Moog Servo Valve Electro-Hydraulic Servo Valve with 290*180mm Size Up to 1000 cc/rev Displacement and Pressure Compensated Control

D061-8312 N122-001
D634-1035 D641-230
122-105 D631-294

• High precision: Control accuracy up to ~0.1%
• Fast dynamic response: Responds within milliseconds
• Programmability: Customizable control algorithms via embedded electronics
• Robustness: Operates in harsh environments (-20°C to 80°C) and resists contamination
• Fail-safe function: Automatic shutdown during power loss or failure

• Torque motor issues:
  • Coil breakage (valve fails to respond)
  • Armature sticking or ball head wear (causing instability)
• Nozzle/flapper blockages: Clogging from oil contamination reduces response and causes system oscillation
• Spool amplifier problems:
  • Edge wear (increases leakage and noise)
  • Spool sticking due to contaminated or degraded oil
• Seal aging: Leads to internal/external leakage

• Oil quality management: Use recommended fluids (e.g., phosphate ester fire-resistant oil) and maintain cleanliness per NAS 1638 Class 5 standards. Regularly check acidity and resistivity
• Routine inspections: Test for electrical issues (e.g., coil resistance), clean filters, and check for loose components
• Pre-startup checks: Ensure oil circulation before powering the valve to prevent clogging

• For unstable operation (e.g., cylinder drift or oscillation):
  • Check servo valve resolution and zero zone stability
  • Inspect for internal leakage or spool wear
  • Verify control system parameters and calibrate zero bias if needed
• If valve doesn't move:
  • Confirm electrical signals and coil connectivity
  • Check for spool sticking caused by debris in oil
  • Ensure correct startup sequence: oil flow before electrical power

Models like the D636/D637 series support fieldbus interfaces and programmable electronics for application-specific tuning.

• Operating pressure: Up to 350 bar
• Flow rate: 5-100 L/min (at Δp 35 bar)
• Voltage/current: Typically 220V, 1.5A
• Mounting: Complies with ISO 4401 standards

• Use high-quality filters and maintain oil cleanliness
• Avoid prolonged operation beyond rated temperatures
• Schedule periodic professional servicing

Aviation, aerospace, steel mills, power generation, and industrial automation.