Woodward 9905 Series Modules – 9905-969

Technical Dossier

Product Details And Specifications

Woodward 9905 Series Technical Notes

The Woodward 9905 Series represents a mature, field-proven line of speed governor control modules deployed across global heavy industry sectors including petrochemical refineries, nuclear power auxiliary systems, offshore platforms, and combined-cycle power generation facilities. These units function as the primary interface between turbine/engine prime movers and their governing actuators, executing precise speed and load control via analog and digital signal processing. The 9905 Series has accumulated decades of installed base across OEM turbine packages from Solar Turbines, GE, Siemens, and MAN Energy Solutions, making long-term spare parts availability a critical operational concern for plant maintenance engineers worldwide.

The Evolution of 9905 Series Architecture

The 9905 Series was introduced as an analog-dominant governor control platform, designed to replace electromechanical hydraulic governors in industrial turbine applications. Early variants relied on discrete analog circuitry for speed sensing, droop adjustment, and actuator output, with limited diagnostic capability. As industrial automation standards evolved through the 1990s and 2000s, Woodward progressively integrated microprocessor-based signal conditioning, EEPROM-based parameter storage, and RS-232/RS-485 serial communication ports into the 9905 architecture.

Compatibility across 9905 sub-variants is not universal. Differences in actuator output current range (20–160 mA vs. 4–20 mA), power supply input voltage (24 VDC vs. 120 VAC), and speed sensor input type (magnetic pickup vs. proximity probe) mean that direct substitution between models requires engineering verification. Many 9905 units are now classified as end-of-life (EOL) by Woodward, with no active production. Plants operating legacy turbine packages must source replacement units from certified aftermarket distributors with documented testing protocols.

9905 Series Full Catalog & Functionalities (SKU List)

The following models represent the documented 9905 Series range. Each unit is categorized by primary function:

Speed Governor Controllers

• 9905-969: Single-channel speed governor control module, analog actuator output, 24 VDC supply, magnetic pickup input, droop/isochronous selectable.
• 9905-292: Speed governor control, 4–20 mA actuator output, dual speed input channels, panel-mount housing.
• 9905-335: Governor control with load sharing interface, RS-232 communication port, 120 VAC powered.
• 9905-459: Isochronous load control module, analog speed reference input, DIN rail mount.
• 9905-502: Speed/load governor, dual actuator outputs, configurable droop 0–10%, 24 VDC.
• 9905-617: Governor control with overspeed trip relay output, magnetic pickup input, EEPROM parameter storage.
• 9905-744: Analog governor module, 20–160 mA actuator output range, suitable for Woodward EG actuator families.
• 9905-812: Speed governor with serial diagnostics port, 4–20 mA output, panel-mount, 24 VDC.

Actuator Driver & Signal Conditioning Modules

• 9905-148: Actuator driver module, 20–160 mA output, compatible with Woodward TG and EG actuator series.
• 9905-233: Signal conditioner for magnetic pickup speed sensors, frequency-to-voltage conversion, DIN rail.
• 9905-381: Isolated analog input/output signal conditioner, 4–20 mA, for governor system integration.
• 9905-426: Actuator current amplifier module, boosts governor output to drive high-impedance actuators.

Power Supply & Interface Modules

• 9905-075: 24 VDC regulated power supply module for 9905 Series governor systems, DIN rail mount.
• 9905-190: 120/240 VAC to 24 VDC converter module, panel-mount, for legacy governor panel retrofits.
• 9905-558: RS-232 to RS-485 communication interface module for 9905 Series serial network integration.
• 9905-683: Discrete I/O expansion module, 8 digital inputs / 4 relay outputs, for governor system interlocks.
• 9905-901: Analog I/O expansion card, 4 additional 4–20 mA channels, for multi-actuator governor configurations.

Quality Control for the 9905 Series Range

Each 9905 Series unit processed by DriveKNMS undergoes a structured functional verification protocol prior to dispatch. The test sequence addresses the specific failure modes documented in this series: analog output drift, EEPROM parameter corruption, speed sensor input circuit degradation, and actuator driver stage failure.