Contactor

A contactor is a type of relay (electrically operated switch) with high power rating (currentrating and voltage rating). Contactors usually refer to devices switching more than 15 amperes or in circuits rated more than a few kilowatts. Contactors are typically used to control electric motors (combination motor starters), lighting, heating, capacitor banks, thermal evaporators, and other electrical loads. The physical size of contactors ranges from a device small enough to pick up with one hand, to large devices approximately a meter on a side.

Contactors usually have provision for installation of additional contact blocks, rated for pilot duty, used in motor control circuits.