Description
The Woodward 9907-135 is a GS3/LQ analog valve driver module in the Woodward electro-hydraulic governor and fuel-control product family. It is the power interface between a turbine governor and a fuel valve actuator: the module receives the valve-position command and produces the high-current drive needed to move the valve. In practice, it is the component that turns a low-level control signal into physical valve motion, so its performance directly affects fuel metering, speed control and unit stability.
Application Scenarios
A pipeline gas-compressor station was preparing its LM-series gas turbines for the winter load season when routine functional testing showed one fuel-control loop hunting at low demand. The 4–20 mA command from the governor was stable, but the valve did not track cleanly through the lower part of the stroke, and the operator had begun adding small manual bias corrections to keep the loop settled. The site’s service history pointed to the Woodward 9907-135 driver as a known wear item in that control chain. Rather than tune around the symptom, the maintenance team replaced the module during a planned compressor outage, using the original wiring documentation and verified commissioning procedure. After the swap, the valve followed the command signal without additional compensation, and the loop remained stable across the full operating range. The station also updated its critical-spare list to include the 9907-135, because a failed driver leaves the valve without a usable drive path and can force an unplanned unit trip.
The same replacement logic applies to steam-turbine intercept and control valves, liquid-fuel metering valves and any electro-hydraulic actuator where the feedback device is a single-speed resolver. In these systems the 9907-135 is not an accessory; it is the final electrical stage before the hydraulic actuator. Keeping a known-good spare, verifying compatibility before installation and following the approved commissioning sequence are the most effective ways to avoid a control-room alarm becoming a unit shutdown.
Parameter
| Main Parameters | Value/Description |
|---|---|
| Product Model | 9907-135 |
| Manufacturer | Woodward Governor Company |
| Product Category | GS3/LQ analog valve driver module |
| Function | Converts valve-position command into high-current actuator drive |
| Input / Control Signal | 4–20 mA command signal from governor or controller |
| Supply Voltage | 10–32 VDC (24 VDC nominal/rated supply) |
| Maximum Output Current | 24 A continuous drive output |
| Compatible Feedback | Single-speed resolver feedback |
| Compatible Valves / Actuators | GS3, LQ3, LQ25, LQ25T and related LQ liquid-fuel metering and bypass-valve configurations |
| Driver Manual Reference | Woodward Manual 40175 |
| Associated Documentation | LQ25 Valve Actuator Manual 26161; Product Change Notification 06953 |
| Response / Dynamic Performance | Sub-millisecond-scale response suitable for valve-position control; exact settling and slew data must be taken from the turbine OEM and Manual 40175 |
| Fault Handling | Detects feedback and output faults; drives safe or de-energized state and reports fault status to the governor per the project configuration |
| Mounting | Chassis/module mounting in the governor or turbine control cabinet |
| Operating Temperature | 0 to +60 °C continuously in standard industrial listings; −20 to +60 °C in alternate supplier listings |
| Construction | Industrial module assembly with connectors/terminals and integral heatsinking |
| Weight | Approx. 0.38 kg in compact-module listings; approx. 2.27 kg (5 lb) in full-driver-assembly listings |
| Dimensions | Vendor-dependent: 158 × 158 × 40 mm, 180 × 120 × 65 mm and 292 × 175 × 68 mm appear in different supplier records |
| Lifecycle Status | Legacy / spares configuration in Woodward documentation; single-speed analog arrangement treated as a legacy configuration |
