ACTUATORSBUYING GUIDE

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ACTUATORS A ThomasNet Buying Guide

Actuators are mechanical or electro-mechanical devices

that provide controlled and sometimes limited

movements or positioning which are operated

electrically manually or by various fluids such as air hydraulic etc Two basic motions are linear and

rotary Linear actuators convert energy into straight line motions typically for positioning applications

and usually have a push and pull function Some linear actuators are unpowered and manually operated

by use of a rotating knob or hand wheel Rotary actuators convert energy to provide rotary motion A

typical use is the control of various valves such as a ball or butterfly Each actuator type has versions for

various power configurations and come in many styles and sizes depending on the application Linear

chain actuators provide push and pull motions with rigid chains

Actuator Types

Electric Linear

Electric Linear Actuators are electrically powered mechanical devices consisting of motors linear

guides and drive mechanisms which are used to convert electrical energy into linear displacement

through mechanical transmission electro-magnetism or

thermal expansion to provide straight line pushpull

motion Key specifications include the intended

application drive type motor type the mounting

configuration as well as other physical dimensions and

electrical characteristics Electric linear actuators are used

primarily in automation applications when a machine

component tool etc requires a controlled movement to

a particular position They are used in a wide range of

industries where linear positioning is needed The

actuators are driven by several means including ball or lead screws belts or voice coils among others

Typical applications include opening and closing dampers locking doors braking machine motions etc

Electric Rotary Electric Rotary Actuators are electrically powered mechanical devices

consisting of motors and output shaft mechanisms with limited rotary

travel which are used to convert electrical energy into rotational motion

Key specifications include the intended application drive method

number of positions output configuration mounting configuration as

ACTUATORS A ThomasNet Buying Guide

Actuators are mechanical or electro-mechanical devices

that provide controlled and sometimes limited

movements or positioning which are operated

electrically manually or by various fluids such as air hydraulic etc Two basic motions are linear and

rotary Linear actuators convert energy into straight line motions typically for positioning applications

and usually have a push and pull function Some linear actuators are unpowered and manually operated

by use of a rotating knob or hand wheel Rotary actuators convert energy to provide rotary motion A

typical use is the control of various valves such as a ball or butterfly Each actuator type has versions for

various power configurations and come in many styles and sizes depending on the application Linear

chain actuators provide push and pull motions with rigid chains

Actuator Types

Electric Linear

Electric Linear Actuators are electrically powered mechanical devices consisting of motors linear

guides and drive mechanisms which are used to convert electrical energy into linear displacement

through mechanical transmission electro-magnetism or

thermal expansion to provide straight line pushpull

motion Key specifications include the intended

application drive type motor type the mounting

configuration as well as other physical dimensions and

electrical characteristics Electric linear actuators are used

primarily in automation applications when a machine

component tool etc requires a controlled movement to

a particular position They are used in a wide range of

industries where linear positioning is needed The

actuators are driven by several means including ball or lead screws belts or voice coils among others

Typical applications include opening and closing dampers locking doors braking machine motions etc

Electric Rotary Electric Rotary Actuators are electrically powered mechanical devices

consisting of motors and output shaft mechanisms with limited rotary

travel which are used to convert electrical energy into rotational motion

Key specifications include the intended application drive method

number of positions output configuration mounting configuration as

well as physical dimensions and electrical characteristics as required Electric rotary actuators are used

primarily in automation applications when a gate valve etc requires controlled movement to particular

rotational positions They are used in a wide range of industries where positioning is needed The

actuators are driven by various motor types voice coils etc Typical applications include quarter-turn

valves windows robotics etc

Fluid Power Linear Fluid Power Linear Actuators are mechanical devices consisting of

cylinder and piston mechanisms that produce linear displacement by

means of hydraulic fluid gas or differential air pressure Key

specifications include the intended application fluid power type

mounting configuration travel length and force capacities as well as

physical dimensions as required Fluid power linear actuators are used

primarily in automation applications when an item requires a controlled

movement to a particular position They are used in a wide range of

industries where linear positioning is needed Typical applications include

the opening and closing of damper doors clamping welding etc

Fluid Power Rotary Fluid Power Rotary Actuators are fluid powered mechanical

devices consisting of cylinder and piston mechanisms

gearing and output shafts giving limited rotational travel

which are used to convert hydraulic fluid gas or differential

air pressure into rotational motion Key specifications include

the intended application fluid power type drive mechanism

mounting configuration output configuration rotation limits and force capacities as well as physical

dimensions as required Fluid power rotary actuators are used primarily in automation applications

when an item requires a controlled rotary movement to a particular position They are used in a wide

range of industries where rotational positioning is needed The actuators are powered by various media

including air or other gases and hydraulic fluid Typical applications include opening and closing dampers

and doors clamping etc

Linear Chain Actuators Linear Chain Actuators are mechanical devices consisting of

sprockets and sections of chain which are used for providing

linear motion via the free ends of the specially designed chains

Key specifications include the intended application drive method

and mechanism actuation length chain size and the mounting

configuration Linear chain actuators are used primarily in motion

control applications for providing a straight line push or pull

motion The chain when straight locks into position with adjacent

links and forms a rigid member They are available in many sizes and chain styles as well as chain

storage options depending on available space in a particular application The actuators typically have

single driving gears or sprockets that produce the forces required for the push and pull motions

