Arc extinguishing structure and circuit breaker

Abstract

The application discloses an arc extinguishing structure and a circuit breaker, which have an arc generating chamber, an arc moving chamber, a first arc extinguishing chamber and a second arc extinguishing chamber. The first arc extinguishing chamber is a narrow-gap arc extinguishing chamber, and the second arc extinguishing chamber is a metal grid arc extinguishing chamber. The narrow-gap arc extinguishing chamber is used for breaking a small current, and the metal grid arc extinguishing chamber is used for breaking a large current. The scheme realizes quick breaking of a small direct current through the narrow-gap arc extinguishing chamber, greatly shortens the arc burning time, and significantly improves the electrical life. The direct current arc can enter more metal grids and be effectively cut through by the combined action of an external magnetic field, an arc self magnetic field and an airflow field on a large direct current, so that the arc voltage is improved, and the breaking difficulty of a low-voltage bidirectional non-polarity direct current with a large current and a small current is effectively solved.

Description

Technical Field

[0001] In the field of low-voltage electrical technology, specifically, it relates to an arc-extinguishing structure and a circuit breaker. Background Technology

[0002] The rapid development of photovoltaic new energy power generation, energy storage, and electric vehicle technologies has made the development of key technologies for low-voltage DC power supply systems increasingly urgent. One key component is the low-voltage DC circuit breaker. The low-voltage DC circuit breaker is an important device used to protect low-voltage DC electrical equipment from overload and short-circuit faults and to interrupt circuits. It also undertakes the task of carrying and controlling normal and non-severe overload currents. Therefore, low-voltage DC circuit breakers are required to have a high electrical life and short-circuit breaking capacity. In other words, low-voltage DC circuit breakers need to meet certain breaking capacity requirements for normal load currents and have sufficient breaking capacity for large currents such as overloads and short circuits.

[0003] Direct current (DC) differs from alternating current (AC). AC current has two natural zero-crossing points per cycle, and all AC switching devices utilize these zero-crossing points to interrupt the current. DC current, however, does not have natural zero-crossing points. In voltage systems, conventional mechanical DC switching devices require increasing the arc voltage to a sufficiently high value to force the DC current to zero. In existing technologies, DC arc voltage is typically increased by lengthening the arc, cooling the arc, compressing the arc, or cutting the arc with metal grids. All of these methods require driving the arc to move or deform, and commonly utilize the arc's own magnetic field and airflow.

[0004] Generally, when the DC current is relatively large, the magnetic field and air blowing effect generated by the arc are strong, allowing the arc to move into the arc-extinguishing chamber. However, when the DC current is relatively small, such as the rated current or critical current, the magnetic field generated by the arc is weak, and the air blowing is also weak, greatly increasing the difficulty of driving the arc. To address this problem, a permanent magnet can be used to apply an external magnetic field to drive the arc. However, permanent magnets generally have a fixed magnetic field direction, thus generating a positive driving force (Lorentz force) on an arc with a defined current direction. If the current direction is reversed, the driving force generated by the permanent magnet on the arc will also be reversed. Therefore, permanent magnets are generally used in polarized low-voltage DC switching devices. For non-polarized low-voltage DC circuit breakers, the arc is often used to generate a sufficient pressure gradient through prolonged burning to drive the arc into the arc-extinguishing chamber. This method causes severe erosion of the internal components of the circuit breaker, significantly limiting its electrical life, and cannot be applied to higher voltage low-voltage DC systems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an arc-extinguishing structure and circuit breaker to solve the problem that in the prior art, the internal components of non-polar low-voltage DC circuit breakers are prone to burn-out and have a short electrical life, making it difficult to apply non-polar low-voltage DC circuit breakers to higher voltage low-voltage DC systems.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] An arc-extinguishing structure includes a first arc-blocking wall and a second arc-blocking wall disposed opposite to each other;

[0008] A first ferromagnetic body and a first permanent magnet are arranged on the outer side of the first arc-blocking wall. The first permanent magnet is located on the outer side of the upper portion of the first ferromagnetic body, and the first permanent magnet and the first ferromagnetic body are in contact. A second ferromagnetic body and a second permanent magnet are arranged on the outer side of the second arc-blocking wall. The second permanent magnet is located on the outer side of the upper portion of the second ferromagnetic body, and the second permanent magnet and the second ferromagnetic body are in contact. A moving contact and a stationary contact are arranged between the first arc-blocking wall and the second arc-blocking wall. The lowest point of both the first permanent magnet and the second permanent magnet is higher than the contact point of the moving contact and the stationary contact. The first ferromagnetic body and the second ferromagnetic body cover the opening and closing areas of the moving contact and the stationary contact.

[0009] A moving arc track is provided between the first and second arc partition walls, and a stationary arc track is provided between the first and second arc partition walls; the moving arc track is located above the stationary arc track; the moving arc track is located on one side of the moving contact, and the stationary arc track is located on the outside of the stationary contact.

[0010] The first arc-isolating wall has a first narrow slit at the end away from the moving contact, and the second arc-isolating wall has a second narrow slit at the end away from the moving contact;

[0011] An arc-extinguishing grid assembly is provided on the rear side of the first narrow slit and the second narrow slit; the arc-extinguishing grid assembly is located between the moving arc track and the stationary arc track;

[0012] The first ferromagnetic body and the first narrow slit are provided with a first outer shell, the second ferromagnetic body and the second narrow slit are provided with a second outer shell, and the bottoms of the first outer shell and the second outer shell are connected by a third outer shell.

[0013] A further improvement of the present invention is that:

[0014] Preferably, both the first and second arc-isolating walls are groove-shaped structures, with the protruding end of the first arc-isolating wall contacting the first outer shell and the protruding end of the second arc-isolating wall contacting the second outer shell.

