Woodward SG Governor User manual

Product Manual 04048
(Revision D, 5/2015)
Original Instructions
SG Governor
This manual replaces manual 04022.
Installation and Operation Manual
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General
Precautions
Read this entire manual and all other publications pertaining to the work to be
performed before installing, operating, or servicing this equipment.
Practice all plant and safety instructions and precautions.
Failure to follow instructions can cause personal injury and/or property damage.
Revisions
This publication may have been revised or updated since this copy was produced.
To verify that you have the latest revision, check manual
26455 , Customer
Publication Cross Reference and Revision Status & Distribution Restrictions, on
the publications page of the Woodward website:
www.woodward.com/publications
The latest version of most publications is available on the publications page. If
your publication is not there, please contact your customer service representative
to get the latest copy.
Proper Use
Any unauthorized modifications to or use of this equipment outside its specified
mechanical, electrical, or other operating limits may cause personal injury and/or
property damage, including damage to the equipment. Any such unauthorized
modifications: (i) constitute "misuse" and/or "negligence" within the meaning of
the product warranty thereby excluding warranty coverage for any resulting
damage, and (ii) invalidate product certifications or listings.
Translated
Publications
If the cover of this publication states "Translation of the Original Instructions"
please note:
The original source of this publication may have been updated since this
translation was made. Be sure to check manual
26455 , Customer Publication
Cross Reference and Revision Status & Distribution Restrictions, to verify whether
this translation is up to date. Out-of-date translations are marked with . Always
compare with the original for technical specifications and for proper and safe
installation and operation procedures.
Revisions—Changes in this publication since the last revision are indicated by a black line
alongside the text.
Woodward reserves the right to update any portion of this publication at any time. Information provided by Woodward is
believed to be correct and reliable. However, no responsibility is assumed by Woodward unless otherwise expressly
undertaken.
Manual 04048
Copyright © Woodward 1986–2015
All Rights Reserved
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Manual 04048 SG Governor
Woodward 1
Contents
WARNINGS AND NOTICES............................................................................3
ELECTROSTATIC DISCHARGE AWARENESS ..................................................4
CHAPTER 1. GENERAL INFORMATION...........................................................5
Introduction.............................................................................................................5
Governor Drive.......................................................................................................5
Speed Adjustment..................................................................................................6
Speed Droop Adjustment .......................................................................................7
Auxiliary Features (Optional)..................................................................................7
CHAPTER 2. PRINCIPLES OF OPERATION .....................................................8
CHAPTER 3. INSTALLATION AND ADJUSTMENT...........................................10
Installation ............................................................................................................10
Linkage.................................................................................................................14
Adjustment............................................................................................................16
Troubleshooting....................................................................................................17
CHAPTER 4. OVERHAUL ............................................................................18
Introduction...........................................................................................................18
Disassembly Instructions......................................................................................18
Repair...................................................................................................................22
Assembly Instructions...........................................................................................23
CHAPTER 5. PARTS INFORMATION .............................................................28
Cover Assembly with Bodine Speed Adjusting Motor..........................................32
Cover Assembly with Pittman PM Speed Adjusting Motor...................................34
Cover Assembly with Vertical Return Spring........................................................36
Subcap Assemblies..............................................................................................38
CHAPTER 6. TROUBLESHOOTING...............................................................46
General.................................................................................................................46
Oil Trouble............................................................................................................46
Speed Droop Adjustment .....................................................................................46
Analysis and Correction of Governing Troubles...................................................46
CHAPTER 7. PRODUCT SUPPORT AND SERVICE OPTIONS...........................49
Product Support Options......................................................................................49
Product Service Options.......................................................................................49
Returning Equipment for Repair...........................................................................50
Replacement Parts...............................................................................................50
Engineering Services............................................................................................51
