What are the main measures to improve the life of contactors?

Promulgator : TAIXIDate : 2018-10-16Views : 103

Household Contactors are divided into AC contactors (voltage AC) and DC contactors (voltage DC), which are used in electric power, distribution and power applications. Contactors in a broad sense refer to the use of coil current in industrial electricity to generate magnetic field, so that the contact closed, in order to control the load of electrical appliances.

The working principle of the Household Contactor is: when the coil of the contactor is electrified, the coil current will produce magnetic field, which makes the static iron core produce electromagnetic attraction to attract the iron core, and drive the AC contactor point action, often close contact break, often open contact close, the two are linked. When the coil is cut off, the electromagnetic suction disappears, and the armature is released under the action of the release spring, which makes the contact restore, and the open contact is disconnected and the closed contact is closed. The working principle of DC contactor is similar to the principle of temperature switch.

Household Contactor is an important component of low-voltage electrical apparatus. Its life is one of the quality evaluation and main indexes. So it is very important to take some measures to improve its life.

Reasonable matching of suction characteristics and reaction characteristics can improve the life of Din Rail Mounted Contactor.

The contact voltage is 85%~110% Un. When the contact is closed and the iron core is sucked in, the first and second runout of the contact may cause the contact to weld and increase its electric erosion. In order to reduce the contact bouncing time, the mass and velocity of the contact should be reduced appropriately, and the initial contact force should be increased appropriately. In order to reduce and prevent the second bounce of contacts (which is more harmful due to the large starting current), besides the good combination of suction and reaction characteristics to reduce the impact energy, the electromagnetic system should be equipped with a buffer device to absorb kinetic energy such as armature.

For rotating structure, changing the lever ratio between armature arm and contact arm properly can change the contact pressure and closing speed of the contact, thus improving the contact bouncing.

The magnetic ring of AC core is a weak link in machinery. When the armature collides with the core, the stress at the root and corner of the outer part of the core is the greatest, and it is easy to break. At present, the commonly used process is to insert the separating ring into the slot of the magnetic pole of the static iron core, and bond it with adhesive around it to increase the mechanical strength.

In order to improve the mechanical life of Din Rail Mounted Contactor, the pole area can also be properly increased to reduce collision stress. The polar surfaces of AC cores and the angular parts of DC cores can also be hardened to extend their service life. It is very effective to reduce the friction coefficient and improve the wear resistance of bearings or guideways that the rotating parts are reasonably selected, such as Plastics-plastics or plastics-metals with small friction coefficient and strong wear resistance, or a small amount of molybdenum disulfide or graphite is added to the thermo-inversion plastics.

What are the contents of the Din Rail Mounted Contactor installation and commissioning?

When installing contactor wiring, attention should be paid not to make screw, washer, wiring head and other parts lost, so as to avoid falling into the Din Rail Mounted Contactor and causing stuck or short circuit phenomenon. The screws should be tightened during installation so as to prevent vibration from loosening.

After checking the correct wiring, the coil should be turned on and off several times before the main contact is energized to check whether the action of the product is reliable.