HIGH PERFORMANCE, TWO-STAGE DESIGN
PROVIDING FLOW CONTROL IN A SIMPLE
AND DEPENDABLE, LONG-LIFE DESIGN
WHAT MOVES YOUR WORLD
Rev. M, January 2021
SERVO VALVES
PILOT OPERATED
FLOW CONTROL VALVE
WITH ANALOG INTERFACE
G771/771 SERIES: ISO 10372-02-02-0-92
G772/772 SERIES: ISO 10372-03-03-0-92
G773/773 SERIES: MOOG SPECIFIC
Moog G77X/-77X Series Flow Control Servo Valves
INTRODUCTION
2
Whenever the highest levels of motion control
performance and design flexibility are required, you’ll find
Moog expertise at work. Through collaboration, creativity
and world-class technological solutions, we help you
overcome your toughest engineering obstacles. Enhance
your machine’s performance. And help take your thinking
further than you ever thought possible.
INTRODUCTION
Product Overview 3
Features and Benefits 4
Description of Operation 5
TECHNICAL DATA
Performance Characteristics 6
Dynamic Characteristics 7
Electrical Data 8
Installation Drawings and
Null Adjust Instructions 9
Hole Pattern for Mounting Surface 10
BACKGROUND
Null Flow Adjustment 11
Flow Calculation and Null Cut Options 12
Related Products 13
Routine Maintenance Guidelines 14
About Moog 15
ORDERING INFORMATION
Accessories and Spare Parts 17
Ordering Code 18
This catalog is for users with technical knowledge. To ensure all necessary characteristics for function and safety of the system, the user has
to check the suitability of the products described herein. The products described herein are subject to change without notice. In case of doubt,
please contact Moog.
Moog is a registered trademark of Moog Inc. and its subsidiaries. All trademarks as indicated herein are the property of Moog Inc. and its
subsidiaries. For the full disclaimer refer to www.moog.com/literature/disclaimers.
For the most current information, visit www.moog.com/industrial or contact your local Moog office.
Rev. M, January, 2021
TABLE OF CONTENTS
PRODUCT OVERVIEW
The G77X/-77X Series flow control servo valves are
throttle valves for 3 and preferably 4-way applications.
They are a high performance, 2-stage design that covers
the range of rated flows from 4 to 57 l/min (1 to 15 gpm) at
210 bar (3000 psi) valve pressure drop per spool land.
The output stage of the valve is a closed center, four-way
sliding spool. The pilot stage is a symmetrical double-nozzle
and flapper, driven by a double air gap, dry torque motor.
Mechanical feedback of spool position is pro vid ed by a
cantilevered spring. The valve design is simple and rugged
for de pendable, long life op era tion.
These valves are suitable for electrohydraulic position,
speed, pressure or force control systems with high dynamic
response requirements. The G77X/-77X is ideally suited for
applications where superior dynamics are a must.
Intrinsically safe valve versions are available for use in
applications with potentially hazardous environments.
Specific models are certified to FM, ATEX, CSA, TIIS and
IECEx standards.
Moog G77X/-77X Series Flow Control Servo Valves
INTRODUCTION
TIIS
Intrinsically safe valve versions are available for use in potentially hazardous environments. Specific models are certified to
FM, ATEX, CSA TIIS and IECEx standards. Contact Moog for details.
Valve design 2-stage, with spool and bushing and dry torque motor
Mounting surface ISO 10372-02-02-0-92 ISO 10372 -03-03-0-92 Moog Specic
Maximum operating pressure 210 bar (3000 psi)
Maximum Flow 17 l/min (4.4 gpm) 57 l/min (15.0 gpm) 63 l/min (16.5 gpm)
Pilot stage Nozzle-apper
Rated ow at ∆ p
n
35 bar / 4 l/min 10 l/min 19 l/min 38 l/min 57 l/min
spool land ( 500 psi /spool land) (1 gpm) ( 2.5 gpm) (5.0 gpm) (10.0 gpm) (15.0 gpm)
Step response time for 0 to 100 % stroke 4 ms 4 ms 4 ms 10 ms 17 ms
3Rev. M, January, 2021
G771/771 G772/772 G773/773
Features Benefits
2-stage design with dry torque motor Compatibility with many different fluids
Low friction, double nozzle pilot stage Symmetrical build provides maximum stability over a
variety of conditions
High spool control force Stable consistent flows can be achieved, thus increasing
accuracies
High dynamics Increased production cycles
Rugged, long-life design Reduced maintenance and down time
High resolution, low hysteresis Improved accuracies for close tolerance applications
Set up at the factory Allows easy installation and setup
Intrinsically safe or explosive proof valve versions are Able to be employed in most hazardous environments
environments
Field adjustable null bias Adjustable for perfect alignment when
interchanging equipment
Loss of electrical signal results in a zero position failsafe Predictable, safe operation
FEATURES AND BENEFITS
Moog G77X/-77X Series Flow Control Servo Valves
INTRODUCTION
4Rev. M, January, 2021
The G77X/-77X Series is proven technology that performs
reliably in machines where high performance, stability and
accuracy are required. Moog’s Mechanical Feedback Valves
are designed to provide high reliability and long service life.
