Contact arc extinguishing device for a circuit breaker

Abstract

A contact arc extinguishing device of a circuit breaker belongs to the technical field of switch electric technology. It comprises a moving contact and a static contact for breaking a circuit, and an arc extinguishing system for extinguishing the arc generated when the moving contact is broken with the static contact. The arc extinguishing system comprises an arc extinguishing grid set, which comprises an arc leading grid and a set of arc extinguishing grids. The set of arc extinguishing grids is arranged from top to bottom and keeps an arc extinguishing grid interval distance between each other. The arc leading grid is arranged above the set of arc extinguishing grids and keeps an arc leading grid interval distance between the arc leading grid and the uppermost arc extinguishing grid in the set of arc extinguishing grids. The feature is that the arc leading grid interval distance is greater than the arc extinguishing grid interval distance. The advantage is that the arc extinguishing efficiency of the arc extinguishing chamber is improved through reasonable arrangement of the arc extinguishing grids, and the safety and reliability of the electrical equipment when breaking the current are ensured.

Description

Technical Field

[0001] This utility model belongs to the field of switch electrical technology, specifically relating to an arc-extinguishing device for the contacts of a circuit breaker. Background Technology

[0002] During the operation of electrical equipment, when the circuit is broken, an electric arc is generated between the moving and stationary contacts. This arc, essentially a high-temperature plasma, not only erodes the contacts, reducing their lifespan, but can also cause electrical faults, affecting the normal performance and safety of the equipment. The arc-extinguishing chamber, as a key component for extinguishing the arc, directly affects the safety and stability of the electrical equipment. This is because without an arc-extinguishing chamber, the arc would burn freely between the contacts, spread, and even splash onto other insulating components of the equipment, leading to phase-to-phase short circuits or grounding faults.

[0003] In the known arc-extinguishing chamber structure of circuit breakers, the arc-extinguishing grid plates are often arranged with consistent spacing between adjacent plates at the top and bottom, or with the spacing between adjacent plates at the top being smaller than that at the bottom. In this structure, because the spacing between adjacent plates at the top is smaller, when breaking low voltage circuits, the arc entering the arc-extinguishing chamber is hindered from rapid diffusion and segmentation. This results in the arc energy being difficult to dissipate quickly, prolonging the arc-extinguishing time. A prolonged arc-extinguishing time indicates reduced arc-extinguishing efficiency, thus increasing the risk of equipment failure. Furthermore, the arc burning within a confined space easily generates high temperatures, damaging the arc-extinguishing grid plates, the arc-extinguishing chamber, and other components such as the contact system, insulation parts, casing, and even the spring mechanism, reducing the safety and reliability of the electrical equipment when breaking circuits. Utility Model Content

[0004] The objective of this invention is to provide a contact arc-extinguishing device for circuit breakers that helps improve the arc-extinguishing efficiency of the arc-extinguishing chamber by rationally arranging the arc-extinguishing grid plates, thereby enhancing the safety and reliability of electrical equipment when breaking circuits, while overcoming technical biases.

[0005] The present invention achieves its objective as follows: a contact arc-extinguishing device for a circuit breaker includes a pair of moving contacts and stationary contacts for breaking a circuit; and an arc-extinguishing system for extinguishing the arc generated when the moving contacts and stationary contacts break apart. The arc-extinguishing system includes an arc-extinguishing grid group, which includes an arc-inducing grid and a set of arc-extinguishing grids. The set of arc-extinguishing grids is arranged from top to bottom and maintains an arc-extinguishing grid spacing distance between each other. The arc-inducing grid is positioned above the set of arc-extinguishing grids, and an arc-inducing grid is maintained at an arc-inducing grid spacing distance from the uppermost arc-extinguishing grid in the set of arc-extinguishing grids. The key feature is that the arc-inducing grid spacing distance is greater than the arc-extinguishing grid spacing distance.

[0006] Preferably, the spacing between the arc-initiating grid plates is 2-3 times the spacing between the arc-extinguishing grid plates.

[0007] Preferably, the arc extinguishing system further includes an arc-isolating cover, in which a moving contact probe inlet is formed at the center of the arc-isolating cover in the height direction for the moving contact to probe and move. A pair of arc-blocking plates extend symmetrically on both sides of the arc-isolating cover in the height direction facing the arc-extinguishing grid assembly and located on both sides of the moving contact probe inlet in the height direction. The space between the pair of arc-blocking plates forms a cavity, which communicates with the moving contact probe inlet. The moving contact is inserted into the cavity through the moving contact probe inlet.

