CN111146028A

CN111146028A - Direct current contactor contact arc extinguishing system

Info

Publication number: CN111146028A
Application number: CN202010042009.4A
Authority: CN
Inventors: 孙吉升; 贾峰; 李思泓; 陈永亮; 傅亮
Original assignee: Shanghai Electrical Apparatus Research Institute Group Co Ltd
Current assignee: Shanghai Electrical Apparatus Research Institute Group Co Ltd
Priority date: 2020-01-15
Filing date: 2020-01-15
Publication date: 2020-05-12

Abstract

The invention relates to a contact arc extinguishing system structure of a direct current contactor, and belongs to the technical field of direct current contactors. The arc extinguishing device comprises a static contact, a moving contact, an arc extinguishing system, an electromagnetic system and a shell; the arc extinguishing system comprises an arc extinguishing chamber, an arc extinguishing cavity and a magnetic field standardizing device; a baffle plate is arranged below a moving contact in a cavity at the upper part of the direct current contactor, an arc extinguish chamber is arranged on the baffle plate, and the arc extinguish chamber is arranged at the periphery of the outer side of a relative movement area of the moving contact and a static contact of the direct current contactor; an arc extinguishing cavity extending from the upper cavity to the lower cavity is arranged between the shell and the periphery of the metal cup of the electromagnetic system. According to the invention, arc extinguishing grid pieces and a magnetic field standardizing device are arranged in a limited cavity space, so that the arc extinguishing capability is improved, the air passage circulation and diffusion of high-temperature arc gas in the upper inner cavity and the lower inner cavity of the contactor are realized, the arc cooling effect is enhanced, the pollution of the main cavity of the direct current contactor is avoided, the arc extinguishing capability is further improved, and the safe use of the direct current contactor is ensured.

Description

Direct current contactor contact arc extinguishing system

Technical Field

The invention relates to a contact arc extinguishing system of a direct current contactor, and belongs to the technical field of direct current contactors.

Background

The dc contactor is a contactor used in a dc circuit, and is mainly used for controlling a dc circuit (a main circuit, a control circuit, an excitation circuit, and the like). The direct current contactor needs to frequently switch large load current, so that the direct current contactor has strong arc extinguishing capability and needs to have a flexible contact system and a reliable electromagnetic system.

In the field of new energy application, for example, a pure electric vehicle generally adopts a high-voltage direct-current contactor to be responsible for switching on and off a power battery system, and can switch off the high-voltage battery system when an accident occurs. The electric contact can generate electric arc and discharge phenomenon in the process from connection to disconnection, the generation of the electric arc can delay the disconnection of a circuit, the electric contact can be burnt even by high electric arc energy, the electric contact is fused and welded, and the ignition and explosion of a switching device can be caused under severe conditions because the existing direct current contactor adopts a sealing mode.

In the prior art, in order to make a direct current contactor product have small volume and high operation load, a high-voltage direct current contactor generally adopts a sealed inflation external magnetic field to transversely elongate a metal phase electric arc, and the electric arc is rapidly cooled and compounded in an arc extinguishing medium to be dissociated. Generally, the arc extinguishing space is limited by the technical means, the arc burning time is long, and metal particles and carbonized impurities generated in the arc extinguishing process are gathered in the arc extinguishing cavity to pollute the cavity, so that the insulation capacity is easily reduced after the electric service life to a certain degree. For example: at present, manufacturers in Taike, Panasonic, LS and the like in the market all apply magnetic quenching technical means, most of the quenching schemes have current polarity requirements, and when the current polarity is reversed, the service life capacity is suddenly reduced, and even explosion can be caused.

The internal structure of the high-voltage direct-current contactor which is common at present is shown in the attached figures 1 and 2. In the prior patent literature, chinese invention patents CN102074387A and CN104412353A disclose two typical structural arrangements of the high voltage dc contactor respectively. The disadvantages of this design are: the contact arc extinguishing system does not fully utilize the volume of a cavity at the upper part of the contactor (fig. 2 is a side view, cavities at two sides of a movable contact bridge are isolated from the contact arc extinguishing system, the cavities are not effectively utilized), arc extinguishing capacity is limited, and meanwhile, the arc extinguishing capacity is difficult to continue to be improved and arc burning time is shortened only by means of a permanent magnet magnetic arc quenching technology under a gas atmosphere condition. And metal particles and carbonized impurities generated in the arc extinguishing process are gathered in the arc extinguishing cavity to pollute the cavity, so that the insulation capacity is reduced after the electric service life is prolonged to a certain degree. The arc extinguishing chamber adopts square closed cavity, and the arc extinguishing passageway is long and narrow, and the unable circulation that flows of high temperature arcing gas appears easily under the disjunction of higher grade and the unable effluvium of arcing gas and quick cooling, and the inner chamber pressure is too big causes the product explosion. And such contactors have strict requirements on the polarity of the current, and thus the environmental suitability is greatly reduced.

In the existing new energy application field, a power battery system is generally 400VDC and can be greatly improved in the future, so that the high-voltage direct-current contactor needs stronger arc extinguishing capability, can safely turn on and off relatively large current, and can avoid damage of fusion welding and excessive electric arc to contacts in the contactor. Therefore, the technical field urgently needs to adopt an arc extinguishing device in the direct current contactor so as to realize an efficient and reliable arc extinguishing effect.

