Electromechanical relays are devices that complete or interrupt a circuit by physically moving electrical contacts into contact with each other.
Understanding Electromechanical Relays
Electromechanical relays are electrically operated switches used to isolate circuits or batteries, detect faults on transmission and distribution lines, and control a high powered circuit using a low power signal. Simple relays consist of a magnetic core wrapped in a wire coil, a movable armature attached to an iron yoke, and one or more set of contacts. When an electric current passes through the coil it generates a magnetic field that activates the armature, therefore moving the contacts to make or break a connection.
The diagram below shows the parts of a relay and its operation. The relay on the left is off, meaning there is no current flowing to the coil. The relay on the right has switched on due to the energizing of the coil and subsequent movement of the armature and contact.