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What is an Actuator?

Malcolm Tatum
Malcolm Tatum
Malcolm Tatum
Malcolm Tatum

An actuator is something that converts energy into motion. It also can be used to apply a force. An actuator typically is a mechanical device that takes energy — usually energy that is created by air, electricity or liquid — and converts it into some kind of motion. That motion can be in virtually any form, such as blocking, clamping or ejecting. Actuators typically are used in manufacturing or industrial applications and might be used in devices such as motors, pumps, switches and valves.

Energy Sources

An air cylinder, a type of actuator.
An air cylinder, a type of actuator.

Perhaps the most common type of actuator is powered by air and is called a pneumatic cylinder or air cylinder. This type of actuator is an airtight cylinder, typically made from metal, that uses the stored energy of compressed air to move a piston when the air is released or uncompressed. These actuators are most commonly used in manufacturing and assembly processes. Grippers, which are used in robotics, use actuators that are driven by compressed air to work much like human fingers.

Solenoid valves can be powered by both air and electricity, and a solenoid can be powered by both hydraulics and electricity.
Solenoid valves can be powered by both air and electricity, and a solenoid can be powered by both hydraulics and electricity.

An actuator also can be powered by electricity or hydraulics. Much like there are air cylinders, there also are electric cylinders and hydraulic cylinders in which the cylinder converts electricity or hydraulics into motion. Hydraulic cylinders, which use liquids, are often found in certain types of vehicles.

Many actuators have more than one type of power source. Solenoid valves, for example, can be powered by both air and electricity. Alternatively, a solenoid can be powered by both hydraulics and electricity.

Types of Motion

Mechanics often rely on a number of pneumatic tools, including air-powered wrenches, cutters and screwdrivers.
Mechanics often rely on a number of pneumatic tools, including air-powered wrenches, cutters and screwdrivers.

Actuators can create a linear motion, rotary motion or oscillatory motion. That is, they can create motion in one direction, in a circular motion or in opposite directions at regular intervals. Hydraulic and air cylinders can be classified as single-acting cylinders, meaning that the energy source causes movement in one direction and a spring is used for the other direction. Alternatively, these cylinders can be double-acting cylinders, meaning that the energy is used in two directions.

Muscles as Actuators

Although actuators typically are discussed in terms of mechanical implements, muscles are sometimes given as an example of actuators. Energy is converted by the muscle into motion. For example, the calories that are in food that a person consumes represent energy that can be used by his or her muscles — which act as actuators — to create motion, such as running, kicking a ball or dancing.

Malcolm Tatum
Malcolm Tatum

After many years in the teleconferencing industry, Michael decided to embrace his passion for trivia, research, and writing by becoming a full-time freelance writer. Since then, he has contributed articles to a variety of print and online publications, including AboutMechanics, and his work has also appeared in poetry collections, devotional anthologies, and several newspapers. Malcolm’s other interests include collecting vinyl records, minor league baseball, and cycling.

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Malcolm Tatum
Malcolm Tatum

After many years in the teleconferencing industry, Michael decided to embrace his passion for trivia, research, and writing by becoming a full-time freelance writer. Since then, he has contributed articles to a variety of print and online publications, including AboutMechanics, and his work has also appeared in poetry collections, devotional anthologies, and several newspapers. Malcolm’s other interests include collecting vinyl records, minor league baseball, and cycling.

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Discussion Comments

darrenjames

The article is informative and provides very useful information regarding actuator. Since an actuator is used to convert energy into motion and create linear motion, rotary motion, or oscillatory motion, the application of an actuator carries various dimensions and applications. Thanks for providing all the information in one place.

anon161312

is a motor an actuator or is it activated by an actuator like a relay?

anon104906

the most common type of actuator used by most people is a linear actuator, weather its electric, pneumatic etc.

anon87897

seems quite a good site from the outside.

have to check whether detailed info is available regarding a particular topic.

anon84362

Thanks a lot.

Cooljedidude

Instructions on a can of Green Gas tell me to attach an actuator before using. Where will I find one of these?

dudla

Another, less common, source of energy for actuators: heat. There are thermal actuators and solar actuators.

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    • An air cylinder, a type of actuator.
      By: Igor Sinitsyn
      An air cylinder, a type of actuator.
    • Solenoid valves can be powered by both air and electricity, and a solenoid can be powered by both hydraulics and electricity.
      By: emel82
      Solenoid valves can be powered by both air and electricity, and a solenoid can be powered by both hydraulics and electricity.
    • Mechanics often rely on a number of pneumatic tools, including air-powered wrenches, cutters and screwdrivers.
      By: uwimages
      Mechanics often rely on a number of pneumatic tools, including air-powered wrenches, cutters and screwdrivers.