Low-voltage contactor operation and maintenance of what? [Answer] Often or regularly check the operation of the contactor, the necessary maintenance is to ensure its reliable operation to extend its life an important measure. Inspection, maintenance should first disconnect the power, according to the following steps. 1, the appearance of inspection to remove dust, cotton cloth can be stained with a small amount of gasoline wipe the oil, and then dry with a cloth; tighten all crimping wire screws to prevent loose parts, causing the connection part of the fever. 2, contact system inspection 1) Check whether the static and dynamic contact is aligned, whether the three-phase closed at the same time, and adjust the contact spring so that the three-phase. 2) shake measuring phase insulation resistance value. Use 500v shake table, the phase resistance should not be less than 10 megohms. 3) Contact wear thickness of more than 1mm, or severe burn, open the welding should be replaced when the new pieces fall off. Slight hair loss or contact surface hair, black does not affect the use, can not be processed. If the impact of contact, can be polished with a small file polished. 4) After repair or replacement of contacts should pay attention to the contact distance, over travel. Contact over travel will affect the final pressure of the contacts. 5) Check the auxiliary contact action is flexible, static contact is loose or off phenomenon, contact distance and stroke to meet the requirements of the multimeter can measure the contact resistance, found that poor contact and difficult to repair, to replace the new contact . 3, arc hood maintenance 1) Remove the arc chute, brush with a brush to remove the shedding or metal particles. If it is found that the arc chute has cracks, it should be replaced promptly. 2) For the grid interrupter, should pay attention to the grid is complete or burned deformation, serious loosening, changes in location, etc., if not easy to repair should be replaced. 4, the maintenance of the electromagnetic coil 1) AC contactor to attract the coil in the power supply voltage of the coil rated voltage of 85% -105% should be able to work reliably. 2) check the solenoid coil overheating, the coil overheating is reflected in the outer surface aging, discoloration, coil overheating is usually caused due to inter-turn short circuit, this time the measured resistance and similar coils can not be repaired should be replaced. 3) Lead wire and rubbing pieces have no welding or will be disconnected. 4) Whether the coil skeleton crack, wear or fixed abnormal situation. If found should be fixed or replaced as soon as possible. 5, core maintenance 1) wipe the end with cotton yarn dipped in gasoline to remove oil or dust; 2) Check the buffer is complete, the location is correct; 3) whether rivets rupture, leading to loose core end face; 4) short-circuit ring with or without falling off, with particular attention to crack. If broken or cause serious noise, should replace the short circuit ring or iron core; 5) Check the electromagnet pull is good, there is no dislocation phenomenon.