[0015] Preferably, the stationary contact is located on the inner wall of the stationary running track.

[0016] Preferably, both the first and second arc-blocking walls are made of insulating materials.

[0017] Preferably, the moving arc track includes a U-shaped arc-attracting part, one end of which is connected to a conductive part, and the other end is connected to an arc-driving part; the conductive part and the moving contact are softly connected; a portion of the arc-driving part is disposed on the front side of the first ferromagnet and the second ferromagnet, and a portion of the arc-driving part is disposed on the lower side of the first ferromagnet, the second ferromagnet, the first narrow slit, the second narrow slit and the arc-extinguishing grid plate group.

[0018] Preferably, a portion of the static running arc track is disposed on the rear side of the first ferromagnet and the second ferromagnet, and a portion is disposed on the upper side of the first ferromagnet, the second ferromagnet, the first narrow slit, the second narrow slit, and the arc-extinguishing grid plate group.

[0019] Preferably, the first narrow slit is composed of a first sidewall and a second sidewall, with a gap between the first sidewall and the second sidewall; the first sidewall is close to the first arc-blocking wall, and the second sidewall is close to the arc-extinguishing grid assembly.

[0020] The second narrow slit is composed of a third sidewall and a fourth sidewall, with a gap between the third sidewall and the fourth sidewall; the third sidewall is close to the second arc-blocking wall, and the fourth sidewall is close to the arc-extinguishing grid assembly;

[0021] The second sidewall has a plurality of second sidewall holes on the side near the first outer shell. The plurality of second sidewall holes are arranged in an array along the height direction of the second sidewall. The second sidewall holes connect the first narrow slit and the arc extinguishing grid plate group.

[0022] The fourth sidewall has a plurality of fourth sidewall holes on the side closest to the second outer shell. The plurality of fourth sidewall holes are arranged in an array along the height direction of the fourth sidewall and the fourth sidewall holes connect the second narrow slit and the arc extinguishing grid plate group.

[0023] Preferably, the first sidewall is part of the first arc-blocking wall, and the second sidewall is part of the second arc-blocking wall.

[0024] Preferably, the arc-extinguishing grid assembly consists of a plurality of metal grid arrays, with the metal grids parallel to the moving arc track.

[0025] A circuit breaker comprising the arc-extinguishing structure described above.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] This invention discloses an arc-extinguishing structure, which comprises an arc-generating chamber formed by a moving contact, a stationary contact, a first arc-isolating wall, and a second arc-isolating wall; an arc-moving chamber formed by a moving arc-running track, a stationary arc-running track, the first arc-isolating wall, and the second arc-isolating wall; a first arc-extinguishing chamber in the form of a narrow-slit arc-extinguishing chamber; and a second arc-extinguishing chamber in the form of a metal grid arc-extinguishing chamber. The narrow-slit arc-extinguishing chamber is used for interrupting smaller currents, while the metal grid arc-extinguishing chamber is used for interrupting larger currents. This structure achieves rapid interruption of smaller DC currents through the narrow-slit arc-extinguishing chamber, significantly shortening the arcing time and significantly improving electrical life. By combining the external magnetic field, the arc's own magnetic field, and the airflow field to act on larger DC currents, the DC arc can enter more metal grids and be effectively cut, increasing the arc voltage and effectively solving the problem of interrupting large and small currents in low-voltage bidirectional non-polar DC currents.

[0028] Furthermore, this arc-extinguishing system utilizes a narrow-slit arc-extinguishing chamber and a metal grid arc-extinguishing chamber for breaking smaller and larger currents, respectively. Through an optimized permanent magnet arrangement, bidirectional small DC currents are driven into the two narrow-slit arc-extinguishing chambers located at one end of the metal grid arc-extinguishing chamber. The small DC current is extinguished by compression and cooling through the narrow slits, while the large current rapidly crosses the narrow-slit arc-extinguishing chamber under the influence of the external magnetic field, the arc's own magnetic field, and the airflow field, directly entering the metal grid arc-extinguishing chamber. This scheme achieves rapid breaking of smaller DC currents through the narrow-slit arc-extinguishing chamber, significantly shortening the arcing time and significantly improving electrical life. By leveraging the external magnetic field, the arc's own magnetic field, and the airflow field to act on larger DC currents, the DC arc can enter more metal grids and be effectively cut, increasing the arc voltage and effectively solving the problem of breaking both large and small currents in low-voltage bidirectional non-polar DC circuits.

[0029] Furthermore, the technical solution provided by this invention separates large and small DC arcs into different arc-extinguishing chambers for arc extinguishing, effectively solving the problem of difficulty in extinguishing smaller DC arcs, realizing rapid interruption of bidirectional DC arcs, greatly shortening the arcing time, significantly improving electrical life, while not affecting the movement and interruption of large short-circuit arcs. The technical solution provided by this invention has a simple structure, low cost, and strong feasibility.

[0030] The present invention also discloses a circuit breaker including an arc extinguishing structure. It only improves the arc extinguishing system of the existing circuit breaker and can significantly improve the arc voltage without adjusting the opening distance, mechanism speed, etc. For DC arc extinguishing of higher system voltage, the number of circuit breaker poles in series will also be reduced, which can achieve a significant cost reduction. Attached Figure Description

[0031] Figure 1 This is a schematic front view diagram of an embodiment of the present invention;

[0032] Figure 2This is a cross-sectional view of an embodiment of the present invention;

[0033] Figure 3 This is a cross-sectional structural diagram 1-1 of an embodiment of the present invention;

[0034] Figure 4 This is a cross-sectional structural diagram of an embodiment of the present invention (2-2).

[0035] Figure 5 This is a cross-sectional structural diagram of an embodiment of the present invention (3-3).

