Emerging industry trends demand compact, accurate, electric actuation for turbine fuel and steam control. Electromechanical actuation (EMA) provides these benefits for applications where high-precision rapid actuation is desired. Young & Franklin's patented Compact Electromechanical Linear Actuators maintain the same high quality as our well-built hydraulic actuators while providing enhanced reliability and controllability in a compact package with diagnostic capability from the control room.

Young & Franklin electromechanical actuators utilize a zero backlash high precision ball screw, selected for long life and high dynamic application. A brushless permanent magnet servomotor supplies the rotating torque to the integrated screw. The ball screw assembly in turn converts the rotary motion of the servomotor to linear motion. A 4-20mA analog position and feedback command signal controls the actuator. Models with integrated fail-safe springs are also available.

Young & Franklin's EMA motor controller is externally mounted on a controller assembly in an EMI-shielded enclosure. The controller interfaces with system computers to monitor valve stroke, position and slew rates from a distance and allow the user to program initial parameters using a personal computer. The enclosure contains the motor controller and the necessary capacitors and filters to deal with cable connections up to 150 meter long.

Young & Franklin 8609 Gas Fuel Rail on a DR990 turbine at Perulack Station. Rail consists of one Y&F 3010 EMA Gas Fuel Control Valve and two Y&F 9200 Isolation Valves.

Advantages of using EMA technology
Several advantages to using EMA actuation instead of conventional hydraulic control are outlined below:

• No need for pumps, motors or fluid conditioning equipment
• No brushes to wear out, and no maintenance is required over the life of the motor
• Reduced system costs
• Greater remote control
• Set parameters can be changed readily
• Smaller envelope: no additional servomotor, filter, manifolding and seals, trip relays or trip valves required
• No contamination issues

Applications
Young & Franklin 7-3000 and 7-3001 EMA's can be used for actuation in hazardous/high temperature locations for controlling valves or as dampers, louvers, or for workpiece positioning. Our EMA's are used in trip/throttle applications on steam turbines and for gas or liquid fuel control on aeroderivative and industrial turbines. Our actuators are designed to mate with existing valve configurations for either linear or rotary actuation making it easy to upgrade hydraulic systems to electric.

A variety of Young & Franklin EMA designs are available for either low- or high-force applications, with both fail-open and fail-close designs available. The standard EMA design includes a resolver for position feedback, but LVDT's can be added for additional control. Our EMA's are compatible with either 120 VAC or 80-180 VDC power sources.

Young & Franklin's EMA actuators and controllers are certified for use in hazardous locations according to North American and European standards. The actuator itself can withstand temperatures up to 100°C and is certified to UL/ CSA standards as Class I, Division 1, Groups B, C and D and to CENELEC standards as EEx d IIB+H2 T3 and ATEX Directive as II 2 G (explosion proof). The controller is certified to UL/ CSA standards.