Model Code Explanation (D661-4061)

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

• 4: Flow rating code (high flow)

• 06: Spool/pressure/configuration base code

• 1: Electrical/feedback & enhanced fail‑safe variant

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)

• 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. 6.0 kg

Electrical

• Supply: 24 VDC (18–32 VDC), quiescent 220 mA, dynamic 380 mAMoog Inc.

• Command Signal: ±10 V differential (10 kΩ impedance)Moog Inc.

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

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

• Step Response (0→100%): ≤15 ms @ 210 bar

• Hysteresis: <0.2% (closed‑loop)

• Linearity: <±0.25%

• Resolution: <0.1%

Interface & Communication

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

• Feedback: Integrated LVDT (full‑stroke closed‑loop control)

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

Key Features

• ServoJet® Pilot: Contamination‑resistant, low leakage (<15 ml/min), long service life

• Integrated Closed‑Loop Electronics: On‑board PID, high accuracy & repeatability

• High‑Flow Design: 250 L/min nominal for high‑capacity hydraulic systems

• Enhanced Fail‑Safe: Spring‑centers on power loss/fault; improved fault detection

• Low Null Leakage: Energy‑efficient for pressure‑holding/standby systems

Applications

• Heavy‑duty industrial automation (large CNC, press lines, steel mills)

• High‑flow test equipment (hydraulic simulators, fatigue test benches)

• Metallurgy (large roll gap, tension control, slab caster systems)

• Aerospace (ground simulation, large flight test benches)

Compatibility

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

• Drop‑in upgrade for high‑flow D633/D634 servovalves

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