1. General Information

1.1 Description

1.2 Model Code

• D633: Series (ISO 4401 Size 03 / NG6)Moog Inc.

• Z7397: Specific configuration (coil, feedback, seals, etc.)

1.3 Intended Use

• Industrial hydraulic systems

• Closed‑loop position, velocity, pressure, or force control

• Applications requiring high dynamic response and accuracy

1.4 Safety Notes

• Read this manual before installation and operation.

• Only qualified personnel should install, commission, or service the valve.

• Maximum pressure: 350 bar – do not exceed system pressure ratingsMoog Inc..

• Disconnect power and relieve hydraulic pressure before maintenance.

2. Technical Specifications

2.1 Hydraulic Data

• Size: ISO 4401 Size 03 (NG6)Moog Inc.

• Max Operating Pressure:

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

  • T port (without Y): 50 bar (725 psi)Moog Inc.

  • T port (with Y): 350 bar (5,000 psi)Moog Inc.

• Rated Flow: 10–40 L/min (at ΔP = 70 bar)

• Leakage: ≤ 0.5 L/min (max)

• Fluid Compatibility:

  • Mineral oils (ISO 11158)

  • Viscosity: 5–400 mm²/s (recommended: 15–100 mm²/s)

  • Temperature: −20 °C to +80 °C

  • Cleanliness: ISO 4406 18/15/12 minimum (17/14/11 recommended)

2.2 Performance Data

• Response Time: 12 ms (0→100% step, typical)Moog Inc.

• Hysteresis: < 0.5% of full scale

• Threshold: < 0.1% of full scale

• Null Shift: < 2% (ΔT = 55 K)

2.3 Electrical Data

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

• Command Signal (selectable):

  • ±10 V (voltage)

  • ±10 mA (current)

  • 4–20 mA (current)Moog Inc.

• Connector: 6+PE (M18)Moog Inc.

• Protection Class: IP65

• Operating Temperature: −20 °C to +60 °C (ambient)

3. Functional Description

1. A command signal (voltage or current) is applied to the valve’s electronics.

2. The electronics drive a permanent magnet linear force motor, which moves the spool from its spring‑centered position.

3. An LVDT (Linear Variable Differential Transformer) measures the spool position and feeds it back to the integrated controller.

4. The electronics compare the command signal with the feedback signal and adjust the motor drive to achieve precise spool positioning.

5. Spool displacement controls flow direction and magnitude to the hydraulic actuator.

4. Installation

4.1 Mechanical Mounting

• Mount the valve on a clean, flat surface conforming to ISO 4401 Size 03.

• Use appropriate O‑rings (supplied) for port sealing.

• Torque mounting bolts to manufacturer’s specifications (typically 8–10 Nm).

• Ensure no mechanical stress or misalignment.

4.2 Hydraulic Connection

• Connect P (pressure), T (tank), A, and B (work ports) correctly.

• If using external drain, connect Y port to low‑pressure return (<50 bar).

• Flush the hydraulic system before installing the valve to achieve ISO 4406 15/12 cleanliness or better.

4.3 Electrical Connection

• Use shielded cable for command signals (twisted pair recommended).

• Connect power (24 VDC), ground (PE), and signal wires per pinout:

  • Pin 1: +24 VDC

  • Pin 2: 0 VDC (GND)

  • Pin 3: Command signal (+)

  • Pin 4: Command signal (−)

  • Pin 5: Enable (optional)

  • Pin 6: Monitor (optional)

  • PE: Protective earth

• Ensure proper shielding and grounding to avoid electrical noise.

5. Commissioning

1. Pre‑start Check:

   • All connections tight and correct.

   • Hydraulic fluid at correct level and temperature.

   • Power supply voltage within 18–32 VDC.

2. Power‑up:

   • Apply 24 VDC power.

   • Valve initializes; LVDT performs self‑check.

3. Signal Configuration:

   • Select command signal type (±10 V, ±10 mA, or 4–20 mA) via internal jumper or software (if applicable).

   • Verify signal range and polarity.

4. Null Adjustment (if required):

   • With zero command signal, adjust null potentiometer (if equipped) for minimal leakage.

5. Performance Test:

   • Apply step commands (e.g., 10%, 50%, 100%).

   • Verify smooth response, no oscillation, and correct flow direction.

6. Operation

• Command Signal:

  • 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.

• Monitoring:

  • Use monitor pin (if available) to read spool position feedback.

  • Check for abnormal noise, heat, or leakage.

7. Maintenance

7.1 Regular Inspection

• Check for external leakage.

• Verify electrical connections and cable condition.

• Monitor fluid cleanliness; replace filters as needed.

7.2 Filter Replacement

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

7.3 Seal Replacement

• If leakage occurs at ports or motor plug, replace O‑rings with genuine MOOG parts.

7.4 Storage

• Store valve in clean, dry environment.

• Seal all ports with protective caps.

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