Our advantage
Global Logistics
We have a 10-year logistics and express cooperation agreement, so our products can be shipped to any place in the world.
Brand new and original
Our products are imported in bulk from the place of origin. Because of the cooperative relationship, our products are all original and 100% new.
24-hour service
We provide 7*24 hours service to our customers. We will be there whenever you need us.
Price advantage
All our products are priced very favorably because we have our own warehouse and supply.
| Company Information | |||
| [email protected] | |||
| Mobile | +8615980777398 | ||
| +8615980777398 | |||
| 15980777398 |

The Woodward 9905-463 ProAct Model II Digital Speed Control is an electronic engine-governing controller used to regulate prime-mover speed in mechanical-drive and generator-set applications. It processes engine-speed feedback and configured reference signals to control a compatible ProAct actuator, adjusting the engine’s fuel input as operating conditions change.
In an industrial generator installation, the engine must maintain the required speed as electrical demand varies. The 9905-463 receives a speed signal from a magnetic pickup and uses its internal control algorithms to determine the required correction. The resulting control action drives the associated actuator, which adjusts the fuel-control mechanism to bring engine speed toward the configured operating point.
The controller supports local speed-reference settings and a 4–20 mA remote speed-reference input. It also provides an auxiliary voltage input for compatible load-sensing equipment, allowing load-sharing or droop-parallel operation when the surrounding system is configured for these functions. Its digital control architecture includes adjustable governing dynamics, speed-reference ramps, and fuel-limit settings.
The 9905-463 belongs to the ProAct Model II control family and uses an external 24 V DC nominal supply. It must be distinguished from ProAct actuator drivers, which perform the separate task of powering and positioning an actuator from a control command. The 9905-463 is the speed controller; the actuator and its associated mechanical linkage perform the physical fuel-control movement.
| Parameter | Specification |
|---|---|
| Manufacturer | Woodward |
| Model / Part Number | 9905-463 |
| Product Family | ProAct |
| Product Type | Model II Digital Speed Control |
| Control Architecture | Microprocessor-based digital speed control |
| Nominal Supply Voltage | 24 V DC |
| Supply Voltage Range | 18–32 V DC |
| Remote Speed Reference | 4–20 mA |
| Speed Feedback | Magnetic pickup |
| Auxiliary Input | Compatible load-sensor or speed-bias signal |
| Control Functions | Speed regulation, speed ramps, fuel limiting, configurable dynamics |
| Operating Applications | Engine-driven generators and mechanical-drive systems |
| Compatible Actuator System | ProAct Model II arrangement, subject to system configuration |
| Applicable Manual | Woodward 04121 |
| Documented Replacement Model | 9907-1290 |
| Dimensions | 315 × 211 × 49 mm |
| Weight | 1.75 kg |
The 9905-463 uses a microprocessor to calculate engine speed from the magnetic pickup signal and compare the measured speed with the configured reference. It then adjusts its control output to correct the difference between commanded and actual engine speed.
A typical governing arrangement follows this sequence:
Magnetic Pickup → 9905-463 Digital Speed Control → ProAct Actuator → Fuel-Control Mechanism → Engine
The remote speed-reference input and optional load-sensing circuit provide additional control information:
Remote 4–20 mA Reference → Speed-Reference Processing
Compatible Load Sensor → Auxiliary Input → Load-Sharing or Droop Control
The magnetic pickup produces an alternating electrical signal as the engine’s rotating target passes the sensor. The controller processes the signal frequency to determine engine speed. Its control algorithm evaluates the difference between the measured speed and the required operating point, then adjusts the actuator command to change the engine’s fuel setting.
For a generator operating under changing electrical demand, the governing system increases or decreases fuel input as needed to maintain the required speed. In a compatible parallel-generator arrangement, the auxiliary input can accept a load-related signal to support the configured load-sharing or droop function.
The controller also allows governing dynamics to be adjusted for the characteristics of the engine and fuel-control mechanism. Gain, stability, and related settings influence how quickly the system responds and how it behaves after a load change. Incorrect settings can produce unstable speed response or excessive overshoot, so commissioning must be performed under controlled conditions.
The 9905-463 does not directly provide the actuator’s mechanical movement. It belongs to the electronic control stage of the governing system and depends on a compatible actuator, correct feedback wiring, and a suitable engine linkage to achieve the intended response.