Disclosure of Invention

The invention aims to solve the technical problem of realizing efficient and reliable arc extinguishing action in a direct current contactor.

In order to solve the above problems, the technical scheme adopted by the present invention is to provide a contact arc extinguishing system of a dc contactor, wherein the dc contactor comprises a static contact, a moving contact, an arc extinguishing system, an electromagnetic system and a housing; the electromagnetic system comprises a middle shaft, a static iron core, a movable iron core, a framework coil, a metal cup and a yoke iron; the arc extinguishing system comprises an arc extinguishing chamber, an arc extinguishing cavity and a magnetic field standardizing device; a baffle plate is arranged below a moving contact in a cavity at the upper part of the direct current contactor, an arc extinguish chamber is arranged on the baffle plate, and the arc extinguish chamber is arranged at the periphery of the outer side of a relative motion area of the moving contact and a static contact of the direct current contactor; an arc extinguishing cavity extending from an upper cavity to a lower cavity of the direct current contactor is arranged between the shell and the periphery of the metal cup of the electromagnetic system; and a magnetic field standardizing device is arranged in the shell.

Preferably, the arc extinguishing chamber comprises an arc extinguishing grid sheet and two arc barriers, two arc barriers are arranged on two sides of a relative movement area of the arc extinguishing chamber relative to a moving contact and a static contact of the direct current contactor, the arc barriers are arranged on the partition, and the surface of each arc barrier is parallel to the central axis of the moving contact of the direct current contactor; a flaky arc extinguishing grid piece is arranged between the two arc isolating plates, is vertical to the arc isolating plates and is spaced in parallel; the arc extinguish chamber is provided with an opening at one side relative to the moving contact of the direct current contactor, and the arc extinguish chamber is provided with an opening at the other side relative to the moving contact of the direct current contactor.

Preferably, the magnetic field specification means comprises a permanent magnet and a yoke; permanent magnets are arranged on the two sides of the direct current contactor contact system and the arc extinguish chamber, the central axis between the two poles of each permanent magnet is parallel to a plane formed by the central point of the moving contact and the central points of the two static contacts, and the polarities of the two permanent magnets are opposite (the N pole corresponds to the N pole or the S pole corresponds to the S pole); and a magnetic yoke is arranged around the peripheries of the two permanent magnets.

Preferably, two U-shaped magnetic yokes are arranged in the direct current contactor shell, the two U-shaped magnetic yokes are connected to form a hollow square structure, and the central axis of the hollow square structure is superposed with the central axis of the direct current contactor; each U-shaped magnetic yoke U-shaped bottom corresponds to an arc extinguish chamber, and the surrounding area formed by connecting the two U-shaped magnetic yokes is internally provided with the permanent magnet, the direct current contactor contact system and the arc extinguish chamber.

Preferably, the grid of the arc extinguishing chamber is provided with an arc striking groove.

Preferably, the baffle plate is provided with an airflow guide; the airflow guide piece comprises a bottom plate, an arc isolation plate and a separation piece; a moving contact in a cavity at the upper part of the direct current contactor is provided with a baffle plate below, the baffle plate is provided with a bottom plate, and the bottom plate is provided with an arc baffle plate and a separator; the separator is arranged at an opening of the other side of the arc extinguish chamber relative to the direct current contactor contact system; the arc extinguishing chamber and the two adjacent sides of the moving area of the moving contact are symmetrically provided with two arc isolating plates by taking the separating piece as a center, each arc isolating plate comprises an arc isolating wall and a gas guide plate, and the arc isolating walls arranged on the two sides of the arc extinguishing chamber extend to the separating piece to be provided with the gas guide plates.

Preferably, the arc chute sheet is made of cold-rolled steel plates, copper plates, meta-aromatic polyamide fiber Nomex profiles or ceramics.

Preferably, the moving contact is provided with a U-shaped structural member bracket which is made of a magnetic conductive material.

Preferably, the moving contact top end is provided with an arc isolating plate, the arc isolating plate is arranged at the middle position of the moving contact top end portion, and two contacts, which are contacted with the fixed contact, of the moving contact are separated in two spaces.

The high-temperature and high-pressure gas always moves to the low-temperature and low-pressure environment, the high-temperature and high-pressure gas generated by the electric arc moves along the direction of the outlet of the arc extinguish chamber, the air blowing and the quick movement of the electric arc are facilitated for cooling, the electric arc is enabled to move forward quickly in the contactor and spread in the arc extinguish chamber, the electric arc is lengthened and cooled, and the contactor is particularly suitable for direct current application, and the lengthened electric arc and the quick cooling electric arc become the most important arc extinguishing means in the direct current contactor because the voltage and current zero crossing process does not exist.

