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

Promulgator : TAIXIDate : 2018-09-10Views : 13

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 Household Contactor.

The operation voltage of Din Rail Mounted Contactor 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 Household 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. Din Rail Mounted Contactor 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.

Household Contactor is the most commonly used low voltage control appliance in electric drive and automatic control system. As an executive element, it is used to connect, break lines, or frequently control the operation of motors and other devices. The utility model is composed of a moving main contact, a static main contact, an arc extinguishing cover, a moving iron core, a static iron core, an auxiliary contact and a support shell, etc. After the electromagnetic coil is electrified, the moving iron core is sucked under the action of electromagnetic force, and the moving contact is contacted with the static contact directly or through the lever drive, and the circuit is connected. After the electromagnetic coil is cut off, the moving iron core returns automatically under the action of the reset spring, commonly known as release, the contacts are separated, and the circuit is broken.

Din Rail Mounted Contactor is a kind of intermediate control element, its advantage is that it can be frequently on and off the line, with small current control large current. Working with thermal relay can also play a role of overload protection for load equipment. Because it works by electromagnetic field suction on and off, it is more efficient and flexible than manual switching circuit. It can divide and close multiple load lines at the same time. It also has self-locking function. After manual short connection, it can enter the self-locking state to work continuously.