (13) pushes seat (12) and pilot valve plunger (11) to a position in bushing (9) where an oil passage is opened and oil is sent to the power piston (6). The pressure of the oil moves the power piston which moves the lever (5). The lever is part of the governor terminal shaft which is connected to the fuel rack or carburetor throttle. The rack or throttle is moved to a more fuel position and there is an increase in engine rpm. As the engine rpm goes up, the governor weights turn faster. The force of rotation (centrifugal force) is larger and the toes of the weights move the thrust bearing and spring seat (12) and pilot valve plunger (11). When the rpm of the engine is again the same as it was before there was an increase in the load, the governor weights have moved the pilot valve plunger to its original position. This closes the oil passage to the power piston (6) to stop the movement of the power piston and linkage to the rack or throttle.

When there is a decrease in the load on the engine there is an increase in the rpm of the engine and the speed of rotation of the governor weights is faster. The toes on the governor weights move the thrust bearing, spring seat (12), and pilot valve plunger (11) to a position in the bushing (9) that permits the oil under the power piston (6) to flow through the drain (10). When the oil under the power piston can flow through the drain, a return spring (4) in the governor linkage moves the linkage to the fuel rack or carburetor throttle to a less fuel position and there is a decrease in the rpm of the engine. The governor weights rotate slower and the governor spring (13) pushes on the spring seat (12) and pilot valve plunger (11). When the rpm of the engine is again the same as it was before there was a decrease in the load, the governor spring has pushed the pilot valve plunger (11) to a position where no oil can flow from the drain from under the power piston (6). The movement of power piston and linkage to the fuel rack or carburetor throttle is now stopped.


CROSS SECTION OF HYDRAULIC GOVERNOR
2. Governor weights. 5. Terminal lever. 6. Power piston. 7. Hydraulic pump. 9. Hydraulic valve bushing and governor drive shaft. 11. Pilot valve plunger. 12. Thrust bearing and spring seat. 13. Governor spring. 14. Buffer piston. 15. Buffer springs (two).

Small movements in the governor weights and springs during rotation of the governor do not cause a change in engine rpm because of compensation by the buffer piston (14) and the buffer springs (15). The buffer springs keep the buffer piston in the center of the power piston (6). The oil which is sent to the power piston must first go through an opening in the bottom of the power piston and push on the buffer piston to move the power piston.

Safety Controls

Safety Control Shutoff

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

The safety control shutoff (1) is installed on the rear 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 (2) sends oil to the water temperature shutoff control valve. Line (3) gives engine oil pressure to the safety shutoff.


SAFETY CONTROL SHUTOFF
1. Safety control shutoff. 2. Line (pressure oil connection to water temperature shutoff). 3. Line (pressure oil to safety shutoff). 4. Release cable. 5. Shutoff for fuel rack. 6. Reset plunger. 7. Lubrication oil drain line. 8. Emergency manual shutoff button.

The overspeed shutoff part of the control stops the engine mechanically if the engine runs too fast.

The emergency manual shutoff button (8) works with the overspeed shutoff and can be used to activated the shutoff in an emergency.

Shutoff control release cable (4) activates the shutoff (5) for the fuel rack.

Reset plunger (6) is used to put the controls in the normal operation position, after the engine has been stopped by the controls.

NOTE: It is not necessary to use reset plunger (6) 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 (7).


NOTICE

It is important that line (7) 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 speed 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 too low for safe operation. If the temperature of the water gets too high, it will open a shutoff control valve and cause low pressure of the lubrication oil. This activates the shutoff control and will stop the engine.

In normal engine operation, engine lubrication oil goes through line (3). (See illustration of Safety Control Shutoff). This oil goes to cover (4) and against control piston (6).


SHUTOFF CONTROL (Cross Section, Front View; Normal Operation)
1. Worm 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 control 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).


SHUTOFF CONTROL (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.

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).

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 control lever for the rack shutoff to move toward the rear of the engine. As the control lever moves and rod connected to the lever assembly contacts the linkage for the fuel rack and moves the fuel rack to the CLOSED position, which will cause the engine to stop.


SHUTOFF CONTROL (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.


SHUTOFF CONTROL (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

If there is an "overspeeding" (engine running too fast) condition, the overspeed shutoff control will activate the release rod and move the fuel rack to the CLOSED position, which will cause the engine to stop.

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 goes up, 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 be moved and move the fuel rack to the CLOSED position, which will cause the engine to stop.

Emergency Manual Shutoff Button

Emergency shutoff button (5) is only used to stop the engine when there is an emergency. Do not use the emergency 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.

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 CLOSED position.


EMERGENCY SHUTOFF
1. Weight. 2. Carrier assembly. 3. Pin. 4. Overspeed plunger. 5. Button.

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 "overspeeding" (engine running too fast).

Setting The Control

If the engine has been stopped by the safety shutoff, the cause of the engine stopping 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

Put the release rod in the normal operation position. Pull the rack shutoff lever on the governor housing, toward the front of the engine. The engine will now start.

Setting After Low Oil Pressure or Water Temperature Shutoff

Push reset plunger (4) for the oil pressure. This will move the piston (3) and pin against guide (1). The movement of the guide will turn slide follower (2) away from 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 (5) in the normal operation position, pull the rack shutoff lever (6), on the governor housing, toward the front of the engine. The engine will now start.


