Working principle of contactor: When the coil is energized, the static iron core generates electromagnetic attraction to attract the moving iron core. Because the contact system is linked with the moving iron core, the moving iron core drives the three moving contacts to run at the same time, and the contacts are closed, thus turning on the power supply. When the coil is powered off, the suction disappears, and the linkage part of the moving iron core is separated by the reaction force of the spring, so that the main contact is disconnected and the power supply is cut off.
Maintenance points of AC contactor
When maintaining electrical equipment, the contactor should be maintained from the following five points.
1, external maintenance:
1) Clean external dust;
2) Check whether the fasteners are loose, especially the conductor connection part, to prevent the contact from loosening and heating;
2, contact system maintenance:
1) Check whether the positions of dynamic and static contacts are aligned and whether the three phases are closed at the same time. If there is any problem, adjust the contact spring;
2) Check the degree of contact wear. The wear depth shall not exceed1mm. If the contact is burnt, it shall be replaced in time when welding falls off. When slightly burned, it generally does not affect the use. Sandpaper is not allowed to be used when cleaning contacts, and plastic files should be used;
3) Measure the insulation resistance between phases, and the resistance value shall be no less than10mΩ; ;
4) Check whether the auxiliary contact moves flexibly, and the contact stroke should meet the specified value. Check whether the contacts are loose and fall off. If problems are found, repair or replace them in time.
3, iron core part maintenance:
1) Clean the dust, especially the dust between the moving parts and the contact surface of the iron core;
2) Check the fastening of the iron core. Loose iron core will increase running noise;
3) Iron core short-circuit ring falls off or breaks, which should be repaired in time.
4. Electromagnetic coil maintenance:
1) Measure the insulation resistance of the coil;
2) Whether the coil insulation is discolored or aging, and the surface temperature of the coil shall not exceed 65 degrees;
3) Check the connection of the coil lead, and repair it in time if there is welding or burning.
5, arc extinguishing cover part maintenance:
1) Check whether the arc extinguishing cover is damaged;
2) whether there is looseness or position change of arc extinguishing cover;
3) Remove metal particles and sundries in the gap of arc extinguishing cover.