[0008] Preferably, the surface of the pair of arc-blocking plates facing the arc-extinguishing grid assembly is stepped, and the upper part of the surface facing the arc-extinguishing grid assembly is formed as an inclined surface sloping downwards, the middle part is formed as a semi-circular arc surface, and the lower part is formed as a vertical surface, wherein the semi-circular arc surface is connected between the inclined surface and the vertical surface.

[0009] Preferably, the arc extinguishing system further includes an arc-blocking plate assembly disposed on the outlet side of the arc-extinguishing grid assembly.

[0010] Preferably, the arc-blocking plate assembly includes a first arc-blocking plate and a second arc-blocking plate, with the second arc-blocking plate abutting against the first arc-blocking plate on the side facing the air outlet of the arc-extinguishing grid assembly.

[0011] Preferably, the first arc-blocking plate is provided with vents spaced apart, and the second arc-blocking plate is attached to the first arc-blocking plate at the position corresponding to the vent.

[0012] Preferably, an arc surface is formed on the first arc-blocking plate and below the vent, so that the first arc-blocking plate and the vent side of the arc-extinguishing grid plate group form an arc-shaped flow channel for airflow to flow towards the vent.

[0013] The technical effect of the solution provided by this utility model is that, by breaking through the conventional design thinking in the existing technology, the arc-quenching grid spacing between the uppermost arc-quenching grid in a group of arc-quenching grids is designed to be greater than the arc-quenching grid spacing between two adjacent arc-quenching grids in the arc-quenching grid group. Therefore, the arc-quenching efficiency of the arc-quenching chamber can be significantly improved by the reasonable arrangement of the arc-quenching grids, which is very beneficial to ensuring the safety and reliability of electrical equipment when interrupting current. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall assembly structure of the circuit breaker of this utility model; Figure 2 for Figure 1 The diagram shown is a schematic of the contact arc-extinguishing device. Figure 3 for Figure 1 and Figure 2 The diagram shows a three-dimensional structure of the contact arc-extinguishing device. Figure 4 for Figure 1 and Figure 2 The diagram shows a three-dimensional structural diagram of the arc-extinguishing system's arc-blocking shield. Figure 5 for Figure 3 The detailed structural diagram of the first arc-blocking plate is shown.

[0015] In the diagram: 1. Shell; 2. Moving contact; 3. Arc extinguishing system; 31. Side plate; 32. Arc extinguishing grid assembly; 321. Arc-initiating grid; 322. A set of arc extinguishing grids; 33. Arc-isolation plate assembly; 331. First arc-isolation plate; 3311. Vent; 3312. Circular arc surface; 332. Second arc-isolation plate; 34. Arc-isolation cover; 341. Arc-blocking plate; 3411. Inclined surface; 3412. Semi-circular arc surface; 3413. Vertical surface; 342. Moving contact probe inlet; 343. Cavity; 4. Stationary contact; 5. Arc-shaped flow channel; D1. Arc extinguishing grid spacing distance; D2. Arc-initiating grid spacing distance. Detailed Implementation

[0016] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings. However, the description of the embodiments is not a limitation on the technical solution. Any formal but not substantive changes made based on the concept of this invention should be considered within the scope of protection of this invention.

[0017] In the following description, all directional (or orientational) concepts involving up, down, left, right, front, and back refer to the position of the figure being described, and are intended to facilitate public understanding. Therefore, they should not be construed as a special limitation on the technical solution provided by this utility model.

[0018] Please see Figures 1 to 3The diagram shows a moving contact 2 and a stationary contact 4 paired together for breaking a circuit; and an arc-extinguishing system 3 for extinguishing the arc generated when the moving contact 2 and the stationary contact 4 are broken. The arc-extinguishing system 3 includes an arc-extinguishing grid group 32, which includes an arc-inducing grid 321 and a set of arc-extinguishing grids 322 between a pair of spaced-apart side plates 31. The set of arc-extinguishing grids 322 are arranged from top to bottom along the arc entry direction and are spaced apart by an arc-extinguishing grid spacing distance D1. The arc-inducing grid 321 is arranged above the set of arc-extinguishing grids 322, and the arc-inducing grid 321 is spaced apart by an arc-inducing grid spacing distance D2 from the uppermost arc-extinguishing grid in the set of arc-extinguishing grids 322.

[0019] The key technical point of the technical solution provided by this utility model is that the aforementioned arc-initiating grid spacing distance D2 is greater than the arc-extinguishing grid spacing distance D1.

