A contactor, also called a contactor switch or a contactor relay, refers to a special type of electromechanical device that is specifically designed to switch on and off an electrical circuit. Even though they are components of the relay family, they differ from the latter in the sense that a contactor is primarily used in industrial applications that require higher current capacity. They can function on their own, as parts of motor starters, and as power control devices. As such, typical applications of contactors involve motors, heating equipment, lighting circuits, and equipment with higher electrical loads.
How do contactors work?
Contactors feature high coil voltages, which enable them to connect with electrical devices that have high current loads, typically anything having more than 10 amperes. This is the major difference between the working characteristic of a contactor and a relay. As far as their working principle is concerned, they are capable of being remotely controlled.
Types of contactors
Contactors come in various types, each equipped with its own characteristic specifications to suit a wide range of applications. The specifications that generally determine the different types of contactors are:
AC and DC contactors featuring coils ranging 12 V, 24 V, 48 V, 110 V, 240 V, 400 V, and 440 V.
The reversing or non-reversing functionalities.
Whether the contactor belongs in the AC3 and AC1 categories.
The number of poles in the contactor, which include variants like 2 poles, 3 poles, 4 poles, 8 poles and 10 poles.
The IEC standards determine the performance of the contactors.