The invention arranges the grid arc-extinguishing chamber in a limited space on the basis of the existing magnetic quenching. The arc is cut into a plurality of short arcs through the grid plate of the arc extinguishing chamber, so that the initial dielectric strength of an arc gap is improved, and meanwhile, the grid plate (such as a copper grid plate, a ferromagnetic grid plate, ceramic and the like) has the functions of enhancing cooling and surface recombination. For high current breaking (such as rated current), the magnetic driving force generated by the grid arc-extinguishing chamber and the magnetic field (fleming's law) generated by the permanent magnet stretch the arc, the arc with extended length can be cooled by gas atmosphere (air, nitrogen or hydrogen, etc.), and meanwhile, the pressure gradient of the arc-extinguishing system is used for driving the arc-burning gas to be discharged to the two sides of the preset flow channel cavity (which can be horizontal or vertical). Finally, the cooling of the arc is further enhanced by the upper and lower arc extinguishing cavities of the contactor and the metal cup. The scheme adopts a mode similar to the mode of exhausting air from the inner cavity to greatly reduce the pressure coefficient of the upper arc-extinguishing chamber, reduce the explosion risk of products and enable high-temperature arcing gas to effectively flow and circularly cool. So not only make it possess bigger arc extinguishing space, shorter arcing time, higher arc voltage to the gaseous flow of arcing gathers metal particle and carbonization impurity in contactor lower part cavity, guarantees the cleanliness factor and the insulation resistance of upper portion main cavity. In addition, according to the present invention, even if an arc is generated in any direction, the arc can be extinguished by inducing the arc in a desired direction by current and magnetic force and contacting the grid arc extinguishing chamber. In addition, the arc extinguishing chamber housing can prevent deterioration of the magnetic force characteristics of the permanent magnet, and can maintain the function of rapidly and reliably extinguishing the arc for a long period of time.

Compared with the prior art, the invention has the following beneficial effects:

according to the technical scheme, the arc extinguishing grid pieces, the magnetic field standardizing device and the airflow guide pieces are arranged in the limited cavity space, so that the arc extinguishing capability is improved, and the non-polar requirement on a power supply is met. And the air flue circulation and diffusion of high-temperature arcing gas in the upper inner cavity and the lower inner cavity of the contactor are realized, the electric arc cooling effect is enhanced, the pollution of a main cavity is avoided, and the arc extinguishing capability is further improved. High-temperature gas generated between the moving contact and the static contact on the two sides of the contact bridge flows in respective gas flow channels. And under the condition of short-circuit fault, the risk of contact fusion welding is reduced, and the contact reliability is improved.

Drawings

Fig. 1 and 2 are typical structures of a conventional high-voltage direct-current contactor;

fig. 3a is a schematic diagram of an arc extinguish chamber of the high-voltage direct-current contactor of the invention;

FIG. 3b is a schematic top view of the high voltage DC contactor structure of the present invention;

FIG. 3c is a partial schematic view of the arc chute structure of the HVDC contactor of the present invention;

fig. 4a is a schematic diagram of a second arc-extinguishing chamber of the high-voltage direct-current contactor according to the present invention;

fig. 4b is a schematic structural diagram of a moving contact mounting bracket in the high-voltage direct-current contactor according to the invention;

fig. 4c is a schematic structural view of a mounting bracket of a moving contact in the high-voltage direct-current contactor according to the present invention;

FIG. 5a is a schematic view of a grid plate flow guiding structure of the HVDC contactor according to the present invention;

FIG. 5b is a schematic view of a grid plate flow guiding structure of the HVDC contactor according to the present invention;

fig. 6a and 6b show two air flow circulation schemes of an upper arc extinguishing chamber of the high-voltage direct-current contactor;

fig. 6c and 6d are schematic structural views of two air deflectors of an upper arc extinguishing chamber of the high-voltage direct-current contactor;

fig. 6e and 6f are partial enlarged schematic diagrams of two gas guide structures and a double gas storage space structure of an upper arc extinguishing cavity of the high-voltage direct-current contactor;

fig. 7a is a schematic structural diagram (top view) of a non-polar scheme of a contact arc extinguishing system of the high-voltage direct-current contactor;

FIG. 7b shows the distribution of magnetic lines of force of the permanent magnet of the HVDC contactor;

FIG. 7c shows the distribution of magnetic lines of force of permanent magnets under the U-shaped magnetic yoke of the high voltage DC contactor;

FIG. 7d shows a non-polar grid arc-extinguishing chamber structure of the high voltage DC contactor;

FIG. 7e is a side view of the arc chute structure of the non-polar grid plate of the high voltage DC contactor;

8a,8b and 8c are schematic diagrams of the nonpolar grid sheet arc extinguish chamber structure of the high-voltage direct current contactor and the structure of an arc baffle.

Detailed Description

In order to make the invention more comprehensible, preferred embodiments are described in detail below with reference to the accompanying drawings:

the first embodiment is as follows:

fig. 3a shows a three-dimensional structure scheme disclosed in the present invention. Wherein the contactor 301 includes:

stationary contacts

302 and 303, movable contact 304,

arc extinguishing chambers

310 and 311, electromagnetic system 312, and housing 313. The electromagnetic system 312 includes a central shaft 305, a stationary core 306, a movable core 307, a bobbin coil 308, a metal cup 309, and a yoke 314. The contact system comprises moving and static contacts (302, 303, 304) for connecting and disconnecting an external direct current load circuit; the electromagnetic system 312 drives the moving contact 304 to complete a contact switching action through the moving iron core 307 and the middle shaft 305, and two ends of the moving contact 304 are respectively contacted with the static contacts (302, 303) to form two pairs of moving and static contact contacts, which are called bridge contact systems;

arc extinguishing chambers

310 and 311 are used for completing arc extinguishing action; the housing 313 serves to accommodate the contact system, the electromagnetic system 312 and the arc extinguishing chambers (310, 311) and also includes lower

