introduction into efb valve
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EFB Valves Training
Assembly and function ofElectrical Feedback valves
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Introduction
Terminology of EFB
The Moog term EFB describes proportional valves with
integrated Electrical FeedBack system
with pilotstageMoog EFB valves are 2 or 3 stage proportional valves
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Assembly
Assembly shown at D661 valve with ServoJet Pilotstage
Main Stage (Hydraulic Amplifier)
Pilotstage (First stage)
IntegratedElectronic
Feedback SystemPosition transducer
Electrical Interfacevalve connector
FailsafeMechanic
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EFB Pilotstage
Strahlrohr/ Jet-Pipe Linear Motor Drive
2 Stage ServovalveServoJet® Moog’sPilotstages
Page 5MOOG MOOG TrainingTraining
Strahlrohr/ Jet-Pipe
ServoJet®
Nozzle-Flapper
ServoJet / Historie
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Hydraulic Amplifier
Electro MechanicalAmplifier
ServoJet / Assembly
The Servojet stage consist of the Electro-Mechnical Amplifier and the Hydraulic Amplifier
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ServoJet / Assembly
1) Coil
3) Permanent Magnets
2) Armature
4) Spring-Rod
5) JetPipe6) Receiver
7) Power Supply
8) Jet
9) Drain Line / to Tank
4
7
8
9
7
1
2
3
5
6
Magnified
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Permanent Magnetic Fluxand Coil Induced Magnetic Flux
PermanentMagnetic Flux
Coil InducedMagnetic Flux
ServoJet / Motor OperationAn armature/jet pipe assembly is mounted on two rods. The single jet spraysbetween two holes in the receiver. An electrical command is applied to the torquemotor coil and creates a induced magnetic force which is superposed to thepermanent magnetic flux. This causes deflection of the armature/jet assembly. Thedeflection of the jet pipe is proportional to the input current which is applied.
+
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ServoJet / Hydraulic Operation
P TA B
P TA B
P TA B
P TA BAttention : Shows only the principle ->no feedback of the spool position
No current applied.Pipe stand in his
middle postion.
Current applied.Pipe will deflect.
Jet is devided and a Delta P is generated.
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ServoJet / Advantages
Advantages of the of ServoJet Pilotstage
Reduced Leakage at null (energy saving)
High Natural Frequency of approx. (500Hz)
Defined Failsafe end position for Failsafe requirementsPressure range form 15 bar up to 280 bars
High Pressure gain for precise position controlling.
Reduced Hysteresis and Threshold
and ...
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Gap between Jetand Receiver is
0,3 -0,4 mm
Advantages of the of ServoJet PilotstageHigh Resistance against contamination due to increase gab
between Receiver and Jet
The recommended fluidcleanliness class for all D660valves per ISO 4406 is <16/13 fornormal operation, and <14/11 for longer life.
ServoJet / Advantages
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EFB Pilotstage
The selection of ServoJet, 2 stage Servovalveor Mini DDV depends on the application andthe specified features.
The JetPipe stage will only be used at ExplosionProtected Valves according ATEX 95 // 94/9/EU
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EFB Main Stage
Servo Valve
Proportional Valve
Comparison of the main stage types
• accurate axis cut (< +- 3%)• Each overlap condition easily possiple (e.g +-10%)• high hydraulic gain• high pressure gain possible• Mechnical Failsafe possible• manufacturing costs lower
• very accurate axis cut (+- 1%)• very high hydraulic gain• very high pressure gain possible• higher manufacturing costs
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EFB Main Stage
Proportional Valves:Spool in Body
Servo Valve: Bushing Spool Assembly BSA
Type of Main Stage (Size NG10)
Modell Series D661 and D681 Modell Series D661- H
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EFB Main Stage
Proportional Valve: Spool in Body Standard
Proportional Valve: Spool in Body / Stub Shaft Spool
Type Main stage (Size NG16-25-32)
Standard spool in BodyUsed only with “MiniDDV” or 2 Stage“MFB-Valves“
Standard Spool with stubshuftUsed only with “ServoJet” and “MiniDDV”
Reduced the space and thus the needed oilfrom Pilotstage to fill up this space.
Modell Series D662/3/4/5 and D682/3/4/5
Modell Series D662/3/4/5 and D682/3/4/5
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EFB Position Transducer
The electrical feedback system exists off• Non-contacting position transducer (Iron Core and LVDT)
• and valve electronic for the evaluation of the LVDT Signal
LVDT : Linear Variable Differential Transducer
Iron Core
LVDT
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EFB Position Transducer
Principle function of electrical Feedback system
• The primary coil is supplied with AC Voltage.
• Due to the iron core a changing magnetically field will be generated.
• This changing magnetically field induces in both secondary coils a voltage
Primary coil
2 Secondary coils
Iron Core
Demodulator
Modulator
Spool in middle Position
0V
• Both secondary coils are mutual connected together. Therfore, if the iron core is positoned in middle, the induced voltage in both coils will cancal each other out.
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EFB Position Transducer
Principle function of electrical Feedback system
• If the iron core moved out of the middle position, the induced voltage in one secondary coil will encrease and in the other one the induced voltage will decrease.
• Due to the diffent level of the induced voltage, a AC output voltage will arise. The value of the voltage is proportional to the spool stoke. The sign +/- will show the direction.
• The AC signal at the input of the demodulator will be converted into a +/- DC Signal
Primary coil
2 Secondary coils
Iron Core
Demodulator
Modulator
Spool in end position
10V
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EFB Valve electronic
The intergrated electonic board include the
- power amplifier for the Pilotstage
- the evaluation of the Position Transducer signal
- Circuits to prozess the input signals (Input-Signal, Logic-Signal)
- the position contoller
- circuits to prozess the output signals (Spool position, Logic-Signal)
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Strukture of Position Controller
This components are part of the integrated position controller of the EFBValve and guaranty the repeatable, proportional property with highperformance.
