Governor Control Systems, Inc.

Woodward Actuators for Steam Turbines

VariStroke Linear Actuator

The VariStroke-I is a linear electro-hydraulic actuator that is designed to provide the linear actuation force to operate steam turbine control valves or valve racks. This integrated actuator is intended for use on mechanical-drive or generator drive steam turbines, and uses a low-pressure hydraulic oil source (typically turbine lube oil) to provide its output shaft force.

The VariStroke-I’s superb accuracy and resolution make it ideal for steam turbine valve control and related turbine speed and load control. The VariStroke-I electronics module accepts one or two (redundant) 4–20 mA position demand signals to position steam control valves. Precise and stable steam valve control directly relates to improved steam turbine speed and load control and reduced system mechanical wear. The actuator’s fast slew time of 100 ms/inch (of shaft travel) allows applied generator or compressor drive turbines to quickly respond to loss-of-load or emergency shutdown events.

The VariStroke-I actuator’s robust design (corrosion resistant materials, single moving rotary valve, 50 lb chip shear force, and self-cleaning port design) make it ideal for challenging applications where dirty or contaminated oil may be present. The VariStroke-I’s redundant features make it ideal for critical steam turbine applications, where turbine up-time and availability are essential. This linear actuator can be configured to accept simplex or dual-redundant position demand inputs, then select the correct input to follow. This linear actuator’s dual-redundant 4–20 mA demand inputs and dual-redundant MLDT (magnetostrictive linear displacement transducer) shaft position sensors allow it to continue to operate even with demand input or feedback sensor failures, ensuring extend run-times between forced outages.

In turbine retrofit applications, the VariStroke-I can be used to directly replace the existing servo system. This saves costly repairs to existing and aging servos, eliminates the difficulty of obtaining spare parts for obsolete equipment, and reduces calibration time and difficulty.

VariStroke Actuator

EHPC
The Woodward Electrohydraulic Power Cylinder (EHPC) provides the force to operate the control valves of a steam turbine. The Woodward EHPC is intended for use on mechanical drives or generator drives. The EHPC integrates the actuator, pilot valve, electronic feedback device, and the power cylinder into a single package, eliminating linkage and reducing hydraulic plumbing and wiring. For critical turbine applications, dual coil option is available.

Woodward EHPC Actuator

EHPS
The Woodward Electrohydraulic Power Servo (EHPS) is a fully integrated three-stage servo valve designed to drive low-pressure steam turbine control valve cylinders. The Woodward EHPS, in conjunction with a new or already installed steam valve cylinder, provides the linear actuation force to operate steam turbine control valves or valve racks. This servo can be configured to drive single or double acting actuators, and to use the system's turbine lube oil supply, or a separate oil source (5.5-17.2 bar, 80-250 psi). This servo is ideal for retrofits where it is desired to upgrade the turbine control and hydraulic system but keep the expensive steam valve power cylinder. In retrofit applications, the Woodward EHPS can directly replace the existing steam valve power cylinder operating system. This saves costly repairs to existing servos and eliminates difficulties in obtaining spare parts for obsolete equipment.

Woodward EHPS Actuator

CPC-II
The Woodward CPC-II (current to pressure converter, generation II) is an electrohydraulic pressure-regulating valve control designed for use in positioning single-acting steam turbine valve servos. This CPC's superb accuracy and resolution make it ideal for steam turbine valve control and related turbine speed and load control. The Woodward CPC accepts a 4-20 mA pressure demand signal 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.

Woodward CPC-II Actuator

EML100
The Woodward EML100 electric actuator is designed to provide highly accurate, closed loop position control of steam and fuel valves that require a linear operator with a stroke length between 13 and 38 mm (0.5 and 1.5 inches). The actuator is designed to be used with the Woodward EM Digital Driver.

Woodward EML100 Actuator

TM-25/-200LP
Woodward TM-25/-200LP actuators are electro-hydraulic, proportional actuators for positioning steam and fuel-control valves requiring low/high force linear inputs. The Woodward TM-25LP and the TM-200LP actuators provide one inch of linear movement of valves for steam or gas turbines. For critical turbine applications, dual coil option is available.

Woodward TM-25 Actuator

TM-55P Proportional Actuator
The Woodward TM-55P Actuator is an electrohydraulic, proportional actuator for controlling diesel and gas engines or steam and industrial gas turbines. It is designed for use with Woodward analog and digital controls. The TM-55P will interface (with an adapter) directly to Woodward liquid and gas fuel valves. It is particularly well suited for use in control systems requiring a rotary mechanical output that is proportional to electrical input.

Woodward TM-55P Proportional Actuator

TM-55 Integrating Actuator
The Woodward TM-55 is an integrating type actuator used for controlling diesel and gas engines or steam and industrial applications of gas turbines, and is designed for use with an adapter directly to Woodward liquid and gas fuel valves. The TM-55 has an electrical position sensor which provides a feedback signal to Woodward electronic controls. This combination allows closed loop control of the actuator output-shaft position.

Woodward TM-55 Integrating Actuator

Hydraulic Amplifier
The Woodward electrically controlled type hydraulic amplifier is a pilot operated, linear servo actuator used in conjunction with Woodward electronic controls. The amplifier contains a Woodward EG-3P actuator which converts the electric control signal to a rotary output which controls the servo output position taken by the amplifier. The amplifier is capable of operating the control mechanisms for steam turbines or large engines which require relatively large forces and work capacity. For critical turbine applications, dual coil option is available.

Woodward Hydraulic Amplifier

TG-13E & TG-17E Actuators
Woodward TG-13E and TG-17E actuators are self-contained electrohydraulic actuators for use on steam turbines where isochronous control, load sharing, or other functions are required. They can be used with all available Woodward electronic governor controls and accessories.

Woodward TG Actuator

PGPL Actuator
The Woodward PGPL Actuator/Driver is an electro-hydraulic actuator with a proportional driver interface which can be used with electronic controls providing a 0 to 200 mA position signal. The actuator is designed for use with Woodward controls.

Woodward PGPL Actuator

UG40 Actuator
The Woodward UG-Actuator and UG40 Actuator offer the advantages of electronic control and load sharing systems while using the convenient, existing UG-type drives and linkages. The actuators provide the muscle for Woodward analog controls such as the 2301A, as well as Woodward digital controls such as the 500-series, 700-series, and the IGEM® engine management system. The actuators can be used with diesel, gasoline, or natural gas engines, as well as with steam and industrial gas turbines. The actuators have a self-contained oil sump so a separate oil supply is not required.

Contact GCS for product specifications and technical manuals

Woodward UG40 Actuator
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