WOODWARD 8273-1011 Electro-Hydraulic Actuator (EGB)

Parameter	Specification
Model	8273-1011
Manufacturer	Woodward
Product Type	Electro-Hydraulic Actuator / EGB
Input Signal	DC Current Signal, common specifications are ±80 mA or ±200 mA (depending on pairing with the governor, e.g., 2301A often uses ±80 mA). Signal polarity determines the direction of movement.
Coil Resistance	Typically 40 Ohms (for ±80 mA configuration) or 20 Ohms (for ±200 mA configuration). Must be verified against the specific nameplate.
Working Stroke	Typically a standard stroke of 1.5 inches (approx. 38.1 mm). The stroke is fixed.
Output Force	High, dependent on system supply pressure. Can generate several hundred kilograms of thrust at typical supply pressures of 150-200 psi (10-14 bar).
Hydraulic Fluid	Clean mineral-based turbine oil or synthetic oil. Typical viscosity: ISO VG 32. Requires filtration to 10 microns or better.

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Description

Woodward 8273-1011 Electro-Hydraulic Actuator (EGB)

Product Overview

The Woodward 8273-1011 is an Electro-Hydraulic Actuator, commonly known as an EGB (Electric Governor Bypass Actuator) or Auxiliary Actuator. It is a critical component of the Woodward 8273 Series digital governor system, designed to operate in conjunction with Woodward electronic speed controllers such as the 2301A or 2301D. The core function of this actuator is to receive a position control signal from the electronic governor and convert it into a precise, high-power hydraulic output. This output mechanically drives the fuel rack (on diesel engines) or the steam/gas valve control linkage (on turbines) to achieve precise control of prime mover speed and load.

The 8273-1011 is, in essence, an integrated servo valve and hydraulic cylinder unit. An internal solenoid coil receives a DC current signal (typically ±40 mA, ±80 mA, or ±200 mA) from the governor controller. This current drives the servo valve spool, which directs externally supplied hydraulic oil into the cylinder, causing the piston rod to extend or retract. The linear displacement of the piston rod is directly linked to the fuel metering mechanism.

Technical Specifications (Typical)

Parameter	Specification
Model	8273-1011
Manufacturer	Woodward
Product Type	Electro-Hydraulic Actuator / EGB
Input Signal	DC Current Signal, common specifications are ±80 mA or ±200 mA (depending on pairing with the governor, e.g., 2301A often uses ±80 mA). Signal polarity determines the direction of movement.
Coil Resistance	Typically 40 Ohms (for ±80 mA configuration) or 20 Ohms (for ±200 mA configuration). Must be verified against the specific nameplate.
Working Stroke	Typically a standard stroke of 1.5 inches (approx. 38.1 mm). The stroke is fixed.
Output Force	High, dependent on system supply pressure. Can generate several hundred kilograms of thrust at typical supply pressures of 150-200 psi (10-14 bar).
Hydraulic Fluid	Clean mineral-based turbine oil or synthetic oil. Typical viscosity: ISO VG 32. Requires filtration to 10 microns or better.
Supply Pressure	Typical range: 150 – 250 psi (10 – 17 bar). Must be stable and clean. The exact value must align with engine/system design requirements.
Position Feedback	Internally integrated Linear Variable Differential Transformer (LVDT). Provides an electrical signal (typically AC) proportional to piston rod displacement to the governor, forming a closed-loop position control system.
Mechanical Interface	Piston rod end is typically a clevis or threaded stud for connection to the engine fuel rack or valve linkage. Actuator body features a mounting flange and fixing holes.
Operating Temperature	Typical: -40°C to +85°C (suitable for most industrial environments).
Protection Rating	Typically IP65 or similar, providing dust and water spray protection.

2301E 8273-1011

Main Features and Advantages

High Power Density & Control Precision: Converts a low-power electrical signal into high-power linear motion with fast response and precise positioning, ensuring stable engine speed control.
Integrated LVDT Feedback: The built-in position sensor enables full closed-loop control, eliminating drift caused by mechanical wear or temperature changes, and guaranteeing long-term repeatable accuracy.
Rugged & Durable Construction: Designed for harsh engine room environments, resistant to vibration, high temperatures, and oil contamination.
Seamless Integration with Woodward Systems: Designed specifically to pair with Woodward 2301 series governors, offering excellent compatibility and well-established tuning parameters.
Modular Design: Facilitates field service or replacement. Components like the LVDT and servo coil are often replaceable individually.

Application Fields

This actuator is primarily used for precise speed control of reciprocating internal combustion engines and some small steam turbines, commonly found in:

Power Generation: Diesel generator sets, gas generator sets (standby, prime, island mode operation).
Oil & Gas Industry: Natural gas compressor drives, oilfield drilling power packs, pump drive engines.
Marine Propulsion: Ship auxiliary engines and main propulsion diesel engines.
Combined Heat and Power (CHP): Engine sets driving generators and providing thermal energy.