Contact Info

D634-327C

Home / Product/ MOOG
D634-327C
May 25, 2026

D634-327C

D634-327C is a single‑stage, pilot‑less direct drive servo valve (DDV) from MOOG D634 series, built to ISO 4401 Size 05 (NG10). It uses a permanent magnet linear force motor to drive the spool directly—no pilot oil required. An integrated LVDT provides closed‑loop spool position control, ensuring high linearity and repeatability. The direct‑drive design delivers pressure‑independent dynamics, while spring centering guarantees a fail‑safe neutral position on power loss. This model is optimized for 100 L/min rated flow and 55–65 Hz bandwidth, ideal for medium‑flow, ultra‑high‑dynamic closed‑loop motion control.

Description

1. General Description

D634-327C is a single‑stage, pilot‑less direct drive servo valve (DDV) from MOOG D634 series, built to ISO 4401 Size 05 (NG10). It uses a permanent magnet linear force motor to drive the spool directly—no pilot oil required. An integrated LVDT provides closed‑loop spool position control, ensuring high linearity and repeatability. The direct‑drive design delivers pressure‑independent dynamics, while spring centering guarantees a fail‑safe neutral position on power loss. This model is optimized for 100 L/min rated flow and 55–65 Hz bandwidth, ideal for medium‑flow, ultra‑high‑dynamic closed‑loop motion control.

2. Model Code (D634-327C)

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

  • 327: Base configuration (100 L/min, high‑response spool, 24 VDC high‑speed electronics)Moog Inc.

  • 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)Moog Inc.

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

  • T‑Port Pressure (with Y port): 350 bar (5,000 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: ≤1.2 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): ≤12 ms

  • −3 dB Bandwidth: 55–65 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

  • Ultra‑fast response: 12 ms step response for high‑speed applications

  • 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

  • High‑speed hydraulic presses

  • Dynamic material testing machines (high‑frequency)

  • Industrial motion control systems requiring ultra‑fast response

  • 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.


Get a Quote

Search

Categories

pages