Large industrial temperature control systems, assembly lines, energy and other complex manufacturing systems all rely on motors for operation. If that motor overheats, it can be damaged or even destroyed. To prevent this from happening, either an electromechanical relay (EMR) or a solid-state relay (SSR) generally is used in these systems to sense whether the motor is overheating, and if so, turn off the motor in time to prevent damage.
Electromechanical relays have been the standard solution for managing load circuits for more than 150 years. However, in the last decade or so, solid-state relays have taken a great deal of the marketshare.