Governor Types

3161 GOVERNORS
1. 3161 Standard Governor. 2. 3161 Governor with Torque Rise. 3. 3161 Generator Set Governor.

The 3161 Standard Governor (1), the 3161 Governor with Torque Rise (2) and the 3161 Generator Set Governor (3) are the three arrangements of this governor that are available.

A mechanical head cover, a pneumatic head cover and a speed adjusting motor head cover are the three top covers available for use with any of the 3161 governors. These top covers make each governor adaptable for use with optional controls. The optional controls can be factory installed or added to a governor already in service without any modification to the governor.

3161 Standard Governor

3161 STANDARD GOVERNOR
1. Pneumatic speed setting control. 2. Air fuel ratio control.

The 3161 Standard Governor is the base governor.

The 3161 Standard Governor is equipped with:

A pneumatic speed setting control (1) or manual mechanical speed control.

An air fuel ratio control (2).

The optional controls for this governor are:

1. Manual mechanical speed control (or pneumatic speed setting control).

2. Manual shutdown.

3. Pressure (pneumatic or hydraulic) shutdown.

4. Electric "energize to shutdown" solenoid.

5. Electric "energize to run" solenoid.

6. Pneumatic mid-speed control.

The shutdown controls (manual, pneumatic and electric) can be used separately or together as needed.

3161 Governor With Torque Rise

3161 GOVERNOR WITH TORQUE RISE
1. Pneumatic speed setting control. 2. Air fuel ratio control.

The 3161 Governor with Torque Rise is a standard base governor with the torque rise components installed.

This governor is used with engine arrangements that require a specific torque rise application. The torque rise control can be adjusted and gives similar engine output to that given by the torque spring and spacer arrangement used in other Caterpillar governors.

The 3161 Governor with Torque Rise comes with:

A pneumatic speed setting control (1) or a manual mechanical speed control;

An air fuel ratio control (2); and

A torque rise control (internal not shown).

The optional controls for this governor are:

1. Pneumatic speed setting control (not to be used with a manual mechanical speed control).

2. Manual shutdown.

3. Pressure (pneumatic or hydraulic) shutdown.

4. Electric "energize to shutdown" solenoid.

5. Electric "energize to run" solenoid.

The shutdown controls (manual, pneumatic and electric) can be used separately or together as needed.

3161 Generator Set Governor

3161 GENERATOR SET GOVERNOR
1. Manual speed setting control. 2. Speed adjusting motor head. 3. External droop adjustment.

The 3161 Generator Set Governor is a special arrangement of the base governor and is primarily for use on electric set engine arrangements.

An electric set engine equipped with a 3161 Generator Set Governor can be paralleled with other generator set engines governed by a 3161, 2301, a hydramechanical governor, or with an infinite bus.

The 3161 Generator Set Governor comes with:

A manual speed setting control (1).

A speed adjusting motor head [24-32 volts DC] (2).

An external droop adjustment (3).

The optional controls for this governor are:

1. Manual shutdown.

2. Pressure (pneumatic or hydraulic) shutdown.

3. Electric "energize to shutdown" solenoid.

4. Electric "energize to run" solenoid.

5. Utility power converter (115-230 volts AC) for speed adjusting motor (24-32 volts DC).

The shutdown controls (manual, pneumatic and electric) can be used separately or together as needed.

Basic Governor

3161 STANDARD GOVERNOR

The 3161 Governor is a mechanical-hydraulic governor that senses (feels) engine speed and is connected to the engine fuel system by mechanical linkage. The governor controls the rate of fuel injected into each of the engine cylinders as needed to adjust for engine loads.

Droop and compensation can be adjusted on the governor as needed for stability of engines with different rates of engine speed changes.

The 3161 Governor has a maximum of 8 N·m (6 lb. ft.) of torque output over the full 42 degrees of terminal (output) shaft rotation in both the fuel ON and OFF directions. Because the governor terminal shafts are moved in both directions by hydraulic pressure, no return spring is used on the outside of the governor. A 1.4 N·m (1 lb. ft.) spring inside the governor moves the terminal shafts to the full shutoff position when the governor is not in operation.

The recommended travel (rotation) of the terminal shafts is approximately 30 degrees from low idle to full load. This gives extra travel at each end for the governor to make a complete shutdown and gives maximum fuel when needed.

