Molded case circuit breaker

Abstract

The application relates to the field of low-voltage switches, in particular to a molded case circuit breaker. The molded case circuit breaker comprises a shell, a moving contact, a static contact, a rear opening for the moving contact to extend into at the rear side of an arc extinguishing chamber, an insulating partition is assembled in the upper and lower directions at the rear opening for shielding the rear opening of the arc extinguishing chamber; the moving contact passes below the insulating partition, so that the insulating partition is driven to move upwards by the moving contact when the moving contact and the static contact are disconnected, and the insulating partition falls down by gravity when the moving contact and the static contact are closed. An arc is generated when the moving contact and the static contact are disconnected, and the heat generated in the arc extinguishing process of the arc extinguishing chamber increases the air pressure in the arc extinguishing chamber. Since the rear opening part of the arc extinguishing chamber is shielded, the heat to the rear side of the arc extinguishing chamber is reduced, the backward movement of the arc is reduced, and the gas pressure in the arc extinguishing chamber is increased to a certain extent, which is beneficial to the ejection of the arc and improves the arc extinguishing effect.

Description

Technical Field

[0001] This invention relates to the field of low-voltage switches, and particularly to a molded case circuit breaker. Background Technology

[0002] When the moving and stationary contacts of a molded case circuit breaker break, an electric arc is generated. In order to prevent the electric arc from damaging the internal structure of the molded case circuit breaker, an arc-extinguishing chamber is installed inside the molded case circuit breaker. An arc-extinguishing grid is installed inside the arc-extinguishing chamber. The arc-extinguishing grid divides the electric arc into many short arcs connected in series, thereby achieving the purpose of arc extinguishing.

[0003] Chinese Patent No. CN206412302U, with an authorization announcement date of August 15, 2017, discloses a large tripping distance DC molded case circuit breaker, including a base. The base is equipped with a contact system, an arc extinguishing system, and an operating system. The contact system includes a moving contact and a stationary contact. The arc extinguishing system includes an arc extinguishing shroud, two arc-isolating plates, and an arc-extinguishing grid plate disposed between the two arc-isolating plates. The arc extinguishing shroud includes wall plates disposed on both sides of the stationary contact. The two wall plates are close to the arc-extinguishing grid plate. The arc-extinguishing grid plate, the two wall plates, and the arc-isolating plates form a movable air chamber within the arc extinguishing chamber for the moving contact to move. When the moving contact breaks off from the stationary contact, the arc between the moving contact and the stationary contact is blown towards the arc-extinguishing grid plate under the action of the internal high-pressure gas. Under the action of the arc-extinguishing grid plate, it is broken into short arcs, thereby achieving the purpose of arc extinguishing. The electric arc generates a large amount of heat that enters the operating mechanism chamber of the molded case circuit breaker through the rear opening of the arc-extinguishing chamber. This is not conducive to the ejection of the electric arc and can easily damage the operating mechanism inside the circuit breaker, affecting the life and stability of the circuit breaker. In addition, during the arc extinguishing process, a large amount of metal vapor is usually generated in the arc-extinguishing chamber. Some of the metal vapor moves into the operating mechanism chamber of the molded case circuit breaker through the rear opening of the arc-extinguishing chamber. The metal vapor condenses into metal particles, making the circuit breaker less stable. Summary of the Invention

[0004] The purpose of this invention is to provide a molded case circuit breaker that solves the problem of poor circuit breaker stability caused by a large amount of arc heat generated when the moving and stationary contacts in the arc-extinguishing chamber move into the operating mechanism chamber during the breakage.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] Molded case circuit breakers include:

[0007] The casing contains an arc-extinguishing chamber.

[0008] The moving contact extends into the arc-extinguishing chamber at its front end and can swing up and down around the hinge axis at its rear end.