InputElectrical-
signal
Upt
U I-sig
Main Stage Pilotstage Position
Controller& Amplifier
Feedback System
U
Output- Flow
- Pressure
Valve
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EFB Valve operating
Upt
U I-sig
Main Stage Pilotstage Position
Controller& Amplifier
Feedback System
U
OutputFlow 0% cis
Spool Position 0%
0% InputSignal
The Spool is position inhis middle position.Null Position
The controller board permanently measurethe position of the Spool and compare istwith the input signal (in this case 0%).
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EFB Valve operating
Upt
U I-sig
Main Stage Pilotstage Position
Controller& Amplifier
Feedback System
U
OutputFlow 0% cis
Spool Position 0%
80% InputSignal
max. mA
An electric command signal(setpoint UI-sig) is applied tothe integrated positioncontrol.
Because of the different signal of U I-sig and U ptthe amplifier of the contoller board will providethe pilotstage with the maximum current.
The Pilotstage will deflect and generate a DeltaP on the two ends of the spool.
Operating
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EFB Valve operating
Upt
U I-sig
Main Stage Pilotstage Position
Controller& Amplifier
Feedback System
U
OutputFlow 60% cis
Spool Position 70%
80% InputSignal
ReducedmA
Due to the Delta P at theend side of the spool, thespool will move into thedirection with the lowerPressure.
The land open and the medium will flow overthe opened lands.
The controler permenently compare U I-sig andU pt . If the two signals come closer, the amplifierwill reduce the current to the Pilotstage and thepilotstage deflect back into the null direction.
Operating
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EFB Valve operating
Upt
U I-sig
Main Stage Pilotstage Position
Controller& Amplifier
Feedback System
U
OutputFlow 80% cis
Spool Position 80%
80% InputSignal
If the spool reached thedefined position thedifferent between U I-sigand U pt will be cero.
The contoller board will control the pilotstageback into it’s null position. Therfore there will beno Delta P at the two ends of the spoolanymore, so the spool will stop moving.
Every distribution which try to change theposition of the spool will be permanentlycompensate by the controller board.
End Position
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EFB Failsafe Mechnismen
Moog Proportional valves are available with
several Failsafemechanismen
Attention :
Depending on demanded safety standard, a simple failsafe protectiondue to the in Moog valve intergrated failsafe systems, does mostly notsuffice.
For the protection of plants and machines against accidents, thegoverments demands repeatedly, redundant safety Failsafesystemes.
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EFB Failsafe Mechnismen
Examples of Failsafe Mechanismen
Shifted null bias of the first Stage
Spring on one side
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EFB Failsafe Mechnismen
- Spring centred spool- with solinoid valve
Short cut between the A and B port ofthe first stage
- Spring centred spool- solinoid valve
Solinoid valve block the pressuresupply to the fist stage
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EFB Interface
Hydraulic Interface for Proportional - Valves according ISO standardD661 / 681 ISO 4401-05-05-0-94 NG10
D662 / D682 ISO 4401-07-06-0-94 NG16
D663 / D683 ISO 4401-08-07-0-94 NG25
D664 / D684 ISO 4401-08-07-0-94 NG25
D665 / D685 ISO 4401-10-08-0-94 NG32
Hydraulic Interface for Servo- Valves according iso standard D661 ISO 4401-05-05-0-94 NG10
D662* ISO 4401-07-06-0-94 NG16
D663** ISO 4401-08-07-0-94 NG25
D664** ISO 4401-08-07-0-94 NG25* Prototype-Phase
** planned
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EFB Interface
Electrical Interface
6+PEWiring for valves with 6+PE pole connectorEN 175201 Part 804
Standard wiring (see catalog).
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EFB Interface
11+PE
Electrical Interface
Wiring for valves with 11+PE pole connectorEN 175201 Part 804
Standard wiring (see catalogue).
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D660 Series
Type D661-.....NG10 at Delta p = 5 bar/land
Rated Flow : 30,60,80 l/minSystem Pressure : 350 barOnboard Electronic : 24V= Analog Electronic
Type D662-....NG16 at Delta p = 5 bar/land
Rated Flow : 150,250 l/minSystem Pressure : 350 barOnboard Electronic : 24V= Analog Electronic
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D660 Series
Type D663-.....NG25 at Delta p = 5 bar/land
Rated Flow : 350 l/minSystem Pressure : 350 barOnboard Electronic : 24V= Analog Electronic
Type D664-....NG25 at Delta p = 5 bar/land
Rated Flow : 550 l/minSystem Pressure : 350 barOnboard Electronic : 24V= Analog Electronic
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D660 Series
Type D665-.....NG32 at Delta p = 5 bar/land
Rated Flow : 1000 l/minSystem Presssure : 350 barOnboard Electronic : 24V= Analog Electronic
Type D665-....NG32 at Delta p = 5 bar/land
Rated Flow : 1500 l/minSystem Presssure : 350 barOnboard Electronic : 24V= Analog Electronic
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D680
Mini DDV Pilotstufe
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D680 Series
D681 (NG10) D683 / D684 (NG32)
D682 (NG16) D685 (NG25)
Technicaldatas see
D660 Series
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Product Advantages D660/ D680
• High dynamic• Robust• Customized Modell possible• Controller accuracy• ServoJet : Contamination resistant• High flow at stable spool position.• Integrated Failsafe Functionen• High flow at stable spool position.• Integrated Failsafe Function• MiniDDV : Less leakage with MiniDDV• MiniDDV : pressure independent
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