Large-opening-distance nozzle type small-size circuit breaker

Abstract

A large-opening-distance nozzle type small-size circuit breaker comprises a wiring assembly, a handle, an electromagnetic assembly, an arc extinguishing assembly, a static contact assembly and a moving contact assembly which are arranged in a shell, the static contact assembly comprises a connecting section, a mounting section and an arc striking section, and an included angle exists between the connecting section and the horizontal line; the included angle between the installation section and the connection section is smaller than 90 degrees, and the two sides of the installation section are symmetrically provided with protection plates used for arc striking. The moving contact assembly comprises a moving contact arranged opposite to the static contact assembly, the moving contact comprises a contact section provided with a moving contact and a middle section, the contact section is perpendicular to the horizontal line during opening, and an included angle larger than 90 degrees exists between the middle section and the contact section. The minimum linear distance from the middle section to the static contact assembly is larger than the minimum linear distance from the movable contact to the static contact. The moving contact is bent, the moving contact point of the moving contact is obviously higher than the middle part of the moving contact, and the measurement position of the electrical gap is changed into the distance between the moving contact point and the static contact point, so that the electrical gap is increased on the premise that the size of the circuit breaker is not increased.

Description

Technical Field

[0001] The invention relates to the field of low-voltage electrical appliances, and in particular to a large-opening-distance nozzle-type small-volume circuit breaker. Background Art

[0002] Circuit breaker: A mechanical switching device that can connect, carry and disconnect current under normal circuit conditions, and can also connect, carry for a certain time and disconnect current under specified abnormal circuit conditions (such as short circuit).

[0003] The breaking capacity of a circuit breaker determines whether it can quickly disconnect the circuit in abnormal situations such as short circuits to prevent equipment damage or the expansion of accidents. This performance indicator is directly related to the safety and stability of the power system and is one of the important bases for selecting circuit breakers. Electrical clearance plays a crucial role in a circuit breaker's breaking capacity. It directly impacts the circuit breaker's insulation performance. In the open state, the clearance between the moving and stationary contacts must be sufficiently large to ensure that the air or other insulating medium between the contacts will not break down under the maximum system voltage the circuit breaker is required to withstand (including power frequency voltage and possible transient overvoltages such as lightning overvoltage or switching overvoltage). This ensures reliable circuit isolation, ensuring the safety of maintenance personnel and equipment isolation. Furthermore, the clearance between the moving and stationary contacts affects the circuit breaker's arc extinguishing capability: the size of the clearance directly affects the arc's elongation and cooling effect. Especially when breaking high currents, sufficient clearance helps the arc elongate, cool, and ultimately extinguish.

[0004] When designing the circuit breaker mechanism, the impact of factors such as manufacturing tolerances, wear during long-term use, and environmental conditions (such as altitude, humidity, and pollution) on insulation strength are taken into consideration, and the electrical gap between the moving and static contacts will be made as large as possible.

[0005] A larger electrical clearance between the moving and static contacts means a greater travel range for the moving contact, necessitating a larger circuit breaker. This clearance is limited by the size of the circuit breaker. A larger circuit breaker takes up more space for transportation and installation. Circuit breakers are typically used in distribution cabinets and distribution boxes, where installation space is limited. Larger circuit breakers make it difficult for customers to select and install them. Furthermore, a larger size consumes more material, increasing manufacturing costs and hindering product competitiveness.

[0006] Improving exhaust capacity is one of the key means of improving the performance of miniature circuit breakers. Rapid exhaust can speed up arc initiation, shorten arc stagnation time and arc burning time, thereby increasing arc voltage and enhancing the circuit breaker's breaking capacity.

[0007] The operating mechanism of existing mainstream miniature circuit breakers has a moving contact fixed on a contact support. When the handle is turned (i.e., the circuit breaker's opening and closing operations), the moving contact will swing with the contact support, making contact or disconnecting with the static contact, thereby realizing the connection and disconnection of the circuit breaker.

[0008] However, due to the existing miniature circuit breakers: The static contact is placed vertically relative to the guide rail mounting surface; The moving contact of the circuit breaker has no bend, and the moving contact point, rotation center and the middle part of the moving contact are in a straight line.

[0009] When the circuit breaker interrupts a large current, the high-pressure gas passes through the space between the static contact and the arc-striking plate, passes through the arc extinguishing cover, and is discharged to the outside of the circuit breaker from the exhaust hole of the shell at the tail of the arc extinguishing cover.

