Benefits and Drawbacks of Electric Valve Actuators in Process Control

Electric Valve Actuators

Electric actuators use electricity to operate a valve. While most of the basic principles utilized in electric actuators have been present since the 1930s, decades of incremental progress have considerably enhanced their capability while lowering their cost. These advancements have reached a tipping point in recent years, making electric actuators the preferred choice for many applications. 

There are many advantages to electric valve actuation. Electricity is relatively cheap, simple to control, and usually available at most industrial sites. Electric actuators often have a lower capital cost per equivalent unit of torque/thrust production. They are also more environmentally friendly and safer to use. Electric actuators can provide higher positioning accuracy for control or modulating valve tasks and options for extensive process monitoring, data logging, and information feedback. Electric actuators include all necessary control functions, lowering capital expenditures. By enabling distributed control, the electric actuator's considerable cost in wiring is cut—through efficient and straightforward control logic through integrating control commands and feedback into customer SCADA or DCS systems. (Traditional electromechanical control systems require a distinct wire for each command and feedback signal, resulting in cable bundles with at least seven cores for each actuator.

On the other hand, a standard bus system can use one twisted pair wire in a daisy chain configuration to transport all required input and output signals.) Electric actuators weigh less and have smaller footprints than pneumatic actuators as torque and thrust requirements increase. Finally, electric actuators can generate exceptionally high output thrust and torque values in conjunction with external gears. 

There are also some disadvantages to electric valve actuation to note. Except for a few specific combinations, electric actuators cannot ensure a fail-safe stroke. Still, they will "fail in the last position"  - the ability of an actuator to move a valve to a specified safe position when power ceases is known as fail-safe stroke. Electric actuators contain more sophisticated and delicate components than other forms of actuators. Electronic technology likewise necessitates regular updating to stay up with component changes and advances. Compared to pneumatic and hydraulic actuators, electric actuators are less cost-effective and have operating speed restrictions beyond a specific size/torque range. Electric actuators require more rigorous certifications and construction features to be regarded safe for usage in hazardous regions with potential exposure to explosive process material. 

For more information about electric valve actuation, contact Swanson Flo. Call them at 800-288-7926 or visit their web site at