AC contactors are commonly used in electromechanical device control circuits to turn the power on or off. It can frequently turn the AC circuit on or off and enable remote control. The contactor is mainly composed of a contact system and an electromagnetic system. The failure of the
AC contactor generally occurs at the coil circuit, the mechanical part, and the contact portion.
First, the noise is too large
(1) When the power supply voltage is too low during operation, only the contactor can be kept in contact. When a large-capacity motor is started, the circuit voltage drop is large, and the corresponding contactor noise is also large, and the noise is reduced when the starting process is completed. Try to increase the voltage of the operating loop.
(2) The magnetic system is improperly assembled or shaken by the vibration or the needle is stuck, so that the iron core cannot be absorbed and noise is generated. The magnetic system should be adjusted during processing to identify and eliminate the cause of the mechanical jam.
(3) Due to the breakage of the short-circuit ring, the static iron core generates noise, and the iron core or short-circuit ring should be replaced.
(4) Electromagnet noise is generated due to excessive contact spring pressure. Usually adjust the contact spring pressure.
(5) There is dirt and debris between the contact surface between the static iron core and the moving iron core. Because the distance between the pole faces becomes large, the reaction force of the recovery spring cannot be overcome, and vibration is generated. If the contactor vibrates for a long time, it will cause the coil to burn out. At this point, the core face should be cleaned.
(6) The pole face of the iron core is excessively worn and uneven. The core should be replaced.
(7) Short circuit between coil turns. Usually the coil can be replaced.
Second, the main contact is overheated or welded
(1) Since the contactor is too slow or stagnant, the contact is in a contact-like non-contact position. After the identification, it can be handled according to the " AC contactor is not normal" treatment.
(2) The surface of the contact is severely oxidized and burned, causing the contact resistance to increase, causing the main contact to overheat. The treatment first removes the oxide layer on the surface of the main contact, and then gently flattens it with a file to make the contacts in close contact.
(3) Due to frequent starting of the equipment, the main contacts are overheated or welded by the impact of the starting current multiple times. Avoid frequent starts at this time, or choose a contactor that can accommodate the operating frequency and power-on duration.
(4) The main contact is overheated or welded due to excessive load current for a long time. In this case, reduce the load on the transmission equipment to operate under rated conditions, or re-select the appropriate contactor according to the operating current of the equipment.
(5) The three-phase main contacts of the contactor are not synchronized when they are closed, and the two-phase main contacts are impacted by a large starting current, causing the main contacts to be welded. In this case, the main contact closure condition should be checked, and the gap between the moving and stationary contacts should be adjusted so that the three-phase main contacts are in synchronous contact.
(6) The main contact itself has poor resistance to melting, such as pure silver contacts that are easily welded. This type of contact should be replaced. A silver-based alloy contact with strong anti-melting ability can be used as the main contact of the contactor.
(7) The overtravel of the contact is too short, and the contact overtravel or contact should be adjusted.
Fluorochemicals
The Fluorochemicals compound is a new field in modern organic chemistry. It has a special physical and chemical properties, so it is widely used in the earliest development of applied pesticides and rat poison. During World War II it was developed in some countries appliedas antimicrobial agents, there are more and more new research suggests that fluorochemical will play an increasingly more important role in the field of anticancer drugs. We started later in the field of fluorochemicals, but we have a strong sense of his enormous potential, and we are increasing investment to catch up. We will custom product which has potential market prospects from gram and kilogram-class through process optimization, enlarged to the size of ton. Currently we have developed more fluorochemical compounds in the benzoic acid range, the number of products have been more than 2017.
Organic Fluorochemical Compound,FluorineCompounds,Containing Benzoic Acids
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