Application Scenarios
A power generation plant operating two GE LM2500 gas turbines experienced recurring fuel control instability during load transitions. The existing driver modules were exhibiting slow actuator response and intermittent position feedback errors, causing the turbines to oscillate between load setpoints and occasionally triggering nuisance shutdowns during grid synchronization. Maintenance engineers traced the root cause to degraded driver output stages and resolver feedback processing.
Replacing the aging modules with 9907-135 GS3/LQ drivers restored precise actuator response within 2 milliseconds and eliminated the position feedback drift. The 9907-135 module’s closed-loop control architecture continuously compares commanded valve position against resolver feedback, adjusting actuator current to maintain fuel metering accuracy even as ambient temperature fluctuated across the turbine enclosure. Since replacement, load transition stability improved measurably, and nuisance trips during synchronization were eliminated—directly contributing to the plant’s ability to meet grid frequency response requirements.
Parameter
| Parameter | Value/Description |
|---|---|
| Product Model | 9907-135 |
| Manufacturer | Woodward |
| Product Category | GS3/LQ Driver Module (Fuel Valve Driver) |
| Compatible Valves | GS3, LQ3, LQ25, LQ25T, LQ bypass series liquid valves |
| Input Signal | 4-20 mA analog command |
| Supply Voltage | 18-32 VDC (24 VDC nominal) |
| Maximum Current | 24 A |
| Feedback Interface | Single speed feedback resolver / valve position feedback |
| Status Output | Relay (NO-C-NC) for OK/Fault indication |
| Response Time | ≤ 2 ms |
| Operating Temperature | -40°C to +85°C |
| Mounting | Panel mount / control enclosure |
| Typical Application | GE LM1600, LM2500, LM6000 gas turbine fuel control |
Technical Principles and Innovative Values
Innovation Point 1: Closed-Loop Actuator Positioning. The 9907-135 does not merely output a fixed current proportional to the command signal. It continuously reads the valve actuator’s resolver feedback and adjusts drive current in real time to maintain the commanded position. This closed-loop architecture compensates for actuator friction, fuel pressure variations, and thermal drift—factors that would cause open-loop drivers to lose metering accuracy over time.
Innovation Point 2: Direct GS3/LQ Valve Integration. The 9907-135 is specifically engineered for Woodward’s GS3/LQ series liquid fuel valves, which use brushless DC rotary actuators with direct-coupled position resolvers. This eliminates the gears, flexible couplings, or intervening linkages common in generic valve control setups. The result is zero backlash in the feedback path and repeatable valve positioning across the full metering range.
Innovation Point 3: Fault-Indicating Status Relay. A dedicated relay output (NO-C-NC contacts) provides hardware-level indication of driver and actuator health. When the driver or actuator enters a fault condition, the relay de-energizes, signaling the turbine control system to initiate protective action. This fail-safe design ensures that driver faults are detected and acted upon even if the control system’s software diagnostics fail to identify the condition.
