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D634-1009

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D634-1009
May 25, 2026

D634-1009

The D634‑1009 is a high‑precision, single‑stage direct‑drive servo valve in the MOOG D634 series, designed for closed‑loop electro‑hydraulic control. It uses a permanent magnet linear force motor to drive the spool directly, with integrated LVDT spool position feedback and 24 VDC PWM electronics. Mounting complies with ISO 4401 Size 05 (NG10). Delivers precise, pressure‑independent flow, direction, and pressure control for demanding industrial machinery.

Description

1. General Information

1.1 Description

The D634‑1009 is a high‑precision, single‑stage direct‑drive servo valve in the MOOG D634 series, designed for closed‑loop electro‑hydraulic control. It uses a permanent magnet linear force motor to drive the spool directly, with integrated LVDT spool position feedback and 24 VDC PWM electronics. Mounting complies with ISO 4401 Size 05 (NG10). Delivers precise, pressure‑independent flow, direction, and pressure control for demanding industrial machinery.

1.2 Model Definition

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

  • 1009: Suffix defines coil parameters, LVDT range, seal material, electronic gain/offset, and performance tuning (1009: highest dynamic response, ultra‑low null drift, optimized for high‑speed 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 actuatorsMoog Inc..

  • Low hysteresis & high resolution: hysteresis <0.5%, resolution <0.1% full scaleMoog Inc..

  • 1009 specific: Fastest step response in D634 series, minimal null shift, ultra‑stable at high frequencies.

1.4 Intended Applications

High‑speed injection molding, blow molding, die‑casting, hydraulic presses, metal forming, fatigue test rigs, and general industrial servo‑hydraulic systems requiring maximum dynamic performance and reliability.

2. Technical Specifications

2.1 Hydraulic Data

  • Mounting: ISO 4401 Size 05 (NG10).

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

  • 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: ≤0.5 L/min (1009, 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 8–12 ms (1009); faster than 1007/1008Moog Inc..

  • Hysteresis: <0.5% full scaleMoog Inc..

  • Threshold (resolution): <0.1% full scaleMoog Inc..

  • Null shift (ΔT = 55 K): <1.0% (1009, best‑in‑class).

  • Frequency response (−3 dB): ≥100 Hz (1009); higher than 1007/1008Moog Inc..

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

An analog command signal (±10 V, ±10 mA, or 4–20 mA) goes to the valve’s integrated electronics. The electronics drive a permanent magnet linear force motor to move the spool from spring‑centered neutral. An LVDT measures spool position and feeds it back to the control electronics. The electronics compare command and feedback, adjusting motor drive for precise spool positioning. Spool displacement regulates flow direction (A→B or B→A) and magnitude to the hydraulic actuator.

4. Installation & Wiring

4.1 Mechanical Mounting

Mount on a clean, flat surface per ISO 4401 Size 05. Use supplied O‑rings for port sealing. Torque M8 mounting bolts to 8–10 Nm. Avoid mechanical stress, misalignment, or impact during installation.

4.2 Hydraulic Connections

  • P: Pressure supply

  • T: Tank return

  • A/B: Work ports

  • Y: Optional external drain

Flush system to ISO 4406 17/14/11 before installation. Route Y port directly to tank (no backpressure) if used.

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

Use shielded twisted‑pair cables for signals. Connect shield to 0 V (power supply side) and connector housing (EMC).

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: D634‑1009

  • 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: Fastest response, lowest leakage, minimal null drift in D634 series


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