What Is an Actuator? Working Principle, Types and Applications

Industrial automation makes production processes more efficient, precise and safe, and actuators are the muscle that does the physical work in the field. So, what is an actuator? In short, it is a device that converts energy into mechanical motion in response to a control signal, performing tasks that range from opening and closing a valve to moving a machine axis.

This article explains how actuators work, how they are classified by energy source and type of motion, where they are used and what to consider when selecting one.

What Is an Actuator?

An actuator is a device that produces mechanical motion using an energy source such as electricity, compressed air or pressurised fluid (hydraulics). A control system (a PLC, thermostat, pressure switch, control panel, etc.) makes the decision, and the actuator turns that decision into physical movement, such as opening or closing a valve, positioning a damper or guiding a robot arm.

How Actuators Work

Actuators operate on different principles depending on their energy source:

• Electric actuators: Generate motion through an electric motor and gear train (or a solenoid). They offer precise position control and need no compressed air supply.
• Pneumatic actuators: Use compressed air to drive a piston or vane mechanism. They are fast, simple and robust.
• Hydraulic actuators: Move pistons with pressurised fluid, usually hydraulic oil. They deliver very high force and torque from a compact unit.

Types of Actuators

Actuators are classified by two main criteria: the type of motion they produce and the energy source they use.

By Type of Motion

• Linear actuators: Produce back-and-forth motion. They are used where the valve stem moves axially, as in gate, globe and control valves.
• Rotary actuators: Produce rotational motion. They are common on quarter-turn (90°) valves such as ball and butterfly valves.

By Energy Source

Where Are Actuators Used?

Actuators are found in almost every area of industrial automation:

• Valve control (ball, butterfly and globe valves)
• Damper control in HVAC systems
• Robotics and production lines
• Packaging machines
• CNC machine tools
• Flight control surfaces in aviation

How to Choose an Actuator

• Torque or force requirement: The actuator must meet the demand of the valve or mechanism under its most severe operating condition, with a safety margin.
• Available utilities: If the plant has compressed air, a pneumatic actuator is often practical; otherwise an electric actuator is usually the better fit.
• Control mode: Decide whether simple on/off operation is enough or modulating control at intermediate positions is needed.
• Fail-safe behaviour: Whether the valve must open, close or stay in place on loss of power or air directly affects the choice.
• Ambient conditions: Temperature, humidity, dust and hazardous areas must be considered when selecting the housing and protection rating.

ORFA Actuator Solutions

ORFA Endüstriyel Mamüller San. ve Tic. A.Ş. supplies a range of actuator types and models for different applications and requirements. Our team provides technical support on choosing the right actuator and helps you identify the most suitable solution for your application.

Frequently Asked Questions

Conclusion

Actuators are one of the core components of modern industrial automation. Selecting the right type and size for the application directly improves the efficiency, accuracy and safety of your processes. To explore electric and pneumatic actuators and valve gearboxes, visit our Actuators and Gear Operators product group.