When the contactor coil is not powered, the auxiliary contact of the contactor is in a natural state and does not conduct. It is usually represented by NO, and normally open is open; Normally closed refers to the contact point where the auxiliary contact is in a conductive state in its natural state, usually represented by NC. Normally closed is connected. Contactors are divided into AC contactors (voltage AC) and DC contactors (voltage DC) according to the main contact connection circuit. Divided by operating mechanism: electromagnetic contactor, permanent magnet contactor. Contactors are mainly used in power, distribution, and electric field applications to effectively protect the mechanical and electrical life of electrical appliances. Next, let's talk about the functions of the normally open and normally closed contacts of the communication contactor.

1、 The role of normally open and normally closed contacts in communication contactors

58彩票Normally open contact: When the contactor is not working, this contact is open circuit;

Normally closed contact: When the contactor is not working, this contact is closed;

58彩票When working, the normally closed contact is disconnected first, and then the normally open contact is closed; When the contactor coil is powered off, the normally open contact opens first, and the normally closed contact closes and resets.

The normally closed point and normally open point are equivalent to two switches, which only serve to connect and disconnect the circuit. What is the voltage applied to the normally open point when the coil is closed.

2、 How to identify the normally open and normally closed contacts of an AC contactor?

The normally open and normally closed contacts of an AC contactor can be measured statically. The general rule is normally closed contacts, while different ones are normally open contacts.

When the contactor coil is not energized, the closed contact is the normally closed contact, and the opened contact is the normally open contact. The opposite is true when the coil is energized and attracted.

The connection point is also defined in this way.

3、 Do AC contactors not need to be normally open or normally closed?

Can the communication contactor be controlled directly with two normally open and normally closed buttons instead of normally open and normally closed? What are the functions of normally open and normally closed on the contactor, and what are the benefits of using normally open and normally closed contactors? An AC contactor controls a motor.

Answer:

58彩票It depends on how to use the AC contactor (assuming understanding). If auxiliary contacts are not used and the button is not self-locking, then only incremental control can be achieved by pressing the button to close the contactor and start the motor. Release the button contactor to stop the motor.

If a self-locking button is used, press the button to start the motor. At this time, the button will lock itself, and even if the contactor is released by hand, it will not be released, and the motor will not stop.

If there are two buttons without self-locking, then the normally open contactor should be used to assist in contacting them and self-locking after they are pulled in.

58彩票The normally closed point of the contactor is generally used for interlocking or signal transmission with other equipment. Interlocking, reversing, stop indication, etc. of star delta contactors.

4、 Why does the positive and negative of alternating current constantly change? The phase line is electrified while the neutral line is not

58彩票Firstly, there is no relationship between the polarity of electric wires and power sources. The reason why wires can electrify people is that wires, the human body, and the earth form a circuit, and there will be current passing through it. When the current passing through is greater than the human body's ability to withstand it, people will feel electrified. Therefore, when a person stands on the ground and touches a wire, as long as the voltage of the wire to ground is greater than a certain value (due to

5、 Does alternating current have two directions of current

58彩票Does alternating current have two directions of current? It is a misconception among most people that alternating current has two directions of current, but in fact, it only has one direction of current. We know that the direction of current always flows from high potential to low potential. It is easier for us to understand direct current, but it seems difficult for people to understand alternating current. We know that the magnitude and direction of alternating current vary periodically according to a sine waveform

6、 Explanation of knowledge on AC short circuit

Explanation of AC Short Circuit Knowledge: AC power can be directly short circuited by connecting wires, and adding a power consuming device in the middle will solve the problem. Below, I will share with you the knowledge of AC short circuit. In fact, the power consuming device added in the middle of the wire is also in a short-circuit state. For example, when a light is added, the current flows from the live wire through the light to the neutral wire. But this short circuit won't burn the wires or jump

7、 How to determine whether it is direct current or alternating current

58彩票How to determine whether it is direct current or alternating current? There is no distinction between positive and negative poles for alternating current. Turn the multimeter on the AC gear, and if the voltage is unknown, select the high gear first, gradually decrease it, and if the test reading remains unchanged, it will be a current. Twist the multimeter to the DC position, with the black and red probes touching the two electrodes respectively. If the probes are reversed, switch the probes again. At this point, the pointer rotates forward and the reading is high, indicating DC

58彩票8、 Principle of power system ice melting and the ratio of AC ice melting to DC ice melting

The principle of power system ice melting and the comparison between AC ice melting and DC ice melting. The principle of power system ice melting is that the resistance generates heat through current to melt the ice on the wire and slowly melt it at the contact point with the wire. It falls off and separates from the wire under the action of gravity. 1、 The principle of heat generation calculation is Q=IRt=RtU/Z, in which: I - current R - resistance t - time U - voltage Z - impedance 2. AC defrosting and DC defrosting

Extended reading:How to use CJX2 AC contactor