G761-3033B is a two-stage electro-hydraulic servo valve from MOOG’s G761 series, specifically designed for DEH systems in thermal/nuclear power steam turbines. It is used for precise control of hydraulic motors and regulating valves and is a mainstream high-precision servo valve in the power generation field.

1、 Basic Information
Model: G761-3033B (the complete model is often G761-3033B-H19JOGM4VPL)
Brand: MOOG (American MOOG)
Series: G761 (two-stage, mechanical feedback, flow control type)
Usage: Steam turbine DEH, EH oil system, power generation/industrial high-precision hydraulic control
Status: Current mainstream models, original factory supply+large number of spare parts/refurbished parts in circulation
2、 Core technical parameters (simplified)
1) Hydraulic parameters
Rated pressure: 315 bar (4500 psi), P port maximum 6750 psi
Rated flow rate: 63 L/min (7 MPa pressure drop)
Working medium: Flame resistant EH oil (phosphate ester), petroleum based hydraulic oil
Oil temperature range: -29 ℃~+135 ℃
Sealing material: Fluororubber (FKM)
2) Electrical and Control
Coil resistance: 80 Ω (single coil)
Rated current: ± 40 mA (control signal)
Input signal: ± 10 V or 4-20 mA
Drive mode: dry torque motor, dual nozzle baffle pilot stage
3) Dynamic performance (key)
Frequency response: ≥ 150 Hz (-3 dB, ± 10% signal)
Step response: 4-16 ms (100% travel)
Hysteresis:<0.5% FS
Resolution:<0.05% FS
Zero bias: factory calibration, on-site adjustable
3、 Structure and Working Principle
Two level structure:
Pilot stage: torque motor → dual nozzle baffle → control pressure difference
Main valve stage: four-way slide valve, mechanical feedback (cantilever spring rod) closed-loop, eliminating idle stroke
Safety design: Fail Safe in case of power failure to prevent uncontrolled door adjustment
Filtering requirements: Built in pilot filter (5 μ m), system oil must have NAS ≤ 6 level and filter element ≤ 5 μ m
4、 Typical applications
Thermal power/nuclear power: DEH system for steam turbine, controlling the opening of main steam valve and regulating valve
Industrial drive: high-precision hydraulic table, vibration testing table, material testing machine
Other: High frequency and high-precision control scenarios required for aviation/shipbuilding, injection molding machines, steel rolling mills, etc
5、 Common model differentiation (G761-3033B vs 3003B)
3033B: 63 L/min, ± 40 mA, H19 plug, EH oil specific (mainstream in power plants)
3003B: 38 L/min, ± 20 mA, industrial use, not specifically for EH oil