D634-305C
May 25, 2026

D634-305C

The D634‑305C is a high‑flow, single‑stage direct‑drive servo valve in the MOOG D634 series. It uses a permanent magnet linear force motor to drive the spool directly—no pilot oil required. Integrated 24 VDC electronics with LVDT closed‑loop spool position feedback deliver high accuracy and dynamics largely independent of supply pressure. Spring‑centered design ensures fail‑safe return to neutral on power loss. The 305C is calibrated for high flow, medium‑high dynamics, closed‑loop position/velocity/pressure control.

Description

1. General Description

The D634‑305C is a high‑flow, single‑stage direct‑drive servo valve in the MOOG D634 series. It uses a permanent magnet linear force motor to drive the spool directly—no pilot oil required. Integrated 24 VDC electronics with LVDT closed‑loop spool position feedback deliver high accuracy and dynamics largely independent of supply pressure. Spring‑centered design ensures fail‑safe return to neutral on power loss. The 305C is calibrated for high flow, medium‑high dynamics, closed‑loop position/velocity/pressure control.

2. Hydraulic Specifications

  • Mounting: ISO 4401 Size 05 (NG10)

  • Max working pressure (P, A, B): 350 bar (5,000 psi)

  • T‑port pressure: 50 bar (without Y‑port); 350 bar (with Y‑port)

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

  • Maximum flow: approx. 185 L/min (48.8 gpm)

  • Internal leakage: ≤ 0.8 L/min

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

  • Fluid temperature: −20 °C to +80 °C

  • Filtration: ISO 4406 17/14/11 or better

  • Weight: approx. 6.3 kg (13.9 lb)

3. Dynamic Performance (Typical)

  • Step response (0 → 100% stroke): ≤ 18 ms

  • −3 dB bandwidth: 65–75 Hz

  • Hysteresis: < 0.4% of full scale

  • Resolution: < 0.08% of full scale

  • Null drift (60 K temp change): < 1.2% of full scale

4. Electrical Specifications

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

  • Max operating current: 3.0 A

  • Command signal (jumper selectable): ±10 V, ±10 mA, 4–20 mAMoog Inc.

  • Spool position feedback output: 0–10 VDC

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

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

  • EMC: CE compliant

5. Key Features

  • High‑flow direct drive: 100 L/min rated, no pilot supply needed

  • Integrated LVDT closed‑loop: excellent linearity and repeatability

  • Pressure‑independent dynamics: stable under varying load conditions

  • Low internal leakage: energy efficient for high‑flow systems

  • Spring‑centered fail‑safe: safe shutdown on power loss

6. Applications

  • High‑flow hydraulic axes

  • Presses & heavy‑duty industrial machinery

  • Injection molding (high‑speed, high‑flow)

  • Material testing systems

  • General‑purpose high‑flow closed‑loop control

7. Wiring Definition

  • Pin 1: +24 VDC

  • Pin 2: Power ground

  • Pin 3: Command signal (+)

  • Pin 4: Command signal (−)

  • Pin 5: Spool position feedback (0–10 VDC)

  • Pin 6: Feedback ground

  • PE: Protective earth

  • Recommendation: Use shielded twisted‑pair cable for signals.


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