MOOG D661-4575C Servo‑Proportional Valve
May 28, 2026

MOOG D661-4575C Servo‑Proportional Valve

Product Overview Model: D661-4575C Type: Two‑stage, 4‑way/3‑position, ServoJet® pilot, integrated 24 VDC electronics, single LVDT closed‑loop feedback Manufacturer: MOOG Series: D661 (ISO 4401‑05/NG10 high‑performance industrial servovalve) Description: Medium‑high‑flow, high‑dynamic response servovalve for precision hydraulic systems; ServoJet pilot; on‑board PID; low hysteresis and excellent null stability.

Description

Model Code Explanation (D661-4575C)

  • D661: Series (ISO 4401‑05 mounting, integrated 24 VDC electronics)

  • 4: 4‑way, zero‑lap, linear flow characteristic

  • 57: Rated flow ≈ 100 L/min (Δp = 35 bar per land)

  • 5: High‑dynamic response, single LVDT feedback, standard null stability

  • C: Standard performance, non‑explosion‑proof

Technical Specifications

Part Number: D661-4575C

Mounting

ISO 4401‑05 (NG10), 4‑hole, M6 bolts (torque 13 Nm, diagonal tightening)

Control Function

4‑way/3‑position, spring‑centered, zero‑lap, closed‑loop spool position control

Hydraulic Parameters

  • Rated Flow (Δp = 35 bar): 100 L/min (±8%)

  • Max Operating Pressure (P/A/B): 350 bar (5,000 psi)Moog Inc.

  • Pilot Pressure (X): 21–280 bar (internal P or external X)

  • T Port Pressure (Y internal): 210 bar; (Y external): 350 barMoog Inc.

  • Fluid: Mineral oil (DIN 51524), viscosity 15–45 mm²/s

  • Temperature: Ambient −20°C to +60°C; Fluid −20°C to +80°C

  • Weight: Approx. 5.8–6.0 kg

Electrical Parameters

  • Supply: 24 VDC (18–32 VDC), quiescent 230 mA, dynamic ~500 mAMoog Inc.

  • Command Signal: ±10 VDC (differential, 10 kΩ impedance) or 4–20 mAMoog Inc.

  • Feedback Signal: 4–20 mA (single LVDT spool position, ±0.02% FS accuracy)

  • Connector: 6+PE (EN 175201‑804, IP65)Moog Inc.

  • Step Response (0→100%): 7–9 ms @ 210 bar (high dynamics for 100 L/min)

  • Hysteresis: <0.25% (closed‑loop)

  • Linearity: <±0.30%

  • Resolution: <0.05%

Interface & Communication Configuration

  • Electrical: 6+PE connector; ±10 V command, 24 VDC power, 4–20 mA LVDT feedbackMoog Inc.

  • Feedback: Single integrated LVDT (full‑stroke closed‑loop, high accuracy)

  • Ports: P, A, B, T; optional external X (pilot) and Y (return)

  • Seal Material: NBR (standard) or FKM (optional, high‑temperature)

Core Functions

  1. 100 L/min Medium‑High Flow: Balanced flow for precision applications needing stable high throughput

  2. High‑Dynamic Response: 7–9 ms step response, robust for 100 L/min duty cycles

  3. Reliable Closed‑Loop Control: Tight LVDT feedback with low hysteresis for consistent positioning

  4. ServoJet® Pilot: Jet‑pipe design reduces energy use, improves contamination resistance, and lowers null shift

  5. Integrated Digital Amplifier: On‑board PID, ramp generator, fault diagnostics, and EMC protection

Applicable Scenarios

  • General Precision Metal Forming: Stamping, blanking, and standard injection molding (stable response prioritized)

  • Industrial Test Systems: Vibration tables, fatigue test rigs, and automotive component testing (reliable dynamics required)

  • Machine Tool Hydraulics: CNC machine positioning, press brakes, and general precision machining centers

  • Industrial Automation: Closed‑loop position/velocity control requiring good accuracy and cost‑effective dynamics

Compatibility & Installation Notes

  • Mechanical: Interchangeable with D661 (G/C/A), D662/D663 (ISO 4401‑05)

  • Upgrade: Drop‑in replacement for D661‑4572C/4573C when standard high dynamics suffice

  • System Requirements: 24 VDC supply, analog controller (±10 V in / 4–20 mA out), ISO 4401‑05 manifoldMoog Inc.

Usage & Maintenance Instructions

  1. Installation: Mount on flat surface (flatness ≤0.02 mm/100 mm; Ra <1 μm) with M6×55/60 bolts (13 Nm, diagonal)

  2. Fluid: ISO VG 32–46, NAS 1638 cleanliness class ≤8

  3. Maintenance: Replace internal filter every 5,000 hours; inspect leaks/connectors periodically

  4. Precautions: Avoid voltage spikes/reverse polarity; do not open standard (C) models in field


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