Contactor types, structure and working principle
The contactor is a voltage-controlled switching device suitable for systems that frequently turn on and off the AC-DC circuit. It belongs to a kind of control device, and it is one of the most widely used low-voltage electrical appliances in electric drive system, machine tool equipment control circuit and automatic control system.
According to the types current which run through the contacts, it can be divided into AC contactor and DC contactor.
Features of AC contactor
The AC contactor is an on-off switch applied in the AC power environment and is most widely used in various control circuits. It features low voltage/zero voltage release protection, reliable operation, stable performance, high operating frequency, and easy maintenance.
In practical applications, the AC contactor is mainly used as an on-off switch in the AC power supply line to achieve long-distance connection and disconnection line functions, such as in frequent starting and breaking control lines of AC motors, welding machines and electric heating equipment.
From the figure below, it can be seen that the AC contactor is installed in the motor control box and is mainly used to control the turning on or off of the power supply of the motor so as to control the start and stop of the three-phase AC motor.
Application of AC Contactor in Continuous Control Circuit of Three-phase AC Motor
DC contactor features
The DC contactor is an on-off switch applied in the DC power supply environment, and also has the characteristics of low voltage release protection, reliable operation, and stable performance.
In practical applications, DC contactors are used to remotely switch on and off the DC power supply or control lines and common DC motor start-stop control.
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