[0036] Figure 6 This is a schematic front view of the running track according to an embodiment of the present invention;

[0037] Figure 7 This is a schematic front view of the stationary contact and stationary running arc according to an embodiment of the present invention;

[0038] Figure 8 This is a rear view schematic diagram of the first narrow slit according to an embodiment of the present invention;

[0039] Figure 9 This is a schematic left view of the first sidewall of the first narrow slit according to an embodiment of the present invention;

[0040] Figure 10 This is a schematic left view of the second sidewall of the first narrow slit according to an embodiment of the present invention;

[0041] Figure 11 This is a rear view schematic diagram of the second narrow slit according to an embodiment of the present invention;

[0042] Figure 12 This is a schematic left view of the first sidewall of the second narrow slit according to an embodiment of the present invention;

[0043] Figure 13 This is a schematic left view of the second sidewall of the second narrow slit according to an embodiment of the present invention;

[0044] Wherein: 1. Moving contact; 2. Stationary contact; 3. First permanent magnet; 4. Second permanent magnet; 5. First ferromagnet; 6. Second ferromagnet; 7. First arc-isolating wall; 8. Second arc-isolating wall; 9. First narrow slit; 901. First sidewall; 902. Second sidewall; 903. Second sidewall hole; 10. Second narrow slit; 1001. Third sidewall; 1002. Fourth sidewall; 1003. Fourth sidewall hole; 11. Moving arc track; 111. Moving arc track arc-attracting part; 112. Moving arc track arc-driving part; 113. Moving arc track conductive part; 12. Stationary arc track; 13. Arc-extinguishing grid assembly; 14. Outer shell; 141. First outer shell; 142. Second outer shell; 143. Third outer shell; 51. Front part; 52. Rear part; 53. Vertical surface; 54. Inclined surface. Detailed Implementation

[0045] The present invention will now be described in further detail with reference to the accompanying drawings:

[0046] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] Please see Figures 1-5 According to the present invention, an arc-extinguishing system comprises an arc-generating chamber, an arc-moving chamber, a first arc-extinguishing chamber, and a second arc-extinguishing chamber. The first arc-extinguishing chamber is a narrow-slit arc-extinguishing chamber, and the second arc-extinguishing chamber is a metal grid arc-extinguishing chamber. The narrow-slit arc-extinguishing chamber is used for interrupting smaller currents, while the metal grid arc-extinguishing chamber is used for interrupting larger currents. This solution achieves rapid interruption of smaller DC currents through the narrow-slit arc-extinguishing chamber, significantly shortening the arcing time and significantly improving the electrical life. By combining the external magnetic field, the arc's own magnetic field, and the airflow field to act on larger DC currents, the DC arc can enter more metal grids and be effectively cut, increasing the arc voltage and effectively solving the problem of interrupting large and small currents in low-voltage bidirectional non-polar DC circuits.

[0048] According to the technical solution provided by the present invention, a three-dimensional magnetic field distribution is generated in the arc generating chamber and the arc moving chamber, including a magnetic field component parallel to the arc-isolating wall and a magnetic field component perpendicular to the arc-isolating wall and in opposite directions in the region near the two arc-isolating walls. For relatively small DC currents several times the rated current and below, the magnetic field component parallel to the arc-isolating wall will cause the arc to deflect towards one side of the arc-isolating wall. According to the solution of the present invention, the component of the magnetic field near the arc-isolating wall that is perpendicular to the arc-isolating wall will drive the arc to move towards the first arc-extinguishing chamber and the second arc-extinguishing chamber, while the magnetic field component parallel to the arc-isolating wall will cause the arc to deflect further towards that side of the arc-isolating wall. When the arc current is small, the arc dissipates heat and is stretched during its movement, thereby extinguishing. When the arc current is large, the arc will move to the region of the first arc-extinguishing chamber and, under the action of the magnetic field component parallel to the arc-isolating wall, enter the narrow slit to extinguish. The arc chamber is compressed and extinguished. If the arc current is opposite, the arc will deflect towards the other side of the arc-isolating wall and enter the narrow-slit arc-extinguishing chamber on the other side. For large DC currents with severe overload or minor short circuit, the arc will deflect towards one side of the arc-isolating wall under the influence of the magnetic field component parallel to the arc-isolating wall, and move rapidly towards the first and second arc-extinguishing chambers. Because the arc current is large, the arc column diameter will also be relatively large. In the first arc-extinguishing chamber region, part of the arc will enter the narrow-slit arc-extinguishing chamber, while part will cross the narrow-slit arc-extinguishing chamber region and enter the second arc-extinguishing chamber. For very large short-circuit DC currents, due to the very strong magnetic field and pressure rise generated by the arc itself, a strong magnetic and air blowing effect will be generated on the arc towards the second arc-extinguishing chamber, while the effect of the external magnetic field is relatively weak. Therefore, the arc will move rapidly into the second arc-extinguishing chamber and complete the arc-extinguishing process of cutting the metal grid.

[0049] The arc generating chamber, the arc moving chamber, the first arc extinguishing chamber, and the second arc extinguishing chamber are all arranged between the first outer shell 141 and the second outer shell 142, in the order of arc generating chamber, arc moving chamber, first arc extinguishing chamber, and second arc extinguishing chamber. The first sidewall 141 and the second sidewall 142 are arranged opposite to each other, and the bottoms of the first outer shell 141 and the second outer shell 142 are connected through the third outer shell 143.