DESCRIPTION OF OPERATION
The G77X/-77X Series Flow Control Servo Valve consists
of a polarized electrical torque motor and two stages
of hydraulic power amplication. The motor armature
extends into the air gaps of the magnetic ux circuit and
is supported in this position by a exure tube. The exure
tube acts as a seal between the electromagnetic and
hydraulic sections of the valve. The 2 motor coils surround
the armature, one on each side of the exure tube.
The apper of the rst stage hydraulic amplier is rigidly
attached to the midpoint of the armature. The apper
extends through the exure tube and passes between
2 nozzles, creating two variable orices between the
nozzle tips and the apper. The pressure controlled by the
apper and nozzle variable orice is fed to the end areas
of the second stage spool.
The second stage is a conventional four-way spool design in
which output ow from the valve, at a xed valve pressure
drop, is proportional to spool displacement from the null
position. A cantilevered feedback spring is xed to the
apper and engages a slot at the center of the spool.
Displacement of the spool defects the feedback spring
which creates a force on the armature/apper assembly.
Input signals induce a magnetic charge in the armature
and cause a deection of the armature and apper. This
assembly pivots about the exure tube and increases the
size of one nozzle orice and decreases the size of the
other.
This action creates a differential pressure from the one end
of the spool displacement causing a force in the feedback
wire which opposes the original input signal torque. Spool
movement continues until the feedback wire force equals
the input signal force.
Moog G77X/-77X Series Flow Control Servo Valves
INTRODUCTION
5Rev. M, January, 2021
P
B
T
A
Feedback Wire
Lower Polepiece
Upper Polepiece
Armature
Spool
Coil
Flapper
Connector
Flexure Tube
Nozzles
Inlet Orifice
Bushing
Magnets (not shown)
Electro-hydraulic Servo Valve Cut-away
Rated flow 4 l/min (1 gpm) 10 l/min (2.5 gpm) 19 l/min (5 gpm) 38 l/min (10 gpm) 57 l/min (15 gpm)
Deviation of rated flow ± 10% of rated flow
Step response time 0-100% stroke 4 ms 4 ms 4 ms 10 ms 17 ms
Threshold ≤ 0.5% of rated signal
Hysteresis ≤ 3.0% of rated signal
Null shift for ∆T - 38°C (100°F) ≤ 2.0% of rated signal
G77X/-77X SERIES SERVO VALVES
Moog G77X/-77X Series Flow Control Servo Valves
TECHNICAL DATA
6Rev. M, January, 2021
General Technical Data
Valve design 2-stage, with spool and bushing
Pilot valve Nozzle Flapper
Mounting surface G771/771 – ISO 10372-02-02-0-92
G772/772 – ISO 10372-03-03-0-92
G773/773 – Moog specific
Installation position Any orientation, fixed or movable
Weight 0.86 kg (1.9 lb)
Storage temperature range -40 to +60 °C (-40 to +140 °F)
Ambient temperature range -40 to +135 °C (-40 to +275 °F)
Vibration resistance (general) 30 g, 3 axis, 10 Hz to 2 kHz
Shock resistance (general) 30 g, 3 axis
Seal material Fluorocarbon (FKM) (Viton™ B) 90 shore
Others upon request
Hydraulic Data
Maximum operating pressure
Ports P, A and B 210 bar (3,000 psi)
Port T 210 bar (3,000 psi)
Rated flow at ∆p
N
35 bar/spool land (500 psi/spool land) 4/10/19/38/57 l/min (1/2.5/5/10/15 gpm)
Maximum flow
G771/771 17 l/min (4.4 gpm)
G772/772 57 l/min (15 gpm)
G773/773 63 l/min (16.5 gpm)
Maximum main stage leakage flow rate (
≈ zero lap) 1.9 l/min (0.49 gpm)
Null adjust authority Greater than 10% of rated flow
Hydraulic fluid Hydraulic oil as per DIN 51524 parts 1 to 3 and ISO 11158
Other fluids on request
Temperature range -40 to +135 °C (-40 to +275 °F)
Recommended viscosity range 10 to 97 mm
2
/s (cSt) @ 38 °C
Maximum permissible viscosity range 5 to 1,250 mm
2
/s (cSt) @ 38 °C
Recommended filter rating
For functional safety ß
10
75 (10 µm absolute)
For longer life ß
5
75 (5 µm absolute)
Static and Dynamic Data
G77X/-77X SERIES SERVO VALVES -STANDARD RESPONSE SERVO VALVES
Moog G77X/-77X Series Flow Control Servo Valves
TECHNICAL DATA
7Rev. M, January, 2021
20
40
60
80
100