[0009] The stationary contact is fixed at the bottom of the arc-extinguishing chamber;

[0010] The arc-extinguishing chamber has a rear opening for the moving contact to extend into;

[0011] An insulating partition, with upper and lower guides, is installed at the rear opening of the arc-extinguishing chamber to block the rear opening of the arc-extinguishing chamber.

[0012] The moving contact passes under the insulating partition so that the insulating partition moves upward when the moving contact separates from the stationary contact, and falls down by gravity when the moving contact closes with the stationary contact. Alternatively, a spring is provided inside the housing to apply elastic force to the insulating partition so that the insulating partition moves downward when the moving contact closes with the stationary contact.

[0013] The beneficial effects of this invention are as follows: An insulating partition is provided at the rear opening of the arc-extinguishing chamber of the molded case circuit breaker of this invention. The insulating partition is used to block the rear opening of the arc-extinguishing chamber. When the moving contact and the stationary contact break, an electric arc is generated. The heat generated by the electric arc increases the gas pressure in the arc-extinguishing chamber. Since the rear opening of the arc-extinguishing chamber is partially blocked during the breaking process, the heat entering the rear of the arc-extinguishing chamber is reduced, which improves the stability of the molded case circuit breaker, reduces the amount of arc movement, and at the same time increases the gas pressure in the arc-extinguishing chamber to a certain extent, which is conducive to the ejection of the electric arc and improves the arc extinguishing effect.

[0014] Furthermore, in order to achieve stable guidance of the insulating partition, a guide plate is provided at the rear opening of the arc-extinguishing chamber, which is parallel to the insulating partition. A guide mating component is provided on the side of the guide plate facing the arc-extinguishing chamber, which is spaced apart from the guide plate to form a guide interval. The guide interval guides the insulating partition up and down. The contact area between the guide plate and the insulating partition is large. The stability of the insulating partition is ensured by the conductor interval formed by the guide plate and the guide mating component.

[0015] Furthermore, to improve the arc-extinguishing capability, the rear opening of the arc-extinguishing chamber is equipped with two parallel guide plates spaced apart horizontally, and a guide plate seat for fixing the guide plates. A movable interval is formed between the two guide plates, allowing the moving contact to swing up and down. The guide plates are fixed to the guide plate seat, and the guide plates are spaced apart front and rear to form the guide interval. The guide plates constitute the guide fitting component. The guide plates guide the insulating partition, simplifying the structure.

[0016] Furthermore, the guide plate is provided in two parts, and the two guide plates are provided with guide surfaces arranged opposite each other. The two guide surfaces cooperate with the insulating partition to restrict the left and right movement of the insulating partition, thereby further ensuring the stability of the insulating partition during movement.

[0017] Furthermore, the guide plate is provided with elongated strip-shaped protrusions extending vertically, and the guide surface is set on the elongated strip-shaped protrusions, which has a simple structure and is easy to process.

[0018] Furthermore, the guide plate and the guide mating plate seat are integrally bent and formed, which results in low cost and good structural stability.

[0019] Furthermore, the housing includes a base and a cover fixed to the top of the base. The cover is provided with a partition receiving groove for the insulating partition to slide into and for the insulating partition to be guided up and down. The distance between the opening of the partition receiving groove for the insulating partition to slide into and the top opening of the guide interval is less than the maximum dimension of the insulating partition in the up and down direction. By guiding the upper and lower parts of the insulating partition, the stability of the up and down movement of the insulating partition is ensured.

[0020] Furthermore, the housing includes a base and a cover fixed to the top of the base. The cover is provided with a diaphragm receiving groove for the insulating diaphragm to slide into and for the insulating diaphragm to be guided up and down. This allows for the adaptation to larger insulating diaphragms. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of a specific embodiment 1 of the molded case circuit breaker of the present invention;

[0022] Figure 2 This is a schematic diagram of the structure of the guide plate, guide plate seat, and guide plate in a specific embodiment 1 of the molded case circuit breaker of the present invention;

[0023] Figure 3 This is a diagram showing the fit between the insulating partition and the guide spacer in a specific embodiment 1 of the molded case circuit breaker of the present invention.

