Model Explanation

D661: MOOG D660 platform two-stage integrated electronic servo valve series complying with ISO4401-05 mounting standard with ServoJet pilot structure

Z: Built-in internal LVDT spool displacement closed-loop feedback plus fully integrated onboard servo drive amplifier

4754: Base specification coding: rated flow 200L/min@ΔP=35bar per single spool land, external independent X pilot oil supply, external Y drain layout, mechanical spring auto-centering upon power loss, 12-pin circular electrical connector; no suffix letter means standard NBR sealing for normal industrial working conditions

Technical Specifications

Hydraulic Parameters

Rated Flow: 200 L/min (@ΔP=35bar per single spool land)

Max Working Pressure: P/A/B main ports:350bar(5000PSI); external Y drain T port:350bar; max allowable pressure for external X pilot supply port:280bar

Pilot Configuration: Separate external X pilot inlet and independent external Y drain returning to tank

Working Medium: Mineral hydraulic oil meeting DIN51524/ISO11158; recommended oil cleanliness NAS6~7

Net Weight: Approx 6.0kg

Fail-safe Feature: Mechanical return spring drives spool back to neutral zero position automatically once power fails to lock actuator position

Electrical Parameters

Power Supply: DC24V (18～32VDC), total power consumption ≤38W

Control Signal: Differential ±10VDC analog input; ±10mA current signal available as optional customization

Full Stroke Step Response (0~100% stroke, supply pressure 210bar):7~10ms

Electrical Connector: Standard 12-pin circular industrial plug

Built-in Protection: Overcurrent, reverse polarity and short-circuit protection for onboard amplifier

Environmental Conditions

Operating Temperature: -20℃～+70℃; Storage & Transportation Temperature:-40℃～+85℃

Humidity:5%~95%RH non-condensing; compliant with EN61000 industrial EMC anti-interference standards

Protection Grade: Electrical connector IP65, valve body IP54

Channel & Feedback Configuration

Hydraulic Port: Standard 4-way P/A/B/T layout following ISO4401-05 manifold installation dimension, with independent external X pilot port and external Y drain port reserved

Feedback Mode: High-precision non-contact internal LVDT displacement sensor collects real-time spool position for inner closed-loop control, no external mechanical feedback rod required

Communication & Interface Configuration

Control Wiring: Shielded analog cable hardwires to analog output channel of D137 module under MSCⅡ control system; control commands are edited via MACS programming software and transmitted to servo valve through screened signal wire

Auxiliary Interface: Zero trimming potentiometer installed on valve side panel for on-site zero-offset adjustment; only analog hardwire control available without onboard EtherCAT or Profibus fieldbus interfaces

Core Function

Convert analog control signals from D136 master controller into proportional hydraulic flow to drive hydraulic cylinders and hydraulic motors for high-precision closed-loop regulation of position, movement speed and test load under large-flow working conditions.

Internal LVDT feeds real spool position back to integrated amplifier to form inner valve closed loop, improving control linearity and restraining zero drift caused by oil temperature fluctuation and supply pressure variation.

The integrated amplifier with multi-protection design outputs fault status which can be captured by D137 digital input channels for system fault alarm and safety interlock.

Power-off spring centering structure avoids actuator runaway accident and improves safety of heavy-load test equipment.

Side-mounted zero adjust potentiometer compensates zero shift resulting from installation tolerance and slight oil contamination.

Applicable Scenarios

Large-flow electro-hydraulic regulation of steam turbine EH governing system; heavy-load fatigue testing for engineering machinery structural components; precision forming control of large hydraulic press; performance test for large-bore aerospace hydraulic actuators; static & dynamic mechanical testing of oversized new material specimens.

Instructions for Installation and Maintenance

Mount the valve on standard ISO4401-05 hydraulic manifold in horizontal or vertical orientation; avoid installation in areas with dense oil mist, water splash and intensive high-temperature radiation.

Install 3μm high-pressure precision filters at upstream of P main oil inlet and X pilot supply port to prevent ServoJet pilot nozzle blockage from hydraulic contaminants.

Retighten all electrical terminals every six months; route shielded analog signal cables separately from high-power cables in different wiring ducts to reduce electromagnetic interference.

Complete full-range zero calibration of the servo valve once per year; periodically inspect external leakage on all hydraulic ports and replace sealing elements in case of abnormal leakage.

Restrict 24VDC power supply fluctuation within ±10% of rated voltage; overvoltage will cause permanent damage to internal integrated amplifier board.