Woodward 8273-1011 Electro-Hydraulic Actuator
The Woodward 8273-1011 is an electro-hydraulic actuator, commonly referred to as an EGB (Electric Governor Bypass) actuator or auxiliary actuator. This precision device is primarily used for accurate speed control of reciprocating internal combustion engines and small steam turbines, commonly found in power generation and mechanical drive applications. The actuator converts an electrical control signal from a Woodward governor or electronic control system into a mechanical output that adjusts the fuel or steam supply to the prime mover, maintaining the desired operating speed under varying load conditions.
Technical Specifications
The Woodward 8273-1011 is designed to operate with a range of control signals and actuator current ranges. The actuator is available in models for three different actuator current ranges, as well as a high-voltage model operating at 90 to 150 V DC or 88 to 132 V AC at 45 to 440 Hz. The control is available for both forward-acting and reverse-acting applications, providing flexibility for integration with various governor system configurations. The actuator can be used with either single or tandem actuator arrangements, accommodating different mechanical configurations and application requirements.
Operational Principles
The electro-hydraulic actuator receives an electrical signal from the controlling governor or electronic control module. This signal is converted into hydraulic pressure that moves the actuator output shaft. The output shaft position corresponds to the desired fuel or steam flow rate to the prime mover. The actuator includes integrated feedback mechanisms that provide position feedback to the control system, enabling closed-loop control of engine speed. This feedback loop allows the control system to continuously adjust the actuator position to maintain the target speed despite changes in engine load or other operating conditions.
Integration and Compatibility
The Woodward 8273-1011 is designed for seamless integration with Woodward governor systems including the 2301E series digital electronic governors and other compatible speed control devices. The actuator serves as the final control element in the speed control loop, translating the governor's electrical output into mechanical motion that positions the fuel rack, throttle, or steam valve. The actuator is compatible with both isochronous and droop speed control modes, supporting applications ranging from isolated generator sets to grid-paralleled systems requiring load sharing capability.
Design Features
The 8273-1011 actuator incorporates robust construction suitable for the demanding environments typical of engine rooms and power generation facilities. The electro-hydraulic design provides high force output in a compact package, enabling direct actuation of fuel system components without requiring additional mechanical amplification. The actuator is engineered for reliability with high-quality internal components designed for extended service life under continuous operation. The actuator includes provisions for field adjustment and calibration to accommodate different engine and governor configurations.
Applications
The Woodward 8273-1011 electro-hydraulic actuator is deployed in power generation, marine propulsion, and industrial drive applications requiring precise prime mover speed control. Typical applications include diesel generator sets for standby and prime power, gas engine-driven compressors in natural gas transmission, marine diesel engines for vessel propulsion, and small steam turbines for industrial process power. The actuator is also used in cogeneration plants where engine-driven generators provide both electrical power and thermal energy for facility heating or industrial processes.