Manual Linear Manual Linear Actuators are mechanical devices providing linear displacement through the translation

of manually rotated screws or gears and consist of hand operated knobs or wheels gearboxes and

guided linear motion mechanisms Key specifications include

intended application actuator type drive mechanism travel length

and other physical dimensions as required Manual linear actuators

are used primarily in commercial applications for precise positioning

such as manipulating tools or workpieces Manual actuators are

unpowered and use a rotating knob or hand wheel to operate

There are several types including those with lead screws racks and

pinions belt drive etc each having its specific load and drive force capability Thermo-mechanical

actuators are another type and operate by means of thermal expansion usually on a micro scale

Manual Rotary Manual Rotary Actuators are mechanical devices providing rotary

output through the translation of manually rotated screws levers or

gears and are usually composed of hand operated knobs levers or

handwheels gearboxes or threaded nut mechanisms and output shafts

Key specifications include the intended application drive method and

mechanism mounting configuration valve type if applicable as well as

physical dimensions as required Manual rotary actuators are used

primarily for the operation of valves They are also known as manual

valve actuators or valve operators Valve types can include ball

butterfly check and globe valves Other applications may include any

that require limited and controlled rotational movement

Applications and Industries

Powered actuators generally incorporate motors cylinders or other motion devices to produce rotation

or linear translation Rack and pinion arrangements ball screws and other kinds of power transmission

components connect the motors etc to the loads

Actuators are segregated by motion and power source Linear actuators produce pushpull action

Rotary actuators produce rotational motion In many cases linear actuators begin with a rotary prime

movermdasha motor typicallymdashwhose rotation is converted to linear motion through a power screw or

similar device The opposite is also true many rotary actuators can begin with linear devices such as

hydraulic cylinders which produce circular motion through rack and pinion arrangements

Actuators are used extensively to operate valves remotely A valve so equipped is termed a control

valve (see Valves Buying Guide for discussion of control valves) A typical actuator for a globe valve

needs to be capable of turning the valve stem through its many revolutions between open and closed

Often a globe valve actuator will consist of an electric motor that drives a worm gear which in turn

rotates a nut that engages the threads of the valve operator stem Quarter-turn valves such as ball

valves often use pneumatic actuators to push and pull racks past pinions which impart rotary motion to

the valve ball butterfly etc In short valve actuator designs are closely aligned with the design of the

valve they are intended to operate

Actuators are also used in many linear motion applications where air power is not available to drive

cylinders or where extra force is needed from compact designs One unusual linear actuator uses chain

which when straight forms a rigid length but which can curve around the driving gear to obtain its

motion Other linear motion actuators use toothed belts lead screws or rack and pinion sets to achieve

pushpull action Smaller linear and rotary actuators

often employ direct drive voice coil motors

Linear actuators are used in packaging machines

medical equipment production machinery etc as

well as in a host of transportation industry

applications from aircraft to rail Linear actuators

sometimes combine stepper motors with ball

screws to achieve precise controllable positioning

(left)

Both linear and rotary actuators are available as

manual models that serve as motion devices for

slides etc and as operators for manually operated valves In some

cases manual valve actuators are used as override devices for control

valves that are normally actuated with fluid or electric powered

actuators (right) They are designed to declutch from the control

actuators during normal automatic operation so as not to harm

bystanders

Considerations Picking powered actuators entails knowing such parameters as loading stroke length timing etc Many

of these parameters have limits as to speed and force and narrowing the selection in this manner can

bring the appropriate technology into focus Other considerations include the kinds of services available

Hydraulic actuators provide large forces in small sizes but need a source of hydraulic pressure Air

powered actuators use readily available factory air but there is a tradeoff to be made due to their bigger

sizes for equivalent forces Electric actuators have advantages of better controllability and are less prone

to leaking an advantage in clean-room settings and more economical in the long run Electric actuators

do tend to have appreciably higher first costs They also have advantages in outdoor installation where

air systems can freeze

storage options depending on available space in a particular application The actuators typically have

single driving gears or sprockets that produce the forces required for the push and pull motions