120
12 15 18
9
36
0
Stroke (% of Rated Signal)
Time (ms)
4, 10 and 19 l/min (1, 2.5 and 5 gpm)
Plot @ 210 bar (3,000 psi)
38 l/min (10 gpm)
Plot @ 210 bar (3,000 psi)
57 l/min (15 gpm)
Plot @ 210 bar (3,000 psi)
400
2
0
–1
–2
–6
–8
–10
–12
–14
–16
40 60
80
10 100
20
200 300
30
0
20
40
60
80
100
120
140
160
180
Phase La
g
(De
g
rees)
Frequency (Hz)
Amplitude Ratio (Decibels)
4, 10 and 19 l/min (1, 2.5 and 5 gpm)
Plot 1 & 3 = ±40% rated signal (solid)
Plot 2 & 4 = ±100% rated signal (dash)
40 60
80
10 100
20
200 300
400
30
2
0
–1
–2
–6
–8
–10
–12
–14
–16
0
20
40
60
80
100
120
140
160
180
Phase Lag (Degrees)
Frequency (Hz)
Amplitude Ratio (Decibels)
10 100
20
200 300
400
30 40 60
80
2
0
–1
–2
–6
–8
–10
–12
–14
–16
20
40
60
80
100
120
140
160
180
Amplitude Ratio (Decibels)
0
Phase Lag (Degrees)
Frequency (Hz)
38 l/min (10 gpm)
Plot 1 & 3 = ±40% rated signal (solid)
Plot 2 & 4 = ±100% rated signal (dash)
57 l/min (15 gpm)
Plot 1 & 3 = ±40% rated signal (solid)
Plot 2 & 4 = ±100% rated signal (dash)
20
40
60
80
100
120
12 15 18
9
36
0
Stroke (% of Rated Signal)
Time (ms)
20
40
60
80
100
120
12 15 18
9
36
0
Stroke (% of Rated Signal)
Time (ms)
ELECTRICAL DATA
Moog G77X/-77X Series Flow Control Servo Valves
TECHNICAL DATA
8Rev. M, January, 2021
Rated current and coil resistance
A variety of coils are available for G77X/-77X Series Servo
Valves, which offer a wide choice of rated currents.
Coil impedance
The resistance and inductance of standard coils are
given below. The 2 coils in each Servo Valve are wound
with equal turns giving a normal production tolerance
on coil resistance of ±12 %. Copper magnet wire is
used, so the coil resistance will vary signicantly with
temperature. The effects of coil resistance changes can be
essentially eliminated through use of a current feedback
servoamplier having high output impedance.
Inductance is determined under pressurized
operating conditions and is greatly inuenced by back
electromagnetic forces of the torque motor. These effects
vary with most operating conditions, and vary greatly
with signal frequencies above 100 Hz. The apparent coil
inductance values given are determined at 50 Hz.
Ordering code Recommended rated current [mA] Coil resistance Power consumption [W]
Command signal [ohms/coil at
25 °C (77 °F)]
Single coil Series coil Parallel coil Single coil Series coil Parallel coil
H ±15 ±7.5 ±15 206 0.045 0.023 0.023
L ±40 ±20 ±40 80 0.128 0.064 0.064
Ordering code Recommended rated current [mA]
Measured at 50 Hz
Single coil Series coil Parallel coil
H 0.72 2.2 0.59
L 0.22 0.66 0.18
Coil connections
A 4-pin electrical connector that mates with an
MS3106F14S-2S is standard. All 4 torque motor leads are
available at the connector so that external connections
can be made for series, parallel, or differential operation.
G77X/-77X Series Servo Valves can be supplied on
special order with other connectors or pigtail.
Configuration for valve opening P B, A T
A B C
DA
B C D
A B C D
Single Series Parallel
A (+), B (-) or C (+), D (-)
A and C (+), B and D (-)
INSTALLATION DRAWINGS AND NULL ADJUST INSTRUCTIONS
B P A
26.9
(1.06)
PIN C
25.4
(1.00)
PIN D
PIN B
7 (.28)
34.11
(1.343)
32
(1.25)
42.88
(1.688)
65
(2.55)
3
5
101
(3.99)
79
(3.11)
95
(3.75)
PIN A
4
2
44
(1.75)
40
(1.56)
55.37
(2.18)
Ø 1.57 (.062)
71
(2.81)
2.5 (.10)
A B C D
Typical Wiring Schematic
1
Moog G77X/-77X Series Flow Control Servo Valves
TECHNICAL DATA
9Rev. M, January, 2021
Fluid:
Industrial hydraulic fluid per DIN 51524 parts 1 to
3 and ISO 11158, maintained to ISO 4406 Code
17/14/11 recommended
Viscosity 10 to 97 mm
2
/s (cSt) at 38 °C
(60 to 450 SUS at 100 °F)
Operating Temperature Range:
Fluid: -40 to +60 °C (-40 to +140 °F)
Ambient: -40 to +135 °C (-40 to +275 °F)
Valve Phasing:
Flow out port B results when:
Series coils: B & C connected, A+, D-
Parallel coils: A & C connected, B & D connected,
A and C+, B and D-
Single coils: A+/B- or C+/D-
Surface:
Surface to which valve is mounted requires flatness
