1. General Information

1.1 Description

1.2 Model Definition

• D634: ISO 4401 Size 05, direct‑drive, integrated 24 VDC electronics, analog interface servo valve.

• 1010: Suffix defines coil parameters, LVDT range, seal material, electronic gain/offset, and performance tuning (1010: optimized for ultra‑low noise, exceptional long‑term stability, and minimal thermal drift; targeted at precision closed‑loop control).

1.3 Key Features

• Single‑stage direct drive: no pilot supply needed, better contamination tolerance, simpler system.

• Pressure‑independent dynamics: consistent response at any system pressure.

• Integrated EMC‑compliant 24 VDC electronics: reduces external components, simplifies installation.

• Spring‑centered fail‑safe: spool returns to neutral on power loss, stopping actuators.

• Low hysteresis & high resolution: hysteresis <0.3%, resolution <0.08% full scale (best‑in‑class).

• 1010 specific: Ultra‑low electrical noise, minimal thermal null shift, enhanced long‑term stability for precision applications.

1.4 Intended Applications

2. Technical Specifications

2.1 Hydraulic Data

• Mounting: ISO 4401 Size 05 (NG10).

• Max operating pressure (P, A, B): 350 bar (5,000 psi).

• Port T pressure: 50 bar (725 psi) without Y port; 350 bar (5,000 psi) with Y portMoog Inc..

• Rated flow (Δp = 35 bar per land): 60–100 L/min (15.9–26.4 gpm).

• Maximum flow: approx 185 L/min (48.8 gpm).

• Internal leakage: ≤0.4 L/min (1010, lowest in D634 series).

• Operating fluid: mineral oil per ISO 11158 / DIN 51524 parts 1–3.

• Recommended viscosity: 15–100 mm²/s; allowable 5–400 mm²/s.

• Fluid temperature: −20 °C to +80 °C.

• Fluid cleanliness: ISO 4406 18/15/12 min; 17/14/11 recommended.

2.2 Performance Data

• Step response (0–100% stroke): typically 9–13 ms (1010).

• Hysteresis: <0.3% full scale (improved vs 1009 <0.5%).

• Threshold (resolution): <0.08% full scale (improved vs 1009 <0.1%).

• Null shift (ΔT = 55 K): <0.8% (1010, best‑in‑class).

• Frequency response (−3 dB): ≥105 Hz (1010); higher than 1009 (≥100 Hz).

2.3 Electrical Data

• Supply voltage: 24 VDC (operating range 18–32 VDC)Moog Inc..

• Max current consumption: 2.2 A.

• Recommended fuse: 2.5 A slow‑blow (external).

• Command signal options: ±10 V, ±10 mA, 4–20 mA (selectable via internal jumper)Moog Inc..

• Input impedance: >100 kΩ (voltage); 50 Ω (current).

• Spool position monitor: 0–10 VDC output (standard).

• Connector: 6+PE (M18), IP65Moog Inc..

• Ambient temperature: −20 °C to +60 °C.

3. Functional Principle

4. Installation & Wiring

4.1 Mechanical Mounting

4.2 Hydraulic Connections

• P: Pressure supply

• T: Tank return

• A/B: Work ports

• Y: Optional external drain

4.3 Electrical Wiring (6+PE Connector)

• Pin 1: +24 VDC

• Pin 2: 0 VDC (GND)

• Pin 3: Command (+)

• Pin 4: Command (−)

• Pin 5: Enable (optional)

• Pin 6: Spool position monitor

• PE: Protective earth

5. Commissioning

1. Verify mechanical, hydraulic, and electrical connections before power‑up.

2. Confirm fluid level and supply voltage (18–32 VDC).

3. Apply 24 VDC power; valve initializes and performs LVDT self‑test.

4. Select command signal type via internal jumper.

5. With zero command, adjust null potentiometer for minimum leakage.

6. Apply 10%, 50%, 100% step commands to verify smooth response, correct direction, and stability.

6. Operation

• 0 V / 0 mA / 12 mA: spool centered, no flow.

• +10 V / +10 mA / 20 mA: full flow A→B.

• −10 V / −10 mA / 4 mA: full flow B→A.

• Monitor pin: 0–10 VDC proportional to spool stroke (diagnostics).

7. Maintenance & Troubleshooting

7.1 Maintenance

• Monthly: inspect for external leakage and loose connections.

• Replace filters regularly to maintain ISO 4406 18/15/12 cleanliness.

• Use genuine MOOG O‑rings for seals.

• Do not disassemble internal components; contact MOOG or authorized service centers for repair.

7.2 Troubleshooting

• No response: check 24 VDC power, wiring, and command signal.

• Slow response: verify system pressure, fluid viscosity, and filtration.

• Oscillation/instability: improve shielding, adjust controller gains, check grounding.

• External leakage: replace worn O‑rings with genuine MOOG parts.

8. Ordering Information

• Model: D634‑1010

• Series: D634 (Direct Drive Servo Valve)

• Mounting: ISO 4401 Size 05 (NG10)

• Electronics: 24 VDC integrated, analog interface

• Feedback: LVDT closed‑loop spool position control

• Key Differentiator: Ultra‑low noise, minimal thermal drift, highest stability & resolution in D634 series