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Common Fault Analysis Of Contactor

Views: 8     Author: Site Editor     Publish Time: 2022-10-11      Origin: Site

The magnetic ac contactor can not only connect and cut off the circuit, but also has the function of low voltage release protection. The magnetic ac contactor has a large control capacity and is suitable for frequent operation and long-distance control. It is one of the important components in the automatic control system.

At present, as the most frequently used electrical component in electrical work, the magnetic ac contactor will have some small faults in daily life. Here are some common fault analysis for you:

1. Contactor Does Not Act Or Acts Abnormally

①. Check whether the terminal is disconnected or loose.

②. If the coil is damaged, use a multimeter to measure the resistance of the coil. If the resistance is ∞, the coil is damaged.

③. The contact spring pressure or release spring pressure is too large, adjust the spring pressure or replace the spring.

④. The button contact or auxiliary contact is in poor contact, clean the contact or adjust the contact point.

⑤. The contact overtravel is too large, adjust the contact overtravel.

⑥. The coil power supply voltage is too low or fluctuates too much. Adjust the coil supply voltage.

⑦. If the thermal relay does not reset after the action, use a multimeter to electrically block the resistance between the two normally closed points of the thermal relay. If the resistance value is ∞, press the reset button of the thermal relay.

⑧. The voltage of the control power supply does not match the voltage of the coil, and the rated voltage of the coil is higher than the line voltage, so replace it with a coil suitable for the control line voltage.

⑨. Insufficient operating power supply capacity or disconnection, wrong wiring and poor contact of control contacts, increase power supply capacity, correct wiring, and repair control contacts.

⑩. If the product itself is damaged (such as the coil is broken or burned, the mechanical movable part is stuck, the rotating shaft is rusted or skewed, etc.), replace the coil, eliminate the stuck fault, and repair the damaged parts.

2. AC Contactor Pull-in Is Abnormal

Abnormal pull-in of the magnetic ac contactor means that the pull-in of the magnetic ac contactor is too slow, the contacts cannot be completely closed, the iron core emits abnormal noise and other abnormal phenomena. The reasons and solutions are as follows:

①. Since the power supply voltage of the control circuit is lower than 85% of the rated voltage, the electromagnetic force generated by the electromagnetic coil after electrification is small, and the moving iron core cannot be quickly attracted to the static iron core, resulting in the magnetic ac magnetic ac contactor pulling slowly or not tightly. The power supply voltage of the control loop should be adjusted to the rated working voltage.

②. The spring pressure is insufficient, causing the magnetic ac magnetic ac contactor to pull in abnormally; the reaction force of the spring is too large, causing the pull-in to be slow. The contact spring pressure is too large, so that the iron core cannot be fully closed. The spring pressure and release pressure of the contacts are too large, causing the contacts to not close completely. The solution is to adjust the spring pressure appropriately and replace the spring if necessary.

③. Because the gap between the static and dynamic iron cores is too large, the movable part is stuck, the rotating shaft is rusted or deformed, causing the magnetic ac contactor to pull in abnormally. During processing, the dynamic and static iron cores can be removed for inspection, the gap can be adjusted, and the rotating shaft and support can be cleaned. Rod, replace accessories if necessary.

④. Due to frequent collisions for a long time, the iron core plate surface is not flat and expands outward along the thickness direction of the laminations. At this time, it can be trimmed with a file, and the iron core can be replaced if necessary.

3.The Contacts Of The Contactor Are Not Firmly Connected

Insufficient contact of the contacts of the magnetic ac contactor will increase the contact resistance between the dynamic and static contacts, resulting in an excessively high temperature of the contact surface, making the surface contact into point contact, or even non-conduction. The reasons for the failure are as follows:

①. If there are oil stains, flowers or foreign objects on the contacts, you can use a cotton cloth dipped in alcohol or gasoline to scrub.

②. Long-term use, the contact surface is oxidized. If it is a silver or silver-based alloy contact, when an oxide layer is formed on the contact surface or a slight burn and blackening are formed under the action of an arc, it generally does not affect the work, and it can be scrubbed with alcohol, gasoline or carbon tetrachloride solution.

③. Arc ablation causes defects, burrs or the formation of metal chip particles. For copper contacts, if the degree of burn is relatively light, it is only necessary to use a fine file to repair the unevenness, but it is not allowed to use a fine emery cloth to polish, so as to avoid quartz sand particles remaining between the contacts and unable to maintain good contact; If the contact surface is low, the new contacts must be replaced.

④. If there is jamming in the moving part, disassemble and check the jammed part and deal with it accordingly.

4.After The Contactor Coil Is Powered Off, The Contactor Does Not Release Or Delays Release

The non-release or delayed release of contactors and intermediate relays can easily cause equipment or personal accidents, and must be eliminated. The causes and treatment methods are as follows:

①. The surface of the newly activated magnetic ac contactor iron core is oily or greasy after a period of use. Wipe the anti-rust grease on the surface of the iron core. The surface of the iron core should be flat, but it should not be too bright, otherwise it is easy to cause delayed release.

② . The anti-welding performance of the contacts is poor. When the motor is started or the line is short-circuited, the high current causes the contacts to be welded and cannot be released, and the pure silver contacts are easier to be welded. The main contact of the magnetic magnetic ac contactor should be made of silver-based alloys with strong welding resistance, such as silver-iron, silver-nickel, etc.

③. The control circuit is connected incorrectly. Correct the wrong connection according to the control wiring diagram.

④ . The contact spring pressure is too small. Adjust the contact parameters.

⑤. Mechanical failure, such as the pin and hole of the bracket are too tight. The screw is not tightened, and it falls into the magnetic ac contactor due to vibration, or other foreign objects fall into the bracket; some are stuck due to poor product quality, and the bakelite shell or bracket is deformed and cannot be released.

⑥. The reaction force spring is damaged, replace the reaction force spring.

⑦. There is oil or dust on the pole surface of the iron core. Clean the pole surface of the iron core.

Contactor Recommendation

CSQ CJX2N Series AC Contactor

Rated Current: 9A-95A

* Permanent torque, reliable installation

* Small and compact, saving space

* Easy installation and time saving

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CJX2N contactors are designed for use in various control systems and can be used as motor starters in various applications.

Maybe You Need: magnetic ac contactor, 220v magnetic contactor, 3 phase magnetic contactor, 4 pole magnetic contactor

ac contactor manufacturers

CJX2-D Series AC Contactor

Rated Current: 9A-95A

* Product design optimization, beautiful appearance

* Compact structure, stable and reliable work

* IP20 protection grade, safe to use

* Ambient operating temperature up to 70%

* Compliant with CCC, CE certification

Suitable for construction and industry.Such as: motor control, air conditioning, water pump and correction power factor, etc.

Maybe You Need: 220v ac contactor, 240v ac contactor, 3 phase ac contactor , 30 amp ac contactor , 40 amp ac contactor

ac contactor supplier

CSQ - ac contactor supplier, more than 30 years of manufacturing experience, factory direct sales.

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13th Floor,Building 6, Huacai International, Xihu District, Hangzhou City,China

  Wenzhou Factory Address: 

No. 198, Wei 3rd Road, Economic Development Zone Of Yueqing, Wenzhou city, China


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