arc extinguishing chambers

315, 316. High-temperature arcing gas (319, 320) generated by the moving contact and the static contact in the breaking process enters the

arc extinguishing chambers

310 and 311 through the upper cavity of the shell, the electric arc is cut into a plurality of short arcs through the grid plates, so that the initial dielectric strength of an arc gap is improved, and meanwhile, the grid plates (such as copper grid plates, ferromagnetic grid plates, ceramics and the like) have the functions of enhanced cooling and surface recombination. In addition, the magnetic driving force generated by the arc extinguishing chambers 310 and 311) and the magnetic field generated by the permanent magnets (fleming's law) stretch the electric arcs (319 and 320), the electric arcs (319 and 320) with extended lengths can be cooled by the gas atmosphere (air, nitrogen, hydrogen, or the like), and the arc combustion gases (319 and 320) are driven by the pressure gradient of the arc extinguishing system to be discharged to the two sides to the flow channel cavity (which can be transverse or longitudinal) preset in the housing 313. Before the electric arc enters the arc extinguish chamber, the generated high-temperature gas blows the electric arc into the arc extinguish chamber, then the high-temperature gas and the high-temperature gas generated by the electric arc in the arc extinguish chamber are discharged out of the arc extinguish chamber at the rear end of the arc extinguish chamber and enter a lower arc extinguish cavity between the shell and the periphery of a metal cup of the electromagnetic system, and thus an air flow moving path line from an upper arc extinguish cavity- > an arc extinguish chamber air outlet- > a lower arc extinguish cavity is formed. Finally, the cooling of the arc is further enhanced by the upper and lower arc-extinguishing cavities (315, 316) of the contactor 301 and the metal cup 309 (high thermal conductivity). The arc-extinguishing

chambers

310 and 311 are arranged at an inclination angle, that is, the stacking direction (as shown in fig. 3c) of the arc-extinguishing grid pieces 317 is at an angle with the side wall 313a of the housing 313, so that the gas outlets formed by the arc-extinguishing grid pieces 317 discharge the arc-extinguishing gas in a downward inclined manner, instead of facing the side wall 313a in the forward direction, and a downward flow guiding effect is exerted on the high-temperature gas. The arc extinguishing grid pieces are arranged in a staggered manner in length to keep consistent with the gap between the moving contact and the static contact, so that arc burning gas (319, 320) is discharged to the

lower cavities

315 and 316 of the contactor 301 quickly and effectively along the guide direction by virtue of pressure gradient, and meanwhile, metal particles and carbonized impurities are gathered in the

lower cavities

315 and 316 by the flowing of the arc burning gas (319, 320), so that the cleanliness and the insulation resistance of the arc extinguishing chambers (310, 311) are guaranteed. And the metal cup 309 not only provides a magnetic conductive action for the electromagnetic system 312, it has a large outer metal surface area and a high thermal conductivity that further contributes to the rapid cooling of the arc gases (319, 320). Fig. 3b is a top view of the lower chamber structure disclosed in this embodiment, in which high temperature arcing gas (319, 320) circulates inside the housing 313, enters the

lower chambers

315 and 316 on both sides, and then diffuses to both sides, and simultaneously cools the outer surface (high thermal conductivity) of the metal cup 309 by the gas atmosphere (hydrogen, nitrogen, air, etc.).

In the top view of fig. 3b, it can be seen that the side wall 313a has an outwardly protruding arc-shaped profile, which helps the arcing

gas

319, 320 to diffuse to both sides when it exits the arc chute, more strongly than the cooling of the high temperature gas. Fig. 3c shows the inclined arc-extinguishing chamber 310 structure adopted in this solution, wherein the arc-extinguishing grid 317 may be made of cold-rolled steel plate, copper plate, Nomex section or ceramic, and the length of the grid is adjusted according to the moving path of the moving contact, so as to keep the gap consistent, and at the same time, the arc-isolating plates 318 are provided on both sides of the grid for supporting and fixing. The length of the arc chute 317 gradually increases in the stacking direction. The stacking direction is a reference direction, and is only used to illustrate the variation of the external dimensions of the arc chute 317, and is not a limitation to the protection scope of the patent technology.

Example two:

fig. 4a is another perspective view of the present invention. Wherein the contactor 401 includes: the

stationary contacts

302 and 303, the movable contact 304, the

arc extinguishing chambers

402 and 403, the electromagnetic system 312, and the housing 404. The electromagnetic system 312 includes a drive shaft 305, a stationary core 306, a movable core 307, a bobbin coil 308, a metal cup 309, and a yoke 314. The contact system comprises moving and static contacts (302, 303, 304) for connecting and disconnecting an external direct current load circuit; the electromagnetic system 312 drives the moving contact 304 to complete the contact switching action through the moving iron core 307 and the middle shaft 305;

arc extinguishing chambers

402 and 403 are used to complete arc extinguishing action; the housing 404 serves to accommodate the contact system, the electromagnetic system 312 and the

arc extinguishing chambers

402 and 403 and also includes lower

arc extinguishing cavities

405, 406.

