1. General Description

2. Model Definition

• D634: Direct drive servo valve series

• 385: Maximum‑flow, high‑response configuration

• C: Revision C

3. Hydraulic Specifications

• Mounting: ISO 4401 Size 05 (NG10)

• Max working pressure (P, A, B): 350 bar穆格中国

• Max T‑port pressure (without Y): 50 bar穆格中国

• Rated flow (Δp = 35 bar): 150 L/min

• Max flow: approx 220 L/min

• Internal leakage: ≤3.0 L/min

• Fluid: ISO 11158 mineral oil

• Fluid temperature: −20 °C to +80 °C

• Fluid cleanliness: ISO 4406 17/14/11

• Weight: approx 7.5 kg

4. Dynamic Performance

• Full‑stroke step response: ≤22 ms穆格中国

• −3 dB bandwidth: 50–60 Hz

• Hysteresis: <0.30% of full scale

• Position resolution: <0.15% of full scale

• Null drift (ΔT = 55 K): <1.8% of full scale

5. Electrical Specifications

• Supply voltage: 24 VDC (18–32 VDC)穆格中国

• Max operating current: 3.3 A

• Standard control signal: ±10 V穆格中国

• Optional signals: ±10 mA, 4–20 mA穆格中国

• Spool position feedback: 0–10 VDC

• Connector: M18, 6‑pin + PE, IP65穆格中国

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

• EMC: CE compliant

6. Key Features

• Pilotless direct drive: simpler installation, lower maintenanceMoog Inc.

• Maximum flow capacity: suited for large‑scale hydraulic systems

• Pressure‑independent dynamics: stable performance under varying loadsMoog Inc.

• Closed‑loop position control: excellent linearity and repeatability

• Spring‑centered fail‑safe: safe shutdown on power lossMoog Inc.

• Integrated electronics: compact, rugged, EMI‑hardened

7. Applications

• Heavy‑duty hydraulic presses

• Large‑scale aerospace & automotive test rigs

• High‑force vibration simulation tables

• Precision control systems for heavy machinery & steel mills

8. Pin Assignment

1. +24 VDC power

2. Power ground

3. Command +

4. Command −

5. Position feedback output

6. Feedback ground

   PE: Protective earth

   Use shielded twisted pair for signal wiring.