Woodward VariStroke-I electro-hydraulic actuator: an innovative solution for steam turbine valve control

5.3 Troubleshooting Guide

The manual provides detailed troubleshooting tables (Tables 7-1 to 7-7) to help users locate the root cause based on observed phenomena (such as shutdown, alarm, actuator failure, poor performance, etc.), such as:

Shutdown: Check if the demand signal is within range, run enable signal, digital communication command, or specific diagnostic fault.

Alarm: Use service tools to view specific alarm information and refer to the manual for correction.

The actuator does not move: check the hydraulic supply, power supply, demand signal, and enable status.

Poor/unstable performance: Check if the fuel supply pressure and flow rate are sufficient, if the performance index is met, and if there is electrical noise interference.

6、 Technological advantages and application value

Strong anti pollution capability: The specially designed rotary servo valve has a debris shear force of 222N, a self-cleaning flow channel, and a configurable "sludge remover" function, allowing it to operate reliably in turbine oil systems containing impurities, water, and sludge.

Flexible stroke adjustment: The "variable stroke" feature allows users to accurately set the maximum stop position of the actuator on site, improving application flexibility.

Lateral load capacity: The output shaft adopts high-precision bearings and triple sealing technology, which can withstand continuous lateral loads up to 10% of the output force and adapt to the circular motion of the valve connecting rod.

Chemical Tolerance Version: Provides a chemical tolerance version for extreme environments where lubricating oil contains chemical pollutants such as ammonia and hydrogen sulfide.

Intelligent diagnosis and communication: Built in advanced diagnostic functions provide rich status information through discrete and analog outputs, supporting future CAN communication expansion.