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Last edited 03 Aug 2023
An actuator is a component of a machine that is responsible for moving or controlling a mechanism or system, by converting energy into motion. It is the mechanism by which a control system acts upon an environment. It can be a simple system, such as fixed or electronic, or software-based, such as robot control.
The most common types of actuator are as follows:
Pneumatic actuators convert energy formed by a vacuum or compressed air at high pressure into either linear or rotary motion. The advantage of this type of actuator is that has a quick response time as the power source doesn’t need to be stored in reserve. Large forces can be produced from relatively small pressure changes.
Hydraulic actuators consist of a cylinder or fluid motor that uses hydraulic power to drive mechanical operation. The motion output can be linear, rotary, or oscillatory. The cylinder consists of a hollow tube along which a piston can slide. Despite having limited acceleration, a hydraulic actuator can exert considerable force as liquids are virtually impossible to compress.
An electric actuator is powered by electrical energy converted by a motor. Electrical energy is used to actuate equipment such as multi-turn valves. Its advantage is that it is one of the cleanest forms of actuator as no oil is required.
 Thermal or magnetic
A mechanical actuator functions by converting rotary motion into linear motion to execute movement. It involves gears, rails, pulleys, chains, and other devices to operate. An example is a rack and pinion mechanism.
NB Guide to Controls (BG 83/2023) written by John Marrow and published by BSRIA in June 2023, defines an actuator as: ‘An electromechanical device which moves the position of a valve or damper in response to a control signal.’
Other types of actuator include:
- Electronically positioned actuators.
- Linear actuators.
- Power fail actuators.
- Pulsed input actuators.
- Rotary actuators.
- Spring actuators.
- Thermoelectric actuators.
- Adaptive structures.
- Air source heat pumps.
- BSRIA announces 2021 European HVAC field device study.
- Electric motor.
- Exhaust air heat pump.
- Institution of Mechanical Engineers.
- Key qualities of springs.
- Mechanical and electrical.
- Mechanical engineer.
- Mechanical ventilation.
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