of 0.05 mm (0.002 in) over 100 mm (3.94 in) and an average
finish R
a
better the 0.8 µm (0.000032 in)
Null Adjust:
Flow out port B results with the clockwise rotation of
the null adjust screw
1 Typical wiring schematic
2 Location pin (refer to section Hole Pattern for position)
3 Valve mounting holes: 4X Ø 5.61 mm (0.221 in) or Ø 6.73 mm (0.265 in) thru
4 Null adjust screw (requires 3/8” wrench and 3/32” hex key)
5 Connector mates with MS3106F14S-2S (Moog P/N: -49054F014S002S)
Notes:
G77X/-77X SERIES HOLE PATTERN FOR MOUNTING SURFACE
Ports
G771/771 Port diameter: 4.85 mm (0.191 in)
O-ring outside diameter: 9.52 mm (0.375 in)
O-ring depth: 1.40 mm (0.055 in) deep
G772/772 Port diameter: 6.60 mm (0.260 in) diameter
O-ring outside diameter:12.65 mm (0.498 in)
O-ring depth: 1.40 mm (0.055 in) deep
G773/773 Port diameter: 7.92 mm (0.312 in)
O-ring outside diameter: 14.27 mm (0.562 in)
O-ring depth: 1.40 mm (0.055 in) deep
G771/771 Designation P A B T G F1 F2 F3 F4
Size Ø mm 4.85 4.85 4.85 4.85 3.45 M5 M5 M5 M5
in 0.191 0.191 0.191 0.191 0.136 .190-32 .190-32 .190-32 .190-32
Position X mm 21.44 13.50 29.38 21.44 11.53 0 42.88 42.88 0
in 0.844 0.532 1.157 0.844 0.454 0 1.688 1.688 0
Position Y mm 9.13 17.07 17.07 25.01 4.37 0 0 34.14 34.14
in 0.360 0.672 0.672 0.985 0.172 0 0 1.344 1.344
Moog G77X/-77X Series Flow Control Servo Valves
TECHNICAL DATA
10Rev. M, January, 2021
T
BA
P
G
F3
F2
F1
F4
Y
X
Recommended Seals
G771/771 Port O-rings 1.78 mm (0.070 in) cross section
by 6.07 mm (0.239 in) inside diameter.
Having compatible compound (universal size -010)
G772/772 Port O-rings 1.78 mm (0.070 in) cross section
by 9.24 mm (0.364 in) inside diameter.
Having compatible compound (universal size -012)
G773/773 Port O-rings 1.78 mm (0.070 in) cross section
by 10.82 mm (0.426 in) inside diameter.
Having compatible compound (universal size -013)
G772/772 Designation P A B T G F1 F2 F3 F4
Size Ø mm 6.63 6.63 6.63 6.63 3.45 M5 M5 M5 M5
in 0.261 0.261 0.261 0.261 0.136 .190-32 .190-32 .190-32 .190-32
Position X mm 21.44 11.53 31.34 21.44 11.53 0 42.88 42.88 0
in 0.844 0.454 1.234 0.844 0.454 0 1.688 1.688 0
Position Y mm 7.16 17.07 17.07 26.97 4.37 0 0 34.14 34.14
in 0.282 0.672 0.672 1.062 0.172 0 0 1.344 1.344
G773/773 Designation P A B T G F1 F2 F3 F4
Size Ø mm 7.92 7.92 7.92 7.92 3.45 M6 M6 M6 M6
in 0.312 0.312 0.312 0.312 0.136 .250-20 .250-20 .250-20 .250-20
Position X mm 21.44 9.54 33.34 21.44 11.53 0 42.88 42.88 0
in 0.844 0.376 1.313 0.844 0.454 0 1.688 1.688 0
Position Y mm 5.17 17.07 17.07 28.97 4.37 0 0 34.14 34.14
in 0.204 0.672 0.672 1.141 0.172 0 0 1.344 1.344
NULL FLOW ADJUSTMENT
It is often desirable to adjust the null flow of a servo
valve independently of other system parameters. Valves
with mechanical null adjustment allow for at least ±10%
adjustment of null flow. The mechanical null adjustment
is an eccentric bushing retainer pin, located above the
tank port designation on the valve body, which if rotated
provides control of the bushing location. Mechanical
feedback elements position the spool relative to the valve
body for a given input signal. Therefore, a movement of the
bushing relative to the body changes the null flow.
Mechanical Adjustment Procedure
With zero current (electrical connector disconnected).
Using a 3/8 inch offset wrench, loosen the self-locking
fitting until the null adjustor pin can be rotated. (This
should usually be less than 1/2 turn). DO NOT remove the
self-locking fitting. Insert a 3/32 inch Allen wrench in the
null adjustor pin. Use the 3/32 Allen wrench to rotate the
mechanical adjustor pin to obtain the desired null flow.
Re-torque the self-locking fitting to 57 in lbs.
Moog G77X/-77X Series Flow Control Servo Valves
BACKGROUND
11Rev. M, January, 2021
FLOW CALCULATION
The actual flow is dependent upon the electrical
command signal and valve pressure drop. The flow for
a given valve pressure drop can be calculated using the
square root function for sharp edge orifices.
