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

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;

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:

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.

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.

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Extended reading:How to use CJX2 AC contactor