D061-8312 N122-001
D634-1035 D641-230
122-105 D631-294 MOOG imported original hydraulic servo electro-hydraulic valve from the United States

FAQ:

What are the key features?

• 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 .

3. What are common failure modes?

• 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 .

4. How to maintain servo valves?

• 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 .

5. How to troubleshoot 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 .

6. What if the 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 .

7. Can Moog servo valves be customized?

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

8. What specifications should I consider?

• 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 .

9. How to ensure long-term reliability?

• Use high-quality filters and maintain oil cleanliness .

• Avoid prolonged operation beyond rated temperatures .

• Schedule periodic professional servicing .

10. Where are Moog servo valves used?

Applications include aviation, aerospace, steel mills, power generation, and industrial automation .

For specific model details (e.g., G761-3004B or D661 series), refer to technical datasheets or contact authorized suppliers .

------

This FAQ is based on general product information and common industry practices. Always consult official Moog documentation for valve-specific guidelines.