Q = Q
N
Q actual flow
Q
N
rated flow
∆ p actual pressure drop per spool land
∆ p
N
rated pressure drop per spool land
Standard Axis Cut Open Center Spool Valves Closed Center Spool Valves
Input Current
Control Flow
Q
I
Overlap
Zone
Input Current
Control Flow
Q
I
Control Flow
Input Current
Q
I
Underlap
Zone
150 (40)
115 (30)
75 (20)
38 (10)
19 (5)
35
(500)
70
(1,000)
140
(2,000)
210
(3,000)
14
(200)
21
(300)
58 (15)
3.8 (1)
7.6 (2)
11.4 (3)
15.2 (4)
57 (15)
38 (10)
19 (5)
10 (2.5)
4 (1)
G773-3005A
G772-3004A
G772-3003A
G771-3002A
G771-3001A
Q [l/min (gpm)]
∆p [bar (psi)]
Flow Diagram
SPOOL NULL CUT OPTIONS
Default, without request for
optional cuts
Normally used in hydraulic motor
applications
Normally used in failsafe
applications
∆ p
∆ p
N
Moog G77X/-77X Series Flow Control Servo Valves
BACKGROUND
12Rev. M, January, 2021
RELATED PRODUCTS
Moog G77X/-77X Series Flow Control Servo Valves
BACKGROUND
13Rev. M, January, 2021
Din Rail Modules - Analog Control Cards
Moog’s DIN rail mounted module analog control cards
are ideal for use in enclosures where space is limited.
Modules include servoamplifers, transducer conditioning
electronics, command and auxiliary function modules,
valve drive ampliers, and power supplies. All of these
modules are CE marked and require a 24V DC supply. The
modules mount to standard 35mm DIN rail mount for easy
installation and removal.
Portable Valve Testers - Evaluates Valves in the Field
Valve testers are a cost effective method for evaluating
valves in the eld. They provide a quick and easy means of
differentiating between hydraulic and electronic problems.
There are ve models to choose from, each with different
levels of capability and exibility to meet your specic
requirements. All valve testers have a compact, easily
portable design.
Mounting Manifolds - Easier Installation and Maintenance
Various mounting manifolds are available for standard
industrial valves, including base and adapter types for
mounting and flushing requirements. Other hardware such
as bolts and connectors are also available.
The specic accessories you may need for a particular
model are listed in the relevant product catalogs and can
be ordered through your local ofce.
The most effective way to reduce life cycle costs of an
oil hydraulic system, regardless of the types of valve
used, is through close attention to contamination control.
For industrial servo systems the ideal system filter
arrangement is summarized as follows:
• Use a 10 micron (Beta 10 >= 75) high pressure filter
without by-pass just before the valve or critical parts
of the valve (e.g. pilot)
• Use a 3 micron (Beta 3 >= 75) low pressure filter in the
return or bypass line.
• Use a filter in the tank breather that is at least the
same filtration level as the finest filter in the system.
This recommendation is based on the fact that most servo
and proportional valves can accept the odd particle up to
25 microns so the pressure filter will protect the valve
from catastrophic failure. The real work is done by the low
pressure filter reducing the small particle contamination
which is the prime contributor to component wear and
silting.
Assuming that the filters are properly dimensioned and
care is taken during initial installation and maintenance,
the aim should be to limit oil contamination to 16/13
(under ISO 4406:1987) or 17/14/11 (under ISO 4406:
1999).
For long life, the maximum levels per ISO 4406: 1987
and 1999 are 13/10 and 16/13/10, respectively.
It is important to note that these are maximum
contamination levels and with proper care and regular
filter change, significantly lower levels can and should
be achieved. Attention must also be paid to a number of
other factors that contribute to oil condition problems
such as elevated temperatures, high tank humidity,
“dirty” new oil, etc.
Filtration - Oil Filtration Requirements for
Industrial Servo Systems
Din Rail Module
Valve Tester
Mounting Manifolds
Hydraulic Filters
Moog G77X/-77X Series Flow Control Servo Valves
BACKGROUND
14Rev. M, January, 2021
ROUTINE MAINTENANCE GUIDELINES
Every six months or 4,000 operating hours, check for
proper operation of the control valve assembly by
performing the preventative maintenance steps outlined
below. These checks do not require removal of the valve
from the process line. If a problem is suspected, repair the
valve assembly prior to returning the unit to service.
• Replace the hydraulic filter element
• Stroke the valve and check for smooth, full-stroke
operation; unsteady motion could indicate a servo
valve, actuator or process valve problem
GENERAL INFORMATION
Effects when Storing Valves
The following effects may occur when storing valves for
a long time:
• Sealing materials become brittle, possibly resulting
in leaks
• Hydraulic fluid becomes gummy, possibly resulting in
friction
• Electrolytic capacitors of the valve electronics may
fatigue, possibly resulting in adverse effects on the
valve electronics
Storage Time
The storage time starts at stock receipt and ends at
mounting of the valve.
Preservatives
If conservation is carried out, use only conservatives
which are compatible with the sealing materials and do
not affect the valve, spare parts and accessories.