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

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 to the length of the worm shaft. This oil pressure also prevents activation of the release lever and rod (5).


RACK SHUTOFF LEVER
6. Lever.

Rack Shutoff Solenoid

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.


RACK SHUTOFF SOLENOID
1. Rack solenoid. 2. Linkage. 3. Outer lever. 4. Lever inside of governor drive housing. 5. Yoke to move fuel rack. 6. Shaft. 7. Return spring.

Linkage (2) is connected to lever (4) through lever (3) and shaft (6). Lever (4) aligns with a yoke (5) connected to the rack.

When the solenoid (1) is activated, force of the plunger in the solenoid moves linkage (2). The movement of the solenoid, through the linkage and levers, pushes the fuel rack to the fuel OFF position to stop the engine.

After the engine has stopped and the rack solenoid (1) is no longer activated, the return springs (7) will then move the linkage and solenoid plunger back to their original positions.

Contactor Switch For Water Temperature

The contactor switch for water temperature is installed in the water manifold or housing for the temperature regulators. 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.


CONTACTOR SWITCH FOR WATER TEMPERATURE

The contactor switch is connected to the rack shutoff solenoid or the magneto and gas valve on gas engines 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 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 or the magneto and gas valve on gas engines 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.

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.


PRESSURE 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 or connects the magneto to ground and closes the gas valve on gas engines.

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.


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.

As pressure of the oil in bellows (6) becomes higher, arm (4) is moved against the force of spring (3). When projection (10) of arm (4) makes contact with arm (9), pressure in the bellows moves both arms. This also moves button (8) of the micro switch to activate the micro switch.

Some of these 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.

Electrical Gauges And Sending Units

The electrical gauges and sending units are to operate in electrical balance. Because of this, the voltage and resistance ratings are important to get the correct indications on the gauges. The following chart shows components that operate together.

Sending Unit for Water Temperature

The sender sends current to the water temperature gauge as soon as the engine is started and oil pressure activates the oil pressure switch.

The water temperature is felt by the bulb (3) of the sender. The resistance in the sender makes the communication of the correct current from connector (1) to the water temperature gauge. The bushing (2) also makes the electrical ground for the system.


SENDING UNIT FOR WATER TEMPERATURE
1. Connection. 2. Bushing. 3. Bulb.

Oil Pressure Sender

The sender sends current to the oil pressure gauge as soon as the engine is started and oil pressure activates the oil pressure switch.


OIL PRESSURE SENDER
1. Connection. 2. Fitting.

The oil pressure is felt by the sender from the pressure delivered to the fitting (2) of the sender. The resistance in the sender makes the communication of the correct current from connection (1) to the oil pressure gauge. The fitting also makes the electrical ground for the system.

Wiring Diagrams


DIAGRAM FOR ELECTRICAL INSTRUMENT PANEL
1. Light switch. 2. Oil pressure gauge. 3. Panel lights. 4. Ammeter. 5. Terminal strip. 6. Water temperature gauge. 7. Gear oil pressure switch. 8. Instrument panel. 9. Wire from battery. 10. Oil pressure switch. 11. Oil pressure sender. 12. Water temperature sender. 13. Gear oil pressure sender.


DIAGRAM FOR OIL PRESSURE AND 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.


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.


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


DIAGRAM FOR OIL PRESSURE, WATER TEMPERATURE & OVERSPEED
1. Contactor switch for oil pressure. 2. Contactor switch for water temperature. 3. Fuel pressure switch (noramlly 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.


DIAGRAM FOR G342 ENGINE CONTROLS
1. Reset button. 2. Magnetic switch. 3. Stop switch. 4. Contactor switch for oil pressure. 5. Magneto. 6. Gas valve. 7. Contactor switch for overspeed. 8. Contactor switch for water temperature.

Hydraulic Starting


HYDRAULIC STARTING SCHEMATIC
1. Reservoir. 2. Starter control valve. 3. Cranking motor. 4. Accumulator. 5. Unloader valve. 6. Gauge. 7. Hand pump. 8. Engine gear driven pump. 9. Filter.

Hydraulic starting systems operate on the principle of pressure oil turning a fluid motor to change pressure to mechanical energy. Pressure oil is kept in a piston type accumulator. The starter control valve sends pressure oil to the cranking motor. Oil is sent into the inlet port of the motor to the pistons in the rotor. The pressure oil moves the piston down against a fixed thrust bearing which is installed at an angle. As the pistons move down, they move down the angle face of the bearing. This movement gives rotation to the rotor. The rotor turns the output shaft and gear, which is connected to the ring gear of the flywheel, to start the engine. Oil then goes through the outlet port of the motor to the oil reservoir.

A belt driven pump sends pressure oil to the accumulator through a high pressure filter. An unloading valve in the pump sends oil back to the reservoir after the accumulator has full charge.

The hand pump is for emergency use when the accumulator has loss its charge.


CRANKING MOTOR
1. High pressure oil. 2. Fixed position thrust bearing. 3. Pinion. 4. Low pressure oil. 5. Rotor. 6. Piston.

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