Model Code Explanation (D661-4479C)

• D661: Series (ISO 4401‑05 mounting, integrated 24 VDC electronics)Moog Inc.

• 4: 4‑way, zero‑lap, linear flow characteristic

• 47: Rated flow ≈ 60 L/min (Δp = 35 bar per land)

• 9: High‑dynamic response, single LVDT feedback

• C: Standard performance, non‑explosion‑proof, premium null stability

Technical Specifications

Part Number: D661-4479C

Mounting

Control Function

Hydraulic Parameters

• Rated Flow (Δp = 35 bar): 60 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)Moog Inc.

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

• Fluid: Mineral oil (DIN 51524), viscosity 15–45 mm²/s

• Temperature: Ambient −40°C to +85°C; Fluid −20°C to +80°C

• Weight: Approx. 5.7–5.9 kg

Electrical Parameters

• Supply: 24 VDC (18–32 VDC), quiescent 230 mA, dynamic ~500 mAMoog Inc.

• Command Signal: ±10 VDC (differential, 10 kΩ impedance) or 4–20 mAMoog Inc.

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

• Connector: 11‑pin + PE (EN 175201‑804, IP65)

• Step Response (0→100%): 6.5–10 ms @ 210 bar (high dynamics)

• Hysteresis: <3% (typical, closed‑loop)

• Linearity: <±0.25%

• Resolution: <0.10%

Interface & Communication Configuration

• Electrical: 11‑pin + PE connector; ±10 V command, 24 VDC power, 4–20 mA LVDT feedback

• Feedback: Single integrated LVDT (full‑stroke closed‑loop, high accuracy)

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

• Seal Material: NBR (standard) or FKM (optional, high‑temperature)

Core Functions

1. 60 L/min Precision Flow: Zero‑lap spool for linear flow gain, minimal dead band, low null leakage (<15 mL/min)

2. High‑Dynamic Response: 6.5–10 ms step response for fast, accurate positioning

3. Closed‑Loop Spool Control: Integrated LVDT ensures real‑time position feedback and consistent precision

4. ServoJet® Pilot: Jet‑pipe design reduces energy use, improves contamination resistance, and lowers hysteresisMoog Inc.

5. Integrated Digital Amplifier: On‑board PID, ramp generator, fault diagnostics, and EMC protection

6. Fail‑Safe Customization: Configurable spool position on power loss (centered/blocked)

Applicable Scenarios

• Metal Forming: Injection molding, die‑casting, stamping presses (medium flow, high precision)Moog Inc.

• Heavy Machinery: Steel mill roll gap control, hydraulic presses, material handlingMoog Inc.

• Test Systems: Aerospace component testing, vibration simulation tables

• Industrial Automation: High‑speed positioning, force control, and closed‑loop hydraulic systems

Compatibility & Installation Notes

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

• Upgrade: Drop‑in replacement for lower‑flow D661‑4xxx models (e.g., 4195/4187)

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

Usage & Maintenance Instructions

1. Installation: Mount on flat surface (flatness ≤0.02 mm/100 mm; Ra <1 μm) with M6×55/60 bolts (13 Nm, diagonal)

2. Fluid: ISO VG 32–46, NAS 1638 cleanliness class ≤8

3. Maintenance: Replace internal filter every 5,000 hours; inspect leaks/connectors periodically

4. Precautions: Avoid voltage spikes/reverse polarity; do not open standard (C) models in field