The actuator is a device which converts one form to a particular motion.
Generally, there are two types of actuators:
Each can be pneumatic, hydraulic, electric or magnetic.
The difference among the above is the type of energy required for rotary or linear actuator.
Hydraulic Actuator: In a hydraulic actuator, pressurized oil is used for the actuator. the actuator is generally hydraulic cylinder (linear ) or motor(rotary).
There are different types of hydraulic linear actuators: single acting, double acting, telescopic, tandem etc. Also rotary actuator: Gear motor, vane motor, piston motor etc.
The hydraulic actuator is used generally where large force and accurate speed and position control is required.
Pneumatic Actuator: In a pneumatic actuator, compressed air is required for the actuator. Same as hydraulic actuator pneumatic actuators are a cylinder(linear) or motor(rotary).
Linear Pneumatic actuator: single acting cylinder, double acting cylinder, tandem cylinder, stopper cylinder etc.
Rotary pneumatic actuator: rotary fixed rotation cylinder, continuous rotation cylinder etc
The pneumatic actuator is used generally where high speed is required rather than large force. It is also less costly among all.
Electric actuator: Electric actuator use power screw with the motor which required electric power. The rotary motion of the motor is converted in linear motion using screw and nut mechanism.
Electric actuator serves between hydraulic and pneumatic system. It can be used for large force and high speed also.
Magnetic actuator: Electromagnetic actuator is generally solenoid. in which electric energy is converted into the magnetic field and due to magnetic field armature moves on.
It is generally used for small stroke and quick response.