The 3161 Governor is connected to the engine lubrication oil system. The oil supply (under pressure) is sent to the governor through an orifice and internal passages. The governor keeps the correct oil level and drains excess oil back into the engine, this gives a constant flow of oil through the governor.

After removal or overhaul, the governor must be filled with approximately 1.8 liters (2. U.S. qt.) of clean engine oil before engine startup. The oil fill plug on all 3161 Governors is located on the top cover.

Governor Components

Gerotor Oil Pump

The gerotor oil pump is located in the base of the governor. The inner rotor of the pump is driven by a pin in the drive shaft, and carries the outer rotor around in mesh, this pushes oil to the accumulator piston.

Accumulator

A single accumulator, that consists of a piston and spring, acts as a relief valve for the oil pump and supplies a reservoir of high pressure oil for rapid power piston movement. Oil is sent to the accumulator by the governor pump, with an increase in pressure as the accumulator spring is put under compression. When the pressure gets to a set point, oil is returned to sump through relief ports in the piston wall.

Power Piston

The power piston is fastened to the output shaft by a link and lever assembly. The power piston has a large area on the bottom and a small area on top (differential piston). A small pressure increase on the large area of the piston will move the piston up, this causes the output shaft to turn in the "increase" direction. The piston can move down only when oil under the piston is released to sump. Oil to or from the bottom of the power piston is controlled by the ballhead pilot valve and ballhead pilot valve bushing.

Pilot Valve System

The pilot valve system is made of two components, the ballhead pilot valve (rotating) bushing, and the ballhead pilot valve plunger. The bushing is turned relative to the pilot valve plunger to reduce friction between the two parts. The control land of the pilot valve plunger controls the flow of oil through the control ports of the ballhead bushing.

When the pilot valve plunger is lowered, oil under high pressure moves through the control port of the bushing, to the bottom side of the power piston, and the piston moves up. When the pilot valve plunger is raised, the oil from the bottom of the power piston is released to sump, and the higher oil pressure on top of the piston moves the piston down. When the engine is running at a steady state, the control land of the pilot valve plunger covers the ports in the ballhead bushing and the power piston does not move. The movement of the pilot valve plunger is controlled by the ballhead assembly.

Ballhead Assembly

The ballhead system has a ballhead, flyweights, speeder spring, thrust bearing, and speeder plug. The ballhead, as part of the pilot valve bushing, is turned by the drive coupling and drive shaft.

As the ballhead turns, the centrifugal force causes the flyweights to pivot outward. At the same time, the force of the speeder spring pushes the thrust bearing down on the flyweight toes against the centrifugal force of the flyweights. When the speeder plug is pushed down this increases the downward pressure on the speeder spring, and the governor speed setting is increased. The engine then runs at a higher speed and puts a higher centrifugal force on the flyweights to equal the speeder spring force and put the system back in balance.

Speeder spring force or speed setting is controlled through the speed setting shaft.

Compensation System

The compensation system has a needle valve and a buffer piston with two springs. This system can be adjusted to give the desired rate of governor control and engine speed stability. Since the governor makes an adjustment rapidly to a change in engine load or speed setting, the engine can go into a "hunt" condition (temporary increase and decrease in engine speed) if too much adjustment is made. The purpose of the compensation system is to prevent overcorrection to the engine load or speed setting change. The system uses a pressure differential that is applied across the compensation land of the pilot valve plunger to give a stable governor control.

Speed Droop

The 3161 Governor is an isochronous governor with the ability to operate with droop by the adjustment of an internal droop pivot pin. The governor may be used with droop to allow for load division between two or more engines connected to a single shaft, or for operating in parallel.

The speed droop of a governor is the percent that the engine speed drops between high idle and full load.

The 3161 Standard and Torque Rise Governors are designed to operate with a 2 to 8 percent droop and have an internal droop pivot pin adjustment.

The 3161 Generator Set Governor is designed to operate with a 0 to 4 percent droop. It has an external adjustment lever connected to the internal droop pivot pin. This permits droop adjustments to be on the outside of the governor housing.

Torque Rise Control

TORQUE RISE COMPONENTS
1. Torque control lever. 2. Cam.

The torque rise control consists of a cam that makes the governor give more fuel to the engine under lug conditions.

