ACTUATORS Types

Thermal actuators are actuators that convert thermal energy into movement. One type of thermal actuator is a bimetallic strip, a strip made from two different metals such as steel and copper. The two metals have different temperature coefficients, which means, that when heated, they expand at two different rates.

Electric actuators use electricity or electrical energy to create motion. An electric motor is a type of an electric actuator. Most direct current (DC) motors operate by current flowing through a coil of wire (the rotor) and creating a magnetic field around the coil. The coil is wrapped around the motor’s rotor, creating a loop, and is positioned between the poles of a permanent magnet or electromagnet.

Mechanical actuators convert a mechanical input into linear or rotary motion. A common example of a mechanical actuator is a screw jack. The picture shows a screw jack in operation. Rotation of the screw causes the legs of the jack to move apart or move together.