Manual Linear Manual Linear Actuators are mechanical devices providing linear displacement through the translation

of manually rotated screws or gears and consist of hand operated knobs or wheels gearboxes and

guided linear motion mechanisms Key specifications include

intended application actuator type drive mechanism travel length

and other physical dimensions as required Manual linear actuators

are used primarily in commercial applications for precise positioning

such as manipulating tools or workpieces Manual actuators are

unpowered and use a rotating knob or hand wheel to operate

There are several types including those with lead screws racks and

pinions belt drive etc each having its specific load and drive force capability Thermo-mechanical

actuators are another type and operate by means of thermal expansion usually on a micro scale

Manual Rotary Manual Rotary Actuators are mechanical devices providing rotary

output through the translation of manually rotated screws levers or

gears and are usually composed of hand operated knobs levers or

handwheels gearboxes or threaded nut mechanisms and output shafts

Key specifications include the intended application drive method and

mechanism mounting configuration valve type if applicable as well as

physical dimensions as required Manual rotary actuators are used

primarily for the operation of valves They are also known as manual

valve actuators or valve operators Valve types can include ball

butterfly check and globe valves Other applications may include any

that require limited and controlled rotational movement

Applications and Industries

Powered actuators generally incorporate motors cylinders or other motion devices to produce rotation

or linear translation Rack and pinion arrangements ball screws and other kinds of power transmission

components connect the motors etc to the loads

Actuators are segregated by motion and power source Linear actuators produce pushpull action

Rotary actuators produce rotational motion In many cases linear actuators begin with a rotary prime

movermdasha motor typicallymdashwhose rotation is converted to linear motion through a power screw or

similar device The opposite is also true many rotary actuators can begin with linear devices such as

hydraulic cylinders which produce circular motion through rack and pinion arrangements

Actuators are used extensively to operate valves remotely A valve so equipped is termed a control

valve (see Valves Buying Guide for discussion of control valves) A typical actuator for a globe valve

needs to be capable of turning the valve stem through its many revolutions between open and closed

Often a globe valve actuator will consist of an electric motor that drives a worm gear which in turn

rotates a nut that engages the threads of the valve operator stem Quarter-turn valves such as ball

valves often use pneumatic actuators to push and pull racks past pinions which impart rotary motion to

the valve ball butterfly etc In short valve actuator designs are closely aligned with the design of the

valve they are intended to operate

Actuators are also used in many linear motion applications where air power is not available to drive

cylinders or where extra force is needed from compact designs One unusual linear actuator uses chain

which when straight forms a rigid length but which can curve around the driving gear to obtain its

motion Other linear motion actuators use toothed belts lead screws or rack and pinion sets to achieve

pushpull action Smaller linear and rotary actuators

often employ direct drive voice coil motors

Linear actuators are used in packaging machines

medical equipment production machinery etc as

well as in a host of transportation industry

applications from aircraft to rail Linear actuators

sometimes combine stepper motors with ball

screws to achieve precise controllable positioning

(left)

Both linear and rotary actuators are available as

manual models that serve as motion devices for

slides etc and as operators for manually operated valves In some

cases manual valve actuators are used as override devices for control

valves that are normally actuated with fluid or electric powered

actuators (right) They are designed to declutch from the control

actuators during normal automatic operation so as not to harm

bystanders

Considerations Picking powered actuators entails knowing such parameters as loading stroke length timing etc Many

of these parameters have limits as to speed and force and narrowing the selection in this manner can

bring the appropriate technology into focus Other considerations include the kinds of services available

Hydraulic actuators provide large forces in small sizes but need a source of hydraulic pressure Air

powered actuators use readily available factory air but there is a tradeoff to be made due to their bigger

sizes for equivalent forces Electric actuators have advantages of better controllability and are less prone

to leaking an advantage in clean-room settings and more economical in the long run Electric actuators

do tend to have appreciably higher first costs They also have advantages in outdoor installation where

air systems can freeze

needs to be capable of turning the valve stem through its many revolutions between open and closed

Often a globe valve actuator will consist of an electric motor that drives a worm gear which in turn

rotates a nut that engages the threads of the valve operator stem Quarter-turn valves such as ball

valves often use pneumatic actuators to push and pull racks past pinions which impart rotary motion to

the valve ball butterfly etc In short valve actuator designs are closely aligned with the design of the

valve they are intended to operate

Actuators are also used in many linear motion applications where air power is not available to drive

cylinders or where extra force is needed from compact designs One unusual linear actuator uses chain

which when straight forms a rigid length but which can curve around the driving gear to obtain its

motion Other linear motion actuators use toothed belts lead screws or rack and pinion sets to achieve

pushpull action Smaller linear and rotary actuators

often employ direct drive voice coil motors

Linear actuators are used in packaging machines

medical equipment production machinery etc as

well as in a host of transportation industry

applications from aircraft to rail Linear actuators

sometimes combine stepper motors with ball

screws to achieve precise controllable positioning

(left)