Different percentages of torque rise can be selected by changing the cam to a programmed rate of rise. This change can be made on or off the engine. Cam selection and high idle settings must be based on factory recommendations.

The torque rise control is factory installed. It is not practical to install it in the field.

The torque rise cam has three distinct profiles: the base circle area (3); the approach ramp area (4); and the cam lift area (5).

The "base circle area" is a radius that does not lift the cam follower. The cam follower must be positioned on the base circle area when the dial indicator is zeroed, for a check or adjustment of the torque rise setting.

The "approach ramp area" is the "transition area" from the base circle to the cam lift area.

The "cam lift area" is the area on the cam that lifts the cam follower and torque rise pilot valve lever, which allows additional fuel for torque rise greater than the natural torque rise of the engine.

TORQUE RISE CAM
3. Base circle area. 4. Approach ramp area. 5. Cam lift area.

During the torque rise cam adjustment the set point of the terminal shaft is positioned by the synchronizing pin at the full load fuel setting. The cam is moved to position the cam follower on the start of the cam lift area at a specified point that will lift the cam follower 1.00 ± 0.05 mm above the base circle. This removes the free travel (clearances) from the governor and fuel control linkages so the torque rise will occur at the correct engine speed.

Limit/Shutdown Pilot Valve

Shutdown of the engine is done with the limit/shutdown pilot valve. With the engine running on speed, the ballhead pilot valve is in the centered position. When the limit/shutdown pilot valve is lowered, pressure oil above the control land of the ballhead pilot valve is drained back to the pump area. As engine speed begins to slow, ballhead flyweights move in, lowering the ballhead pilot valve plunger. Oil under the power piston is then drained to the pump area. As the power piston moves down, the output shaft is turned in the decrease direction, and the engine is shut down.

Operation Of The 3161 Governor

Make reference to the 3161 Governor Schematic for use with the systems operations that follow. The schematic shows the governor pilot valve in the increase fuel position.

The 3161 Governor uses engine lubrication oil for its hydraulic system. The oil supply (under pressure) is sent to the governor through an orifice and internal passages. The oil goes from the suction side to the pressure side of the gerotor pump as the drive shaft is turned by the engine. An accumulator spring and piston keeps the pump pressure at approximately 690 kPa (100 psi). The accumulator piston moves up in its cylinder until the pump pressure is 690 kPa (100 psi). At this time, ports in the piston are opened to control the pump pressure.

The pump pressure, as set by the accumulator, controls the work output of the governor. Pump pressure is also used for the auxiliary controls installed on the governor top cover.

Increase In Speed Setting

When the speed setting shaft is turned clockwise, the speed setting of the governor is increased. The high idle screw limits the high speed setting of the governor. As the speed setting shaft turns, the speed setting lever pushes down on the floating lever which is fastened to the speeder plug. The downward pressure on the speeder plug puts the speeder spring under compression. The speeder spring force then becomes greater than the centrifugal force of the ballhead flyweights, and the ballhead pilot valve plunger is moved down. This increases the governor speed setting.

As the pilot valve plunger is moved down, pressure oil moves under the power piston and pushes the piston up. This moves the terminal lever up and the output shafts are turned in the "increase" fuel direction to increase the engine speed.

Before the engine gets to the new set speed, the compensation system starts to move the pilot valve plunger back to its center position and put the governor under stable control as follows.

The oil above the power piston is connected to the upper side of the buffer piston and lower side of the pilot valve compensation land. As the power piston moves up the oil pressure moves the buffer piston down and increases the compression of the lower buffer piston spring. The force of the spring works against the buffer piston movement and this results in a small increase in oil pressure on the upper side of the buffer piston. This higher pressure is directed to the lower side of the pilot valve compensation land and makes a force to push the pilot valve plunger up toward its center position. This stops the flow of pressure oil to the lower side of the power piston and movement of the piston is stopped.

As the pilot valve plunger is returned to its center position and the power piston movement is stopped, there is oil leakage through the needle valve orifice. This lets the oil pressure above and below the pilot valve compensation land become equal and the pilot valve plunger movement is stopped and the engine speed is returned to a stable condition. As the pressure above and below the compensation land become equal, the buffer springs return the buffer piston to its center position.