[0050] The moving contact 1 and the stationary contact 2 are arranged opposite each other, with a gap between them. The first arc-isolating wall 7 and the second arc-isolating wall 8 are arranged on both sides of the moving contact 1 and the stationary contact 2, and between the first ferromagnetic body 5 and the second ferromagnetic body 6. In other words, the first permanent magnet 3, the first ferromagnetic body 5, and the first arc-isolating wall 7 are located on one side of the moving contact 1 and the stationary contact 2, and their distances from the moving contact 1 and the stationary contact 2, from near to far, are the first arc-isolating wall 7, the first ferromagnetic body 5, and the first permanent magnet 3. The second permanent magnet 4, the second ferromagnetic body 6, and the second arc-isolating wall 8 are located on the other side of the moving contact 1 and the stationary contact 2, and their distances from the moving contact 1 and the stationary contact 2, from near to far, are the second arc-isolating wall 8, the second ferromagnetic body 6, and the second permanent magnet 4. Both the first arc-isolating wall 7 and the second arc-isolating wall 8 are U-shaped structures. The two protruding ports of the first arc-isolating wall 7 are connected to the first outer shell 141. A first ferromagnetic body 5 and a first permanent magnet 3 are placed in the cavity enclosed between the first arc-isolating wall 7 and the first side wall 141. The two protruding ports of the second arc-isolating wall 8 are connected to the second outer shell 142. A second ferromagnetic body 6 and a second permanent magnet 4 are placed between the cavity enclosed by the second arc-isolating wall 8 and the second side wall 142. The area enclosed by the moving contact 1, the stationary contact 2, the first arc-isolating wall 7, and the second arc-isolating wall 8 is the arc-generating chamber.

[0051] The first ferromagnetic body 5 and the second ferromagnetic body 6 have the same structure, comprising two integrally connected parts, namely a front part 51 and a rear part 52. The rear end face of the front part 51 and the front end face of the rear part 52 are integrally connected. The upper part of the front end face of the front part 51 is a vertical surface 53, and the lower part is an inclined surface 54, making the front part 51 an irregular body and the rear part 52 a cuboid. The upper end face of the front part 51 is in contact with the permanent magnet, and the rear end face of the rear part 52 is in contact with the narrow slit. The structures of the first ferromagnetic body 5 and the second ferromagnetic body 6 are the same as those of the first arc-blocking wall 7 and the second arc-blocking wall 8.

[0052] The first arc-isolating wall 7 covers the first ferromagnetic body 5, and the second arc-isolating wall 8 covers the second ferromagnetic body 6. The first arc-isolating wall 7 and the second arc-isolating wall 8 are made of high-temperature resistant insulating material, which can be a gas-generating material or a non-gas-generating material.

[0053] Between the first arc-isolating wall 7 and the second arc-isolating wall 8, there are a moving arc track 11 and a stationary arc track 12 arranged opposite to each other; the moving arc track 11 is located at one end of the moving contact 1, and the moving arc track 11 and the moving contact 1 are connected by braided copper wire and are at the same potential; the stationary arc track 12 is located at the outer end of the stationary contact 2, and the stationary arc track 12 and the stationary contact 2 are fixedly connected and are at the same potential; the area enclosed by the moving arc track 11, the stationary arc track 12, the first arc-isolating wall 7, and the second arc-isolating wall 8 is the arc motion chamber.

[0054] A first narrow slit 9 is arranged at the end of the first arc-isolating wall 7 away from the moving contact 1 and the stationary contact 2, and a second narrow slit 10 is arranged at the end of the second arc-isolating wall 8 away from the moving contact 1 and the stationary contact 2. The two ends of the channel of the first narrow slit 9 are the moving arc track 11 and the stationary arc track 12, respectively, and the two ends of the channel of the second narrow slit 10 are the moving arc track 11 and the stationary arc track 12, respectively. The first narrow slit 9 and the second narrow slit 10 form the first arc-extinguishing chamber, which is used to extinguish smaller DC arcs.

[0055] The arc-extinguishing grid plate group 13 is composed of multiple parallel metal grid plates stacked together and located between the stationary arc track 12 and the arc track 11 and the first side wall 141 and the second side wall 142 of the outer shell. The metal grid plates are parallel to the stationary arc track 12 and the arc track 11 that are close to each other at both ends. The arc-extinguishing grid plate group 13, the stationary arc track 12, and the arc track 11 form the second arc-extinguishing chamber for extinguishing large DC arcs.

[0056] In the first embodiment, the arc extinguishing system and structure of this embodiment includes a moving contact 1, a stationary contact 2, a first permanent magnet 3, a second permanent magnet 4, a first ferromagnetic body 5, a second ferromagnetic body 6, a first arc-isolating wall 7, a second arc-isolating wall 8, a first narrow slit 9, a second narrow slit 10, a moving arc track 11, a stationary arc track 12, and an arc-extinguishing grid assembly 13.

[0057] In this embodiment, the moving contact 1 and the stationary contact 2 are arranged opposite to each other, and the stationary contact 2 is fixedly arranged relative to the outer casing. The moving contact 1 can make contact and separate relative to the stationary contact 2 to complete the opening and closing operation of the circuit breaker involved in this embodiment. When closing, the circuit current is conducted through the moving contact 1 and the stationary contact 2. When opening, an electric arc will be generated between the moving contact 1 and the stationary contact 2.

[0058] The first permanent magnet 3 and the second permanent magnet 4 are identical in shape, size, volume, material, and performance. They are rectangular magnets with two polar surfaces that are the two largest side surfaces. They are arranged on both sides of the moving contact 1 and the stationary contact 2, respectively. The lower edges of the two permanent magnets are higher than the contact points of the moving contact 1 and the stationary contact 2. In addition, the same polarity surfaces of the first permanent magnet 3 and the second permanent magnet 4 are arranged opposite each other. For example, the N polarity surfaces of the first permanent magnet 3 and the second permanent magnet 4 both face the moving contact 1 and the stationary contact 2, or the S polarity surfaces of the first permanent magnet 3 and the second permanent magnet 4 both face the moving contact 1 and the stationary contact 2.

