MOOG D661-4858 Electro‑Hydraulic Servo Valve
May 29, 2026

MOOG D661-4858 Electro‑Hydraulic Servo Valve

Product Description The D661-4858 is a two‑stage, pilot‑operated ServoJet® servo valve from MOOG’s D661 high‑response series, featuring integrated 24 VDC amplifier and LVDT spool position feedback. It complies with ISO 4401‑05 (NG10) mounting standard, designed for ultra‑high‑flow, high‑precision closed‑loop hydraulic control in heavy‑duty industrial and test applications.

Description

Model Definition

  • D661 = Series (integrated electronics, 24 VDC, NG10)Moog Inc.

  • 4858 = Spool/sleeve assembly; rated flow 180 L/min @ ΔP=35 barMoog Inc.

  • Typical full config example: P180HAAM7NSX2‑A

    • P180 = Ultra‑high flow & high frequency response version

    • HAAM = Standard hydraulic layout, 24 VDC, ±10 V/±10 mA command, centered nullMoog Inc.

    • 7 = 7+PE connector, IP65Moog Inc.

    • NSX2 = NBR seals, wide temperature range, LVDT feedback 4–20 mAMoog Inc.

    • A = Standard ServoJet® pilot stageMoog Inc.

Technical Specifications

Hydraulic Parameters
  • Rated flow: 180 L/min (ΔP=35 bar)Moog Inc.

  • Max working pressure: 350 bar (P/A/B); 210 bar (internal drain T) / 350 bar (external drain T)Moog Inc.

  • Step response: 12–16 ms (0→100%, 210 bar)Moog Inc.

  • Hysteresis: <0.2%

  • Resolution: <0.1%

  • Null drift: <1.5% (ΔT=55 K)

  • Null leakage: <22 mL/min

  • Fluid cleanliness: NAS 1638 Class 6 / ISO 4406 18/15Moog Inc.

Electrical Parameters
  • Power supply: 24 VDC (18–32 VDC)Moog Inc.

  • Control signal: ±10 V (differential) or ±10 mAMoog Inc.

  • Feedback signal: 4–20 mA (LVDT spool position)Moog Inc.

  • Connector: 7+PE, IP65Moog Inc.

  • Current draw: ≤800 mA

Physical & Environmental
  • Operating temperature: −40 ℃ to +85 ℃Moog Inc.

  • Weight: approx. 9.8 kg

Interface & Communication Configuration

  • Hydraulic interface: P/A/B/T, ISO 4401‑05 (NG10)Moog Inc.

  • Electrical interface:

    • Power: 24 VDC, GND, PEMoog Inc.

    • Command: ±10 V / ±10 mAMoog Inc.

    • Feedback: 4–20 mA (spool position)Moog Inc.

    • Status: Fault alarm outputMoog Inc.

Core Functions

  • ServoJet® pilot stage: Superior contamination resistance, low null drift, extended service lifeMoog Inc.

  • Integrated high‑response amplifier: Built‑in PID, dead‑zone compensation, overload protectionMoog Inc.

  • LVDT closed‑loop feedback: High linearity and precision across full strokeMoog Inc.

  • Fail‑Safe centering: Spool returns to neutral on power lossMoog Inc.

  • Ultra‑high‑flow dynamics: Optimized for 180 L/min with stable response for large‑scale hydraulic systems

Application Scenarios

  • Metallurgy: Ultra‑high‑flow AGC roll gap control for extra‑heavy plate mills, high‑force tension controlMoog Inc.

  • Test equipment: High‑precision dynamic material testers, large‑scale high‑force vibration tablesMoog Inc.

  • Industrial automation: Extra‑large CNC machine tools, ultra‑heavy‑duty hydraulic presses, large blow molding machinesMoog Inc.

  • Energy & heavy industry: Wind turbine pitch control (high‑power), marine main propulsion hydraulic systems, heavy‑duty steel mill hydraulic drivesMoog Inc.

Usage & Maintenance

  • Installation: Horizontal/vertical mounting; avoid severe vibrationMoog Inc.

  • Fluid: ISO VG46 mineral oil; maintain cleanliness per NAS 1638 Class 6Moog Inc.

  • Commissioning: Apply 24 VDC power; connect ±10 V/±10 mA command; calibrate zero and gain via 4–20 mA feedbackMoog Inc.

  • Maintenance: Inspect fluid contamination regularly; calibrate zero/gain every 6 months; avoid long idle periods at high pressure


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