Model Code Explanation (D661-4081)

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

• 4: Flow rating code (ultra‑high‑flow platform)

• 08: Spool/pressure/heavy‑duty base code

• 1: Industrial heavy‑duty, standard fail‑safe, maximum contamination resistance

Technical Specifications

Hydraulic

• Nominal Flow (Δp = 35 bar): 250 L/min (±10%)

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

• Pilot Pressure (X): 21–210 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/s; maximum contamination tolerance

• Temperature: Ambient −20°C to +65°C; Fluid −20°C to +85°C (extended range)

• Weight: Approx. 6.3 kg

Electrical

• Supply: 24 VDC (18–32 VDC), quiescent 250 mA, dynamic 420 mAMoog Inc.

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

• Feedback Signal: 4–20 mA (single LVDT spool position, ±0.025% FS accuracy)

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

• Step Response (0→100%): ≤18 ms @ 210 bar (heavy‑duty tuned for stability)Moog Inc.

• Hysteresis: <0.25% (closed‑loop)

• Linearity: <±0.3%

• Resolution: <0.12%

Interface & Communication

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

• Feedback: Single integrated LVDT (full‑stroke closed‑loop, fault‑monitoring capable)

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

Key Features

• Ultra‑High Flow: 250 L/min nominal for large‑scale hydraulic systems

• Max Contamination Resistance: 4× higher than standard ServoJet models; ideal for dirty fluids

• Heavy‑Duty Ruggedization: Conformal coating, vibration‑hardened components, extended temp range

• Low Null Leakage: <15 ml/min, energy‑efficient for 24/7 operations

• Standard Fail‑Safe: Spring‑centers on power loss/fault; high‑pressure Y port ratingMoog Inc.

Applications

• Heavy industrial automation (large forging presses, steel mill rolling stands)

• High‑contamination test benches (industrial simulators, long‑duration endurance testing)

• Metallurgy (roughing mill gap control, high‑temperature tension systems)

• Heavy machinery (mining equipment, waste compactors, large injection molding machines)

• Energy (large hydraulic control systems, turbine auxiliary systems)

Compatibility

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

• Drop‑in upgrade for D633/D634 and lower‑flow D661 models (4051/4055/4059/4060/4061/4069/4070/4072/4077)

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