D634-386C
May 25, 2026

D634-386C

D634-386C belongs to MOOG D634 direct drive servo valve series with standard ISO 4401 Size 05 mounting interface. Permanent magnet linear force motor directly drives the spool without pilot oil supply. Built-in LVDT sensor realizes closed-loop position control to guarantee reliable precision and repeatability. Dynamic performance keeps stable against pressure variation. Spring centering structure returns spool to neutral position automatically and provides fail-safe protection when power fails. This high flow model is applicable to heavy-duty large hydraulic control systems.

Description

1. General Description

D634-386C belongs to MOOG D634 direct drive servo valve series with standard ISO 4401 Size 05 mounting interface. Permanent magnet linear force motor directly drives the spool without pilot oil supply. Built-in LVDT sensor realizes closed-loop position control to guarantee reliable precision and repeatability. Dynamic performance keeps stable against pressure variation. Spring centering structure returns spool to neutral position automatically and provides fail-safe protection when power fails. This high flow model is applicable to heavy-duty large hydraulic control systems.

2. Model Definition

D634: Direct drive servo valve series
386: Extra high flow and medium dynamic configuration
C: Revision version C

3. Hydraulic Specifications

Mounting standard: ISO 4401 Size 05 (NG10)
Max working pressure of P, A, B ports: 350 bar
Max pressure of T port: 50 bar
Rated flow at 35 bar pressure drop: 180 L/min
Maximum flow rate: approximately 250 L/min
Internal leakage: ≤3.5 L/min
Applicable fluid: ISO 11158 mineral oil
Fluid temperature range: -20 °C ~ +80 °C
Required fluid cleanliness: ISO 4406 17/14/11
Total weight: approximately 7.8 kg

4. Dynamic Performance

Full stroke step response: ≤24 ms
-3dB frequency bandwidth: 45~55 Hz
Hysteresis: less than 0.35% full scale
Position resolution: less than 0.18% full scale
Null drift under 55K temperature change: less than 2.0% full scale

5. Electrical Specifications

Supply voltage: 24 VDC, working range 18~32 VDC
Maximum operating current: 3.6 A
Standard control signal: ±10 V
Optional signal: ±10 mA, 4-20 mA
Spool position feedback output: 0-10 VDC
Connector type: M18, 6 pins with PE terminal, IP65 protection grade
Ambient temperature: -20 °C ~ +60 °C
EMC certification: CE compliant

6. Key Features

Pilotless direct drive design simplifies installation and maintenance
Super large flow capacity meets heavy load hydraulic driving demands
Pressure independent dynamic characteristic ensures stable operation
High precision closed-loop control achieves accurate motion adjustment
Fail-safe spring reset mechanism protects system during power outage
Integrated electronic drive unit features compact and anti-interference structure

7. Application Scope

Heavy industrial hydraulic press and forging equipment
Large aerospace and automotive component test rigs
High force hydraulic drive and simulation machinery
Industrial closed-loop position, velocity and pressure control systems

8. Pin Assignment

Pin 1: +24 VDC power
Pin 2: Power ground
Pin 3: Command signal positive
Pin 4: Command signal negative
Pin 5: Position feedback output
Pin 6: Feedback ground
PE: Protective earth
Shielded twisted pair cable is recommended for signal wiring


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