Woodward 9905-792 ProAct Plus Digital Speed Control

Woodward 9905-792 ProAct Plus Digital Speed Control Module

The Woodward 9905-792 ProAct Plus Digital Speed Control is an electronic governor designed for high-precision speed, load, and position regulation on prime movers. Engineered specifically for harsh mechanical environments, including marine propulsion systems, shipboard auxiliary gensets, reciprocating gas engines, and industrial turbo-machinery, the 9905-792 module interfaces directly with Woodward ProAct series electromagnetic actuators (such as ProAct I, II, and Digital Plus variants).

This unit provides closed-loop PID governing. It dynamically counteracts heavy step-load additions and rejections common in isolated busbars and marine microgrids. With integrated continuous self-diagnostics, configurable dual dynamics, and ruggedized chassis shielding against electromagnetic interference (EMI), the 9905-792 guarantees transient recovery and deterministic actuator response.

Model Details

• Manufacturer: Woodward Inc.
• Product Series: ProAct / ProAct Plus Series
• Model Number (MPN): 9905-792
• Hardware Type: Standalone / Integrated Digital Speed Control Assembly
• Associated Manual Publications: Woodward Manual 04183 (ProAct Digital Speed Control System) / Manual 26112 / Manual 03231

Features

1. Advanced PID Dynamic Control: Features independent PID parameter curves with speed gain ratio and window width tuning, mitigating steady-state mechanical hunting while delivering transient response during large block load steps.
2. Flexible Sensor & Actuator Interface: Integrates an onboard high-resolution magnetic pickup (MPU) circuit capable of reading 0 to 10,000 RPM, translating speed errors into high-bandwidth actuator driver outputs.
3. Industrial & Marine Grade Architecture: Surface-mount PCB housed in a die-cast chassis with conformal coating, offering shock and vibration resistance rated for continuous on-engine or bulkhead installation.
4. Comprehensive Real-Time Diagnostics: Monitors input voltage fluctuations, feedback tracking, open-circuit MPU signals, and driver thermal conditions to trigger fail-safe engine alarms or orderly shutdowns.
5. Digital Communication & Service Tool Support: Onboard RS-232/RS-485 serial communication compatible with Woodward Watch Window and hand-held programmer units for rapid parameter cloning and field diagnostics.

Technical Specifications

Compatibility

• Actuators: Woodward ProAct I, ProAct II, ProAct Model ISC, and ProAct Digital Plus electric actuators.
• External Synchronizers & Load Sensors: Woodward SPM-A Synchronizers, Woodward Generator Load Sensors (9907-026), and 2301A/D compatible load-sharing lines.
• Marine Automation Platforms: Kongsberg AutoChief, Lyngsø Marine, Deif Delomatic, Siemens S7 automation cabinets, and Woodward easYgen paralleling controllers.
• Engine Makes & Models: Caterpillar 3500/3600 Series, Cummins QSK/KTA series, Wärtsilä 20/26 auxiliary engines, MTU 2000/4000 series, and Jenbacher/Waukesha industrial gas engines.

Frequently Asked Questions

What is the primary function of the Woodward 9905-792 control module?

The Woodward 9905-792 is a high-speed digital governor module that measures prime mover rotational velocity via a magnetic pickup, compares it against programmed setpoints, and drives an electric actuator (such as the ProAct series) to govern fuel delivery and maintain exact generator frequency or engine RPM under fluctuating loads.

Can the Woodward 9905-792 be used for both isochronous and droop operation?

Yes. The module supports dedicated discrete inputs and software settings to switch between isochronous mode (constant speed regardless of load, ideal for standalone island generators) and droop mode (speed decreases predictably as load increases, essential for paralleling multiple gensets or utility grids).

How do I configure or re-tune parameters on the 9905-792?

Configuration and dynamic tuning can be performed using a plug-in Woodward 9907-205 handheld terminal via the RS-232 serial diagnostic port, or via a PC running Woodward Watch Window software communicating through an RS-232/RS-485 serial converter.

What is the recommended input power protection for the module?

The 9905-792 requires an 18–32 VDC power supply (nominal 24 VDC). It is recommended to install a fast-acting 5A to 10A DC inline fuse or miniature circuit breaker (MCB) on the positive supply line to protect against severe transient battery charging spikes or accidental reverse polarity.

How do you diagnose a “Loss of Speed Signal” alarm?

First, measure the AC voltage across the MPU input terminals during cranking using a true-RMS multimeter; you should read a minimum of 1.0 to 1.5 VRMS. If the voltage is lower, re-gap the pickup closer to the gear teeth. If zero voltage is detected, inspect the cable continuity, verify the shield drain, and confirm that the pickup tip has not collected ferrous debris from the flywheel housing.