Steam Turbine Actuators

VariStroke Linear Electro-Hydraulic Actuators for Steam Turbines

Woodward solves steam turbine users’ #1 reliability problem . . . dirty oil!

The patented dirt tolerant and self-cleaning technology of Woodward’s VariStroke actuators ensure greater overall reliability of your steam turbine. The VariStroke line of linear electro-hydraulic valve actuators operate mechanical-drive or generator-drive steam turbines. These linear actuators utilize a low-pressure, hydraulic oil source (typically turbine lube oil) to provide output shaft force. Their superb accuracy and resolution make them ideal for steam valve control and related turbine speed and load control, where turbine up-time and availability is essential.

The VariStroke line is configurable via a simple user-friendly, computer-based PC service tool, allowing users to easily configure, calibrate, and adjust all internal functions and response settings. Its integrated driver includes a 4-20 mA output channel to indicate output shaft (control valve) position, as well as unit alarm and shutdown relay outputs for use as unit health and status indications. The 4-20 mA demand inputs and dual-redundant shaft position sensors allow it to continue to operate even with demand input or feedback sensor failures, ensuring extended run-times between forced outages and on-line system repair.

Learn more http://www.woodward.com/varistroke.aspx?terms=VariStroke

Download:

PS_VariStroke I_03397_E

PS_VariStroke II_03378_B

ProAct™ Digital Actuator

Woodward’s ProAct™ digital electric actuator and positioner incorporate a rotary output shaft used to accurately position steam turbine control valves. The ProAct Digital actuator includes an integral digital driver/positioner that:
• controls the actuator
• monitors the health of the actuator
• communicates with the control system
• Output—Rotary shaft, 75 degrees, 7 to 37 J (5 to 27 ft-lb)
• Input Power—18-32 Vdc, 20 A max

Learn more: http://www.woodward.com/SteamTurbineProact.aspx

Download: PS_ProAct_03231_H

CPC II (Current to Pressure Converter)

Woodward’s Current to Pressure Converters (CPC-II and CPC-DX Redundant Version) are electrohydraulic pressure regulating control valves used to position single-acting steam turbine valve servos/actuators. The CPC-II and CPC-DX Redundant version accepts 4-20 mA pressure demand signals and accurately controls oil pressure to precisely position single-acting steam turbine governor-valves. Precise and stable steam valve control directly relates to improved steam turbine speed and load control and reduced system mechanical wear.

Both automatic and manual transfer logic are available for use within this skid assembly, depending on the system’s design. This skid’s automatic transfer logic simplifies system design as it requires no external relay/switching logic to operate, minimizing both converter-to-converter and control-to-converter interface wiring. The CPC’s configurable alarm/shutdown logic allows users to easily configure which system conditions force an automatic transfer from the master CPC to the slave CPC.

Learn more: http://www.woodward.com/SteamTurbineCPC.aspx?terms=CPC-II

Download: CPC-DX-Product-Spec03421