[0059] The first ferromagnetic body 5 and the second ferromagnetic body 6 are arranged on both sides of the moving contact 1 and the stationary contact 2, and between the first permanent magnet 3 and the second permanent magnet 4. The first ferromagnetic body 5 and the second ferromagnetic body 6 cover the area involved in the opening and closing of the moving contact 1 and the stationary contact 2, and extend to the first narrow slit 9 and the second narrow slit 10. The first permanent magnet 3 is located on the outer side of the upper part of the first ferromagnetic body 5, and the inner wall of the first permanent magnet 3 is in contact with the first ferromagnetic body 5. The second permanent magnet 4 is located on the outer side of the upper part of the second ferromagnetic body 6, and the inner wall of the second permanent magnet 4 is in contact with the second ferromagnetic body 6. Ferromagnetic materials have many magnetic domains. When there is no external magnetic field, the magnetic domains are arranged randomly, and their magnetic properties cancel each other out, so they do not show magnetism externally. However, when there is an external magnetic field, the magnetic domains will align along the direction of the magnetic field, forming an additional magnetic field. When a ferromagnetic material comes into contact with or approaches a permanent magnet, it will be magnetized. The intensity and area of ​​magnetization will vary depending on the strength of the permanent magnet and the magnetization characteristics of the ferromagnetic material itself. In this embodiment, the upper end of the first ferromagnetic material 5 contacts the N-polarity surface of the first permanent magnet 3. After being magnetized, the polarity of the first ferromagnetic material 5 is S in the area in contact with the N-polarity surface of the first permanent magnet 3 and a very small nearby area. The other side of the first ferromagnetic material 5, away from the first permanent magnet 3, is entirely N-pole. On the side of the first permanent magnet 3 that is in contact with the N-polarity surface, the portion away from the first permanent magnet 3 is also an N pole. Similarly, after the second ferromagnet 6 is magnetized by the second permanent magnet 4, the polarity of the second ferromagnet 6 in the area in contact with the N-polarity surface of the second permanent magnet 4 and a very small nearby area is S, while the other side of the second ferromagnet 6 away from the second permanent magnet 4 is entirely N pole. Furthermore, on the side of the second ferromagnet 6 that is in contact with the N-polarity surface of the second permanent magnet 4, the portion away from the second permanent magnet 4 is also an N pole. Therefore, the first ferromagnet 5 and the second ferromagnet 6 in the areas of the moving contact 1, the stationary contact 2, and extending to both sides of the areas of the first narrow slit 9 and the second narrow slit 10 are all N poles inward. On the other hand, since the magnetic field strength of the first ferromagnetic body 5 and the second ferromagnetic body 6 in the region where the first permanent magnet 3 and the second permanent magnet 4 are located is much higher than the magnetic field strength of the first ferromagnetic body 5 and the second ferromagnetic body 6 in the region far away from the contact, a magnetic field component will be generated in the region between the first ferromagnetic body 5 and the second ferromagnetic body 6 in the direction from the region of the moving contact 1 and the stationary contact 2 toward the region of the first narrow slit 9 and the second narrow slit 10 and parallel to the first ferromagnetic body 5 and the second ferromagnetic body 6.

[0060] After receiving the tripping command, the circuit breaker involved in this embodiment of the invention operates by tripping the circuit breaker. The moving contact 1 separates from the stationary contact 2 under the drive of the mechanism, and an electric arc is generated between the moving contact 1 and the stationary contact 2. If the arc current flows from the stationary contact 2 to the moving contact 1, according to the left-hand rule, the arc will be subjected to a Lorentz force in the direction inward along the paper under the action of the magnetic field components parallel to the first ferromagnetic body 5 and the second ferromagnetic body 6 in the region of the moving contact 1 and the stationary contact 2, as described above. That is, it will move towards the direction of the second ferromagnetic body 6. When the arc approaches the side of the second ferromagnetic body 6, since the side of the second ferromagnetic body 6 facing the moving contact 1 and the stationary contact 2 is the N pole, the arc will be subjected to a downward Lorentz force towards the arc movement chamber. The arc moves downward and transfers to the area between the stationary arc track 12 and the moving arc track 11. The arc will still move towards the second narrow slit 10 against the second arc partition wall 8 under the action of the magnetic field components parallel to the first ferromagnetic body 5 and the second ferromagnetic body 6 and the magnetic field component perpendicular to the side of the second ferromagnetic body 6. During its movement, the electric arc is stretched and dissipates heat, causing the arc voltage to rise. If the current is small, the arc voltage may be large enough to extinguish the arc before it reaches the second narrow slit 10. If the arc current is relatively large, when the arc reaches the second narrow slit 10, it will enter the second narrow slit 10 under the action of the Lorentz force. Under the compression, stretching, and heat absorption and cooling of the slit wall, the arc voltage will rise rapidly and extinguish the arc. If the arc current is very large, when the arc reaches the second narrow slit 10, it cannot completely enter the slit, and the arc voltage increased by the slit is insufficient to extinguish the arc. In this case, the arc will continue to move forward under the action of strong airflow and the arc itself and the external magnetic field, and enter the arc-extinguishing grid assembly 13. There, it will be cooled, stretched, and cut by the metal grid, thereby providing sufficient arc voltage to extinguish the arc. Conversely, if the arc current flows from the moving contact 1 to the stationary contact 2, the arc will be subjected to a Lorentz force biased towards the first ferromagnetic body 5. When the arc is biased towards the first ferromagnetic body 5, it will move towards the arc movement chamber under the influence of the magnetic field near the first ferromagnetic body 5. Then the arc will transfer to the space between the stationary arc track 12 and the moving arc track 11, and continue to move to the first narrow slit 9. As mentioned above, the arc with a smaller current will be extinguished during the movement, the arc with a larger current will be extinguished in the first narrow slit 9, and the arc with a very large current will be extinguished in the arc extinguishing grid assembly 13.