SCHEMATIC OF THE 3161 GOVERNOR (Increased Fuel Position)

Decrease In Speed Setting

When the speed setting shaft is turned counterclockwise, the speed setting of the governor is decreased. The low idle screw limits the low speed setting of the governor. As the speed setting shaft is turned counterclockwise, the force of the speed setting lever on the floating lever is removed. This lowers the compression of the speeder spring. Centrifugal force from the ballhead flyweights lifts the pilot valve plunger to open the control port in the rotating bushing. Control oil under the power piston now drains to the sump and lets the power piston move down. The output shafts are turned in the "decrease" fuel direction and the engine speed is decreased.

Before the engine gets to the new set speed, the compensation system starts to move the pilot valve plunger back to its center position and put the governor under stable control as follows.

When the pilot valve plunger is lifted the oil under the power piston is released to drain back to the governor sump. Pump pressure oil on the bottom of the buffer piston now forces the buffer piston up. The oil above the buffer piston then puts a force on the top of the power piston to move the power piston down.

The movement of the buffer piston up increases the compression of the upper buffer piston spring. The force of the upper spring works against the buffer piston movement and this results in a small increase to the pump oil pressure on the lower side of the buffer piston and on the top surface of the pilot valve plunger compensation land. This small increase is greater than the pressure sent to the bottom surface of the compensation land. This pressure difference on the two sides of the compensation land makes a force (greater at the top) to push the pilot valve plunger back down to the center position.

When the output shaft has turned far enough to satisfy the new fuel setting, the force of the pressure difference on the compensation land puts the pilot valve plunger in its center position (even though the engine speed is not yet completely back to normal). The movement of the power piston, and the output shaft, is now stopped.

The continued decrease of engine speed to its steady-state setting, results in a continued increase in downward force of the speeder spring on the pilot valve plunger as the ballhead flyweights move in. At the same time, the pressure difference on each side of the buffer piston (and at top and bottom of the compensation land) is being released by the flow of oil through the needle valve orifice. This controlled discharge allows the buffer piston to return slowly to its normal, "centered" position. The speeder spring continues to push down on the pilot valve plunger until the spring force and ballhead flyweight force become equal. At the same time the controlled reduction of the pressure difference on the two sides of the compensation land occur exactly at the same rate (while the pilot valve plunger remains centered) until the engine is again at the on-engine speed condition at the new speed setting.

NOTE: An increase or decrease in engine load will give the similar governor movement as an increase or decrease in governor speed setting.

Shutdown

The limit/shutdown pilot valve is located in the pump oil pressure supply line to the ballhead pilot valve. When the engine shutdown system is activated, the limit/shutdown rod pushes the limit/shutdown pilot valve plunger below the supply passage. This drains oil from the supply to the ballhead pilot valve plunger. Control oil from under the power piston now drains past the control land of the pilot valve plunger. The power piston then moves down and the output shaft is turned in the "decrease fuel" direction. As the engine speed decreases, the ballhead flyweights move in and this lowers the ballhead pilot valve. Oil from under the power piston is now drained to the governor sump at a faster rate. As the power piston continues to move down, the output shaft is turned to the shutdown position until the engine is stopped.

Auxiliary Controls

This section describes the Auxiliary Controls and attachments that are available for the 3161 Governor. These controls are installed and calibrated at the factory before shipment to the user. The shutdown controls can be added to a governor already in service without any further modification to the governor.

The controls that can be fastened to the governor top cover are:

1. Manual Shutdown

2. Mechanical Shutdown

3. Electric Shutdown

4. Pneumatic Speed Setting Control

5. Air Fuel Ratio Control

Other controls added to the governor include:

1. Speed Adjusting Motor Head

2. Manual Speed Setting Control

3. Manual Mechanical Speed Control

4. Pneumatic Mid Speed Control

Manual Shutdown

MANUAL SHUTDOWN
1. Threaded shutdown handle. 2. Boot. 3. Shutdown plunger.

The manual shutdown assembly is installed on the right front corner of the governor top cover.

To shutdown the engine, the threaded shutdown handle can be either pushed down or tilted in any one of the 360 degrees to make contact with the shutdown rod. As the shutdown handle is tilted, the flat disc of the shutdown handle lowers the shutdown/limit pilot valve, to let control oil drain and cause engine shutdown.

The manual shutdown can be used in addition to the pressure or electric shutdown controls.