BEFORE STORAGE
Note: If the valves are exposed to aggressive
environmental influences during storage, vacuum
packaging may be necessary. We recommend the
following preparatory measures for storage:
Mount the shipping plate on the valve.
This is the only way of adequately protecting the valves
against the ingress of dirt and moisture and protecting
the seals against the effects of ozone and UV.
Put the valve, spare parts and accessories into the
original packaging.
Package each valve separately.
Enclose anti-tarnish paper or package the valve, spare
parts and accessories with corrosion inhibiting film.
(Only for storage time > 1 year.)
Multipacks of single valves in their individual packages
are allowed.
Seal the original packaging properly.
This is the only way of adequately protecting the valves,
spare parts and accessories against damage.
STORAGE CONDITIONS
We recommend the following ambient conditions for
storage:
• Dust-free, moderately ventilated
• As vibration-free and shock-free as possible
Shock resistance (as per EN 60068-2-27):
50 g, 6 directions, half-sine 3 ms
Vibration resistance (as per EN 60068-2-6):
30 g, 3 axes, frequency 10 to 2,000 Hz
Temperature
Recommended: +15 to +25 °C (+59 to +77 °F)
Permissible: -40 to +60 °C (-40 to +140 °F)
Temperature fluctuations >10 °C (50 °F) must be
avoided.
Distance to shielded radiators: > 1 m (3 ft)
No direct exposure to sunlight
No sources of light with a high UV content
UV rays generate ozone, which damage sealing
materials.
Relative air humidity: < 65 %, non condensing
AFTER STORAGE
We recommend to check the original packaging, valve,
spare parts and accessories for possible damage or
alterations due to storage, that is, before use.
Damaged or not functional valves, spare parts and
accessories must not be started up.
Sealing materials with the following characteristics
must not be used:
• Contamination
• Cracking
• Hardening/softening
• Stickiness
• Discoloration
Storage Time > 5 Years
We recommend that the valve be checked by us or one
of our authorized service centers after a storage time
of more than 5 years.
Storage Time > 10 Years
After a storage time of more than 10 years the valves
have to be checked by us or one of our authorized
service centers.
ABOUT MOOG
Moog G77X/-77X Series Flow Control Servo Valves
BACKGROUND
15Rev. M, January, 2021
Moog Inc. is a worldwide designer, manufacturer and
integrator of precision control components and systems.
Moog’s Industrial Group designs and manufactures
high performance motion control solutions combining
electric, hydraulic, and hybrid technologies with expert
consultative support in a range of applications including
energy production and generation machinery, industrial
production machinery and simulation and test equipment.
We help performance-driven companies design and
develop their next-generation machines.
Moog maintains facilities in 26 countries around the globe.
This vast scope ensures that our engineers remain close
to the needs of machine builders and provide flexible
design solutions and technical expertise tailored to our
customers’ toughest challenges.
Moog experts work in close collaboration with machine
builders and application engineers to design motion
control systems for greater productivity, higher reliability,
superior connectivity, less costly maintenance and more
effective operations. Our regional presence, industry
knowledge and design flexibility ensures Moog motion
control solutions are tailored to their environment—
from meeting operating regulations and performance
standards, to taking machine performance to a higher
level.
Products
At the heart of every Moog solution is an array of products
engineered for precision, high performance and reliability.
For more than six decades, Moog products have been
specified for critical machine applications.
Some are developed specifically for unique operating
environments. Others are standard equipment on
machines across many industries. All are continuously
improved to take advantage of the latest technology
breakthroughs and advancements.
Moog products include:
• Servo Valves and Proportional Valves
• Servo Motors and Servo Drives
• Servo Controllers and Software
• Radial Piston Pumps
• Actuators
• Integrated Hydraulic Manifold Systems and Cartridge
Valves
• Slip Rings
• Motion Bases
Servo Valves
Radial Piston Pumps
Servo Drives
Active Cartridge Valves
Moog G77X/-77X Series Flow Control Servo Valves
BACKGROUND
16Rev. M, January, 2021
ABOUT MOOG
Hydraulic solutions
Since Bill Moog invented the first commercially viable
servo valve in 1951, Moog has set the standard
for world-class hydraulic technology. Today, Moog
products are used in a variety of applications -
providing high power, enhanced productivity and ever
better performance for some of the world’s most
demanding applications.
Electric solutions
Clean operation, low noise generation, less
maintenance and reduced power consumption
make Moog electric solutions ideal for applications
worldwide. Moog is the ideal partner for applications
where transitioning technologies requires special
expertise.
Hybrid solutions
By incorporating the advantages of existing hydraulic
and electric technologies - including modular
flexibility, increased efficiency and cleanliness -
into innovative hybrid solutions, Moog offers new
performance potential in specialized applications.
Moog Global Support
Moog Global Support is our promise to offer world-class
Repair and Maintenance Services delivered expertly by our
trained technicians. With the reliability only available from
a leading manufacturer with facilities around the world,
Moog offers you service and expertise you can count on to
keep your equipment operating as it should.