High-

temperature arcing gas

413 and 414 generated by the moving contact and the static contact in the breaking process enters the

arc extinguishing chambers

402 and 403 through the upper cavity of the shell, the

arcs

413 and 414 are cut into a plurality of short arcs through the grid plates, so that the initial dielectric strength of an arc gap is improved, and meanwhile, the grid plates (such as copper grid plates, ferromagnetic grid plates, ceramics and the like) have the effects of enhancing cooling and surface recombination. In addition, the magnetic driving force generated by the

arc extinguishing chambers

402 and 403 and the magnetic field generated by the permanent magnets (fleming's law) stretch the arc, and the

arc

413 and 414 having an extended length can be cooled by the gas atmosphere (air, nitrogen, hydrogen, or the like) around the arc extinguishing chamber, and the arc-burning gas is driven to discharge to both sides by the pressure gradient of the arc extinguishing system to the flow channel cavity (either in the horizontal direction or in the vertical direction) provided in the housing 404. Finally, the cooling of the

arcs

413 and 414 is further enhanced by the upper and lower arc-extinguishing

cavities

405 and 406 of the contactor 401 and the metal cup 309. The

arc extinguishing chambers

402 and 403 are arranged horizontally, and arc extinguishing grids are arranged in parallel, so that the arrangement is favorable for

arc burning gases

413 and 414 to generate larger pressure in the arc extinguishing chambers, the pressure is effectively discharged to the

lower cavities

405 and 406 of the contactor 401 by virtue of pressure gradient, and because the gas outlet area of the arc extinguishing chamber cavity is smaller than that of the scheme in fig. 3a, the initial flow velocity of the

arc burning gases

413 and 414 is faster, and the arc burning gases can reach the depths of the

lower cavities

405 and 406 more easily. While the flow of the arcing

gases

413 and 414 collects the metal particles and the carbonized impurities in the

lower cavities

405 and 406, ensuring the cleanliness and insulation resistance of the

arc extinguishing chambers

402 and 403. The metal cup 309 not only provides a magnetic conductive action for the electromagnetic system 312, but it has a large area of outer metal surface that further contributes to the rapid cooling of the

arc gases

413 and 414. The distance from the grid plate installed in the arc extinguish chamber to the shell 404 is larger than the distance from the metal cup 309 near the air outlet of the arc extinguish chamber to the shell 404, the metal cup 309 is arranged at the

lower cavity

405 and 406, the distance from the metal cup 309 to the shell 404 is larger than the distance from the metal cup 309 near the air outlet to the shell 404, thus the air outlet with the cross section being gradually increased from large to small is formed from the arc extinguish

chamber

402 and 403 to the

lower cavity

405 and 406, an air jet with a Venturi effect is formed, and the air flow movement is accelerated.

Fig. 4b and 4c are schematic diagrams (side views) of the internal structure of the contact arc extinguishing system, wherein the movable contact 304 is provided with a bracket 410 of a U-shaped structural member at the upper part, and the bracket 410 is made of a magnetic conductive material. The upper part of the electromagnetic system 312 is provided with a partition 411, the partition 411 is made of a plastic material with high flame-retardant grade, a gas generating material can be added if necessary to enhance the gas blowing action, and the plastic material containing hydrogen is used to improve the heat conductivity inside the arc, so that the heat energy of the arc can be easily diffused. The electromagnetic system 312 is completely surrounded by a metal cup 309, the metal cup 309 primarily takes on the role of a magnetic yoke, the large area metal outer surface of which assists in arc cooling. The metal cup 309 is made of a magnetically conductive metal material, such as electrically pure iron, and is plated on its outer surface. The arc-extinguishing grid 412 can be made of cold-rolled steel plates, copper plates, Nomex profiles or ceramics, and the like, and the arc-extinguishing grid 412 adopts a U-shaped structure, so that the non-polarity of the arc-extinguishing chamber 402 can be realized under the magnetic blow-out action of the permanent magnet.

The movable contact 304 is provided with a U-shaped structural member bracket 410 at the upper part, and the bracket 410 is made of a magnetic conductive material. When the power battery system has a short-circuit fault, the short-circuit current can reach thousands of amperes, so that the moving and static contacts need to bear a great electric repulsion force, and the electric repulsion force is equal to the resultant force of Holm force and Lorentz force on the surfaces of the contacts. In the prior art, in order to resist electric repulsion and prevent the contact from being repelled and welded, a contact spring with a large force value is required. After the U-shaped support 410 is added on the moving contact 304 of the traditional structure, the density of the magnetic force lines on the upper portion of the contact 304 is obviously increased, and because the difference of the magnetic field strength of the upper side and the lower side of the contact 304 can offset the influence (electrodynamic force compensation) caused by a part of electric repulsion, under the premise that the contact spring keeps a certain force value, the risk of contact fusion welding can be reduced and the contact reliability can be improved under the condition that short circuit fault occurs.