Contacting Woodward’s Support Organization ....................................................51
Technical Assistance............................................................................................52
REVISION HISTORY....................................................................................53
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SG Governor Manual 04048
2 Woodward
Illustrations and Tables
Figure 1-1. Typical SG Governor with New Style Cover........................................6
Figure 1-2. Early Type SG Governor......................................................................6
Figure 2-1. Schematic Diagram of a Typical SG Governor....................................9
Figure 3-1. Recommended Engine Oil System for Quick Starts..........................11
Figure 3-2. SG Governor Outline with Direct Pneumatic Speed Setting..............12
Figure 3-3. SG Governor Outline with Reverse Pneumatic Speed Setting..........12
Figure 3-4. SG with Fuel Rod and Bodine Electric Motor for Speed Setting........13
Figure 3-5. Wiring Diagram for Bodine Motor (Switch not furnished)...................13
Figure 3-6. Wiring Diagram for PM Motor (switch not furnished).........................14
Figure 3-7. Recommended Governor Terminal Shaft Travel...............................14
Figure 3-8. Linear Linkage Arrangement..............................................................15
Figure 3-9. Non-linear Linkage Arrangement.......................................................16
Figure 4 1 Bushing Driver.....................................................................................21
Figure 4-2. Bushing and Gear Stud Replacement ...............................................24
Figure 4-3. Centering Pilot Valve Plunger............................................................26
Figure 5-1. Typical SG Governor Parts (later models).........................................29
Figure 5-2. Typical SG Governor Parts (early models)........................................31
Figure 5-3. Bodine Speed Adjusting Motor and Installation Parts........................33
Figure 5-4. Speed Adjusting Motor Parts.............................................................33
Figure 5-5. Pittman PM Speed Adjusting Motor and Installation Parts................35
Figure 5-5a. Vertical Return Spring Cover and Installation Parts ........................37
Figure 5-6. Subcap Assembly Parts (linear output)..............................................39
Figure 5-7. Subcap Assembly Parts (internal return spring) ................................40
Figure 5-8. Spring driven, Oil-Damped Ballhead Parts........................................41
Figure 5-9. Spring-Driven Ballhead Parts.............................................................42
Figure 5-10. Outline Drawing of SG Governor with Speed Adjusting Motor........43
Figure 5-11. Outline Drawing of SG Governor with Subcap (internal return spring)
and Speed Adjusting Motor .............................................................44
Figure 5-12. Outline Drawing of SG Governor with and without PM Motor, with
Pneumatic Speed Setting Assembly ...............................................45
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Manual 04048 SG Governor
Woodward 3
Warnings and Notices
Important Definitions
This is the safety alert symbol. It is used to alert you to potential
personal injury hazards. Obey all safety messages that follow this
symbol to avoid possible injury or death.
DANGER—Indicates a hazardous situation which, if not avoided, will result
in death or serious injury.
WARNING—Indicates a hazardous situation which, if not avoided, could
result in death or serious injury.
CAUTION—Indicates a hazardous situation which, if not avoided, could
result in minor or moderate injury.
NOTICE—Indicates a hazard that could result in property damage only
(including damage to the control).
IMPORTANT—Designates an operating tip or maintenance suggestion.
Overspeed /
Overtemperature /
Overpressure
The engine, turbine, or other type of prime mover should be
equipped with an overspeed shutdown device to protect against
runaway or damage to the prime mover with possible personal injury,
loss of life, or property damage.
The overspeed shutdown device must be totally independent of the
prime mover control system. An overtemperature or overpressure
shutdown device may also be needed for safety, as appropriate.
Personal Protective
Equipment
The products described in this publication may present risks that
could lead to personal injury, loss of life, or property damage.
Always wear the appropriate personal protective equipment (PPE) for
the job at hand. Equipment that should be considered includes but is
not limited to:
Eye Protection
Hearing Protection
Hard Hat
Gloves
Safety Boots
Respirator
Always read the proper Material Safety Data Sheet (MSDS) for any
working fluid(s) and comply with recommended safety equipment.
Start-up
Be prepared to make an emergency shutdown when starting the
engine, turbine, or other type of prime mover, to protect against
runaway or overspeed with possible personal injury, loss of life, or
property damage.
Automotive
Applications
On- and off-highway Mobile Applications: Unless Woodward's
control functions as the supervisory control, customer should install
a system totally independent of the prime mover control system that
monitors for supervisory control of engine (and takes appropriate
action if supervisory control is lost) to protect against loss of engine
control with possible personal injury, loss of life, or property
damage.
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SG Governor Manual 04048
4 Woodward
Battery Charging
Device
To prevent damage to a control system that uses an alternator or
battery-charging device, make sure the charging device is turned off
before disconnecting the battery from the system.
Electrostatic Discharge Awareness
Electrostatic
Precautions
Electronic controls contain static-sensitive parts. Observe the
following precautions to prevent damage to these parts:
Discharge body static before handling the control (with power to
the control turned off, contact a grounded surface and maintain
contact while handling the control).
