AC contactor is a kind of electrical equipment which is widely used in the field of power system and electrical control. Its main function is to control, cut off and protect the current in the circuit. AC contactor consists of coil, contact, magnetic circuit and mechanical drive part, through the magnetic field generated by the coil to control the switching state of the contact.
The main working principle of AC contactor is to utilize the force generated by electromagnetic induction and mechanical spring force to realize the closing and disconnecting of contacts. When current passes through the coil, the magnetic field generated by the coil causes the contactor's iron core to be attracted to the coil and at the same time compresses the mechanical spring force, thus closing the contact point. When the current stops passing through the coil, the magnetic field disappears and the mechanical spring force causes the iron core to return to its original position, closing the contacts.
The wiring method of AC contactor will be different according to the specific use scenario and requirements, the following describes the general common wiring method:
Normally open contact control: In this wiring method, the normally open contact of the AC contactor is used to control the on-off of the circuit. Connect the load to the normally open contact and connect the power supply to the other end of the load to control the on-off state of the circuit by controlling the coil current of the AC contactor.
Normally closed contact control: In this wiring method, the normally closed contact of the AC contactor is used to control the circuit. Connect the load to the normally closed contact and connect the power supply to the other end of the load to control the on-off state of the circuit by controlling the coil current of the AC contactor.
Cross-control: This wiring method is often used in the need to switch two circuits alternately. The use of two AC contactors, respectively, to control the two circuits. The normally open contact of AC contactor 1 is connected in series with the coil of AC contactor 2, while the normally open contact of AC contactor 2 is connected in series with the coil of AC contactor 1. In this way, controlling the coil current of either AC contactor allows alternate switching between the two circuits.
In addition to the above wiring methods, there are some special wiring methods, such as star angle start, reverse control, etc. According to the specific requirements and control functions, you can choose the appropriate wiring method.
To summarize, AC contactor as a kind of electrical equipment, through the control of the coil current to achieve the closure and disconnection of the contacts, so as to control the circuit on and off. Its main working principle is to use the force generated by electromagnetic induction and mechanical spring force to realize the switching of contacts. According to different use scenarios and requirements, different wiring methods can be selected to realize different control functions.