[0010] There are the following disadvantages: The static contacts are placed vertically. During the gas discharge process, the gas passes through the space between the static contacts and the arc-striking pieces. The exhaust space will be reduced first, which is not conducive to gas discharge. The blockage of high-temperature gas is not conducive to the cooling and extinction of the arc, thereby reducing the breaking capacity of the circuit breaker.

[0011] When a circuit breaker interrupts a high current, generating high-temperature, high-pressure gas, some of the gas surges upward until it fills the space above the coil. During this process, the gas carries the arc in the opposite direction of the arc extinguishing chamber. This process prolongs the arc's dwell time on the contacts, slows its movement, exacerbates arc erosion of the contacts, and reduces the circuit breaker's interrupting performance.

[0012] The electrical gap between the static contact and the moving contact is the distance between the bent part of the static contact and the middle part of the moving contact. The electrical gap is smaller than the straight-line distance between the static contact and the moving contact.

[0013] At the same time, an arc will be generated when the static contact and the moving contact are disconnected. Especially when the circuit breaker breaks a large current, the static contact is the part that is most susceptible to arc erosion. After erosion, the circuit breaker will fail to energize. Therefore, the static contact needs to be made of a high-melting-point and ablation-resistant material, such as silver-graphite alloy, silver-nickel alloy, etc., which has high material costs. Summary of the Invention

[0014] In view of the shortcomings of the prior art, the present invention aims to provide a small-volume circuit breaker with a large-opening nozzle.

[0015] To achieve the above object, the present invention provides the following technical solutions: A large-opening nozzle type small-volume circuit breaker, comprising a housing, wherein the housing is provided with: Two wiring assemblies are respectively arranged at two ends of the housing; A handle rotatably disposed on the upper end of the shell; an electromagnetic assembly, disposed on the lower side of the handle; An arc extinguishing assembly, arranged on the lower side of the electromagnetic assembly; a static contact assembly located in the upper front of the arc extinguishing assembly, the static contact assembly comprising a connecting section electrically connected to the winding of the electromagnetic assembly, a mounting section formed by bending the connecting section downward and used to support the static contact, and an arc striking section formed by bending the mounting section upward, wherein an angle is formed between the connecting section and the horizontal line, and the angle between the mounting section and the connecting section is less than 90°, and guard plates for arc striking are symmetrically provided on both sides of the mounting section; A moving contact assembly is rotatably disposed within the housing, with its upper end linked to the handle via a U-shaped connecting rod, comprising a moving contact disposed opposite the static contact assembly, the moving contact comprising a contact section provided with a moving contact point and an intermediate section connected to a contact bracket, the contact section being disposed perpendicular to a horizontal line when the switch is open, an angle greater than 90° being formed between the intermediate section and the contact section, and a minimum straight-line distance from the intermediate section to the static contact assembly being greater than the minimum straight-line distance from the moving contact point to the static contact; In the open state, the moving contact and the mounting section form an inverted V-shaped nozzle.

[0016] The bottom of the shell is also provided with an arc-starting plate, which has at least one inclined section, and the inclined section is arranged opposite to the mounting section, and the distance between the inclined section and the mounting section gradually increases toward the arc extinguishing chamber to form a nozzle structure.

[0017] A straight-line distance between the upper end of the inclined section and the plane where the mounting section is located is smaller than a straight-line distance between the lower end of the inclined section and the plane where the mounting section is located.

[0018] The arc striking plate is further provided with a vertically arranged back plate. When in the open state, the back surface of the moving contact and the back plate are in a collinear state.

[0019] The guard plate is formed by integrally bending two sides of the mounting section, and a space for accommodating the moving contact is formed between the two.

[0020] The guard plate is fixedly connected to the mounting section by riveting or welding.

[0021] The housing is further provided with double gold sheets. When the switch is in the open state, the back surface of the moving contact is parallel to the double gold sheets.

[0022] An arc-shaped arc-blocking plate is provided on one side of the moving contact assembly, and when in a closed state, the arc-shaped arc-blocking plate is tangent to the upper surface of the connecting section.