Pressure Shutdown

PRESSURE SHUTDOWN
1. Shutdown plunger. 2. Shutdown piston. 3. Shutdown control pressure passage.

The pressure shutdown assembly is installed on the right front cover of the governor top cover.

This shutdown uses either pneumatic or hydraulic pressure at a minimum of 276 kPa (40 psi) to shutdown the engine. When the pressure (air or oil) is applied to the shutdown piston, the piston is moved down and makes contact with the shutdown plunger. The plunger then pushes down on the shutdown rod and the shutdown/limit pilot valve. The pilot valve then lets control oil drain from under the power piston and causes engine shutdown. The shutdown will reset when pressure goes below 138 kPa (20 psi) and lower.

The pressure shutdown can be used in addition to the manual or electric shutdown controls. If this shutdown is added after the governor has been shipped from the factory, and is not used with any other shutdown, a small cover and gasket must be installed on top of the shutdown assembly.

Electric Shutdown

The electric shutdown assembly (1) is installed on the right front corner of the governor top cover.

This shutdown uses a 24 volt DC (energized-to-shutdown) solenoid that positions the shutdown lever and shutdown/limit pilot valve. When the solenoid is energized the plunger moves down. It lowers the shutdown rod and shutdown/limit pilot valve to let control oil drain from under the power piston and cause engine shutdown.

ELECTRIC SHUTDOWN
1. Electric shutdown assembly.

There is a diode used in the circuit for the electric solenoid because it is polarity sensitive. If the wires are connected the wrong way the solenoid will not operate.

The electric shutdown can be used by itself, or in addition to the manual and pressure shutdown controls. If this shutdown is added after the governor has been shipped from the factory, an adjustment must be made. See TESTING AND ADJUSTING section for the correct adjustment.

When the electric shutoff is used by itself, a small cover and gasket must be installed on top of the shutdown assembly.

Pneumatic Speed Setting Control

The pneumatic speed setting control is installed on the left front corner of the governor top cover. Because of its design, it is not practical to add the pneumatic speed control on the 3161 Governor in the field.

System air pressure from a remote throttle and internal pressure oil from the governor operate the control to increase or decrease the speed at which the engine runs. This control has the ability to repeat constant speed settings over a large range of conditions.

The pneumatic speed setting control has a standard air pressure range of 70 to 415 kPa (10 to 60 psi). Special applications of this control can use a pressure range of 35 to 380 kPa (5 to 55 psi) or 35 to 620 kPa (5 to 90 psi).

Increase Engine Speed

As control air pressure enters the speed setting bellows through the inlet port, expansion of the bellows takes place. The bellows pushes down on the speed setting lever to the left of the pivot. This lifts the right end of the speed setting lever against the feedback spring force to close the nozzle to drain.

Supply oil flows through an orifice to the lower side of the speed setting pilot valve plunger and then to drain through the nozzle. When oil flow from the nozzle is stopped by the speed setting lever, oil pressure increases and the speed setting pilot valve plunger moves up. This lets control oil go to the top of the speed setting piston. As the control oil pressure increases, the speed setting piston moves down to increase the governor speed setting through a rod and lever connected to the governor speed setting shaft.

As the speed setting piston moves down, the feedback spring is put under compression and pushes the speed setting lever away from the nozzle. Control oil can now go to drain and the pilot valve loading spring pushes the pilot valve plunger down to stop oil flow to the top of the speed setting piston. This results in the speed setting piston stopped in a new position that is proportional to the air pressure supplied to the speed setting bellows.

Decrease Engine Speed

When the control air pressure is lowered, the speed setting bellows moves back toward its original position. The feedback spring now pushes the speed setting lever away from the nozzle and control oil goes to drain through the nozzle.

As control oil pressure goes to drain, the oil pressure below the speed setting pilot valve plunger is decreased and the pilot valve loading spring moves the plunger down. This lets control oil above the speed setting piston go to drain and the feedback spring pushes the piston up. When the piston moves up, the force on the governor speed setting lever is lowered and the governor speed setting is reduced.

The speed setting piston moves up until the force of the feedback spring and the speed setting bellows moves the speed setting lever to close control oil to drain at the nozzle. At this time, the speed setting pilot valve plunger moves up to stop control oil movement above the speed setting piston. This results in the speed setting piston stopped in a new position that is proportional to the air pressure applied to the speed setting bellows.

