G771K227 Moog Two-Stage Electro-Hydraulic Servo Valve

Product Description
G771K227 is a Moog G771 series two-stage electro-hydraulic servo valve, with part variant S10FOFA4VA4. It adopts dry torque motor and double nozzle-flapper pilot stage structure, converting analog current command signal into precise hydraulic flow output to control hydraulic actuator position, velocity and force. This is an obsolete industrial servo valve, widely used in material test rigs, flight simulators and precision hydraulic control systems. The upgraded replacement model is G771K227A.

Key Features

• Two-stage servo valve, dry torque motor, low hysteresis and high resolution
• Max working pressure up to 3000 psi, ISO size 02 mounting standard
• Analog current control signal input, matched with external servo amplifier
• High dynamic response, stable performance under continuous cyclic load
• Built-in mechanical feedback, field adjustable null bias for on-site calibration
• Compact rugged housing, suitable for high vibration test bench environment
• Original production discontinued; available as surplus NOS or refurbished spare parts

Application Scenarios

• Material fatigue test machines, structural component test benches
• Aerospace flight motion simulators
• Steel mill hydraulic press and precision rolling control
• Legacy hydraulic servo system maintenance and spare replacement
• Automotive component durability test equipment

FAQ

Q: What is the substitute for G771K227?
A: Moog G771K227A is the updated successor version, compatible for direct replacement.

Q: What control signal does G771K227 use?
A: Analog current signal, requires an external servo drive amplifier.

Q: What oil cleanliness requirement for this servo valve?
A: Recommended ISO 4406 17/14/11 or better to prevent nozzle blockage.