Avoid all plastic, vinyl, and Styrofoam (except antistatic
versions) around printed circuit boards.
Do not touch the components or conductors on a printed circuit
board with your hands or with conductive devices.
To prevent damage to electronic components caused by improper
handling, read and observe the precautions in Woodward manual
82715 , Guide for Handling and Protection of Electronic Controls,
Printed Circuit Boards, and Modules.
Follow these precautions when working with or near the control.
1. Avoid the build-up of static electricity on your body by not wearing clothing
made of synthetic materials. Wear cotton or cotton-blend materials as much
as possible because these do not store static electric charges as much as
synthetics.
2. Do not remove the printed circuit board (PCB) from the control cabinet
unless absolutely necessary. If you must remove the PCB from the control
cabinet, follow these precautions:
Do not touch any part of the PCB except the edges.
Do not touch the electrical conductors, the connectors, or the
components with conductive devices or with your hands.
When replacing a PCB, keep the new PCB in the plastic antistatic
protective bag it comes in until you are ready to install it. Immediately
after removing the old PCB from the control cabinet, place it in the
antistatic protective bag.
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Manual 04048 SG Governor
Woodward 5
Chapter 1.
General Information
Introduction
This manual provides description, operation, overhaul and replacement parts
information for SG governors (Figure 1-1) and various optional auxiliary features.
The SG governor is a hydraulic speed droop type governor used on small diesel,
gas, or gasoline engines where isochronous (constant speed) control is not
required. The design of the speed droop governor is such that the governor
operates at a slower speed as engine load increases. It is through this
characteristic that stability of the governed system is achieved, and division of
load between paralleled units made possible.
SG governors are available with 10.8 or 21.7 inch-pounds (1.2 or 2.5 J) of work
capacity over 36° of terminal shaft (output) travel.
The torque, work capacity, and maximum work values of the SG
governor are based on 25 psi (172 kPa) supply oil pressure to the
governor. These values can vary depending on the supply oil
pressure.
If not supplied with an internal return spring, the 10.8 inch-pound governor
requires an external return spring (not furnished by Woodward) that exerts a 20
pound-inch (2.3 Nm) torque on the terminal shaft in the closing direction. The
21.7 inch-pound governor requires a spring that exerts a 40 pound-inch (4.5 Nm)
torque on the terminal shaft in the closing direction.
A new cover for the standard SG governor is a vertical return-spring type cover.
This cover is used with or without a return spring, and also, with or without a
Pittman PM (Permanent Magnet) speed-setting motor. For SG governors without
a motor, the cover is furnished with a guide plug for the low-speed stop screw
(see Figures 1-1 and 1-2).
The SG governor is usually arranged to operate at 2400 or 3600 rpm at normal
rated engine speed, and will control down to approximately 25% of normal
speed. Special configurations are available, however, to meet other speed
requirements.
The governor uses engine oil or oil from a separate sump (not furnished by
Woodward) as a control medium; it does not have an independent sump.
Governor Drive
The governor drive shaft is splined to fit into the engine drive (see Figures 5-11
and 5-12). The governor may be mounted vertically or horizontally. If mounted
horizontally, the terminal shaft must also be horizontal and a 3/8-inch drain line
provided to connect to a 1/4-inch pipe-tapped or 0.438-20 (-4) straight-thread
port in the tower end of the governor cover. For connection of the drain line on
the new-style cover, see Figure 1-2 for vertical installation or Figure 5-12 for
horizontally mounted governors.
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SG Governor Manual 04048
6 Woodward
The governor drive shaft may be rotated in either direction. However, the
governor relief valve assembly must, when viewing the governor from the
nameplate end, be on the left if the governor is rotated clockwise (when viewed
from above). The relief valve assembly must be on the right for counterclockwise
rotation of the drive.
Figure 1-1. Typical SG Governor with New Style Cover
Figure 1-2. Early Type SG Governor
Speed Adjustment
The speed adjusting shaft is used to set the governor for the desired running
speed. Low speed and high speed stop screws are provided to limit the speed
range of variable speed governors. If the engine is to be operated at one speed
setting, the stop screws may be used to lock the position of the speed adjusting
shaft.
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Manual 04048 SG Governor
Woodward 7
The terminal shaft may extend on either or both sides of the governor. Shutdown
of the engine can be accomplished by turning the speed adjusting shaft below
the idle speed setting position.