[0023] An outer shell baffle is provided on the inner wall of the shell corresponding to the arc-shaped baffle, and the outer shell baffle is arranged concentrically with the arc-shaped baffle, and the highest surface of the outer shell baffle is lower than the lowest surface of the arc-shaped baffle.

[0024] A clamping block is provided at the tail of the contact bracket, and the moving contact part is placed between the clamping block and the mounting surface.

[0025] Beneficial effects of the present invention: 1: The guard plate structure can lead the arc from the static contact to the guard plate to prevent the static contact from being burned. Even if the guard plate is burned, it will not affect the performance of the circuit breaker. This design can reduce the material burning resistance requirements of the static contact, reduce the material cost of the static contact, and improve the breaking capacity of the circuit breaker. 2: The moving contact is bent and the moving contact point is significantly higher than the middle part of the moving contact. The measurement position of the electrical gap changes to the distance between the moving and static contacts, thereby increasing the electrical gap without increasing the size of the circuit breaker. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is the main view of the present invention (opening gate).

[0026] Figure 2 It is a three-dimensional schematic diagram of the present invention.

[0027] Figure 3 It is a schematic diagram of the coordination of the moving and static contacts of the present invention.

[0028] Figure 4 It is a structural schematic diagram of the present invention when the switch is closed.

[0029] Figure 5 Schematic diagram of the coordination between the static contact assembly and the winding.

[0030] Figure 6 This is a structural diagram of the static contact.

[0031] Figure 7 It is a structural diagram of the moving contact assembly. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0034] like Figure 1 and Figure 2As shown, the present invention discloses a large-opening nozzle type small-volume circuit breaker, which includes a shell 10, in which a wiring assembly 500, a handle 100, an electromagnetic assembly 200, an arc extinguishing assembly 300, a static contact assembly 400 and a moving contact assembly 600 are arranged. The two wiring assemblies 500 are respectively arranged at both ends of the shell 10 for connecting incoming and outgoing lines, and the handle 100 is rotatably arranged at the upper end of the shell 10. The shell is divided into two parts, left and right, with the handle as the boundary, wherein the electromagnetic assembly, the arc extinguishing assembly and the static contact assembly are arranged in the left part, and the moving contact assembly is arranged in the right part. At the same time, the electromagnetic assembly, the arc extinguishing assembly and the handle are arranged along the height direction of the shell, that is, the handle, the electromagnetic assembly and the arc extinguishing assembly are arranged in sequence from top to bottom, and the static contact assembly is arranged between the electromagnetic assembly and the arc extinguishing assembly, that is, the static contact assembly is arranged in the upper front of the arc extinguishing assembly and close to the moving contact assembly. At the same time, the static contact assembly is also electrically connected to the winding of the electromagnetic assembly.

[0035] like Figure 6 As shown, the static contact assembly 400 is located in the upper front of the arc extinguishing assembly 300. The static contact assembly 400 includes a connecting section 410 electrically connected to the winding 310 of the electromagnetic assembly 200, a mounting section 420 formed by bending the connecting section 410 downward to support the static contact, and an arc striking section 430 formed by bending the mounting section 420 upward, wherein an angle a3 is formed between the connecting section 410 and the horizontal line, as shown in FIG. Figure 6 As shown in the figure, the dotted line L5 is a horizontal line, that is, the connecting section is directly tilted so that the connection between the connecting section and the mounting section is set as downward as possible, and the straight-line distance from the position of the moving contact and the non-moving contact is increased as much as possible, and the angle a2 between the mounting section 420 and the connecting section 410 is less than 90°. The mounting section is retracted inward so that a nozzle b1 is formed between it and the moving contact, and guard plates 440 for arc striking are symmetrically provided on both sides of the mounting section 420. When the circuit breaker interrupts a large current, an arc is generated between the moving and static contacts. Because the electrical distance between the guard plate and the moving contact is smaller than the distance between the static contact and the moving contact, the arc will be transferred from the static contact to the guard plate, thereby achieving the purpose of protecting the static contact. Even if the guard plate is burned, it will not affect the performance of the circuit breaker, can reduce the ablation resistance requirements of the static contact material, reduce the cost of the static contact material, and improve the breaking capacity of the circuit breaker. The moving contact assembly 600 is rotatably arranged in the housing 100, and its upper end is linked to the handle 100 through a U-shaped connecting rod. It includes a moving contact arranged opposite to the static contact assembly 400, and the moving contact includes a contact segment 620 with a moving contact point and an intermediate segment 610 connected to the contact bracket 630. The contact segment 620 is arranged perpendicular to the horizontal line when the switch is opened. The vertical refers to the setting of the back side of the contact segment perpendicular to the horizontal line L5. There is an angle a1 greater than 90° between the intermediate segment 610 and the contact segment 620. The minimum straight-line distance L3 from the intermediate segment 610 to the static contact assembly 400 is greater than the minimum straight-line distance L4 from the moving contact point to the static contact. Figure 3 As shown, in the open state, the moving contact and the mounting section form an inverted V-shaped nozzle. The static contact is tilted in opposite directions from the moving contact, forming a nozzle-shaped layout. This structure facilitates the discharge of high-temperature gases, facilitating arc cooling and extinguishing, while also increasing the distance between the moving and static contacts when the circuit breaker is in the open state. That is, when the circuit breaker is in the open state, the moving and static contacts form a nozzle structure, gradually increasing the exhaust space and facilitating gas discharge.