[0024] Figure 4 This is a partial structural schematic diagram of a specific embodiment 1 of the molded case circuit breaker of the present invention;

[0025] Figure 5 This is a schematic diagram of the state of the moving contact and stationary contact when the circuit breaker is open, according to a specific embodiment 1 of the molded case circuit breaker of the present invention.

[0026] In the figure: 1-shell; 10-guide gap; 12-rear opening; 13-base; 14-shell cover; 141-partition receiving groove; 2-moving contact; 3-stationary contact; 4-insulating partition; 5-arc extinguishing grid; 6-grid fixing plate; 7-guide mating plate; 8-guide mating plate seat; 9-guide plate; 91-long strip protrusion. Detailed Implementation

[0027] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0028] A specific embodiment 1 of the molded case circuit breaker of the present invention is as follows: Figures 1 to 5As shown, the molded case circuit breaker includes a housing 1, a moving contact 2, and a stationary contact 3, both of which are housed within the housing 1. The housing 1 contains an arc-extinguishing chamber with a rear opening 12 for the moving contact 2 to extend into it. The front end of the moving contact 2 extends into the arc-extinguishing chamber through the rear opening 12, and the rear end of the moving contact 2 is hinged within the housing 1. The moving contact 2 can swing up and down around its rear hinge axis. The stationary contact 3 is fixed to the bottom of the arc-extinguishing chamber. The arc-extinguishing chamber contains an arc-extinguishing grid 5 and a grid fixing plate 6 for fixing the arc-extinguishing grid 5. When the moving contact 2 and the stationary contact 3 separate, the arc-extinguishing grid 5 can break the arc into short arcs, thereby extinguishing the arc.

[0029] An insulating partition 4 is slidably mounted vertically and vertically at the rear opening 12 of the arc-extinguishing chamber. The moving contact 2 passes under the insulating partition 4, so that the insulating partition 4 is driven upward by the moving contact 2 when the moving contact 2 and the stationary contact 3 are disconnected, and falls down by gravity when the moving contact 2 and the stationary contact 3 are closed. In this embodiment, the hinge axis of the moving contact is set horizontally when the molded case circuit breaker is in use. The insulating partition 4 is used to block the rear opening 12 of the arc-extinguishing chamber. When the moving contact 2 and the stationary contact 3 are disconnected, the electric arc and metal vapor generated in the arc-extinguishing chamber enter the rear cavity of the housing 1 through the rear opening 12. The insulating partition 4 blocking the rear opening 12 of the arc-extinguishing chamber can reduce the amount of high-pressure hot gas and metal vapor entering the rear cavity, and can also reduce the amount of arc displacement.

[0030] like Figure 1 and Figure 2 As shown, a guide plate 7 and a guide plate seat 8 for fixing the guide plate 7 are fixed at the rear opening 12 of the arc-extinguishing chamber. Two guide plates 7 are arranged on the left and right sides, and the two guide plates 7 are arranged in parallel and spaced apart, forming an movable interval between the two guide plates 7 for the moving contact 2 to swing up and down. In order to improve the arc-extinguishing capability of the arc-extinguishing chamber, the guide plate 7 in this embodiment is an arc-extinguishing plate with its own gas-generating function, made of gas-generating material. The material of the arc-extinguishing plate is existing technology, for example, it can be the same as the material of the arc-extinguishing cover in the authorization announcement number CN206412302U, and will not be described in detail here. In other embodiments, the guide plate may only guide the insulating partition and does not have an arc-extinguishing function.

[0031] Two guide plates 9, parallel to the insulating partition 4, are fixed to the rear end of the guide mating plate base 8. Both guide plates 9 are perpendicular to the guide mating plate 7, and both guide plates 9 and the guide mating plate 7 form a guide gap 10 for guiding the insulating partition 4. The guide gap 10 and the insulating partition 4 are vertically guided and engaged. In this embodiment, the guide mating plate base 8 and the guide plates 9 are integrally bent and formed, which is convenient to process and has low cost.

