1. General Description

2. Model Code (D634-326C)

• D634: Series = Direct Drive Servo Valve, ISO 4401 Size 05 (NG10)

• 326: Base configuration (100 L/min, optimized spool, 24 VDC electronics)

• C: Revision C (latest baseline version)

3. Hydraulic Specifications

• Mounting: ISO 4401 Size 05 (NG10)

• Max Working Pressure (P, A, B): 350 bar (5,000 psi)

• T‑Port Pressure (no Y port): 50 bar (725 psi)Moog Inc.

• Rated Flow (Δp = 35 bar/land): 100 L/min (26.4 gpm)

• Max Flow: ≈180 L/min (47.6 gpm)

• Internal Leakage: ≤1.5 L/min

• Fluid: Mineral oil (ISO 11158 / DIN 51524)

• Fluid Temperature: −20 °C to +80 °C

• Filtration: ISO 4406 17/14/11

• Weight: ≈6.3 kg (13.9 lb)

4. Dynamic Performance (Typical)

• Step Response (0→100% stroke): ≤20 msMoog Inc.

• −3 dB Bandwidth: 45–55 Hz

• Hysteresis: <0.2% FS

• Resolution: <0.1% FS

• Null Drift (ΔT = 55 K): <1.5% FS

5. Electrical Specifications (Standard)

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

• Max Current: 3.5 A

• Control Signal: ±10 V (standard); optional ±10 mA / 4–20 mAMoog Inc.

• Spool Position Feedback: 0–10 VDC

• Connector: M18, 6+PE pins, IP65Moog Inc.

• Ambient Temperature: −20 °C to +60 °C

• EMC: CE Compliant

6. Key Features

• No pilot oil needed: Simplifies installation and maintenance

• High precision: Closed‑loop LVDT control for linearity and repeatability

• Pressure‑independent dynamics: Stable performance under varying loads

• Fail‑safe: Spring‑centered design returns spool to neutral on power loss

• Integrated PWM electronics: Compact, reliable, energy‑efficient

7. Applications

• Medium‑to‑high flow hydraulic presses

• Dynamic material testing machines

• Industrial motion control systems

• Closed‑loop position, speed, and pressure control systems

8. Pin Assignment (6+PE Connector)

1. +24 VDC Power

2. Power Ground

3. Command Signal (+)

4. Command Signal (−)

5. Spool Position Feedback Output

6. Feedback Ground

   PE: Protective Earth

   Wiring: Use shielded twisted‑pair cables for signals.