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AC Contactor Self-locking State Of Continuous Work
Jun 21, 2017

AC contactor through its own normally open auxiliary contact so that the coil is always in the state of power is called self-locking. This normally open auxiliary contact is called a self-locking contact. In the contactor coil power, the use of its own normally open auxiliary contact to maintain the loop connected to the state, the general object is the control of its own loop. Such as the normally open auxiliary contact in parallel with the start button, so that when the start button is pressed, the contactor moves, the auxiliary contact is closed, the state is maintained, and then the start button is released and the contactor is not disconnected The

AC contactor is an intermediate control element, can be frequent through, off the line, with a small current control high current. With the thermal relay used together, but also on the load equipment to play a certain role in overload protection. Compared with the manual hand, closing circuit, AC contactor is more efficient, can be used flexibly, and at the same time, together with multiple load lines, as well as self-locking function, through the manual short after the pull, you can enter from The lock state continues to work.

First, the three-phase power supply connected to the contactor's main contacts L1, L2, L3, and then from the contactor T1, T2, T3 connected to the three terminals of the three terminals, the main circuit.

Control circuit: from L1 leads to a line stop button (stop button is normally closed, start button is normally open, this should know it!) From the stop button out of the start button and one end of the contactor auxiliary contact, And then from the other end of the start button to the other end of the auxiliary contact (this part is the self-locking), from the end of the line connected to the coil A1, coil A2 outlet L2 or L3.

Let's take a look at the AC contactor wiring diagram and the AC contactor.

Use the connection

First, the general three-phase contactor a total of 8 points, three input, three output, there are two control points. Output and input are corresponding, it is easy to see. If you want to add self-locking, you also need to output a line from the terminal to the control input point.

Second, we should first know the principle of AC contactor. He is using the external power supply to the coil, resulting in electromagnetic fields. The power is applied and the contact point is disconnected after power failure. Know the principle, you should figure out the connection of the external power supply, that is, the coil of the two contacts, generally in the lower part of the contactor, and each side. The other few input and output in the upper part of the general, a look to know. Also note that the voltage applied to the power supply is much (220V or 380V), are generally marked with. And note that the contact point is normally closed or normally open. If there is self-locking control, according to the principle of the line on it.

working principle

When the coil is energized, the static core produces electromagnetic attraction, the moving core will be sucked, because the contact system is linked with the moving core, so the moving core drives the three action contacts at the same time, the main contact is closed, and the main Contact mechanical connection of the auxiliary normally closed contact open, auxiliary normally open contact closed, thus turning on the power. When the coil is powered off, the suction disappears, and the moving core interlocking part is separated by the reaction force of the spring so that the main contact is disconnected and the auxiliary normally closed contact which is mechanically connected with the main contact is closed and the auxiliary normally open contact is disconnected , Thereby cutting off the power supply.

Above is the AC contactor wiring diagram display, do not know we read Xiaobian introduced above to the use of solutions and working principle, is not on the AC contactor wiring diagram with a further understanding of it? Electromagnetic, permanent magnet and Vacuum is the AC contactor of the three categories, we can according to their own needs to buy, there is little need to pay attention to, AC contactor can only be used in the AC line, so can not connect the AC contactor on the DC , Otherwise it will burn the line, serious words will burn the equipment.