Example three:

fig. 5a and 5b are two arc extinguishing chamber structures (top views) of an arc extinguishing chamber on the upper layer of the contactor; the sector arc extinguishing chamber cavity 501 contains the moving contact 304, a moving contact arc striking plate 504 and

arc extinguishing chambers

505 and 507, and

permanent magnets

502 and 503 are arranged outside the cavity 501 in parallel. The cavity 501 has a small middle section and gradually larger sections at two ends, and is formed into a fan-like structure, forming an approximate bow-tie or ear-shaped structure, as shown in fig. 5 a. The contact system is arranged in the middle of the cavity 501, where the cross section is smaller, and the

arc extinguishing chamber

505 or 507 is arranged at the two ends, i.e. the sectors, of the cavity 501. The arc chute grid comprises

roots

505a, 507a close to the contact system and

extensions

505b, 507b expanding towards the sector of the cavity 501. In the embodiment, as shown in fig. 5a, the middle position of the grid of the arc-extinguishing chamber 505 is provided with a T-shaped arc-striking groove 505c, the arc gas moves to the depth of the arc-extinguishing chamber 505 through the arc-striking groove 505c after being generated from the contact system, and due to the existence of the T-shaped groove, the arc-shaped housing side wall and the effect that the high-temperature gas generally expands from the place with high temperature to the place with low temperature, the arc gas moves around the grid part on the side of the T-shaped groove from both sides, so that the arc gas circulates, as shown in fig. 5 a. In conjunction with the configuration of fig. 3a or 4a, the arc gases are circulated and moved toward the

lower cavities

315 and 316 or the

lower cavities

405 and 406 in spatial locations, which accelerates the cooling of the gases.

Further, in the embodiment shown in fig. 5b, the grid of the arc-extinguishing chamber 507 has a long groove-shaped arc-striking groove 507c with one end open and a separation blade 507d at the end of the grid segment.

High-temperature arcing gas (509a and 509b) generated by the moving contact and the static contact in the high-level breaking process enters the arc extinguish chamber 505, and the arcs (509a and 509b) are cut into a plurality of short arcs through the grid pieces, so that the initial dielectric strength of an arc gap is improved, and meanwhile, the grid pieces (such as copper grid pieces, ferromagnetic grid pieces, ceramics and the like) have the functions of enhancing cooling and surface recombination. In addition, the arcs (509a, 509b) are stretched by the magnetic driving force generated by the arc extinguishing chamber (505) and the magnetic field generated by the permanent magnet (fleming's law), the arcs (509a, 509b) with extended lengths can be cooled by the gas atmosphere (air, nitrogen, hydrogen, or the like), and the arc gas (509a, 509b) is driven to flow and circulate in the gas storage space 508 of the sector cavity by the pressure gradient of the arc extinguishing system. The arc extinguishing chambers 505 are arranged horizontally, arc extinguishing grids are arranged in parallel, and the grids are made of magnetic materials, such as cold-rolled steel plates. Due to the influence of the magnetic conductivity arc-extinguishing grid pieces, the coverage length of the

permanent magnets

502 and 503 is greatly reduced compared with the conventional scheme, so that the arc-extinguishing chamber cavity structure can be improved from the existing rectangular cavity scheme to the fan-shaped cavity 501, the capacity of an arc-extinguishing chamber is increased, and the internal circulation of high-temperature arc-burning gas (509a and 509b) on the upper layer of the contactor can be promoted. As shown in fig. 5a and 5b, the arc extinguishing chamber 505 adopts two different grid-shaped structural forms, and can achieve the arc extinguishing effect.

Example four:

fig. 6a and 6b show two air flow circulation schemes of an arc extinguishing cavity on the upper layer of the contactor; fig. 6c and 6d are schematic diagrams of air passages adopted by an upper arc extinguishing cavity of the contactor. As shown in the figure, the

arc extinguishing chambers

601 and 602 are adopted, and the guide 603 of fig. 6a and the guide 604 of fig. 6b are respectively added in the sector arc extinguishing chamber 501, so as to respectively complete the inner cavity circulation mode of the arc burning gas 605 shown in fig. 6a and 6 b.

The guide 603 includes a bottom plate 603a, an arc plate 603b, and a spacer 603 c. The bottom plate 603a serves as a support for the arc barriers 603b and the spacers 603c, or the bottom plate 603a, the arc barriers 603b, and the spacers 603c are integrally injection-molded. The arc barrier 603b has an arc barrier 603b1 and an air guide 603b2, the arc barrier 603b has two pieces symmetrically disposed at two sides of the partition 603c, and the air guide 603b2 extends from the arc barrier 603b1 and is deflected toward the partition 603 c.

The guide 604 includes a bottom plate 604a, an arc plate 604b, a spacer 604c, and an arc blocking air guide plate 604 d. The bottom plate 604a, the arc baffle 604b and the partition 604c are similar to the guide 603, except that the partition 604c further has an arc baffle air guide 604d extending towards both sides, the arc baffle air guide 604d includes an arc baffle 604d1, an air guide 604d2 and a sharpened end 604d3, the air guide 604d2 extends from the arc baffle 604d1 and is bent to wrap the air guide 604b2, and the sharpened end 604d3 is formed at the end of the air guide 604d 2. The bend of the air guide 604d2 and the arc stop 604d1 is opposite the air guide 604b 2.

According to fig. 6a, 6c and 6e, an air outlet is formed at a distance a1 between the air guide 603b2 and the housing wall of the cavity 501; an air outlet with a distance a2 is formed between the arc separating wall 603b1 and the shell wall of the cavity 501; air storage space S1 is provided between air outlet a1 and air outlet a 2.

6b, 6d and 6f, an air outlet is formed between the air guide plate 604b2 and the arc baffle 604d1 with a distance b 1; an air outlet with a distance b2 is formed between the arc-separating wall 604b1 and the air guide 604d 2; an air outlet with a distance b3 is formed between the end 604d3 and the housing wall of the cavity 501; and a gas storage space S2 is formed between the gas outlet b1 and the gas outlet b2, and high-temperature gas can enter the gas storage space S3 after passing through the gas outlet b 3. The guide 604 forms a double air guide structure and a double air storage space structure.

