A magnetic clutch relay is a type of electromagnetic device that is used to engage and disengage two rotating shafts. The device consists of an electromagnet, which is energized when a current is applied to it, and a ferromagnetic disk that is mounted on the shaft. When the electromagnet is energized, it creates a magnetic field that attracts the disk and causes it to rotate. The amount of force exerted by the electromagnet can be controlled by adjusting the current.