PNEUMATIC SPEED SETTING CONTROL SCHEMATIC
1. Speed setting bellows. 2. Speed setting piston. 3. Orifice. 4. Spring seat. 5. Pilot valve loading spring. 6. Speed setting pilot valve plunger. 7. Base speed adjusting screw. 8. Upper speed setting bias spring. 9. Speed setting lever. 10. Lower speed setting bias spring. 11. Pivot. 12. Nozzle. 13. Feedback spring.

Air Fuel Ratio Control

3161 GOVERNOR WITH AN AIR FUEL RATIO CONTROL
1. Air fuel ratio control.

The air fuel ratio control assembly (1) is installed on the right rear corner of the top cover. The control is factory calibrated and installed. This control is not for field installation.

The air fuel ratio control is similar to hydraulic air fuel ratio controls used on current Caterpillar engines. This control automatically controls the governor output shaft movement in the "fuel increase" direction, until air pressure in the engine inlet manifold is high enough to give complete fuel combustion.

The air fuel ratio control limits the fuel to the engine in proportion to the amount of turbocharger boost pressure (pressure above atmospheric) in the inlet manifold. The control is not activated during engine start up and is cocked (activated) by a combination of oil pressure and the initial surge of boost when the engine is first loaded.

Engine Start Up

As the engine is started and the speed or load is increased, air pressure from the inlet manifold increases and pushes up on the rolling diaphragm assembly to put the limiter spring under compression. As the rolling diaphragm assembly moves up, the fuel limiter plunger also moves up and closes off the port in the limiter piston. Now the supply oil can not drain through the limiter piston and the pressure of the oil starts to increase. When the oil pressure is high enough, the limiter piston is pushed down against the limiter servo spring force. The lower edge of the fuel limiter plunger opens the port in the limiter piston when the piston has moved down far enough. This lets supply oil go to drain. The air fuel ratio control is now activated and can operate as needed.

Engine Load Increases

As more load is put on the engine, the air pressure in the inlet manifold is increased. The increased air pressure pushes the rolling diaphragm assembly up and lifts the fuel limiter plunger more. Oil pressure on the limiter piston decreases as the limiter piston drain port is opened and the limiter piston moves up until the port is closed again. At this time the limiter piston is stopped in a new position that is proportional to the air pressure in the inlet manifold.

Now, with the engine in operation at a steady speed, load added decreases engine speed. The governor moves to increase fuel as the power piston moves up to turn the output shafts in the "increase" direction. As the output shafts turn, the right end of the limit floating lever is lifted. Because the limit floating lever is fastened to a pivot (pivot position is set by the air fuel ratio control), the left end of the lever pushes the limit/shutdown rod down. The limit/shutdown pilot valve plunger closes off governor control oil to the power piston and limits the power piston movement.

As the engine picks up load, air pressure to the air fuel ratio control increases. The rolling diaphragm assembly moves up and lifts the fuel limiter plunger which opens the port in the limiter piston. Oil pressure on the limiter piston is lowered, and lets the limit servo spring push the piston and output rod up. This lets the limit/shutdown pilot valve move up. Fuel limit level is then increased.

NOTE: The air fuel ratio control fuel limit range is set by the position of the limit cam on the limit lever. When the cam is moved away from the shutdown rod, the limit range is longer. When the cam is moved closer to the shutdown rod, the limit range is shorter.

SCHEMATIC OF AIR FUEL RATIO CONTROL ON THE 3161 GOVERNOR

Speed Adjusting Motor Governor Head

3161 GENERATOR SET GOVERNOR
1. Conduit connection. 2. Speed adjusting meter. 3. Electric shutdown assembly.

The speed adjusting motor governor head includes a 24/32 Volt DC remote control speed adjusting motor (2) for changing engine speeds from remote locations. The speed adjusting motor is installed on the governor top cover and is connected to the governor speed setting mechanism through a friction clutch. The motor drives through the friction clutch and rotates the speed adjusting screw to position the governor's speed adjusting lever. The governor set speed may be increased or decreased at the rate of 13 rpm/second. One revolution of the manual adjusting screw will increase engine speed 63 rpm (approximately).