Both linear and rotary actuators are available as

manual models that serve as motion devices for

slides etc and as operators for manually operated valves In some

cases manual valve actuators are used as override devices for control

valves that are normally actuated with fluid or electric powered

actuators (right) They are designed to declutch from the control

actuators during normal automatic operation so as not to harm

bystanders

Considerations Picking powered actuators entails knowing such parameters as loading stroke length timing etc Many

of these parameters have limits as to speed and force and narrowing the selection in this manner can

bring the appropriate technology into focus Other considerations include the kinds of services available

Hydraulic actuators provide large forces in small sizes but need a source of hydraulic pressure Air

powered actuators use readily available factory air but there is a tradeoff to be made due to their bigger

sizes for equivalent forces Electric actuators have advantages of better controllability and are less prone

to leaking an advantage in clean-room settings and more economical in the long run Electric actuators

do tend to have appreciably higher first costs They also have advantages in outdoor installation where

air systems can freeze

Pneumatic valve actuators fall into two camps double acting and spring return Double acting means

that air pressure moves the valve in both directions Spring return means that a spring is used on one

stroke which the air pressure must overcome to open (or close) the valve It makes a difference as to

how the valve will behave upon a loss of air pressure A spring return valve will return the valve to its

unpowered state upon an air-pressure loss Hydraulic valve actuators can be fitted in similar fashions

For motion control actuators are selected based on speed requirements and precision Some linear

actuators are designed for micropositioning and rely on piezo crystals to produce very small high

resolution motions which are useful in the nanometer world of optics

semiconductor manufacturing etc More typically belt and ball screw

based actuators impart motion to positioning stages and the like to

achieve repeatability measured in thousandths of an inch Some linear

actuators are used with hand controls such as those found in dental

chairs and do not require positional feedback other than end-of

stroke limit switches Some manufactures even eliminate these limit

switches by providing integral freewheeling at the end of stroke such

as the actuators shown at right

Important Attributes

Mounting Configuration This attribute describes the way in which the actuator attaches to the actuated device Valve actuators

sometimes mount directly to the valve flange or use trunnion mounts to give access to valve stem

packing glands Relative advantages of each method are described in the reference cited below

Actuation Features Selecting double acting or spring return here will choose the failure mode of the actuator upon loss of

air or hydraulic pressure

Output Torque Output torque applies to both electric and fluid powered rotary actuators and describes the rotational

force the actuator can apply to the valve to close it It is usually expressed in in-lb or Nm

Maximum ExtensionRetractionHolding Force These attributes apply to linear actuators and may be sometimes be expressed as a single value such as

maximum thrust force They are usually given in lbf or N

Maximum Speed For powered actuators this is the highest linear or rotational speed the unit can deliver It is usually

expressed as rpm for rotary actuators and as insec for linear devices

Enclosure Protection Rating Electrical enclosures are specified in accordance with NEMA or IEC criteria for environment and ingress

protection

Related Product Categories

Valves see our Valves Buying Guide

Power Screws are mechanical devices or assemblies composed of threaded screws mating nuts

and optional end supports used to convert rotary motion to linear motion

Jacks are electromechanical switches used to protect various devices from voltage current or

thermal overloads

Guides are mechanical devices that are used to position or move objects with high degrees of

accuracy and repeatability

Slides are mechanical devices or systems that provide controlled motion along linear or curved

paths

Hydraulic Cylinders are mechanical devices consisting of pistons and rod assemblies housed

within cylindrical bores and capped on their ends which are actuated by incompressible fluid

pressure

Pneumatic Cylinders are mechanical devices consisting of pistons and rod assemblies housed

within cylindrical bores and capped on the ends which are actuated by air

Resources

General Trade Groups httpwwwvmaorg White Papers httprollonnewscomwhite-papers httpwwwphysikinstrumentecomtechnologyhtml Discussion of ISO valve interfaces httpswwwyoutubecomwatchv=R8zB1BfzK60

Manufacturers and Suppliers httpacmecontrolserviceincthomasnet-navigatorcomcategorypneumatic-actuators httpproductsairmaticcomcategoryactuators-2 httpwwwarivalvecomactuatorshtm httphypercylthomasnet-navigatorcomviewitemsall-categoriescategory-1007 httpasgjergensthomasnet-navigatorcomitemasg-product-groupsrotary-actuatorsitem-1465ampbc=100 httpgobdcthomasnet-navigatorcomcategoryall-category-actuators httpbaelznathomasnet-navigatorcom

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