Woodward 8256-016 EPG Rotary Actuator — 24 VDC High-Torque Engine Fuel Control Actuator

Brand WOODWARD

Model Woodward 8256-016

The Woodward 8256-016 is a rotary electro-mechanical actuator purpose-built for the Woodward EPG (Electrically Powered Governor) family, serving as the execution element that converts a controller’s analog current command into precise mechanical rotary displacement. As part of a closed-loop governing system, the Woodward 8256-016 works in tandem with a dedicated Woodward electronic speed controller and a magnetic pickup sensor to regulate engine speed by continuously positioning the fuel rack or throttle valve on diesel, gasoline and gaseous-fuel prime movers. This three-piece architecture replaces traditional mechanical-hydraulic governing with a cleaner, faster and more accurate fully electronic solution.

Engineered around the Model 1724 base design, the Woodward 8256-016 is rated for a nominal 24 VDC supply and is classified as a high-response servo actuator rather than a simple on/off solenoid. It is positioned as the “muscle” of the EPG loop: the controller computes the required fuel quantity from sensed speed and load, and the actuator delivers that command to the engine with repeatable torque and minimal delay. The unit’s value lies in its combination of compact footprint, ruggedized sealing, bidirectional equal rotation and strong starting torque even at the low end of the supply range, making it equally suitable for new installations and as a direct replacement in legacy governing systems.

In automation terms, the Woodward 8256-016 bridges the final control element and the electronic governor. Its sealed aluminum housing, IP65 protection and wide ambient rating allow it to live directly on the engine skid in harsh, oily and high-vibration environments where reliability is non-negotiable.

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Description

Technical Specifications

Parameter	Value
Product Model	8256-016
Manufacturer	Woodward Inc. (USA)
Product Type	EPG Rotary Electric / Servo Actuator (Model 1724 base)
Supply Voltage	24 VDC nominal (20–28 VDC continuous, 32 VDC transient 100 ms)
Rated / Peak Power	60 W rated; 95 W maximum transient
Operating Current	≤0.8 A static hold; 3.6 A RMS full-stroke
Output Torque	3.4 N·m (30 in-lb) rated; ≤0.32 N·m min. start torque at 22 VDC
Rotary Travel	35° full mechanical stroke, bidirectional with overtravel stops
Output Shaft	0.375″-36 SAE serrated double-ended spline
Response Time	≤30 ms minimum-to-maximum stroke
Coil Insulation	Class F (120 VAC, 50 Hz, 1 min withstand)
Operating Temperature	-40 °C to +93 °C (-40 °F to +200 °F)
Ingress Protection	IP65 fully sealed enclosure
Construction	Cast aluminum housing with sealed bearings
Dimensions / Weight	Approx. 253 × 43 × 102 mm; 7.75 kg (net ~454 g per base actuator)
Compliance	CE, RoHS, UL-rated industrial components

Main Features and Advantages

The Woodward 8256-016 earns its place at the heart of an EPG system through a balance of torque density, response speed and environmental resilience. Its 3.4 N·m rated output in a compact body is sufficient to drive fuel racks and throttle levers on mid-range diesel and gas engines without requiring a bulky hydraulic actuator, while the ≤0.32 N·m starting torque at 22 VDC ensures authority remains predictable even during battery-voltage sag at engine start.

The <30 ms full-stroke response is a defining performance attribute. Under sudden load rejection or step loading, the Woodward 8256-016 moves fuel almost instantaneously, allowing the governor controller to keep speed deviation tight and recover smoothly. This directly translates into stable generator frequency, reduced speed droop and cleaner load sharing when multiple sets run in parallel.

Mechanical robustness is built in rather than added on. The IP65 sealed housing, sealed bearings and corrosion-resistant internal components protect against oil mist, spray, dust and condensation common in engine rooms and outdoor skids. The unit is rated for continuous operation from -40 °C to +93 °C, so it performs equally well in arctic standby duty and in high-ambient compressor stations.

The 0.375″-36 SAE serrated dual-ended shaft deserves particular mention: it prevents linkage slip under vibration, accepts interchangeable linkage assemblies on either end, and simplifies retrofits into tight compartments. Class F coil insulation and a 60 W optimized steady-state design keep holding current low (≤0.8 A), reducing battery-charger load and heat while reserving peak power for transient demand. With no internal brushes to wear under normal duty and minimal wearing parts, the Woodward 8256-016 is effectively low-maintenance, keeping lifecycle cost and unplanned downtime down.