Overview

The Woodward 9905-211 is a low-voltage speed control and load-sharing unit from the 2301A series, developed for governing diesel engines, gas engines, and turbine-driven generators. It is widely used in power generation systems requiring accurate speed regulation and stable load distribution.

Designed for 24 VDC systems, this controller delivers reliable actuator control while maintaining consistent engine performance under varying load conditions.

Technical Specifications

Control Capabilities

Dual Operating Modes

The controller supports two standard governing modes:

• Isochronous control maintains constant engine speed regardless of load variation

• Droop control enables proportional speed reduction, supporting generator synchronization with grid or parallel units

This flexibility allows the module to adapt to both standalone and grid-connected applications.

Accurate Load Distribution

When interconnected via load-sharing lines, multiple controllers coordinate to balance power output across generators. This prevents uneven loading and eliminates the risk of one machine driving another.

System Protection Features

Speed Signal Loss Detection

The controller continuously monitors the MPU input. In the event of signal failure, the output to the actuator is automatically disabled, preventing uncontrolled fuel delivery and potential overspeed conditions.

Reverse Power Compatibility

The unit can operate alongside external reverse power protection systems, helping safeguard generators during abnormal load flow or synchronization issues.

Tuning and Adjustment

Front Panel Calibration Controls

Accessible potentiometers allow precise system tuning:

• Speed setting adjustment for rated RPM

• Gain and reset parameters for dynamic response optimization

• Actuator matching to align with fuel system characteristics

These adjustments enable stable operation while minimizing oscillation or slow response.

Installation and Integration

Low Voltage Operation

Optimized for 24 VDC control systems, the unit integrates easily into standard industrial and generator control panels.

Actuator Compatibility

The 0–200 mA output signal is designed to drive Woodward proportional actuators directly, ensuring smooth fuel control and accurate speed regulation.

Application Scenarios

• Generator set load sharing systems

• Diesel and gas engine speed control

• Turbine governing applications

• Standby and prime power installations

• Parallel power systems with multiple generators

FAQ

What type of engines can this controller be used with?

It is suitable for diesel engines, gas engines, and small to medium gas turbines.

Does the unit support parallel generator operation?

Yes, it is specifically designed for load sharing across multiple generator sets.

What signal is required for speed sensing?

A magnetic pickup (MPU) signal within the specified frequency range is required.

Is this a standalone controller or part of a system?

It can operate independently or as part of a coordinated multi-unit load-sharing system.