[0032] Two guide plates 9 are spaced apart on the left and right. The moving contact 2 extends from the gap between the two guide plates 9 into the gap between the two guide mating plates 7. The arrangement of the guide plates 9 also reduces the size of the rear opening 12 of the arc-extinguishing chamber, thus reducing the amount of metal vapor ejected backward from the arc-extinguishing chamber. To prevent the insulating partition 4 from moving left and right, in this embodiment, both guide plates 9 are provided with elongated protrusions 91. The elongated protrusion 91 on the left guide plate 9 is located on the left side of the guide plate 9, and the elongated protrusion 91 on the right guide plate 9 is located on the right side of the guide plate 9. The elongated protrusions 91 are provided with guide surfaces. The guide surfaces on the two guide plates 9 are arranged opposite each other on the left and right. The two guide surfaces guide and cooperate with the insulating partition 4 to restrict the left and right movement of the insulating partition 4.

[0033] To ensure the stability of the insulating partition 4, in this embodiment, the housing 1 includes a base 13 and a cover 14 fixed to the top of the base 13. The operating mechanism chamber and the arc-extinguishing chamber of the circuit breaker are disposed on the base, and the moving contact and the stationary contact are both disposed on the base. The cover 14 is provided with a partition receiving groove 141 for the insulating partition 4 to slide into and slide in a vertical guide. The distance between the opening of the partition receiving groove 141 for the insulating partition 4 to slide into and the top opening of the guide interval is less than the maximum vertical dimension of the insulating partition 4, ensuring that the insulating partition 4 will not detach from the guide during movement. In other embodiments, when the vertical dimension of the guide interval is large enough, the cover may not be provided with a partition receiving groove, or when the vertical dimension of the partition receiving groove is large enough, the guide interval may not be provided.

[0034] It should be noted that since the generation of electric arc and heat mainly occurs during the separation process between the moving contact and the stationary contact, the insulating partition of the present invention mainly functions during the separation process between the moving contact and the stationary contact of the circuit breaker. When the molded case circuit breaker of the present invention is tripped, the moving contact 2 and the stationary contact 3 are disconnected. The electric arc generated between the moving contact 2 and the stationary contact 3 is broken into short arcs under the action of the arc-extinguishing grid 5. At this time, the air pressure in the arc-extinguishing chamber increases, and metal vapor is generated in the arc-extinguishing chamber. The arc-extinguishing chamber is usually provided with exhaust ports for venting high-pressure gas from the molded case circuit breaker near the incoming line side and the top of the arc-extinguishing chamber. Metal vapor and heat are ejected outward from the exhaust ports of the arc-extinguishing chamber. Since an insulating partition 4 is provided at the rear opening 12 of the arc-extinguishing chamber, the insulating partition 4 blocks the rear opening 12 of the arc-extinguishing chamber during the tripping process, increasing the air pressure in the arc-extinguishing chamber. This is beneficial for the electric arc to be ejected onto the arc-extinguishing grid and extinguished, reducing the amount of hot gas entering the rear side of the arc-extinguishing chamber, reducing the amount of arc movement backward, and also reducing the amount of metal vapor ejected backward from the rear opening 12 of the arc-extinguishing chamber, thus improving the stability of the molded case circuit breaker.

[0035] The second specific embodiment of the molded case circuit breaker of the present invention differs from the first specific embodiment in that a spring is provided between the insulating partition and the cover. When the insulating partition is lifted, the spring is compressed, and when the moving contact and stationary contact close, the insulating partition can move downwards under the force of the spring. In this embodiment, the insulating partition does not rely on gravity for reset. Therefore, the use of the molded case circuit breaker is applicable not only to cases where the insulating partition is vertically installed, but also to cases where the insulating partition is inclined or horizontally installed.