Speed Droop Adjustment
Speed droop adjustment is provided inside the governor. The droop setting
required to gain stability varies with each installation; in most instances it must be
set to increase unit speed two or three percent over the terminal shaft rotation
used from rated power output at rated speed to zero power output. The range of
adjustment is from one-half of one percent to approximately seven percent over
the full 36° available travel of the governor terminal shaft.
Auxiliary Features (Optional)
Speed Adjusting Motor
The SG governor can be fitted with a speed adjusting motor to enable the
switchboard operator to match the frequency of an alternator with that of other
units or a system before synchronizing, and to change load distribution after
synchronizing. Two types of motor are available.
The Bodine motor is of the split field, series wound, reversible type (see Figures
3-8and 3-9). It is available in all standard voltages.
The Pittman motor is of the permanent magnet type 12 or 24 Vdc (see Figures
5-3 and 5-5). When motor supply voltage is other than 12 or 24 Vdc, the following
control boxes are available for conversion to 24 Vdc:
24 Vdc P/N 8272-515
110 Vdc P/N 8272-518
110 Vdc P/N 8272-516
220 Vdc P/N 8272-517
A manual speed adjusting knob with friction clutch assembly is included on units
fitted with a speed adjusting motor.
Vibration Attenuating Ballhead Assemblies
A spring-driven oil-damped ballhead assembly (Figure 5-8) may be used in SG
governors in place of the standard solid ballhead assembly where it is necessary
to overcome undesirable torsional vibrations transmitted from the engine drive to
the governor ballhead.
Subcap Assemblies
Different subcap assemblies are available to match the particular needs of the
SG governor installation (see Figures 5-7 and 5-12). Figure 5-7 illustrates the
subcap used for an installation with a linear output, Figure 5-12 illustrates a
rotary output with an internal return spring. Subcaps usually include a fuel-rack
stop screw.
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SG Governor Manual 04048
8 Woodward
Chapter 2.
Principles of Operation
A schematic arrangement of a typical SG governor is shown in Figure 2-1.
As described earlier, the governor uses engine oil as a control medium and does
not have an independent sump. The engine oil enters the governor at the relief
valve, drops down into the cavity on the suction side of the governor oil pump,
and is carried by the pump gears around to the pressure side of the pump. If the
supply of pressure oil is greater than is required for governing purposes, the
governor pump will build up pressure until the relief valve plunger is pushed to
the right against the force of the relief valve plunger spring. The governor pump
will then recirculate the oil within the governor.
If pressure oil is used for governing purposes, the pressure will be reduced and
the spring will move the relief valve plunger to the left. The recirculating passage
is thus blocked so that operating pressure is maintained.
The pilot valve plunger controls the movement of the power piston by directing oil
to and from the area beneath the power piston. The power piston, operating
through the power piston pin and terminal lever, positions the terminal shaft to
which the engine fuel linkage connects.
When the governor is running on-speed, the control land of the pilot valve
plunger covers the control port of the ballhead bushing, and the power piston
remains stationary.
If the engine load is increased, the governor speed decreases, and speeder
spring force—now greater than the lifting effect of the centrifugal force developed
by the rotating ballarms—pushes the pilot valve plunger down. Pressure oil is
directed to the area under the power piston and pushes the piston up. The power
piston and pin rotate the terminal lever and terminal shaft in the direction to
increase fuel.
Note that, as the terminal lever rotates in the “increase fuel” direction, the speed
droop pin is raised. The right end of the floating lever pivots about the speed
adjusting lever pin as the left end of the lever is raised. Raising the left end of the
floating lever raises the spring fork and decreases the speeder spring force.
Thus, the governor ballhead is enabled to re-center the pilot valve plunger at
lower speeds as fuel is increased, a characteristic described as “speed droop”.
Closing the control port stops further movement of the power piston
simultaneously with return of the engine to the lower speed, a speed determined
by the new speeder spring force.
If the engine load is decreased, the governor speed increases and the ballarms
lift the pilot valve plunger against the downward force of the speeder spring. The
uncovered control port in the ballhead bushing connects the oil under the power
piston to sump. The absence of pressure under the power piston allows the
external spring force to rotate the terminal shaft and terminal lever in the
“decrease fuel” direction.