The section distance of any gas storage space is larger than that of the gas outlet communicated with the gas storage space, so that the speed of high-temperature gas is accelerated according to the Venturi effect, and meanwhile, a large amount of gas is contained in the gas storage space, and the high-temperature gas cannot be accumulated at the accessories of the gas outlet.

After entering the arc extinguish

chambers

601 and 602, the high-temperature arcing gas is separated into two directions by the guide grooves (the comb-shaped feature of the guide structure 604 separates the outlets of the arc extinguish

chambers

601 and 602 into two parts), and flows along the paths provided by the

guide structures

603 and 604, and finally, the high-temperature arcing gas meets the splitting positions of the moving contact and the fixed contact at the four outlet positions, so that the flow channel circulation of the whole inner cavity is completed.

Example five:

fig. 7a is a schematic structural diagram (top view) of a non-polar scheme of a contact arc extinguishing system; the contact arc extinguishing system 710 comprises

permanent magnets

701 and 702, wherein the two permanent magnets are arranged in parallel and have opposite polarities (N-N or S-S). The

permanent magnets

701, 702 are externally covered by a yoke, which may be made of two ferromagnetic U-shaped pieces, such as the

yokes

703 and 704 of fig. 7 a. I.e. in the space of the

yokes

703 and 704. Thus, the magnetic field directions of the

permanent magnets

701 and 702 start from the N pole, pass through the

magnetic yokes

703 and 704 which are respectively closest to the N pole, and return to the S pole of the magnetic yokes, so that the magnetic field route is standardized, and the magnetic blow effect is better.

The trend of the magnetic field (711, 712) of the permanent magnet is changed from the trend of the magnetic field diffused into the air to flow along the U-shaped magnetic yoke, so that the magnetic force lines are conveniently concentrated to the required position, the arc extinguishing effect is greatly enhanced, the volume required by the permanent magnet is reduced, and the cost is saved. The arc-quenching system 710 houses two sets of U-shaped arc-extinguishing

chambers

705 and 706. The magnetic force lines of the arc extinguishing system 710 are oriented as shown in fig. 7a, and the magnetic force lines (711, 712) in the fan-shaped direction formed by the arc extinguishing system arranged in this way can pass through the centers of the contacts, so that a magnetic blow-out force F is formed at the corresponding contact, wherein the direction of the magnetic blow-out force F forms an angle with the connecting line between the two contacts.

According to the moving and static contact system on the left side of fig. 7a, assuming that the arc current flows from the driven contact to the static contact, the N poles of the

permanent magnets

701 and 702 are opposite, and according to fleming's left-hand rule, the arc current is subjected to an ampere force F on the lower left side, moves towards the lower left side of the arc extinguish chamber and gradually moves towards the depth direction of the arc extinguish chamber; if the arc current flows from the fixed contact to the movable contact, the arc current moves towards the upper left side of the arc extinguish chamber and gradually moves towards the depth direction of the arc extinguish chamber under the action of the ampere force F on the upper left side.

The

permanent magnets

701 and 702 are used for guiding the arc at the contact breaking position to the U-shaped arc extinguishing chamber, the direction of the force is as shown in the figure, and the F force of the arc extinguishing chamber approaches to the 45-degree oblique direction regardless of the current direction, so that the

arc extinguishing chambers

705 and 706 can play a role in cutting the arc. According to the structure, the arc blowing direction is on the diagonal line, so that the arc blowing space is larger, arc breaking is facilitated, the arc extinguishing capability is stronger, and the space utilization rate of a product is higher.

Fig. 7b shows the distribution of magnetic lines of force of the permanent magnet, and the magnetic lines of force at the breaking position are more divergent and the blowing F force value is smaller without the coating of the U-shaped magnetic yoke. Fig. 7c shows the distribution of magnetic lines of force of the permanent magnet under the coating of the U-shaped magnetic yoke, the magnetic lines of force at the breaking position are more concentrated, and the value of the blowing F force is larger.

Figure 7d is a non-polar grid arc chute configuration; the U-shaped arc extinguish chamber 705 is composed of two

U-shaped grid sheets

707 and 708 which are respectively nested with the moving contact and the static contact to keep a consistent gap. In a region where the current is large (for example, rated current), the magnetic flux passing through the U-shaped slits of the plurality of

grid pieces

707 and 708 magnetically drives the arc deep into the space formed by the plurality of U-shaped slits. The long arc is cut into short arcs by the arc extinguishing chamber 705, a voltage drop occurs, the arc voltage for maintaining the arc rises, and if the arc voltage becomes higher than the power supply voltage, the arc is extinguished. And in the process of arc cutting each time, the heat transfer efficiency of the large-area grid piece is higher, and the rapid cooling of the arc is facilitated.

FIG. 7e is a side view of this arrangement; according to the present invention, even if an arc is generated in any direction, it can be induced in a desired direction by current and magnetic force and brought into contact with the arc shielding member, whereby the arc can be extinguished, and the deterioration speed of the case 404 can be greatly slowed down. Since the

permanent magnets

701 and 702 are mounted inside the case 404 and physically separated from the inside of the arc extinguishing chamber to prevent arc contamination, the arc extinguishing chamber case 404 can also prevent deterioration of the magnetic characteristics of the

permanent magnets

701 and 702, and can maintain the function of rapidly and reliably extinguishing an arc for a long period of time.

