How to Select Contactors

Promulgator : TAIXIDate : 2019-01-02Views : 34

Contactors are mainly composed of electromagnets and contacts. Household Contactor with larger capacity also have arc extinguishing devices. When the coil is not electrified, the disconnected contact is called the constant open contact, and the closed contact is called the constant closed contact. When the coil is electrified, the electromagnet generates suction and attracts the armature, closing the normally open contacts and disconnecting the normally closed contacts. When the coil loses power, the electromagnet loses its suction, the open contacts are often disconnected, and the closed contacts are often closed, thus realizing the opening and closing of the circuit.

Selection of contactors should meet the following requirements:

(1) The rated working voltage of the main contact of the Din Rail Mounted Contactor shall be greater than or equal to the rated voltage of the load.
(2) The rated working current of the main contact of the contactor should be greater than or equal to the current of the load circuit. If the motor is controlled by a contactor, the rated current of the main contact of the contactor is generally reduced to one level.
(3) The breaking capacity and overload current tolerance of the contactor should be higher than the current value that may occur in the circuit.
(4) The types of contactors used should be adapted to the requirements of control objects and operating conditions.

How Consumers Choose AC Household Contactor Correctly

What makes our AC contactors so popular and enduring? Next, let me share with you some of my company's common sense about AC contactor purchase:

1. How to choose the size of AC Din Rail Mounted Contactor according to the size of motor?
The choice of AC contactor should first consider the large, medium and small motors. In general, the AC contactor used in small and medium-sized motors is chosen according to the rated current of the motor. That is to say, if the current of 10KW motor is about 22A, the AC contactor selection should be 20A. Of course, also consider whether your motor is always in full load. Large motors choose AC contactors according to the rated current of the motor 1.5-2 times.

2. After determining the appropriate size of AC Household Contactor, what factors should we consider next?
Usually after we have determined the rated current and voltage of AC contactor, we should consider the practical functions of AC contactor, such as: whether the AC contactor is too big to install; whether the power consumption of AC contactor is too large, thereby reducing the service life of AC contactor; whether the AC contactor has arc extinguishing and dust-proof related safety performance design. Wait a minute. If the AC contactor you have purchased has the above performance at the same time, then congratulations, you are a satisfactory AC contactor, you can safely purchase and use.

The working principle of AC Din Rail Mounted Contactor: When the coil of AC contactor is connected to the power supply, the magnetic field is generated by the passage of current in the coil. Under the action of electromagnetic force, the static core of AC contactor conquers the reaction force of spring and sucks the dynamic core together, so that the dynamic and static contacts are contacted and the main circuit is connected. When the coil of AC contactor is cut off, the electromagnetic attraction of the static core disappears. The moving iron core is reset under the reaction force of the spring, so that the moving contact and the static contact are separated and the main circuit is cut off.