To increase the speed setting, the motor shaft rotates clockwise. As the motor shaft rotates, it turns the speed adjusting screw to make contact with the speed adjusting lever and lowers it to increase the governor's speed setting. The motor shaft turns the speed adjusting screw until the speed adjusting lever contacts the high speed stop. If the motor continues to run, the clutch will slip to prevent damage to the motor.

NOTE: If the speed adjusting motor has been allowed to run after the low speed setting has been reached, it may take a period of time for the speed adjusting screw to turn in and make contact with the speed adjusting lever (when an increase in speed setting is required).

All wiring and power to the remote speed setting motor on the governor must be low voltage DC. A converter drop box which will convert 115 or 230 volt AC (50 to 60 Hertz) to 24 volt DC is available (2W4523). This box should be remote mounted from the engine to isolate the engine wiring harness from high voltage AC currents.

An internal one-half inch thread conduit connection (1) is on top of the governor cover. It is used for installations which require conduit protection for the wiring.

The top governor cover is made for installation of any of the three shutdown assemblies.

Manual Speed Setting Control

3161 GENERATOR SET GOVERNOR

The manual speed setting control is located on the front of the speed adjusting motor governor head. Engine speed is set manually as the speed setting screw is turned. The high and low idle stops limit the speed range.

TOP COVER OF THE 3161 GENERATOR SET GOVERNOR
1. Speed adjusting screw.

An indicator lever is attached to the governor speed setting shaft with a bolt. The bolt can be loosened and the indicator lever can be set to the reference points on the identification and information plate to correspond with the number on the dial. The indicator lever will show the speed setting before the engine is started.

The manual speed setting control and the speed adjusting motor use a common speed adjusting screw which contacts the governor speed adjusting lever.

The speed adjusting motor clutch is above the gear and connects the motor to the speed adjusting screw. This clutch keeps force off of the speed adjusting motor as the speed setting is adjusted manually.

Manual Mechanical Speed Control

3161 GOVERNOR
1. Shaft. 2. Handle assembly. 3. Guide. 4. Hub. 5. Quadrant. 6. Ratchet mounting plate.

The manual mechanical speed control with remote and positive lock is available for torque rise and non-torque rise equipped governors. The control is used for manually setting different engine speeds, or it can be used as a remote speed control.

The shaft (1) goes through the handle assembly (2) and is threaded into the hub (4) on the spline of the speed setting shaft. The guide (3) rotates on the speed setting shaft and supports the handle assembly. The ratchet mounting plate (6) is bolted to the front of the governor and has notches to hold the handle for different engine speeds. The quadrant (5) can be engaged with the handle assembly and used as a mechanical linkage to the speed setting shaft. A cable or rod can be connected to the quadrant and used for remote speed control.

To increase or decrease engine speed, push on the shaft and lift on the handle assembly. This disengages the handle assembly from the ratchet mounting plate. The control can then move the speed setting shaft. Movement of the handle in the clockwise direction increases the engine speed.

To disengage the handle assembly from the ratchet and connect the quadrant, push on the shaft and lift on the handle assembly. With the handle assembly raised, turn it 180 degrees and connect it to the quadrant. The control can now be used for remote operation.

NOTE: The manual mechanical speed control with remote and positive lock should not be used with a pneumatic speed control. Vibration can cause the manual mechanical speed control to engage and stop pneumatic speed control operation.

Pneumatic Mid Speed Control

A pneumatic speed control is normally used on 3161 Governors on vehicular engine arrangements to control the engine speed. A pneumatic mid speed control is also used to make the engine go from low idle to mid speed for dynamic braking with the direct current generator and drive motors.

This control is installed on the front of the governor. With a lever fastened to the speed setting control shaft, the control cylinder sets the engine speed from low idle to mid speed. The mid speed setting of the governor is set by the position the control lever is fastened to the speed setting control shaft.

PNEUMATIC MID SPEED CONTROL

The control cylinder rod is spring activated (extended) and air retracted. When the cylinder rod is extended the lever moves the speed setting shaft in the "fuel increase" direction. As air pressure is supplied to the control cylinder, the cylinder rod moves away from the speed setting shaft lever. The governor turns the output shafts in the "fuel decrease" direction to lower the engine speed. When there is a loss or reduction of air pressure, the control moves the speed setting shaft and the engine runs at a speed set by the governor proportional to speed setting shaft position.