Function
AC contactor is used to control AC motor (such as AC motor, fan, water pump, oil pump, etc.) and has the function of protection.
1. Start the motor according to the prescribed procedure so that it can work reliably in the control circuit.
2. Connecting and breaking the circuit and controlling the operation of the motor according to the prescribed procedures or not exceeding the rated current and voltage.
3. When the speed of the motor needs to be changed, the speed of the motor may be changed by operating the handle, and the electromagnetic force of the motor may not be abruptly increased.
5. In case of shutdown or power failure, the motor may be stopped immediately or run at a lower frequency (e.g., 40 Hz) by operating the handle.
Main structure
The main structures of AC contactors are as follows:
1、 The main contact is composed of iron core, insulating clapboard and contact.
2、 The auxiliary contact is composed of electrostatic contact and moving iron.
3、 Moving iron core: Moving iron consists of electromagnetic iron core and coil.
4、 Iron core is the core component of the AC contactor, which is composed of an iron core and a coil which are coaxial with the main iron core, and is the main part of the contactor. The utility model is mainly used for absorbing or releasing the large current in the main circuit of the main contact and connecting the small current circuit.
5、 Enclosures are used to protect internal components, such as fuses and air switches, also known as “insulated” elements in AC contactors.
6、 Insulating diaphragm is static iron and moving iron used for dividing contactor to ensure sufficient separation between the two contacts to ensure normal operation of contact.
Principle of operation
Working principle of AC contactor: The main circuit of AC contactor is a control circuit, which is composed of electromagnetic system, iron core and shell.
When the main circuit is turned on, a closed magnetic field is generated between the coil core and the moving iron in the electromagnetic system.
Because the electromagnetic system is a static magnetic field, when the coil of the electromagnetic system is cut off, the magnetic system still produces an electromagnetic force between the core and the shell.
Due to the existence of electromagnetic force, the moving iron remains in a separate state. The coil then maintains a certain flux (the magnetic flux of the coil itself) and a voltage (alternating voltage).
When the coil is electrified, the electromagnetic system will generate a very large magnetic field, the electromagnetic force in the role of the iron off the coil quickly;
Requirements for Safe Use
V、 Precautions.
1. The working voltage level of the contactor shall be AC 220V, and the contactor shall work at the rated working voltage. Like the direct current contactor, attention shall be paid to:
(1) Before use, it is necessary to check whether the wiring is correct and whether the contact of the contactor is worn or oxidized.
(2) Before installation, the surface dirt, dust and other impurities shall be removed, and the sealing surface and anti-rust layer of the contactor shall be inspected.
(3) The terminal shall be fastened after installation.
(4) When the contactor is in use, when the coil is energized, there is a “Weng” sound, indicating that the contact has been sucked, do not arbitrarily rotate, so as not to damage the coil or the contact. The main contact of the contactor in use shall be kept normally open.
(5) If the contact action is not flexible in use, the coil and contact shall be timely checked to see whether the coil and contact are broken or damaged.
Post time: Mar-01-2023