The Woodward 9907-1200 is an Electro-Hydraulic Converter (EHG) / Current-to-Pressure (CPC) actuator interface manufactured by Woodward, Inc. It serves as the physical link between electronic turbine control systems (such as the Woodward 505, 505E, Peak 150, or MicroNet controllers) and hydraulic servo mechanisms.
The 9907-1200 converts an electrical control signal (typically 4–20 mA or 0–200 mA) into precise, proportional hydraulic fluid pressure or mechanical stroke to position steam turbine governor valves, gas turbine fuel valves, and industrial hydraulic actuators.
Technical Specifications
| Parameter | Specification |
| Manufacturer | Woodward, Inc. |
| Part Number | 9907-1200 |
| Device Type | Electro-Hydraulic Converter / Proportional Actuator |
| Input Command Signal | 4–20 mA DC or 0–200 mA DC (from digital governor / DCS) |
| Hydraulic Fluid Compatibility | Mineral oils, synthetic fluids (e.g., Fyrquel, phosphate esters) |
| Operating Hydraulic Supply Pressure | Standard industrial range (typically 10 to 207 bar / 150 to 3000 psi) |
| Feedback Mechanism | Internal/External LVDT (Linear Variable Differential Transformer) / Mechanical position feedback |
| Operating Temperature | -40°C to +85°C (-40°F to +185°F) |
| Enclosure Rating & Certification | NEMA 4X / IP66 / Class I, Div 1 or Div 2 Hazardous Location rated |
| Response Time | High-speed dynamic bandwidth (< 50 ms step response) |
Core Features & Operating Capabilities
- High-Accuracy Electro-Hydraulic Conversion: Translates low-power electrical command outputs from digital governor systems into high-force hydraulic positioning to move heavy steam and gas turbine valves.
- Proportional Linear Control: Provides smooth, repeatable valve regulation across the entire 0% to 100% stroke range, minimizing overshoot and hunting during fast load swings.
- Synthetic & Mineral Oil Compatibility: Built with internal seals and materials resistant to high-temperature synthetic hydraulic fluids (such as phosphate ester / Fyrquel) as well as standard petroleum-based turbine oils.
- Hazardous Location Protection: Designed for harsh energy and petrochemical plant environments with explosion-proof or intrinsically safe enclosure ratings.
- Fail-Safe Operation: Configured with predictable fail-safe action (fail-closed or fail-open via spring return) upon loss of electrical control signal or hydraulic supply pressure.
Related Woodward Control & Actuation Hardware
- Woodward 505 / 505E (9907-162 / 9907-164) — Digital Governor Controllers for steam turbines.
- Woodward CPC-II (Current-to-Pressure Converter) — Next-generation electro-hydraulic converter platform.
- Woodward EG-3P / EG-6P / EG-10P — Electro-hydraulic proportional actuators.
- Woodward TM-25 / TM-200 — Torque Motor Actuators for gas turbine fuel metering.
