MOOG G761-3054B Two Stage Electrohydraulic Servo Valve

MOOG G761-3054B Two-Stage Electrohydraulic Servo Valve (4500 PSI)

The MOOG G761-3054B is an electrohydraulic flow control servo valve engineered for closed-loop motion, force, velocity, and dynamic positioning control systems. Combining an isolated, frictionless dry torque motor with a hydraulic nozzle-flapper pilot amplifier, the G761-3054B isolates its magnetic air gaps from working hydraulic fluids to prevent magnetic particulate contamination and sluggish spool drift.

Spool displacement is mechanically regulated by a carbide-tipped cantilever feedback wire acting directly on the center land of a hardened 440C stainless steel spool and sleeve assembly. Operating with a maximum working pressure up to 315 bar (4500 PSI), this valve delivers high dynamic stiffness, low threshold hysteresis, and predictable line-to-line flow response. It is designed for applications where downtime is not an option—from marine propulsion pitch positioning to turbine governor actuation.

Model Details

• Manufacturer: MOOG Inc.
• Model Part Number (MPN): G761-3054B
• Factory Model Code / Type Designation: H40JOGM4VPY
• Mounting Standard: ISO 10372-04-04-0-92 (4-port subplate mounting interface)
• Design Architecture: 2-Stage Mechanical Feedback (MFB), Frictionless Dry Torque Motor, Symmetrical Double-Nozzle Flapper Pilot, 4-Way Closed-Center Sliding Spool Output Stage

Features

1. Double-Air-Gap Dry Torque Motor: Eliminates particulate contamination in motor air gaps, preventing magnetic-oil choking in demanding mineral and synthetic oil loops.
2. Hardened 440C Stainless Steel Bushing & Spool Assembly: Precision-lapped with micro-inch tolerances to deliver minimal null leakage and superior wear resistance under boundary-lubrication regimes.
3. High-Flow Double-Nozzle Flapper Pilot Stage: Provides dynamic acceleration across high pilot flows, achieving step response times down to 7 ms for 0–100% stroke.
4. Field-Accessible 35-Micron Pilot Filter & External Null Bias Adjuster: Allows inline preventative flushing, servicing, and calibrated mechanic-level zero drift compensation without disassembly.

Technical Details

Part Number Cross-References & Direct Equivalents

• Direct Matching Part Numbers: G761-3054B, G7613054B, 761-3054B, G761-3054, H40JOGM4VPY
• Series Sibling Models (Variant Flow / Configuration):
  • G761-3004B (38 L/min / 10 GPM standard response version)
  • G761-3005B (63 L/min / 16.5 GPM standard high-flow configuration)
  • G761-3003B (19 L/min / 5 GPM model)
  • G761-3002B (10 L/min / 2.5 GPM model)
• Direct Functional Interchanges:
  • Moog 760 Series: 760-103A, 760-104A (requires verify of mounting bolt threads: M8 vs 5/16-18 UNC).
  • Rexroth: 4WSE2ED10 series servo valves (with manifold cross-port adapter plate).
  • Parker Hannifin: BD15 series electrohydraulic servo valves.
  • Abex / Denison: Jet-pipe series (cross-over conversion manifold required).

Frequently Asked Questions

What makes the MOOG G761-3054B a high-response servo valve?

The G761-3054B features the “H” and “G” design designations, signifying a high-performance armature-flapper kinematic arrangement coupled with a high-flow pilot stage. This configuration enables the valve to achieve full spool transit (0 to 100% stroke) in less than 7 milliseconds, providing dynamic responsiveness for closed-loop hydraulic positioning circuits.

Can I install the MOOG G761-3054B in any mounting orientation?

Yes, the valve is completely dynamically balanced and can be mounted in any orientation (vertical, horizontal, or inverted) without affecting null stability or spool displacement. However, in marine installations subject to severe roll and pitch, mounting the spool axis parallel to the vessel’s centerline minimizes inertial forces exerted on the spool during sea states.

How do I maintain and replace the built-in pilot stage filter?

The G761 series features a field-replaceable 35-micron disc filter accessible from the base manifold face without dismantling the torque motor or spool body. During major scheduled maintenance intervals, isolate hydraulic pressure, remove the valve from the subplate, unscrew the filter retainer plug, extract the disc filter, ultrasonic clean or replace it, install new Viton O-rings, and torque back to spec.