[0036] The moving contact's point is significantly higher than its center, and the moving contact is bent. The center is positioned away from the stationary contact. This design ensures that the shortest distance between the moving and stationary contacts is the same as the distance between the point and the stationary contact. In other words, the electrical clearance is equal to the straight-line distance between the moving and stationary contacts.

[0037] The bent portion of the static contact can also be modified, such as concave toward the side away from the moving contact, so that the electrical gap between the moving and static contacts equals the linear distance between the two contacts. Alternatively, the corner radius can be increased to increase the distance from the middle section of the moving contact. Alternatively, the height of the moving and static contacts can be increased (including increasing their thickness) to shorten the distance between them, so that the distance equals the electrical gap between the two contacts.

[0038] The bottom of the housing 10 is also provided with an arc striking plate 700, which has at least one inclined section 710. The inclined section 710 is arranged opposite to the mounting section, and the distance between the inclined section 710 and the mounting section gradually increases toward the arc extinguishing chamber to form a nozzle structure. The straight-line distance L1 between the upper end of the inclined section 710 and the plane where the mounting section is located is less than the straight-line distance L2 between the lower end of the inclined section 710 and the plane where the mounting section is located. Figure 1 The tilted placement of the static contact increases the distance between the moving and static contacts when the circuit breaker is disconnected without increasing the length of the circuit breaker. Furthermore, the static contact and the lower arc striker plate form a nozzle-shaped layout pointing toward the lower left corner. This nozzle shape facilitates the discharge of high-temperature gas and arc cooling, gradually increasing the arc length and facilitating arc extinguishing.

[0039] The arc-starting plate 700 also features a vertically positioned backplate 720. When in the open state, the back surface 621 of the moving contact is collinear with the backplate 720. When the circuit breaker is in the open state, the back surface of the moving contact is collinear with the back surface of the arc-starting plate and parallel to the bimetallic strip. This design maximizes the space reserved for bimetallic strip adjustment while increasing the electrical clearance between the contacts. This prevents the back surface of the moving contact from contacting the bimetallic strip when the circuit breaker is in the open state, thereby improving the stability of the circuit breaker's delayed protection.

[0040] The guard plate 440 is formed by integrally bending two sides of the mounting section 420 , and a space for accommodating the moving contact is formed between the two.

[0041] The guard plate 440 is fixedly connected to the mounting section 420 by riveting or welding. When a separate structure is used, the guard plate and the static contact can be made of different materials, and other conductive metals can be used for the guard plate. If a magnetically conductive metal such as iron or nickel is used, the guard plate can also function as a magnetic blowout arc extinguisher.

[0042] The housing 10 is also equipped with a bimetallic strip 800. When the circuit breaker is in the open state, the back of the moving contact is parallel to the bimetallic strip 800. This design prevents the back of the moving contact from contacting the bimetallic strip when the circuit breaker is in the open state, which would affect the reserved space for bimetallic strip debugging and improve the stability of the circuit breaker's delayed protection.

[0043] like Figure 5 As shown, one side of the connecting section is bent to form a side wall 411, which is welded to the winding of the electromagnetic component. That is, when the winding adopts enameled wire winding, the side wall is directly welded to the long side of the winding.

