Model Definition

• D661 = Series (integrated electronics, 24 VDC, NG10)

• 4651 = Spool/sleeve assembly; rated flow 30 L/min @ ΔP=35 bar

• G35JOAA6VSX2HA = Configuration code breakdown:

  • G = Standard spool, ServoJet® pilot

  • 35 = Frequency response class (≥120 Hz)

  • J = 24 VDC supply, analog ±10 V/±10 mA

  • O = Null position: centered (fail‑safe)

  • AA = Electrical & hydraulic base configuration

  • 6 = 6+PE connector, IP65

  • VSX2HA = LVDT feedback (4–20 mA), high‑response seals, industrial temperature range.

Technical Specifications

Hydraulic

• Rated flow: 30 L/min (ΔP=35 bar)

• Max working pressure: 350 bar (P/A/B); T‑port 210 bar (internal drain) / 350 bar (external drain)Moog Inc.

• Step response: 6.5–14 ms (0→100%, 210 bar)

• Hysteresis: <0.2%

• Resolution: <0.1%

• Null drift: <1.5% (ΔT=55 K)

• Null leakage: <8 mL/min

Electrical

• Power supply: 24 VDC (18–32 VDC)

• Control signal: ±10 V or ±10 mA

• Feedback signal: 4–20 mA (LVDT spool position)

• Connector: 6+PE, IP65

• Current draw: ≤300 mA

Physical & Environmental

• Operating temperature: −40 ℃ to +85 ℃

• Weight: approx. 5.1 kg

• Fluid cleanliness: NAS 1638 Class 6 / ISO 4406 18/15

Interface & Communication

• Hydraulic: P/A/B/T, ISO 4401‑05 (NG10)

• Electrical:

  • Power: 24 VDC, GND, PE

  • Command: ±10 V (diff) or ±10 mA

  • Feedback: 4–20 mA (spool position)

  • Alarm: Fault/status output

Core Features

• ServoJet® pilot: Superior contamination resistance, low drift, long life

• Integrated closed‑loop amplifier: PID, dead‑zone compensation, overload protection

• LVDT position feedback: High linearity & precision across full stroke

• Fail‑Safe: Spool returns to center on power loss

• G35 high‑response: ≥120 Hz bandwidth for dynamic applications

Application Scenarios

• Metallurgy: AGC roll gap, tension control (medium flow)

• Test equipment: Material testers, fatigue rigs, small vibration tables

• Industrial automation: Precision machine tools, injection molding, hydraulic presses

• Energy & heavy industry: Wind turbine pitch control, shield machine auxiliaries, marine steering

Usage & Maintenance

• Installation: Horizontal/vertical; avoid heavy vibration

• Fluid: ISO VG46 mineral oil, cleanliness NAS 1638‑6 or better

• Commissioning: 24 VDC power; apply ±10 V/±10 mA command; tune zero/gain via 4–20 mA feedback

• Maintenance: Check fluid contamination regularly; calibrate zero/gain every 6 months; avoid long idle periods at high pressure