[0020] Based on professional knowledge, the aforementioned set of arc-extinguishing grid plates 322 can be arranged in a parallel state or in a fan-shaped arrangement. When the set of arc-extinguishing grid plates 322 are arranged in a parallel state, the spacing between the arc-extinguishing grid plates is the same, or the spacing between the arc-extinguishing grid plates near the stationary contact is slightly larger than the spacing between the arc-extinguishing grid plates above them. The aforementioned arc-initiating grid plate spacing distance D2 is greater than the arc-extinguishing grid plate spacing distance D1 near the contact. When the set of arc-extinguishing grid plates 322 are arranged in a fan-shaped arrangement, the arc-extinguishing grid plate spacing distance D1 is the largest among the series of spacing distances between two adjacent arc-extinguishing grid plates in the set, and the aforementioned arc-initiating grid plate spacing distance D2 is greater than the spacing distance D1 between two adjacent arc-extinguishing grid plates.

[0021] When the moving and stationary contacts 2 and 4 of the circuit breaker break, the arc gas generated by the breaking can be quickly discharged through the airflow channel between the arc-initiating grid 321 and the first set of arc-extinguishing grids 322 close to the arc-initiating grid 321, preventing damage to the circuit breaker housing.

[0022] Depend on Figure 1 As shown, the aforementioned moving and stationary contacts 2 and 4 are installed within the housing 1 of the circuit breaker's structural system. The aforementioned set of arc-extinguishing grid plates 322 are arranged in a fan shape. Figure 1 and Figure 2 (See illustration). The arc-extinguishing grid spacing distance D1 is the largest of the series of spacing distances between two adjacent arc-extinguishing grids in a set of arc-extinguishing grids.

[0023] Preferably, the aforementioned arc-initiating grid spacing distance D2 is 2-3 times the arc-extinguishing grid spacing distance D1, and more preferably 2.5 times. The applicant should note that if, for the purpose of circumventing this utility model, the arc-initiating grid spacing distance D2 is changed to be slightly less than or greater than 2-3 times the arc-extinguishing grid spacing distance D1, then according to marginal effects, it should still be considered as not deviating from the aforementioned 2-3 times range.

[0024] Please see Figure 3 and Figure 4 The aforementioned arc extinguishing system 3 also includes an arc-isolating cover 34. A moving contact inlet 342 for the moving contact 2 to be inserted and moved is formed in the middle of the arc-isolating cover 34 in the height direction. A pair of arc-blocking plates 341 extend symmetrically on both sides of the arc-isolating cover 34 in the height direction facing the arc-extinguishing grid plate group 32 and in the height direction of the moving contact inlet 342. The space between the pair of arc-blocking plates 341 is formed as a cavity 343. The cavity 343 communicates with the moving contact inlet 342. The moving contact 2 enters the cavity 343 through the moving contact inlet 342.

[0025] When the moving and stationary contacts 2 and 4 are opened, an electric arc will be generated. When the electric arc enters a set of arc-extinguishing grid plates 322, it will cause ablation of the grid plate corners. The arc-blocking plate 341 extends into the arc-extinguishing chamber assembly, which can reduce the erosion of the grid plate corners by the electric arc.

[0026] Preferably, the shape of the surface of the pair of arc-blocking plates 341 facing the arc-extinguishing grid plate group 32 is stepped, and the upper part of the surface facing the arc-extinguishing grid plate group 32 is configured as an inclined surface 3411 that slopes from top to bottom to facilitate the rapid diffusion and transfer of the arc when the moving contact 2 is in the repulsion position. The middle part is configured as a semi-circular arc surface 3412 that can sufficiently reduce the gas pressure in the arc-extinguishing chamber and prevent the gas impact caused by the breakage from damaging the arc-extinguishing chamber. The lower part is configured as a vertical surface 3413 that facilitates contact with the stationary contact 4. The semi-circular arc surface 3412 is connected between the inclined surface 3411 and the vertical surface 3413.

[0027] See you later Figure 1 , Figure 3 And see Figure 5 The aforementioned arc extinguishing system 3 further includes an arc-blocking plate assembly 33, which is disposed on the air outlet side of the aforementioned arc-extinguishing grid assembly 32. The aforementioned arc-blocking plate assembly 33 includes a first arc-blocking plate 331 and a second arc-blocking plate 332, with the second arc-blocking plate 332 abutting against the first arc-blocking plate 331 on the air outlet side facing the aforementioned arc-extinguishing grid assembly 32.