[0044] In this embodiment, the static contact is bent to allow for welded contact with the long side of the enameled wire winding. Other conductive connection methods, such as soldering or riveting, can also be used. The welding of the enameled wire winding to the static contact is located on one side of the circuit breaker, not in the center. A space exists between the static contact connection and the trip unit, allowing for the arc-shaped arc shield to extend into this space.

[0045] An arc guide plate 450 is provided below the stationary contact assembly. Its upper surface is electrically connected to the lower surface of the connecting segment and the short side of the enameled wire winding. Specifically, the upper surface of the arc guide plate is electrically connected to the assembled connecting segment and the short side, increasing the contact area. Simultaneously, the stationary contact and the long side of the winding are in electrical contact, while the arc guide plate and the short side of the winding are in electrical contact, allowing both sides of the rectangular coil to conduct electricity.

[0046] Furthermore, with this method, the rectangular enameled wire lead-out end of the enameled wire winding does not need to be twisted 90 degrees to adjust its direction. This means that the internal stress of the enameled wire winding is not affected, thereby increasing the service life of the enameled wire winding.

[0047] The moving contact has a through hole, and a rotating shaft adapted to the through hole is correspondingly provided on the mounting surface of the contact bracket. The moving contact can be rotatably arranged on the contact bracket, and a torsion spring is also provided on the outside of the moving contact. The torsion spring is sleeved on the rotating shaft, and one end of the torsion spring is against the contact support, and the other end is bent and located on the other side of the moving contact.

[0048] When a circuit breaker interrupts a high current, generating high-temperature, high-pressure gas, some of the gas surges upward until it fills the space above the coil. During this process, the gas carries the arc in the opposite direction of the arc extinguishing chamber. This process prolongs the arc's dwell time on the contacts, slows its movement, exacerbates arc erosion of the contacts, and reduces the circuit breaker's interrupting performance.

[0049] like Figure 7 As shown, the movable contact assembly 600 is provided with an arc-shaped arc-blocking plate 631 on one side. When the movable contact assembly rotates relative to the static contact assembly, the arc-shaped arc-blocking plate is always located above the movable and static contacts. When in the closed state, the arc-shaped arc-blocking plate 631 is tangent to the upper surface of the connecting section 410, as shown in FIG. Figure 4 As shown in the figure, the connecting section of the static contact is inclined and tangent to the arc of the arc baffle. This design prevents the contact support from rotating during the circuit breaker opening and closing process and prevents the gas generated by the breaking process from escaping from between the arc baffle and the static contact. (To account for differences in parts production, a certain gap is left between the static contact mounting surface and the arc baffle, which can be considered as tangent to them.)

[0050] like Figure 2 As shown, a shell baffle 11 is provided on the inner wall of the shell 10 corresponding to the arc baffle 631 , and the shell baffle 11 is arranged concentrically with the arc baffle 631 , and the highest surface of the shell baffle 11 is lower than the lowest surface of the arc baffle 631 .

[0051] The highest surface of the housing baffle is lower than the lowest surface of the arc-shaped baffle, meaning the two arc-shaped baffles are staggered. When the circuit breaker interrupts high currents, these two baffles restrict the discharge direction of gas within the circuit breaker, forcing it to escape in a single, defined direction. This helps accelerate arc movement and cooling, achieving rapid arc extinguishing and improving the circuit breaker's interrupting capacity.

[0052] The moving contact is fixed to the contact support only by the elastic force of the torsion spring, and lacks positioning in the axial direction. It has high requirements on the geometric dimensions of the contact support, moving contact, and spring. If the clearance between the hole of the moving contact and the shaft of the contact support is too large, or the difference in the geometric dimensions of the spring is too large, the moving contact will be offset or tilted, and the contact quality with the static contact will deteriorate, affecting the performance of the circuit breaker.

[0053] A clamping block 632 is provided at the tail of the contact bracket 630 , and the moving contact portion is placed between the clamping block 632 and the mounting surface.

[0054] The moving contact is installed into the contact support along the through hole. After the torsion spring is installed, the movement along the axial direction is restricted and the problem of deviation and tilt will not occur.

[0055] The distance between the clamping block 611 and the mounting surface 612 matches the thickness of the moving contact 620. The clamping block on the contact support restricts the moving contact from tilting or moving along the axial direction of the hole, securing the position of the moving contact and reducing the dimensional accuracy requirements of the components. This ensures reliable contact between the moving and stationary contacts, thereby improving circuit breaker performance.

