Model Explanation (D661-4023)

D661: Series Code (ISO 4401-05, Integrated 24VDC Electronics)

4: Flow Grade Code (High Flow)

02: Valve Core / Pressure / Configuration Combination Code

3: Electrical / Feedback Variant (Command ±10 V; Feedback 4–20 mA) Technical Specifications

Part Number: D661-4023

Valve Specification: ISO 4401-05 (CETOP 05), bore Ø6 mm

Control Function: Four-way three-position, spring centered, zero cover, closed-loop position / flow / pressure control

Rated Flow (Δp = 35 bar): 80 L/min (±10%)

Maximum Working Pressure (P/A/B): 350 bar (Moog Inc.)

Pilot Pressure: 21–210 bar (internal P or external X for oil supply); Moog Inc. T port pressure: 210 bar (internal Y return oil); 350 bar (external Y return oil); Moog Inc.

Response Time (0→100%): ≤12 ms

Hysteresis: <0.2% (closed-loop)

Linearity: <±0.25%

Resolution: <0.1%

Electrical:

Power Supply: 24 VDC (18–32 VDC), static 200 mA, dynamic 350 mA; Moog Inc.

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

Feedback Signal: 4–20 mA (LVDT valve core position); Moog Inc.

Connector: 6+PE (EN 175201-804); Moog Inc. Protection Level: IP65 (connected state)

Hydraulic Oil: Mineral oil (DIN 51524), viscosity 15–45 mm²/s

Temperature:

Environment: -20°C ~ +60°C

Oil: -20°C ~ +80°C

Weight: Approximately 5.7 kg

Sealing: Standard NBR; optional FPM (fluorine rubber); Moog Inc.

Interface and Communication

Electrical Interface: 6+PE connector; analog command ±10 V, 24 VDC power supply, position feedback 4–20 mA; Moog Inc.

Feedback: Integrated LVDT valve core position sensor (full travel closed-loop)

Installation: 4-hole ISO 4401-05 installation (M5 screws, torque 8 Nm); Moog Inc.

Oil Ports: P, A, B, T; optional external Y return oil (T > 210 bar); Moog Inc. Core feature

ServoJet Preamplifier: Anti-pollution, low leakage (<15 ml/min), long lifespan

Integrated closed-loop electronics: On-board PID, high accuracy and repeatability

High dynamic response: ≤12 ms step response, suitable for high-speed and high-precision working conditions

Low zero-point leakage: Energy-saving, suitable for long-term pressurized / standby systems

Fault safety design: Valve core alignment in case of power failure / fault; customizable safety position Moog Inc. Application scenario

Industrial Automation: High-precision machine tools, CNC machining centers, robot hydraulic systems

Testing Equipment: Material testing machines, fatigue test benches, hydraulic simulation platforms

Metallurgy: Roll gap control, tension control system

Aerospace: Ground simulation equipment, flight test benches

Compatibility

Series Compatibility: Can be interchanged with D661 (G/C/A type), D662/D663 (ISO 4401-05) Moog Inc.

Upgrade Replacement: Directly replace the old D633/D634 servo valves to enhance dynamic performance

System Requirements: 24 VDC power supply, analog quantity controller (±10 V input / 4–20 mA output), ISO 4401-05 standard valve block