What are contactors and what are their characteristics?

Promulgator : TAIXIDate : 2018-11-30Views : 37

Household Contactor refer to electrical appliances in industry that use coil current to generate magnetic field to close the contacts so as to control the load.

Contactors have the advantages of high operating frequency, long service life, reliable operation, stable performance, low cost and simple maintenance. They are mainly used to control motor, electrothermal equipment, welding machine, capacitor bank, etc. They are one of the widely used control devices in electric drive automatic control circuit.

Household Contactor can be divided into AC contactors and DC contactors according to the types of current through their contacts.

Household Contactor
are divided into AC contactors (voltage AC) and DC contactors (voltage DC), which are used in power, distribution and power applications. Contactors in a broad sense refer to electrical appliances that use coil current to generate magnetic field and close contacts in order to control load.

The working principle of the Din Rail Mounted Contactor is that when the coil of the contactor is electrified, the coil current will generate magnetic field, which will make the static iron core attract the core by electromagnetic attraction, and drive the action of the AC contactor point. The contacts of the contactor are often disconnected and the contacts of the contactor are often closed. The two are linked. When the coil is cut off, the electromagnetic attraction disappears, and the armature is released under the action of the release spring, which restores the contacts. The open contacts are often disconnected and the closed contacts are often closed. The working principle of DC contactor is similar to that of temperature switch.

AC contactor is a kind of intermediate control element, which has the advantage of frequent on-off and off-line to control large current with small current. Cooperating with thermal relay can also play a certain role in overload protection of load equipment. Because it relies on electromagnetic field suction to turn on and off, it is more efficient and flexible than manual switch-on and switch-off circuit. It can split and close multiple load lines at the same time. It also has self-locking function. After manual short engagement, it can enter self-locking state and work continuously. Din Rail Mounted Contactor are widely used in power switching and control circuits. AC contactor uses main contacts to turn on and off the circuit and auxiliary contacts to execute control instructions. The main contacts usually have only regular open contacts, while the auxiliary contacts often have two pairs of contacts with normal open and normal closed functions. Small contactors are often used as intermediate relays to cooperate with the main circuit. The contact of AC contactor is made of Ag-W alloy, which has good conductivity and high temperature ablation resistance. The action power of Din Rail Mounted Contactor comes from AC electromagnet. The electromagnet is composed of two "hill" shaped young silicon steel sheets. One of them is fixed and coils are coiled on it. There are many options for working voltage. In order to stabilize the magnetic force, a short circuit ring is added to the absorbing surface of the iron core. After the AC contactor loses power, it relies on spring to reset. The other half is a movable core, which is constructed like a fixed core to drive the opening and closing of the main and auxiliary joints. Contactors above 20 amperes are equipped with an arc-extinguishing cover to quickly pull out the arc to protect the contacts by utilizing the electromagnetic force generated when the circuit is disconnected. As a whole, the shape and performance of AC contactor are constantly improving, but its function remains unchanged. No matter how far the technology develops, the common AC contactor still has its important position.