When moving in the decrease fuel direction, the terminal lever lowers the speed
droop pin. The floating lever lowers the spring fork to increase the speeder spring
force. The increase in speeder spring force re-centers the pilot valve plunger,
and requires an increase in speed to keep it centered. Closing the control port
stops further movement of the power piston simultaneously with return of the
engine to the higher speed required by the higher spring force.
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Manual 04048 SG Governor
Woodward 9
The amount of speed change for a given terminal shaft rotation depends upon
the setting of the speed droop pin. Moving the pin towards the ballhead
decreases the speed change; moving it away from the ballhead increases the
speed change.
Figure 2-1. Schematic Diagram of a Typical SG Governor
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SG Governor Manual 04048
10 Woodward
Chapter 3.
Installation and Adjustment
Installation
Introduction
These instructions apply to three types of SG governors differentiated by their
speed settings:
Lever
Pneumatic
Electric
Additional considerations for governors with pneumatic or electric speed setting
are listed under respective headings.
Direction of Rotation
Rotation of the governor drive shaft as viewed from the top of the governor must
be the same as that of the engine drive when looking down on the mounting pad.
When the governor is to be rotated clockwise (when viewed from above), the
governor relief valve assembly must, when viewing the governor from the
nameplate end, be on the left.
When the governor is to be rotated counterclockwise (when viewed from above),
the governor relief valve assembly must, when viewing the governor from the
nameplate end, be on the right.
Be sure engine mounting-pad drive and governor drive rotation are
the same. Incorrect drive rotation will cause the governor to become
inoperative and may cause governor damage.
Place a gasket between the base of the governor and the engine mounting pad.
Mount the governor square with the engine drive and in line with the linkage. The
splined drive shaft must fit the engine drive freely with no tightness. Do not force
the governor onto the mounting pad.
Be sure the gasket does not block off the three drain holes In the
base. See Figures 5-10, 5-11, and 5-12.
Oil Supply
Connect a 0.250 inch ID oil supply line to the 0.125 inch pipe-tapped hole in the
relief valve. Oil from the engine must supply a minimum of 5 psi (34 kPa) to the
governor. If a separate sump is used, the distance the governor must lift the oil
should not exceed 12 inches (30 cm), and a foot valve with a capacity of 2 US
gallons per minute (7.6 L/min) must be used. Use a 2 USgal/min (7.6 L/min), 40
µm filter in the oil supply line. In suction lift applications, the filter must not be in
series with the inlet line to the governor. Keep oil lines as short as possible.
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Manual 04048 SG Governor
Woodward 11
If mounted horizontally, the terminal shaft must also be horizontal and a 3/8 inch
external drain line provided to connect to either a 1/4-Inch pipe tapped hole or
0.438-20 (-4) straight-thread port In the lower end of the governor cover or
subcap. See Figure 5-12 to connect the drain to the new style cover when the
governor is mounted horizontally.
Use a supply system similar to Figure 3-1 for applications requiring quick starts.
Figure 3-1. Recommended Engine Oil System for Quick Starts
Minimum drainage or siphon level is that oil level in the governor below which the
governor pump gears are no longer submerged in oil. Oil level in the oil tank
must always be as high as, or higher than, this line. If not, governor pump gears
are no longer submerged in oil and will cavitate when the prime mover is started,
causing possible loss of governor control.
Most problems of mechanical hydraulic governors occur because of
dirty oil. Be sure to use clean oil.
Keep the end of the overboard drain line above the engine sump oil level.
Most standard 1 to 2 quart housings (approximately 1 to 2 L), with filter omitted,
can be adapted for this system.
Pneumatic Speed Setting
There are two types. The reverse acting increases speed with a decrease in air
pressure, while the direct acting increases speed with an increase in air
pressure.
The pneumatic speed-setting cover has two tapped holes for the oil reservoir.
Use one of the two holes for the reservoir and plug the other. Always mount the
oil reservoir with the hole for the air connection up. Be sure the other hole is
plugged (see outline drawing, Figure 3-2 or 3-3). Install the governor on the
engine. Using a funnel, fill the oil reservoir to approximately 3/8 inch (10 mm)
from the top via the hole for the air connection in top of the reservoir.
Attach the air signal pressure line to the hole in top of the oil reservoir.
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SG Governor Manual 04048
12 Woodward
Figure 3-2. SG Governor Outline with Direct Pneumatic Speed Setting
Figure 3-3. SG Governor Outline with Reverse Pneumatic Speed Setting
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Manual 04048 SG Governor
Woodward 13
Electric Speed Setting
The Bodine motor and the PM motor are coupled to the governor speed-setting
mechanism through a friction clutch. If the operator runs the speed adjustment to
its limit, the clutch is set to slip, thereby protecting the speed-adjusting motor.