This promise offers many benets to our customers
including:
• Reduce your downtime by keeping critical machines
running in peak performance
• Protect your investment by ensuring reliability,
versatility and long-life of products
• Better plan your maintenance activities and make
systematic upgrades
• Leverage our exible programs to meet the unique
service requirements of your facility
Look to Moog for global support including:
• Repair services using OEM parts are performed by
trained technicians to the latest specications
• Stock management of spare parts and products to
prevent unplanned downtime
• Flexible programs, tailored to your needs such as
upgrades, preventative maintenance and annual/
multi-year contracts
• On-site services bring the expertise to you,
providing quicker commissioning, set-up and
diagnostics
• Access to reliable services that are guaranteed to
offer consistent quality anywhere in the world
For more information on Moog Global Support
visit www.moog.com/industrial/service.
Flight Simulation
Formula One Simulation Table
ORDERING INFORMATION
17
Rev. M, January, 2021
Part designation Description Moog part number
Mounting screws
G771/-771 and 4 required M5 x 50 ISO 4762-10.9 (0.190-32 by 2.0 long) tightening B64929-006B050 (C39674-532)
G772/-772 Series torque to 5 Nm (44 lbf-in) (without motor cap spacer)
4 required M5 x 65 ISO 4762-10.9 (0.190-32 by 2.50 long) tightening B64929-006B065 (C39674-540)
torque to 5 Nm (44 lbf-in) (with motor cap spacer)
G773/-773 Series 4 required M6 x 60 ISO 4762-10.9 (0.250-20 by 2.25 long) tightening B64929-007B060 (C66391-136B)
torque to 7.5 Nm (66 lbf-in)
Mating connector 4 pin electrical connector -49054F014S002S (MS3106F14S-2S)
Servo amplier P - I servo amplier - compact DIN rail housing G122-829A001
Mounting Manifold Base mounting manifold
G771/-771 Series B64389AM005
G772/-772 Series B64389AM003
G773/-773 Series B64389AM001
Flushing plate Manifold employed in place of valve when initially cleaning hydraulic uids
G771/-771 and O-ring included A01704AM001
G772/-772 Series
G773/-773 Series A01704AM002
AMO manifold Adjustable metering orice manifold used to bleed uid between A and B
G773/-773 Series ports for better pressure control A72684AM006
O-rings included
ADB Manifold Adjustable dual bypass manifold used to mitigate the effect of
G771/-771 Series contamination and heat, by allowing hydraulic uid to continuously ow CA96566-001
from the active servo valve port(s) to tank
O-rings included
CRV manifold Cross port relief manifold used to limit pressure levels in ports A and B
G773/-773 Series O-rings included A72682AM001-XXXX
ACCESSORIES AND SPARE PARTS
Series Dependent Accessories and Spare Parts
Accessories G77X/-77X Series
Moog G77X/-77X Series Flow Control Servo Valves
Part designation Description Material Moog part number
Base O-ring 4 required for P, T, A, and B ports 6.0 mm
G771/-771 Series (0.239 in) inside diameter x 1.8 mm (0.070 in) -42082-007
cross section. Equivalent MIL-R-83248 size -010
G772/-772 Series 4 required for P, T, A, and B ports 9.24 mm -42082-013
(0.364 in) inside diameter x 1.8 mm (0.070 in)
cross section. Equivalent MIL-R-83248 size -012
G773/-773 Series 4 required for P, T, A, and B ports 10.8 mm -42082-022
(0.426 in) inside diameter x 1.8 mm (0.070 in)
cross section. Equivalent MIL-R-83248 size -013
Replaceable lter 60 mu (absolute) C39486-005-060
Filter replacement kit Contains the following: B52555RK054K001
4 pieces O-ring 1.8 mm (0.070 in) inside diameter
x 1.0 mm (0.040 in) cross section
Moog specic size
2 pieces O-ring 6.9 mm (0.270 in) inside diameter
x 1.8 mm (0.070 in) cross section.
Equivalent Parker size 5-052
2 pieces O-ring 5.3 mm (0.208 in) inside diameter
x 1.8 mm (0.070 in) cross section.
Equivalent MIL-R-83248 size -009
1 piece lter tube 60 mu (absolute)
Spare Parts G77X/-77X Series
Documents (not included in scope of delivery)
Part designation Description Remark Moog part number
Catalog G77X/-77X series general information Note: Visit CDL6651
www.moog.com/installation
to download document
Service manual G77X/-77X standard series Note: Visit CDS6674
www.moog.com/installation
to download document
Service manual G77XK/-77XK intrinsically safe Note: Visit CDS6768
(K) series www.moog.com/installation
to download document
Additional options may be available upon request. Please contact Moog for details.