[0061] In the first embodiment of the present invention, if the polarity surfaces of the first permanent magnet 3 and the second permanent magnet 4 facing the regions of the moving contact 1 and the stationary contact 2 are both S poles, then after the first ferromagnetic body 5 and the second ferromagnetic body 6 are magnetized, the sides facing the regions of the moving contact 1 and the stationary contact 2 will all be S poles. Simultaneously, a magnetic field component will be generated in the region between the first ferromagnetic body 5 and the second ferromagnetic body 6, extending from the regions of the first narrow slit 9 and the second narrow slit 10 toward the regions of the moving contact 1 and the stationary contact 2 and parallel to the first ferromagnetic body 5 and the second ferromagnetic body 6. When the moving contact 1 and stationary contact 2 open and generate an arc, similar to the previous analysis, the arc will be deflected towards one side of the arc-extinguishing wall under the influence of the magnetic field component parallel to the arc-extinguishing wall. The component of the magnetic field near that side of the arc-extinguishing wall, perpendicular to that side, will drive the arc to move towards one of the narrow slits in the first arc-extinguishing chamber and enter it. Arcs with smaller currents will extinguish during the movement, while arcs with larger currents will enter the first narrow slit 9 and extinguish. Arcs with very large currents will continue to move and enter the arc-extinguishing grid assembly 13, where they will be cooled, stretched, and cut by the metal grids, thereby providing sufficient arc voltage to extinguish the arc. This process is similar for arc currents flowing from stationary contact 2 to moving contact 1 or from moving contact 1 to stationary contact 2. The only difference is that arcs with opposite current directions are deflected towards different side walls, but all are towards the first and second arc-extinguishing chambers.

[0062] Please see Figure 6 The moving arc track 11 has an arc-attracting part 111, an arc-driving part 112, and a conductive part 113. The arc-attracting part 111 has a U-shaped structure, with the bottom of the U-shaped structure close to the moving contact 1. The arc-driving part 112 and the conductive part 113 are connected to the two arms of the U-shaped structure of the arc-attracting part 111. The conductive part 113 is connected to the moving contact via a flexible connection. The arc-driving part 112 extends through the arc motion chamber and the first arc-extinguishing chamber to one end of the arc-extinguishing grid plate group 13 in the second arc-extinguishing chamber. The width of the part of the moving arc track 11 between the arc-attracting part 111 and the first arc-extinguishing chamber is narrower than the width of the rest of the moving arc track 11 in the direction from the first arc-extinguishing chamber to the second arc-extinguishing chamber.

[0063] Please see Figure 7 One end of the stationary arc track 12 is fixedly connected to the stationary contact 2, and the other end of the stationary arc track 12 extends through the arc motion chamber and the first arc extinguishing chamber to the other end of the arc extinguishing grid plate group 13 in the second arc extinguishing chamber. The width of the portion of the stationary arc track 12 between the stationary contact 2 and the first arc extinguishing chamber is narrower than the width of the rest of the stationary arc track 12 in the direction from the first arc extinguishing chamber to the second arc extinguishing chamber.

[0064] Please see Figures 8-13The first narrow slit 9 and the second narrow slit 10 have the same structure and are arranged opposite to each other, respectively between the first arc-isolating wall 7 and the arc-extinguishing grid plate group 13, and between the second arc-isolating wall 8 and the arc-extinguishing grid plate group 13; the first sidewall 901 and the second sidewall 902 of the first narrow slit 9 and the first outer shell 141 form a concave first narrow slit 9, and the distance between the first sidewall 901 and the second sidewall 902 is not greater than 4mm; the third sidewall 1001 and the fourth sidewall 1002 of the second narrow slit 10 and the second outer shell 142 form a concave second narrow slit 10, and the distance between the third sidewall 1002 and the fourth sidewall 1002 is not greater than 4mm; the first sidewall 1001 and the second sidewall 1002 of the first narrow slit 9 and the third sidewall 1001 and the fourth sidewall 1002 of the second narrow slit 10 are all made of high-temperature resistant insulating material, which can be a gas-generating material or a non-gas-generating material.

[0065] In another embodiment of the arc-extinguishing system and structure provided by the present invention, the first sidewall 901 of the first narrow slit 9 is replaced by the wall adjacent to the first arc-isolating wall 7, and the second sidewall 902 is adjacent to the arc-extinguishing grid assembly 13. The first sidewall 1001 of the second narrow slit 10 is replaced by the wall adjacent to the second arc-isolating wall 8, and the second sidewall 1002 is adjacent to the arc-extinguishing grid assembly 13. Thus, there is only one insulating layer between the first narrow slit 9 and the first ferromagnetic body 5, and only one insulating layer between the second narrow slit 10 and the second ferromagnetic body 6. The magnetic field strength generated by the first ferromagnetic body 5 and the second ferromagnetic body 6 at the positions of the first narrow slit 9 and the second narrow slit 10 will be stronger, thereby increasing the Lorentz force that drives the arc into the narrow slit, which helps the arc enter the narrow slit and extinguish.

[0066] In another embodiment of the arc extinguishing system and structure provided by the present invention, a plurality of second sidewall holes 903 are provided on the second sidewall 902 of the first narrow slit 9 near the end of the first outer shell 141. The second sidewall holes 903 connect the first narrow slit 9 and the arc extinguishing grid plate group 13, and the positions of the second sidewall holes 903 are located at the grid plate intervals of the arc extinguishing grid plate group 13; a plurality of fourth sidewall holes 1003 are provided on the fourth sidewall 1002 of the second narrow slit 10 near the end of the second outer shell 142. The fourth sidewall holes 1003 connect the second narrow slit 10 and the arc extinguishing grid plate group 13; and the positions of the fourth sidewall holes 1003 are located at the grid plate intervals of the arc extinguishing grid plate group 13.