Connect the electric speed setting as shown in Figure 3-5 or 3-6. Figure 3-5 is for
the Bodine motor, and Figure 3-6 is for the PM motor. Voltage for the Bodine
motor is shown on the motor.
Figure 3-4. SG with Fuel Rod and Bodine Electric Motor for Speed Setting
Figure 3-5. Wiring Diagram for Bodine Motor (Switch not furnished)
The permanent magnet motor operates on dc power. If a 115 or 230
Vac or Vdc power source is used, convert the power source to 24 to
32 Vdc. A converter can be ordered from Woodward. See Chapter 1,
Speed Adjusting Motor.
Connect to correct voltage.
If a new cover and PM motor is ordered for use on an existing governor, all that
is required to install the new cover is to remove the old cover and set the new
assembly In place. If some adjustment is necessary. loosen the screws holding
the PM motor in place and align the motor shaft with the clutch. Apply Loctite 242
or equivalent to the screws and tighten to 10 lb-in (1.1 Nm).
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SG Governor Manual 04048
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Figure 3-6. Wiring Diagram for PM Motor (switch not furnished)
When the cover is used without the PM motor, a screw is placed in the hole
where the motor drive shaft normally fits. This screw is then used as a low-speed
stop. The cover also houses a vertical return spring when one is used.
Linkage
Linear
Use a linear linkage for diesel-engine applications. Adjust the fuel linkage to
provide control of engine fuel from the minimum to the maximum engine fuel
stops. Use two-thirds of the output shaft travel between the fuel rack’s no load
and full load positions. See Figure 3-7 for recommended governor terminal shaft
travel. Adjust the maximum-fuel-rack stop screw to obtain the maximum output
rotation. Maximum rotation for vertical-return-spring governors is 40°. Maximum
rotation for other units is 36°.
Figure 3-7. Recommended Governor Terminal Shaft Travel
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Manual 04048 SG Governor
Woodward 15
Attach the fuel rack linkage to the governor output shaft. Be sure there is no lost
motion or binding in the linkage. See Figure 3-8 for linear linkage arrangement.
Be sure to allow sufficient overtravel at each end of the terminal
shaft so the governor can shut down the engine and also give
maximum fuel when required.
The torque and work capacity values quoted are based on 25 psi (172
kPa) supply pressure to the governor. These values can vary,
depending on the oil supply pressure.
Figure 3-8. Linear Linkage Arrangement
Governor output can be with either terminal shaft or with fuel rod: connect linkage
accordingly. Some subcaps with a fuel rod have a knob which can be pushed in
to open the fuel racks when starting an engine, or pulled out to close the fuel
racks and stop the engine.
Non-Linear
Applications involving a butterfly valve, such as on a gas engine, require a non-
linear linkage.
Figure 3-9 illustrates the relationship between governor output shaft and butterfly
obtained with simple linkage of maximum non-linearity. When installing this
linkage, make sure the two following conditions are attained when the linkage is
in the no-load position:
1. The lever which is attached to the governor and the connecting link is in line
with the governor output shaft and the point of attachment of the connecting
link to the butterfly lever.
2. The butterfly lever must be at 90 degrees with the connecting link.
Refer to the prime-mover manufacturer’s manual for the correct linkage selection
and installation.
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SG Governor Manual 04048
16 Woodward
Figure 3-9. Non-linear Linkage Arrangement
Adjustment
Starting the Engine for the First Time
Start the engine as instructed by the engine manufacturer. For a safe start-up,
adjust the governor for a reduced speed and allow the engine to warm up.
Be prepared to make an emergency shutdown when starting the
engine, turbine, or other type of prime mover, to protect against
runaway or overspeed with possible personal injury, loss of life, or
property damage.
Make the following adjustments to the governor only if the engine
does not stabilize, The governor was adjusted at the factory and
should not require any adjustment.
Speed Droop Adjustment
(The cover must be removed to access the speed droop adjustment. Use caution
if internal return springs are used. See Figure 5-1, part 15, or Figure 5-2, part
111.)