Referring to fig. 8a,8b and 8c, the present embodiment further includes an arc-isolating plate 3041, which is mounted on the driving shaft 305 at the middle position of the movable contact 304 and separates two contacts of the movable contact 304 into two spaces. So that the high-temperature gas generated between the moving contact and the static contact at the two sides of the contact bridge flows in the respective gas flow channels.

While the invention has been described with respect to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. Those skilled in the art can make various changes, modifications and equivalent arrangements, which are equivalent to those of the embodiments of the present invention, without departing from the spirit and scope of the present invention, and which can be made by utilizing the technical content disclosed above; meanwhile, any changes, modifications and variations of the above-described embodiments, which are equivalent to those of the technical spirit of the present invention, are within the scope of the technical solution of the present invention.

Claims

1. A direct current contactor contact arc extinguishing system comprises a static contact, a moving contact, an arc extinguishing system, an electromagnetic system and a shell; the electromagnetic system comprises a middle shaft, a static iron core, a movable iron core, a framework coil, a metal cup and a yoke iron; the method is characterized in that: the arc extinguishing system comprises an arc extinguishing chamber, an arc extinguishing cavity and a magnetic field standardizing device; a baffle plate is arranged below a moving contact in a cavity at the upper part of the direct current contactor, an arc extinguish chamber is arranged on the baffle plate, and the arc extinguish chamber is arranged at the periphery of the outer side of a relative movement area of the moving contact and a fixed contact of the direct current contactor; an arc extinguishing cavity extending from an upper cavity to a lower cavity of the direct current contactor is arranged between the shell and the periphery of the metal cup of the electromagnetic system; and a magnetic field standardizing device is arranged in the shell.

2. A dc contactor arc quenching system as claimed in claim 1, wherein: the arc extinguish chamber comprises an arc extinguish grid sheet and arc isolation plates, two arc isolation plates are arranged on two sides of a relative movement area of a moving contact and a static contact of the arc extinguish chamber relative to a direct current contactor, the arc isolation plates are arranged on the baffle plates, and the surfaces of the arc isolation plates are parallel to a central shaft of the moving contact of the direct current contactor; flaky arc extinguishing grid pieces are arranged between the two arc isolating plates, are perpendicular to the arc isolating plates and are spaced in parallel; the arc extinguish chamber is provided with an opening on one side relative to the moving contact of the direct current contactor, and the arc extinguish chamber is provided with an opening on the other side relative to the moving contact of the direct current contactor.

3. A dc contactor arc quenching system as claimed in claim 2, wherein: the magnetic field normalizing device comprises a permanent magnet and a magnetic yoke; permanent magnets are arranged on the two sides of the direct current contactor contact system and the arc extinguish chamber, the central axis between the two poles of each permanent magnet is parallel to a plane formed by the central point of the moving contact and the central points of the two static contacts, and the polarities of the two permanent magnets are opposite (the N pole corresponds to the N pole or the S pole corresponds to the S pole); and a magnetic yoke is arranged around the peripheries of the two permanent magnets.

4. A dc contactor arc quenching system as claimed in claim 3, wherein: two U-shaped magnetic yokes are arranged in the direct current contactor shell and connected to form a hollow square structure, and the central axis of the hollow square structure is superposed with the central axis of the direct current contactor; every U-shaped yoke U-shaped bottom corresponds the explosion chamber, is equipped with in the surrounding area that two U-shaped yokes are connected and are constituted permanent magnet, direct current contactor contact system with the explosion chamber.

5. The direct current contactor arc quenching system of claim 4, wherein: and the grid of the arc extinguish chamber is provided with an arc striking groove.

6. The direct current contactor arc quenching system of claim 5, wherein: the baffle plate is provided with an airflow guide piece; the airflow guide piece comprises a bottom plate (603a), an arc isolation plate (603b) and a separator (603 c); a moving contact in a cavity at the upper part of the direct current contactor is provided with a clapboard below, the clapboard is provided with a bottom plate (603a), and the bottom plate (603a) is provided with an arc-isolating plate (603b) and a separator (603 c); the separator (603c) is arranged at the opening of the other side of the arc extinguish chamber relative to the direct current contactor contact system; the two arc isolating plates (603b) symmetrically arranged at two sides of the arc extinguish chamber adjacent to the moving region of the movable contact by taking the separating piece (603c) as a center comprise arc isolating walls (603b1) and air guide plates (603b2), and the arc isolating walls (603b1) arranged at two sides of the arc extinguish chamber extend to the separating piece (603c) and are provided with the air guide plates (603b 2).

7. A dc contactor arc quenching system as claimed in claim 2, wherein: the arc extinguishing grid sheet is made of cold-rolled steel plates, copper plates, meta-position aromatic polyamide fiber Nomex section bars or ceramics.

8. A dc contactor arc quenching system as claimed in claim 1, wherein: the moving contact is provided with a U-shaped structural member support which is made of magnetic conductive materials.

9. A dc contactor arc quenching system as claimed in claim 1, wherein: the moving contact top be equipped with the flash barrier, the intermediate position at moving contact top portion is located to the flash barrier, separates two spaces with two contacts that the moving contact contacted with the static contact.