[0067] As mentioned earlier, when the current is not very large, the DC arc will enter either the first narrow slit 9 or the second narrow slit 10 under the influence of the Lorentz force, determined by the interaction between the current direction and the magnetic field direction. Because the temperature of the arc is extremely high, typically several thousand or even tens of thousands of degrees, the arc burning in the narrow slit will generate a huge local pressure increase. Due to the influence of the huge pressure difference inside and outside the narrow slit, the air blowing effect will tend to cause the arc to leave the narrow slit, which, contrary to the effect of the magnetic field, will to some extent hinder the extinguishing of the arc in the narrow slit. By providing several second sidewall holes 903 on the second sidewall 902 of the first narrow slit 9 near the first outer shell 141, and several fourth sidewall holes 1003 on the second sidewall 1002 of the second narrow slit 10 near the second outer shell 142, the pressure increase caused by the arc burning in the narrow slit is released through the second sidewall holes 903 or the fourth sidewall holes 1003, which is beneficial to the maintenance of the arc in the narrow slit. At the same time, the hot free gas released through the second sidewall holes 903 or the fourth sidewall holes 1003 enters the grid leg space of the arc-extinguishing grid assembly 13 and makes full contact with the grid legs, which can also achieve the cooling effect of the gas in the arc-extinguishing chamber, and indirectly promote the extinguishing of the arc.

[0068] The working principle of the arc extinguishing system and structure of the present invention is as follows:

[0069] An external magnetic field drives a DC arc, causing it to move along the arc-isolating wall on one side of the circuit breaker towards the arc-extinguishing chamber. Simultaneously, a narrow slit and a group of metal arc-extinguishing grids are sequentially arranged along the arc's movement direction. This allows small-current arcs to extinguish during their movement or within the narrow slits, while large-current arcs are extinguished within the arc-extinguishing grids. To achieve an effective external magnetic field distribution for both bidirectional DC arcs, a pair of permanent magnets with opposite faces of the same polarity and a pair of ferromagnets positioned between them are used. The ferromagnets are magnetized by the permanent magnets, causing the sides of both ferromagnets facing the arc generation and movement area to exhibit the same polarity, identical to the polarity of the opposite faces of the permanent magnets. On the other hand, since the magnetic field strength is strongest near the permanent magnet after the ferromagnet is polarized, in the solution provided by this invention, the permanent magnet is located at the upper end of the contact point between the moving and stationary contacts, resulting in a magnetic field component parallel to the arc-isolating wall in the magnetic field of the arc generation and movement area. This magnetic field component tends the arc towards one side of the arc-isolating wall, while the magnetic field near this side of the arc-isolating wall has a magnetic field component perpendicular to the arc-isolating wall that tends the arc towards the arc-extinguishing chamber. During its movement, the arc is subjected to the combined effects of multiple forces, including the upstream and downstream air blowing, the magnetic field of the arc itself and the current-carrying magnetic field of the arc track, and the magnetic field generated by the ferromagnet. After an electric arc is generated between the moving and stationary contacts, the aforementioned forces drive the arc to rapidly transfer to the arc track, enter the arc motion chamber, and continue its movement. If the current value is small, the arc will extinguish during its movement; if the current value is large, the arc continues to move along one side of the arc-extinguishing wall. When it reaches the narrow slit position, the magnetic field of the ferromagnetic material plays a major role, pressing the arc into the narrow slit to extinguish it; if the current value is very large, when the arc reaches the narrow slit position, a portion of the arc rapidly crosses the narrow slit and enters the arc-extinguishing grid area. Part of the arc is forced into the narrow slit, forming two parallel current channels. If the arc resistance in the narrow slit is greater than the arc resistance in the arc-extinguishing grid area, the arc current will transfer to the arc in the arc-extinguishing grid area, and the arc in the narrow slit will disappear. If the resistance in the narrow slit is less than the arc resistance in the arc-extinguishing grid area, the arc current will transfer to the narrow slit area, and the arc in the narrow slit will burn violently, causing a huge increase in local pressure inside, driving the arc out of the narrow slit, and under the action of air blowing and magnetic blowing, it will enter the arc-extinguishing grid area and then extinguish the arc.

[0070] Therefore, the technical solution provided by the present invention, compared with the prior art, adds the effect of an external magnetic field, which provides more driving force for the arc in the initial stage of arc generation and movement, so that the arc leaves the contact area more quickly and reduces the ablation of the contact material. For DC arcs with smaller currents, the arc can be extinguished quickly through the accelerated movement of the external magnetic field and the narrow slit arc extinguishing chamber, without affecting the large short-circuit current entering the metal arc extinguishing grid plate arc extinguishing chamber for arc extinguishing.

[0071] The present invention also provides a circuit breaker having any of the above-described arc extinguishing systems.

