MOOG D661-4443C Servo‑Proportional Valve
May 28, 2026

MOOG D661-4443C Servo‑Proportional Valve

Product Overview Model: D661-4443C Type: Two‑stage, 4‑way/3‑position, ServoJet® pilot, integrated 24 VDC electronics, high‑flow industrial servovalve Manufacturer: MOOG Series: D661‑G…C (ISO 4401‑05/NG10, 24 VDC integrated electronics, standard T‑port) Description: High‑flow, medium‑response servo valve with high‑stability electronics, designed for closed‑loop hydraulic control requiring good flow capacity and reliable null performance.

Description

Model Code Explanation (D661-4443C)

D661: Series (ISO 4401‑05, 24 VDC integrated electronics, bushing‑type spool)

4: High‑flow platform

44: 440 L/min nominal flow (Δp=35 bar)

3: Medium dynamics (≈10–12 ms step response)

C: High‑stability electronics, enhanced null performance, low drift

(Implied G): Standard zero‑lap spool, linear flow characteristic

Technical Specifications

Part Number: D661-4443C

Mounting: ISO 4401‑05 (NG10), 4‑hole M5, standard T‑port

Control Function: 4‑way/3‑position, spring‑centered, zero‑lap, closed‑loop

Hydraulic

Nominal Flow (Δp=35 bar): 440 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), NBR seals (−20 °C to +80 °C)

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

Weight: Approx. 5.7 kg

Electrical

Supply: 24 VDC (18–32 VDC), quiescent ≈230 mA, dynamic ≈500 mA

Command Signal: ±10 V differential (10 kΩ impedance)

Feedback Signal: Optional 4–20 mA (integrated LVDT, ±0.02% FS accuracy)Moog Inc.

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

Step Response (0→100%): ≤10–12 ms @ 210 barMoog Inc.

Hysteresis: <0.25% (closed‑loop)

Linearity: <±0.30%

Resolution: <0.10%

Interface & Communication

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

Feedback: Single integrated LVDT (full‑stroke closed‑loop, optional)

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

Key Features

440 L/min High Flow: Slightly higher than 430 L/min models for larger system demands

10–12 ms Medium Dynamics: Stable, predictable response for general high‑flow applications

C‑Code High‑Stability Electronics: Excellent null stability, minimal drift, long‑term accuracy

ServoJet® Pilot: Low hysteresis, robust pressure gain, proven reliabilityMoog Inc.

±10 V Analog Interface: Wide compatibility with industrial controllers

Applications

Large‑scale hydraulic forging presses

High‑flow injection molding & die‑casting machines

Steel rolling mills & heavy‑duty industrial test benches

Closed‑loop systems (position/velocity/pressure control)

Hydraulic machinery prioritizing flow and stability over fast response

Compatibility

Interchangeable with D661‑4436C/4438E/4439C (same ISO 4401‑05 footprint)

Requires 24 VDC supply, ±10 V controller, ISO 4401‑05 manifold

Drop‑in upgrade for lower‑flow D661‑4209/4196


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