Introduction Into EFB Valve

EFB Valves Training

Assembly and function ofElectrical Feedback valves

MOOG MOOG TrainingTraining

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


Assembly

Assembly shown at D661 valve with ServoJet Pilotstage

Main Stage (Hydraulic Amplifier)

Pilotstage (First stage)

IntegratedElectronic

Feedback SystemPosition transducer

Electrical Interfacevalve connector

FailsafeMechanic


EFB Pilotstage

Strahlrohr/ Jet-Pipe Linear Motor Drive

2 Stage ServovalveServoJet® Moog’sPilotstages


Strahlrohr/ Jet-Pipe

ServoJet®

Nozzle-Flapper

ServoJet / Historie


Hydraulic Amplifier

Electro MechanicalAmplifier

ServoJet / Assembly

The Servojet stage consist of the Electro-Mechnical Amplifier and the Hydraulic Amplifier


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


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.

+


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.


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 ...


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


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


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


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


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


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



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.



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


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)


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


EFB Valve operating

Upt

U I-sig



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%).


EFB Valve operating

Upt

U I-sig



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


EFB Valve operating

Upt

U I-sig



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


EFB Valve operating

Upt

U I-sig



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


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.



Examples of Failsafe Mechanismen

Shifted null bias of the first Stage

Spring on one side



- 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


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


EFB Interface

Electrical Interface

6+PEWiring for valves with 6+PE pole connectorEN 175201 Part 804

Standard wiring (see catalog).


EFB Interface

11+PE

Electrical Interface

Wiring for valves with 11+PE pole connectorEN 175201 Part 804

Standard wiring (see catalogue).


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


D660 Series


Rated Flow : 350 l/minSystem Pressure : 350 barOnboard Electronic : 24V= Analog Electronic


Rated Flow : 550 l/minSystem Pressure : 350 barOnboard Electronic : 24V= Analog Electronic


D660 Series


Rated Flow : 1000 l/minSystem Presssure : 350 barOnboard Electronic : 24V= Analog Electronic


Rated Flow : 1500 l/minSystem Presssure : 350 barOnboard Electronic : 24V= Analog Electronic


D680

Mini DDV Pilotstufe


D680 Series

D681 (NG10) D683 / D684 (NG32)

D682 (NG16) D685 (NG25)

Technicaldatas see

D660 Series


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

Introduction Into EFB Valve

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