1. General Description

2. Ordering Code (D634‑524A)

• D634: Series, ISO 4401‑05 (NG10)

• 524: High‑flow core model

• A: Standard electronics, ±10 V control signal

3. Basic Data

• Brand: MOOG

• Model: D634-524A

• Type: Pilotless electro‑hydraulic direct‑drive servo valve (DDV)

• Mounting: ISO 4401‑05 (NG10)

• Actuation: Permanent magnet linear force motor (no pilot oil)

• Power Supply: 24 VDC (18–32 VDC), max 2.2 A

• Feedback: Integrated LVDT spool position closed‑loop

• Centering: Spring‑centered; fail‑safe neutral on power loss

• Protection: IP65

• Weight: ~6.5 kg

• Connector: M18 6‑pin + PE

4. Hydraulic Specifications

• Max working pressure (P/A/B): 350 bar

• Max T‑port pressure: ≤50 bar (internal drain)

• Rated flow (Δp=35 bar): 100 L/min

• Peak flow: ~160 L/min

• Null leakage: 0.3–2.0 L/min

• Fluid: ISO 11158 mineral oil

• Fluid temperature: –20 °C to 80 °C

• Cleanliness: ISO 4406 17/14/11

5. Dynamic Performance

• Full‑stroke step response: ≤20 ms

• –3 dB bandwidth: 50–70 Hz

• Hysteresis: <0.2% full scale

• Resolution: <0.08% full scale

• Temperature drift: <1.2% full scale

6. Electrical Data

• Standard control signal: ±10 VDC

• Optional signals: ±10 mA, 4–20 mA

• Spool position feedback: 0–10 VDC

• Ambient temperature: –20 °C to 60 °C

• Certification: CE compliant

7. Key Features

• No pilot oil: Higher reliability, lower contamination risk

• Integrated closed‑loop: LVDT feedback ensures high accuracy and repeatability

• Pressure‑independent dynamics: Stable response under varying load pressures

• 24 VDC PWM electronics: Energy‑efficient, low power at null

• Fail‑safe design: Spring return to neutral on power loss

8. Applications

• High‑tonnage hydraulic presses & forging equipment

• Large injection molding & die‑casting machines

• High‑force vibration test benches

• Heavy‑duty industrial hydraulic systems

• High‑flow closed‑loop position/velocity/pressure control