Fluorocarbon (FKM)
(Viton™ B), 90 shore
(MIL-R-83248/2 Type I,
Class 2)
Fluorocarbon (FKM)
(Viton™ B), 90 shore
(MIL-R-83248/2 Type I,
Class 2)
ORDERING CODE
ORDERING INFORMATION
18Rev. M, January, 2021
H
S
V
04
10
4
G
J
M
Z
H
L
±8 mA ±4 mA
±10 mA ±5 mA
±20 mA ±10 mA
±50 mA ±25 mA
±200 mA ±100 mA
±15 mA ±7.5 mA
±40 mA ±20 mA
V
Fluorocarbon (FKM) (Viton™ B) 90 shore
4
M
A
B
A
B
2
1
C
D
J
H
12345678910
4
19
19
F
K
F
G
3,000
5,000
V
4
10
G77/-77
Model ascension number (factory assigned)
Model revision (factory assigned)
1 Valve version
High response 4 to 38 l/min (1-10 gpm)
Standard response 57 l/min (15 gpm)
Super high response 4 to 19 l/min (1-5 gpm)
2 Rated flow in l/min (gpm)
3 Maximum operating pressure in psi (bar) and body material
(210) aluminum
(350) stainless steel
Single or parallel coil value Series coil value
10 Command signal for 100% spool stroke
8 Seal material
4 pin MS threaded connector over RH (C1, A)
4 pin MS threaded connector over LH (C2, B)
4 lead pigtail over RH (C1, A)
4 lead pigtail over LH (C2, B)
6 pin MS threaded connector over RH (C1, A)
6 pin MS threaded connector over LH (C2, B)
6 lead pigtail over RH (C1, A)
6 lead pigtail over LH (C2, B)
Supply (x) Return (y)
Internal Internal
7 Pilot connections
Standard flow, nozzle flapper, torque motor first stage
High flow, nozzle flapper, torque motor first stage
5 Pilot stage design
6 Spool position without electrical signal
Mid-position defined
P->B, A->T
P->A, B->T
For = 35 bar (500 psi) per spool land p
9 Valve connector
Model number (assigned at the factory) Type designation
(2.5)
(1)
(5.0)
N
Optional features
Series specification
Intrinsically safe
-
K
Base Number
.625 in Port circle
.780 in Port circle
.937 in Port circle
1
2
3
38
38 (10.0)
57
57 (15.0)
O
4-way / axis cut / linear
4 Main spool type
D
4-way / ±10% overlap / linear
X771/X772/X773
X771/X772/X773
X771/X772/X773
X772/X773
X773
Model Number Type Designation Rated Flow (∆1,000 psi) Rated Current
l/min gpm (single or parallel coil) mA
G771-3001A H04FOFM4VBL 4 1.0 ±40
G771-3002A H10FOFM4VBL 10 2.5 ±40
G772-3003A H19FOFM4VBL 19 5.0 ±40
G772-3004A S38FOFM4VBL 38 10.0 ±40
G773-3005A S57FOFM4VBL 57 15.0 ±40
Preferred Models
Moog G77X/-77X Series Flow Control Servo Valves
All combinations may not be available. Other options available upon request.
Please contact Moog for non-standard configurations.
TAKE A CLOSER LOOK
Moog designs a range of motion control products that complement the performance of those featured in this catalog.
Visit our website for more information and contact the moog facility nearest you.
Argentina
+54 11 4326 5916
info.argentina@moog.com
Australia
+61 3 9561 6044
info.australia@moog.com
Brazil
+55 11 3572 0400
info.brazil@moog.com
Canada
+1 716 652 2000
info.canada@moog.com
China
+86 21 2893 1600
info.china@moog.com
Finland
+358 9 2517 2730
info.nland@moog.com
France
+33 1 4560 7000
info.france@moog.com
Germany
+49 7031 622 0
info.germany@moog.com
Hong Kong
+852 2 635 3200
info.hongkong@moog.com
India
+91 80 4057 6666
info.india@moog.com
Ireland
+353 21 451 9000
info.ireland@moog.com
Italy
+39 0332 421 111
info.italy@moog.com
Japan
+81 46 355 3767
info.japan@moog.com
Korea
+82 31 764 6711
info.korea@moog.com
Luxembourg
+352 40 46 401
info.luxembourg@moog.com
The Netherlands
+31 252 462 000
info.thenetherlands@moog.com
Norway
+47 6494 1948
info.norway@moog.com
Russia
+7 8 31 713 1811
info.russia@moog.com
Singapore
+65 677 36238
info.singapore@moog.com
South Africa
+27 12 653 6768
info.southafrica@moog.com
Spain
+34 902 133 240
info.spain@moog.com
Sweden
+46 31 680 060
info.sweden@moog.com
Switzerland
+41 71 394 5010
info.switzerland@moog.com
Turkey
+90 216 663 6020
info.turkey@moog.com
United Kingdom
+44 168 429 6600
info.uk@moog.com
USA
+1 716 652 2000
info.usa@moog.com
www.moog.com/industrial
Moog is a registered trademark of Moog Inc. and its subsidiaries. All
trademarks as indicated herein are the property of Moog Inc. and its
subsidiaries.
©2021 Moog Inc. All rights reserved.
G77X/-77X Series Flow Control Servo Valves
SMM/PDF, Rev. M, January 2021, Id. CDL6651-en
WHAT MOVES YOUR WORLD
All combinations may not be available. Other options available upon request.
Please contact Moog for non-standard configurations.