Model Code Explanation (D661-4168)

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

4: High‑flow platform

16: 160 L/min nominal flow rating

8: Ultra‑high‑dynamic, single‑feedback, maximum‑response base

(No suffix): Standard electronics, premium null stability

Technical Specifications

Part Number: D661-4168

Mounting: ISO 4401‑05 (NG10), 4‑hole, M5 screws (torque 8 Nm)

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

Hydraulic

Nominal Flow (Δp = 35 bar): 160 L/min (±8%)Moog Inc.

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

Pilot Pressure (X): 21–280 bar (internal P or external X)Moog Inc.

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

Fluid: Mineral oil (DIN 51524), viscosity 15–45 mm²/sMoog Inc.

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

Weight: Approx. 5.8–6.0 kg

Electrical

Supply: 24 VDC (18–32 VDC), quiescent 230 mA, dynamic 480 mAMoog Inc.

Command Signal: ±10 V differential (10 kΩ impedance); optional ±10 mAMoog Inc.

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

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

Step Response (0→100%): ≤10 ms @ 210 bar (faster than 4158B)

Hysteresis: <0.20% (closed‑loop)Moog Inc.

Linearity: <±0.25%Moog Inc.

Resolution: <0.08%Moog Inc.

Interface & Communication

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

Feedback: Single integrated LVDT (full‑stroke closed‑loop, high‑accuracy for 160 L/min flow)Moog Inc.

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

Key Features

160 L/min Nominal Flow: Higher flow than 4157B/4158B for larger hydraulic systemsMoog Inc.

Ultra‑High‑Dynamic Response: 10 ms step response for critical high‑speed control

High‑Pressure Rated: 350 bar max working pressure for extreme‑duty applicationsMoog Inc.

Premium Null Stability: Enhanced null shift performance for long‑term precisionMoog Inc.

Single‑LVDT Precision: Reliable closed‑loop feedback for consistent accuracy at high flowMoog Inc.

Applications

Extreme‑dynamic test benches (high‑frequency fatigue testing, aerospace component simulation)

Heavy‑duty industrial automation (large forging presses, heavy steel rolling mills)

Metallurgy (high‑precision roll gap control, high‑tension systems)

Heavy machinery (mining excavators, high‑tonnage die‑casting, large injection molding)

Energy (high‑flow hydraulic control, turbine governing systems)

Compatibility

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

Drop‑in upgrade for D661‑4158B (higher flow, faster response) and 4157B/4125E/4099

Requires 24 VDC supply, analog controller (±10 V in / 4–20 mA out), ISO 4401‑05 manifold