The 9905-463 occupies the speed-control layer between the engine’s sensing circuits and the actuator. It evaluates speed feedback and reference inputs, while the actuator changes the fuel setting and the engine supplies mechanical power to the driven equipment.
Speed Sensor + Reference Inputs → 9905-463 → ProAct Actuator → Engine Fuel System → Prime Mover
| System Component | Function |
|---|---|
| Woodward 9905-463 | Calculates the speed-control response and manages configured governing functions |
| Magnetic Pickup | Provides engine-speed feedback |
| Remote Speed Reference | Supplies the external 4–20 mA speed command |
| Compatible Load Sensor | Provides load information for supported sharing or droop arrangements |
| ProAct Actuator | Converts the controller’s output into mechanical movement |
| Fuel-Control Linkage | Transfers actuator movement to the engine’s fuel mechanism |
| Diesel or Gas Engine | Supplies mechanical power to the driven equipment |
| Generator | Converts mechanical energy into electrical output |
| Handheld Programmer | Provides access to control parameters and diagnostic information |
| Independent Protection System | Provides required overspeed shutdown and other protective functions |
| Application | Typical Use |
|---|---|
| Diesel Generator Sets | Maintaining engine speed as electrical demand changes |
| Gas Engine Generators | Regulating engine speed through a compatible actuator |
| Industrial Power Plants | Controlling prime-mover speed in generator installations |
| Standby Power Systems | Supporting stable engine governing during changing load conditions |
| Remote Generator Stations | Providing electronic speed regulation with external sensing equipment |
| Mechanical-Drive Engines | Regulating engine speed for compatible driven machinery |
| Parallel Generator Systems | Supporting load-sharing or droop operation when correctly configured |
| Gas Compression Equipment | Governing compatible engines used to drive compressors |
| Industrial Engine Packages | Coordinating speed reference, feedback, and fuel-control response |
| Engine Retrofit Projects | Replacing an existing ProAct Model II controller after configuration verification |
| Component | Function |
|---|---|
| Woodward 9905-463 Digital Speed Control | Processes speed feedback and configured reference inputs |
| Magnetic Pickup Speed Sensor | Measures engine rotational speed |
| Compatible ProAct Actuator | Adjusts the engine’s fuel-control mechanism |
| Remote 4–20 mA Reference Source | Provides external speed-reference adjustment |
| Compatible Load Sensor | Supplies load information for supported parallel operation |
| Handheld Programmer | Provides access to control settings |
| Engine Fuel-Control Linkage | Transfers actuator movement to the fuel system |
| External 24 V DC Supply | Powers the Model II control system |
| Generator Set or Mechanical Drive | Uses the controlled prime mover’s mechanical output |
| Independent Overspeed Protection | Provides a separate protective shutdown function |
| Model | Product Type | Selection Consideration |
|---|---|---|
| Woodward 9905-463 | ProAct Model II Digital Speed Control | Original controller reference for the specified system configuration |
| Woodward 9907-1290 | ProAct Model II Speed Control Replacement | Documented replacement reference; verify system-specific conversion requirements |
| Woodward 9905-462 | ProAct Model I Speed Control | Different ProAct control configuration requiring supply and system compatibility checks |
| Woodward 9905-792 | ProAct Plus 4–20 mA Fuel Limiter | Related control product with a different fuel-limiting function |
| Woodward 8405-010 | ProAct Model II Speed Control | Related ProAct Model II control arrangement; verify exact application and interface |
| Woodward ProAct Model II Actuator | Electronic Engine Actuator | Compatible actuator family for the documented governing arrangement, subject to configuration |
The input provides an external speed-reference command that the controller interprets according to its configured scaling and operating limits. The signal source, wiring, and programmed reference range must be compatible with the intended speed-control application.
The magnetic pickup generates a signal related to engine rotational speed. The controller processes the signal frequency to determine actual speed and uses that information in its governing calculations.
It can support compatible load-sharing or droop-parallel arrangements through its auxiliary input when the appropriate load-sensing equipment and system configuration are provided. The complete generator control system must be configured for the intended parallel operation.
Check the magnetic pickup signal, actuator direction and mechanical linkage, supply voltage, speed-reference scaling, and governing-dynamics settings. Also verify that the replacement control is compatible with the original actuator and application before adjusting gain or stability parameters.