What Is a Solenoid Actuator?

A solenoid actuator is a device that uses electromechanical forces to control internal mechanisms. These devices often include a similar set of internal components. Basically, magnetism created by solenoid electromagnets activates the mechanisms that move a central armature. There are many applications for solenoid actuators and a number of different designs that are most commonly used. Solenoid actuators are considered to have several benefits, especially when compared with hydraulic and pneumatic designs.

Typical configurations for a solenoid actuator include a stem connected to an armature and a spring. Additionally, solenoid electromagnets and associated electrical connections are considered the defining features of these devices. Most of these parts are contained within an often metallic housing. In essence, these actuators are mechanical devices depending on electromagnetism to produce needed force.

When the solenoids are charged, they exert magnetic force on the spring. This activated spring typically connects with the armature and stem, putting the device in an open state. When the solenoids lose power, the spring releases the armature and stem, which usually forces the device into a closed state.

The simplicity of a solenoid actuator allows it to be used in several applications. Brake actuators, for instance, might depend on solenoid electromechanical processes for safe operation. More often, however, a solenoid actuator is used to manage smaller air supply valves. The limited power of these actuators means they can often be used only to a certain threshold before more complex or heavy-duty valves are required.

Most solenoid actuators can be classified as an either direct acting or air pilot design. Direct-acting actuators tend to be used to control low-volume valves, because they contain a single set of electromechanical controls. Air pilot actuators, on the other hand, are a combination of actuator valves and can often be used for higher-volume applications. In air pilot actuators, the solenoids act as a sort of starting mechanism and tend to activate another actuator.

There are several benefits to using a solenoid actuator, especially compared to pneumatic or hydraulic actuator designs. Solenoid actuators tend to operate faster and are typically easier to install and maintain. Both pneumatic and hydraulic actuators tend to be more complex and might require more consistent maintenance and more complex installation procedures. Solenoids generally provide consistent electromechanical forces even as the devices age. A solenoid actuator also is considered reliable, despite being less powerful than some other actuator designs.