[0056] The embodiments should not be regarded as limiting the present invention, but any improvements based on the spirit of the present invention should be within the scope of protection of the present invention.

Claims

1. A small-volume circuit breaker with a large opening nozzle, comprising a housing (10), characterized in that: The housing (10) is provided with: Two wiring assemblies (500) are respectively arranged at two ends of the housing (10); A handle (100) rotatably disposed on the upper end of the housing (10); An electromagnetic assembly (200), arranged on the lower side of the handle (100); An arc extinguishing assembly (300) is arranged on the lower side of the electromagnetic assembly (200); A static contact assembly (400) located in the upper front of the arc extinguishing assembly (300), the static contact assembly (400) comprising a connecting section (410) electrically connected to the winding (310) of the electromagnetic assembly (200), a mounting section (420) formed by bending the connecting section (410) downwards and used to carry the static contact, and an arc striking section (430) formed by bending the mounting section (420) upwards, wherein an angle exists between the connecting section (410) and a horizontal line, and an angle between the mounting section (420) and the connecting section (410) is less than 90°, and guard plates (440) for arc striking are symmetrically provided on both sides of the mounting section (420); A moving contact assembly (600) is rotatably arranged in the housing (100), and its upper end is linked to the handle (100) via a U-shaped connecting rod, and comprises a moving contact arranged opposite to the static contact assembly (400), the moving contact comprising a contact section (620) provided with a moving contact point and an intermediate section (610) connected to a contact support (630), the contact section (620) being arranged perpendicular to a horizontal line when the switch is opened, an angle greater than 90° is formed between the intermediate section (610) and the contact section (620), and a minimum straight-line distance from the intermediate section (610) to the static contact assembly (400) being greater than a minimum straight-line distance from the moving contact point to the static contact; In the open state, the moving contact and the mounting section form an inverted V-shaped nozzle.

2. The large-opening nozzle type small volume circuit breaker according to claim 1, characterized in that: The bottom of the housing (10) is further provided with an arc striking plate (700), which has at least one inclined section (710), and the inclined section (710) is arranged opposite to the mounting section, and the distance between the inclined section (710) and the mounting section gradually increases towards the arc extinguishing chamber to form a nozzle structure.

3. The large-opening nozzle type small volume circuit breaker according to claim 2, characterized in that: The straight-line distance between the upper end of the inclined section (710) and the plane where the installation section is located is smaller than the straight-line distance between the lower end of the inclined section (710) and the plane where the installation section is located.

4. The large-opening nozzle type small volume circuit breaker according to claim 2, characterized in that: The arc striking plate (700) is further provided with a vertically arranged back plate (720); when in an open state, the back surface (621) of the moving contact and the back plate (720) are in a collinear state.

5. The large-opening nozzle type small volume circuit breaker according to claim 1, characterized in that: The guard plate (440) is formed by integrally bending two sides of the mounting section (420), and a space for accommodating the moving contact is formed between the two.

6. The large-opening nozzle type small volume circuit breaker according to claim 1, characterized in that: The guard plate (440) is fixedly connected to the mounting section (420) by riveting or welding.

7. The large-opening nozzle type small-volume circuit breaker according to claim 1, characterized in that: A double gold sheet (800) is further provided in the housing (10); when in the open state, the back surface of the moving contact is parallel to the double gold sheet (800).

8. The large-opening nozzle type small-volume circuit breaker according to claim 1, characterized in that: An arc-shaped arc-blocking plate (631) is provided on one side of the moving contact assembly (600), and when in a closed state, the arc-shaped arc-blocking plate (631) is tangent to the upper surface of the connecting section (410).

9. The large-opening nozzle type small-volume circuit breaker according to claim 8, characterized in that: An outer shell baffle (11) is provided on the inner wall of the shell (10) corresponding to the arc-shaped baffle (631), and the outer shell baffle (11) and the arc-shaped baffle (631) are arranged concentrically, and the highest surface of the outer shell baffle (11) is lower than the lowest surface of the arc-shaped baffle (631).

10. The large-opening nozzle type small-volume circuit breaker according to claim 1, characterized in that: A clamping block (632) is provided at the tail of the contact bracket (630), and the moving contact portion is placed between the clamping block (632) and the mounting surface.

Images