[0028] Preferably, the first arc-blocking plate 331 is provided with a plurality of vents 3311 spaced apart, all preferably elliptical in shape, but also possibly circular. The function of the vents 3311 is twofold: firstly, to increase the gas pressure in the arc-extinguishing chamber, thereby increasing the arc voltage during the breaking process and accelerating the arc extinguishing speed; secondly, to allow gas to be quickly discharged through the vents 3311, preventing damage to the circuit breaker housing and improving the overall breaking capacity. The second arc-blocking plate 332 is positioned abutting against the first arc-blocking plate 331 at the location corresponding to the vents 3311. The positive significance of this abutment is that, during the discharge of breaking gas, the second arc-blocking plate 332 flips outwards towards the outside of the circuit breaker, thus both improving the protection level of the housing and reducing the impact on the exhaust speed. In this embodiment, the second arc-blocking plate 332 is made of an elastic material, preferably cardboard. An arc surface 3312 is formed on the aforementioned first arc-blocking plate 331 and below the aforementioned vent 3311. The arc surface 3312 forms an arc-shaped flow channel 5 between the first arc-blocking plate 331 and the vent side of the aforementioned arc-extinguishing grid plate group 32, allowing airflow to flow in the direction of the vent 3311.

[0029] In summary, this utility model improves the arc-extinguishing efficiency of the arc-extinguishing chamber through a unique grid arrangement design, ensuring the safety and reliability of electrical equipment when breaking circuits.

Claims

1. A contact arc-extinguishing device for a circuit breaker, comprising a moving contact (2) and a stationary contact (4) paired together for breaking a circuit; an arc-extinguishing system (3) for extinguishing the arc generated when the moving contact (2) and the stationary contact (4) are broken, the arc-extinguishing system (3) comprising an arc-extinguishing grid group (32), the arc-extinguishing grid group (32) comprising an arc-inducing grid (321) and a set of arc-extinguishing grids (322), the set of arc-extinguishing grids (322) being arranged from top to bottom and maintaining an arc-extinguishing grid spacing distance (D1) between each other, and the arc-inducing grid (321) being arranged above the set of arc-extinguishing grids (322), and the arc-inducing grid (321) maintaining an arc-inducing grid spacing distance (D2) between the arc-inducing grid (321) and the uppermost arc-extinguishing grid in the set of arc-extinguishing grids (322), characterized in that: The spacing between the arc-initiating grid plates (D2) is greater than the spacing between the arc-extinguishing grid plates (D1).

2. An arc contact device for a circuit breaker according to claim 1, characterized in that The arc-initiating grid spacing (D2) is 2-3 times the arc-extinguishing grid spacing (D1).

3. An arc contact device for a circuit breaker according to claim 1, wherein The arc extinguishing system (3) also includes an arc-blocking cover (34). A moving contact probe inlet (342) is formed in the middle of the arc-blocking cover (34) in the height direction for the moving contact (2) to probe and move. A pair of symmetrical arc-blocking plates (341) extend in the height direction of the arc-blocking cover (34) on one side facing the arc-extinguishing grid plate group (32) and on both sides of the moving contact probe inlet (342). The space between the pair of arc-blocking plates (341) is formed as a cavity (343). The cavity (343) communicates with the moving contact probe inlet (342). The moving contact (2) passes through the moving contact probe inlet (342) and probes into the cavity (343).

4. An arc contact device for a circuit breaker according to claim 3, wherein The surface of the pair of arc-blocking plates (341) facing the arc-extinguishing grid plate group (32) is stepped, and the upper part of the surface facing the arc-extinguishing grid plate group (32) is formed as an inclined surface (3411) sloping downwards, the middle part is formed as a semi-circular arc surface (3412), and the lower part is formed as a vertical surface (3413). The semi-circular arc surface (3412) is connected between the inclined surface (3411) and the vertical surface (3413).

5. The contact-arc device of claim 1 wherein The arc extinguishing system (3) also includes an arc-blocking plate assembly (33), which is disposed on the air outlet side of the arc-extinguishing grid assembly (32).

6. An arc contact device for a circuit breaker according to claim 5, wherein The arc-blocking plate assembly (33) includes a first arc-blocking plate (331) and a second arc-blocking plate (332), with the second arc-blocking plate (332) abutting against the first arc-blocking plate (331) on the air outlet side facing the arc-extinguishing grid assembly (32).

7. An arc contact device for a circuit breaker according to claim 6, wherein A vent (3311) is provided at intervals on the first arc-blocking plate (331), and the second arc-blocking plate (332) is attached to the first arc-blocking plate (331) at the position corresponding to the vent (3311).

8. An arc contact device for a circuit breaker according to claim 7, wherein An arc surface (3312) is formed on the first arc-blocking plate (331) and below the vent (3311). The arc surface (3312) forms an arc-shaped flow channel (5) between the first arc-blocking plate (331) and the vent side of the arc-extinguishing grid assembly (32) to allow airflow to flow in the direction of the vent (3311).

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