A contactor is a type of switchgear that uses electromagnetic, pneumatic or hydraulic principles to control the on-off of the main circuit. It is widely used in industrial automation and new energy vehicles, mainly for controlling electrical loads such as electric motors and electric welding machines. It has characteristics such as strong current interruption capability, rapid operation, and long-distance control. It is often used in combination with fuses, and can be classified by driving method as electromagnetic or permanent magnet types. It can also be classified by arc extinguishing medium as air type or vacuum type. [5] [10]
A contactor consists of an electromagnetic mechanism, a contactor system, and an arc extinguishing device. When the coil is energized, it generates magnetic force to drive the contacts to close. The new hybrid DC contactor uses reverse parallel thyristors to achieve arc-free interruption, and the permanent magnet operating mechanism uses an energy storage capacitor to reduce energy consumption. Intelligent contactors have autonomous interruption protection and reset functions, and multiple insulation designs enhance safety in high-voltage environments. The national standard GB/T 14048.4-2020 stipulates the usage categories and overload ratings of AC-3 and AC-4, etc.