SINGLE ENGINE OPERATION—If engine speed does nor stabilize, shut down
the engine. Increase droop slightly (about 0.0625 inch [1.588 mm] movement of
bracket away from the governor ballhead), and restart the engine. Manually
move the engine fuel linkage to cause a temporary engine speed change.
Continue to increase the droop until operation is satisfactory.
Not enough droop can cause instability in the form of hunting, surging, or
difficulty in response to a load change. Too much droop can result in slow
governor response in picking up or dropping off load.
OPERATING IN PARALLEL WITH OTHER ALTERNATORS—Droop is used to
divide and balance load between units driving the same shaft or paralleled in the
electrical system. It total load does not divide properly, increase droop on units
taking too much of the load.
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Manual 04048 SG Governor
Woodward 17
On interconnected units, set the least amount of droop possible to provide
satisfactory load division.
The no load to full load speed change must be equal for all paralleled
units.
Adjust the speed setting of SG governors or other governors with speed droop to
get distribution of load between synchronized units. Increasing the speed setting
of a particular unit will increase the load on that unit.
If the governor output shaft does not use the full 2/3 of available
travel from “NO LOAD” TO “FULL LOAD”, droop wilt also be reduced
proportionately.
Normally, the amount of droop set into the SG governor to make it stable in a
system will be enough to allow the units to parallel.
Troubleshooting
If engine hunts or surges:
a. Adjust and align linkage, check for lost motion, binding, excessive friction,
and linearity of load to governor travel.
b. Increase speed droop.
c. Make sure that the ballhead cavity is not lull of oil. This could be a drain
problem.
If engine speed increases as load increases:
a. Increase droop slightly.
Load does not divide properly on interconnected engines:
This applies when load is increased or decreased. and speed setting is constant.
a. Repeat speed droop adjustment.
b. Check voltage regulator droop.
c. Adjust droop to divide load properly.
d. Increase droop to resist picking up (or dropping off) load.
e. Reduce droop to increase picking up (or dropping off) load.
f. Adjust droop and tighten screw securely.
Engine will not pick up rated full load:
a. Adjust and align fuel linkage, check for lost motion, binding, excessive
friction, and linearity of load to governor travel.
b. Adjust maximum speed stop.
c. Check speed-adjusting linkage, if present, for interference.
d. Check for insufficient fuel flow.
e. If engine is at maximum fuel stop and still cannot pick up rated full load, the
problem is elsewhere in the system and not in the governor.
Governor oil overflows:
Make sure that oil flow through the two drain holes is not restricted by the gasket
between the governor base and engine. See Figure 5-10 for drain holes.
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SG Governor Manual 04048
18 Woodward
Chapter 4.
Overhaul
Introduction
The components of the SG governor have undergone substantial modification
since first introduced. For this reason it is imperative that requests for information
or parts for SG governors include:
Governor model and serial number as shown on governor nameplate.
Manual number (this is manual 04048).
Part reference number and name or description of part.
Exploded views of the most recent and early versions of the SG governor are
shown in Figures 5-1 and 5-2.
Disassembly Instructions
Governor
It is suggested that the best mechanic available—preferably one with small parts
assembly experience—be assigned to all governor maintenance and repair work.
Cleanliness of tools and work area is essential to a satisfactory overhaul of any
governor. Aside from the usual hand tools, one would require only a pair of
Waldes No. 2 external snap ring pliers. A work bench with vise, an arbor press,
and containers for cleaning solvents should be provided.
If the governor is to be taken apart completely, proceed in this manner:
1. Clamp the governor lightly in a vise; vise jaws must grasp the base below
the base-case joint on the sides under the terminal shaft.
2. Remove cover screws. Lift off cover. Use caution if a return spring is
present.
At this point, inspection of the terminal lever (13, Figure 5-1, or 113, Figure
5-2) will reveal whether the governor is of the type shown in Figure 5-1 or
Figure 5-2. The first number following in parenthesis identifies parts shown
in Figure 5-1; the second number, parts shown in Figure 5-2.
3. Remove speed droop screw (10/109), washer(s) (11 and 12/110), and
bracket (15/111).
4. Remove cotter pins (14/112) from terminal lever (13/113).
5. Remove long terminal shaft (37/136) and synthetic rubber seals (36/135).
6. Insert a 5/16-inch diameter rod in the opening left by the long terminal shaft
and drive short terminal shaft (39/138) out; plug (32/139) will be forced out
at this time.
7. Remove terminal lever (13/113) from the governor.
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