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Common faults, diagnosis and treatment of AC contactor

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    I. armature and static core cannot be reliably closed

    (1) the power supply voltage is too low. In this case, the reduction of the electromagnetic induction absorption force of the armature's reliable engagement will lead to the armature's sometimes engagement and sometimes disconnection, which cannot be reliably engaged. Therefore, the power supply voltage should be increased.

    (2) if the coil is disconnected or damaged, or the rated voltage of the coil is too low, the coil shall be replaced.

    (3) the power supply voltage fluctuates greatly. It will make the electromagnetic induction adsorption force fluctuate from low to high, and then make the armature unable to be reliably absorbed.

    (4) the short circuit fault ring is broken. Maintenance method: fix the welding car with epoxy resin glue at the fracture. If it cannot be repaired, the short circuit fault ring shall be removed and replaced to the core.

    (5) when the power supply is disconnected, check the route from the power supply to the contactor to avoid the disconnection of one phase line. If the contactor operates the motor, it will cause unilateral operation of the motor, which will cause great damage to the motor. If it is serious, it will burn the motor and cause short-circuit fault safety accident.

    (6) the iron core is inclined, or a movable part of the mechanical equipment is stuck. The maintenance method is to adjust the core position or adjust the parts that are stuck with each other.

    (7) too much contact spring pressure and release spring pressure. The maintenance method is to adjust the elastic yellow pressure or to remove and replace the elastic yellow armature under the effect of elastic yellow. If the elastic yellow pressure is too large, it will prevent the armature from closing. The main parameters of the contact shall be adjusted according to the regulations.

    (8) there must be floating dust and stains when the iron core is corroded. Wipe the dust with a thin cloth.

    (9) the iron core pole is damaged too much and uneven. The solution is to change the core.

    II. When the coil is powered off, the armature does not release or releases slowly

    (1) the contact produces fusion welding. When the amount of current passing through the contact is too large, the high temperature caused by the large electric flow is very easy to fuse and weld the closed contact together. After the contact is fused and welded, it is not easy to disconnect, which will cause that the armature cannot be released. Use the cutter head to hang off the welding core gently. If the fusion welding is serious, remove and replace the contact.

    (2) there is oil stain on the iron core pole. The maintenance method is to wipe off the oil stain with a clean thin cloth.

    III. the coil of AC contactor is overheated or burnt

    (1) the power supply voltage is too high. The amount of current passing through the coil will be increased and the supply voltage should be adjusted to a suitable value.

    (2) the power supply voltage is too low. The armature can not be reliably closed, and the connection point will be connected and disconnected from time to time, because the current through the coil is very large at the moment of connection and disconnection, which will cause the coil current to be too large, which will overheat the coil and damage the coil. The armature is not fully closed, resulting in the expansion of coil current (this common fault is accompanied by vibration and noise. The solution is to take effective measures according to the cause of incomplete armature engagement.

    (3) if the technical parameters of the coil, such as the rated voltage, do not conform to the actual application standard, replace the appropriate coil.

    (4) the actual operation frequency is too high. The solution is to increase the actual operation time interval or replace the coil or contactor contact with high actual operation frequency, which will make the coil current too large. Choose another suitable contactor.

    (5) the coil is not manufactured well or the insulation layer is damaged. Remove and replace the coil and remove the common faults that cause the insulation layer of AC contactor coil to be damaged.

    (6) special application environment standard: for example, the gas is wet and cold, with corrosive vapor or the working temperature is too high, the coil with special design scheme shall be selected. The coil is damaged and electrified due to the wet and cold installation environment or corrosive vapor. The solution is to remove and replace the coil with special insulating layer and to adopt waterproof and anti-corrosion measures.

    (7) part of the AC contactor movement is stuck. Check the stuck position and fault detection.

    (8) there must be dirt, dust and rust on the surface of the communication iron core to absorb the displacement of the surface, so as to eliminate the roadblock and level the surface.

    (9) the coil has inter turn short circuit fault. The solution is to replace the coil.

    IV. high noise during operation

    (1) the power supply voltage is too low. When the armature vibrates, the power supply voltage should be increased.

    (2) the short circuit fault ring is broken. The short-circuit fault ring has the function of clearing the armature vibration and noise. If the short-circuit fault ring is broken, the noise cannot be removed. Replace the core or reinstall the short-circuit fault ring.

    (3) if the iron core pole is damaged too much and uneven, remove and replace the iron core.

    (4) there are stains, floating dust or rust on the iron core pole. Remove the iron core.

    (5) excessive contact spring pressure. The armature vibrates, causing noise and adjusting the contact spring yellow pressure.

    (6) the magnetic system software is inclined or the mechanical equipment is stuck, so that the iron core can not be closed. Clear common faults of mechanical equipment stuck.

    V. contact welding

    (1) the actual operation frequency is too high or the electric flow in operation is too large, and the disconnection volume is insufficient. The solution is to replace some contactors with larger rated voltage.

    (2) long term overweight application. The current passing through the contact expands, and the high temperature burns the contact around the contact.

    (3) if the contact spring pressure is too small or too large, adjust the contact spring pressure.

    (4) short circuit fault at load side. If the short-circuit fault causes a large short-circuit capacity of the control line, the power supply shall be disconnected, the load control line shall be checked, the short-circuit fault shall be cleared, and the contact shall be removed and replaced. When the breaking capacity of the contact is not enough, the contact will be stuck after the load side short circuit fault occurs. The solution is to remove and replace the contact, and the more complete method is to change it into a contactor with high breaking capacity.

    (5) during the closing process, the vibration is too strong, and several times of vibration are produced. The solution is to find out the cause of vibration (for example, the voltage supplied by the coil is too low to make the contact vibrate due to the vibration of the closing), and then take effective measures.

    (6) after the contact of the AC contactor is seriously ablated, the surface of the contactor becomes smaller and looser. The maintenance method is: use a fine filigree knife to carefully repair and repair the surface, if not, remove and replace the new contact.

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