Vauum interrupter contactor common arc extinguishing way has elongated arc, strong cold arc, etc., strong cold arc with a series coil magnetic stripping arc, and excitation coil magnetic stripping, permanent magnet magnetic stripping arc, slit arc , Grating and other forms of arc. The interrupter structure is also based on one or both of the above-mentioned combination of the arc extinguishing system.
The use of the contact circuit electromotive force and the arc extinguishing chamber with the gate plate are provided. (Including magnetic blown and balloon interrupter, magnetic blown and wide seam interrupter, magnetic blower transverse diaphragm interrupter, labyrinth interrupter, maze with arc extinguishing gate) vacuum interrupter and other forms). The disadvantage of this type of arc extinguishing is that the capacity of the contactor is large if it is large, and if the volume is small, the capacity can not be increased and there are varying degrees of blowing distance. What is described herein is a fully sealed arc-extinguishing structure using a pressurized gas arc, which is more difficult to heat away from the arc column in the compressed gas than the atmospheric pressure, and the thermal conductivity increases. Arc in the arc is easy to go out.
Part of the main screen shield and bellows shield, generally use oxygen-free copper or stainless steelmain effect:1) to prevent the contact in the arcing process to produce a large number of metal vapor and droplet splashing, pollution of the inner wall of the insulating shell, to avoid causing the Vacuum interrupter for vacuum circuit breaker shell insulation strength decreased or flashover. Bellows shield is mainly to protect the bellows from the corrosion of metal vapor and lead to leakage, and now some of the design is more bold, abolished the bellows shield to reduce costs, reduce the size
2) Improve the electric field distribution inside the vacuum interrupter3) absorbs part of the arc energy, condensing the vacuum interrupter. In particular, the vacuum interrupter in the breaking short-circuit current, the arc generated by the heat most of the shielding system is absorbed, help to improve the strength of the media between the contact recovery. The greater the amount of absorption of the arc generator, the greater the energy he absorbs, which is good for increasing the breaking capacity of the vacuum interrupter.You said that the epoxy resin is usually through the APG process, the arc chamber to seal the required materials, the direction is completely different
(1) the arc chamber pressure is an important basis for the formation of air blowing, but too high pressure will cause the arc chamber shell strength is too high.
(2) the pressure of the arc chamber is an important basis for the formation of air blowing, but too high pressure will cause excessive pressure on the arc chamber shell requirements.
(3) vacuum interrupter optimization design of an important goal is to improve the breaking performance at the same time, as much as possible to reduce the pressure inside the arc chamber.
(4) the use of gas-generating materials to improve the pressure of the arc chamber to promote air blowing, while the use of gas generated by cooling the Vacuum interrupter for vacuum circuit breaker , can significantly improve the disconnection of the arc chamber performance. Choosing the right gas-producing material is important for optimizing the design of the interrupter.
(P) (POM), nylon, PBT (polycarbonate) three kinds of gas production materials, experiments show that nylon is more suitable for gas production materials.
vacuum interrupter design is the core of the low voltage circuit breaker research and development. The performance of the interrupter is directly related to the breaking performance of the low-voltage circuit breaker, which determines whether the product can meet the requirements of intelligent, highly reliable new current selective protection and fault location. To this end, domestic and foreign scholars and research institutions have been committed to the field of technical research, and access to a large number of applications, such as through the double breakpoint arc technology to improve the arc voltage and mechanism speed; through gas production of reasonable settings, Improve the arc voltage and dielectric recovery strength, etc., to effectively improve the product breaking performance.
At present, the design and analysis of the low-voltage circuit breaker Vacuum interrupter for vacuum circuit breaker is mainly through the test method and simulation analysis method. The experimental method mainly uses high-speed photography, optical fiber array and so on to study the movement characteristics of arc; simulation analysis method mainly through the establishment of arc model to study the arc. Product design is often used decoupling approach to mechanical movement, magnetic blowing layout, gas flow, respectively, were designed. In this paper, the fluid analysis model is established by the airflow field of the interrupter, and the simulation software is used to simulate and evaluate the structure of a small circuit breaker.The arc of the arc chamber is assumed to be in the event of a fault current, and the static and static contacts are opened. The medium of the contact gap produces a very high temperature, which emits strong light and conducts the gas. The calculation analysis involves electromagnetic fields, Gas flow field and temperature field.
The vacuum bottle interrupter in the vacuum bubble is an electric vacuum device which utilizes the high vacuum working insulating arc quenching medium to realize the on-off function of the power circuit by a pair of contacts sealed in vacuum.
When it breaks a certain value of the current, the static and dynamic contact in the separation of the moment, the current shrink to the contact just separated from the point, there is a sharp increase in resistance between the electrodes and the temperature increased rapidly until the occurrence of electrode metal evaporation, Extremely high electric field strength, resulting in a very strong launch and gap breakdown, resulting in 12KV vacuum interrupter, when the power frequency current close to zero, but also the opening distance increases, the vacuum arc plasma quickly spread to the surrounding, After the arc current is zero, the medium of the contact gap is rapidly changed from the conductor to the insulator, and the current is broken.
Due to the special construction of the contacts, the contact gap will produce a suitable longitudinal magnetic field during the arcing, which allows the arc to be evenly distributed on the contact surface to maintain a low arc voltage, so that the vacuum interrupter has a higher arc Post-medium strength recovery rate, small arc energy and small corrosion rate. In this way, it improves the ability and life of the vacuum interrupter to break the current.