[0072] In summary, the arc-extinguishing system, structure, and circuit breaker provided by this invention separate large and small DC arcs into different arc-extinguishing chambers for arc extinguishing, effectively solving the problem of difficulty in extinguishing smaller DC arcs. This achieves rapid interruption of bidirectional DC arcs, significantly shortens the arcing time, and significantly improves electrical life, while not affecting the movement and interruption of large short-circuit arcs. Furthermore, the technical solution provided by this invention is simple in structure, low in cost, and highly feasible. It only requires improvements to the arc-extinguishing system of existing circuit breakers, without adjusting the opening distance, mechanism speed, etc., to achieve a significant increase in arc voltage. For DC arc extinguishing with higher system voltages, the number of circuit breaker poles in series can also be reduced, resulting in substantial cost reduction.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An arc-extinguishing structure, characterized in that, Including a first diaphragm wall (7) and a second diaphragm wall (8) that are set opposite to each other; A first ferromagnetic body (5) and a first permanent magnet (3) are provided on the outer side of the first arc-blocking wall (7). The first permanent magnet (3) is located on the outer side of the upper part of the first ferromagnetic body (5), and the first permanent magnet (3) and the first ferromagnetic body (5) are in contact. A second ferromagnetic body (6) and a second permanent magnet (4) are provided on the outer side of the second arc-blocking wall (8). The second permanent magnet (4) is located on the outer side of the upper part of the second ferromagnetic body (6), and the second permanent magnet (4) and the second ferromagnetic body (6) are in contact. A moving contact (1) and a stationary contact (2) are provided between the first arc-blocking wall (7) and the second arc-blocking wall (8). The lowest point of the first permanent magnet (3) and the second permanent magnet (4) is higher than the contact point of the moving contact (1) and the stationary contact (2). The first ferromagnetic body (5) and the second ferromagnetic body (6) cover the opening and closing areas of the moving contact (1) and the stationary contact (2). A moving arc track (11) is provided between the first arc partition wall (7) and the second arc partition wall (8), and a stationary arc track (12) is provided between the first arc partition wall (7) and the second arc partition wall (8); the moving arc track (11) is located above the stationary arc track (12); the moving arc track (11) is located on one side of the moving contact (1), and the stationary arc track (12) is located on the outside of the stationary contact (2); The first arc-blocking wall (7) has a first narrow slit (9) at the end away from the moving contact (1), and the second arc-blocking wall (8) has a second narrow slit (10) at the end away from the moving contact (1). Arc-extinguishing grid plate group (13) is provided on the rear side of the first narrow slit (9) and the second narrow slit (10); the arc-extinguishing grid plate group (13) is provided between the moving running arc track (11) and the stationary running arc track (12); A first outer shell (141) is provided outside the first ferromagnetic body (5) and the first narrow slit (9), and a second outer shell (142) is provided outside the second ferromagnetic body (6) and the second narrow slit (10). The bottoms of the first outer shell (141) and the second outer shell (142) are connected by a third outer shell (143).

2. The arc-extinguishing structure according to claim 1, characterized in that, Both the first arc-blocking wall (7) and the second arc-blocking wall (8) are groove-shaped structures. The protruding end of the first arc-blocking wall (7) is in contact with the first outer shell (141), and the protruding end of the second arc-blocking wall (8) is in contact with the second outer shell (142).

3. The arc-extinguishing structure according to claim 1, characterized in that, The stationary contact (2) is located on the inner wall of the stationary running arc (12).

4. The arc-extinguishing structure according to claim 1, characterized in that, Both the first arc-blocking wall (7) and the second arc-blocking wall (8) are made of insulating materials.

5. The arc-extinguishing structure according to claim 1, characterized in that, The moving arc track (11) includes a U-shaped arc-attracting part (111), one end of which is connected to a conductive part (113) and the other end is connected to an arc-driving part (112); the conductive part (113) and the moving contact (1) are softly connected; a part of the arc-driving part (112) is disposed on the front side of the first ferromagnetic body (5) and the second ferromagnetic body (6), and a part of the arc-driving part (112) is disposed on the lower side of the first ferromagnetic body (5), the second ferromagnetic body (6), the first narrow slit (9), the second narrow slit (10) and the arc-extinguishing grid plate group (13).

6. The arc-extinguishing structure according to claim 1, characterized in that, A portion of the static running arc (12) is located behind the first ferromagnetic body (5) and the second ferromagnetic body (6), and a portion is located above the first ferromagnetic body (5), the second ferromagnetic body (6), the first narrow slit (9), the second narrow slit (10), and the arc-extinguishing grid plate group (13).

7. The arc-extinguishing structure according to claim 1, characterized in that, The first narrow slit (9) is composed of a first sidewall (901) and a second sidewall (902), with a gap between the first sidewall (901) and the second sidewall (902); the first sidewall (901) is close to the first arc-blocking wall (7), and the second sidewall (902) is close to the arc-extinguishing grid assembly (13). The second narrow slit (10) is composed of a third sidewall (1001) and a fourth sidewall (1002), with a gap between the third sidewall (1001) and the fourth sidewall (1002); the third sidewall (1001) is close to the second arc-blocking wall (8), and the fourth sidewall (1002) is close to the arc-extinguishing grid assembly (13). The second sidewall (902) has a plurality of second sidewall holes (903) on the side near the first outer shell (141). The plurality of second sidewall holes (903) are arranged in an array along the height direction of the second sidewall (902). The second sidewall holes (903) connect the first narrow slit (9) and the arc extinguishing grid plate group (13). The fourth sidewall (1002) has a plurality of fourth sidewall holes (1003) on the side near the second outer shell (142). The plurality of fourth sidewall holes (1003) are arranged in an array along the height direction of the fourth sidewall (1002). The fourth sidewall holes (1003) connect the second narrow slit (10) and the arc extinguishing grid plate group (13).

8. The arc-extinguishing structure according to claim 7, characterized in that, The first sidewall (901) is part of the first arc-blocking wall (7), and the second sidewall (902) is part of the second arc-blocking wall (8).

9. The arc-extinguishing structure according to claim 1, characterized in that, The arc-extinguishing grid plate group (13) consists of several metal grid plate arrays, with the metal grid plates parallel to the moving arc track (11).

10. A circuit breaker comprising the arc-extinguishing structure of claim 1.

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