[0036] In other embodiments, a guide plate and a guide fitting component forming a guide interval with the guide plate can be provided only at the rear opening of the arc-extinguishing chamber. The guide fitting component can be a guide rod, a guide block, or a vertical plate parallel to the guide plate. In other embodiments, only one guide groove can be provided at the rear opening of the arc-extinguishing chamber to guide the insulating partition. In this case, the guide groove is provided on the base or the shell cover. In other embodiments, a guide groove can also be provided on the elongated protrusion to restrict the forward, backward, left, and right movement of the insulating partition. In other embodiments, the guide plate may not be fixed to the guide fitting plate seat. For example, it can be directly fixed to the base or fixed to the shell cover.

[0037] In other embodiments, a guide rod may be provided inside the housing, and a guide hole corresponding to the guide rod may be provided on the insulating partition.

[0038] In other embodiments, a guide groove may be provided on the guide plate, and a guide block adapted to the guide groove may be provided on the insulating partition, with the guide surface that restricts the left and right movement of the insulating partition being provided in the guide groove.

[0039] In other embodiments, the guide plate and the guide mating plate seat can be welded together or fixed by bolts.

[0040] The descriptions of "up," "down," "left," "right," "front," and "back" in the above embodiments are merely for the convenience of introducing the relevant structures and do not constitute a unique limitation on the relevant structures. The actual positional relationship of each component varies depending on the actual usage conditions. However, when the insulating partition falls onto the moving contact under gravity, this only applies to the case of a molded case circuit breaker that is horizontally set, i.e., when the hinge axis of the moving contact is horizontally set.

Claims

1. Molded case circuit breakers, including: The casing contains an arc-extinguishing chamber. The moving contact extends into the arc-extinguishing chamber at its front end and can swing up and down around the hinge axis at its rear end. The stationary contact is fixed at the bottom of the arc-extinguishing chamber; The arc-extinguishing chamber has a rear opening for the moving contact to extend into; Its features are, Molded case circuit breakers also include: An insulating partition, with upper and lower guides, is installed at the rear opening of the arc-extinguishing chamber to block the rear opening of the arc-extinguishing chamber. The moving contact hinge axis is horizontally set, and the moving contact passes under the insulating partition so that the insulating partition moves upward when the moving contact separates from the stationary contact, and falls down by gravity when the moving contact closes with the stationary contact. Alternatively, a spring is provided inside the housing to apply elastic force to the insulating partition so that the insulating partition moves downward when the moving contact closes with the stationary contact. A guide plate is provided at the rear opening of the arc-extinguishing chamber, parallel to the insulating partition. A guide fitting is provided on the side of the guide plate facing the arc-extinguishing chamber, spaced back and forth with the guide plate to form a guide interval, which guides the insulating partition up and down. Two guide fitting plates are provided at the rear opening of the arc-extinguishing chamber, parallel to each other, and a guide fitting plate seat is provided to fix the guide fitting plates. An movable interval is formed between the two guide fitting plates, allowing the moving contact to swing up and down. The guide plate is fixed on the guide fitting plate seat. The guide fitting plates are spaced back and forth with the guide plate to form the guide interval, and the guide fitting plates constitute the guide fitting.

2. The molded case circuit breaker according to claim 1, characterized in that, The guide plate is provided in two parts, and the two guide plates are provided with guide surfaces arranged opposite each other. The two guide surfaces cooperate with the insulating partition to restrict the left and right movement of the insulating partition.

3. The molded case circuit breaker according to claim 2, characterized in that, The guide plate is provided with elongated strip-shaped protrusions extending vertically, and the guide surface is disposed on the elongated strip-shaped protrusions.

4. The molded case circuit breaker according to any one of claims 1-3, characterized in that, The guide plate and the guide mating plate seat are integrally bent and formed.

5. The molded case circuit breaker according to any one of claims 1-3, characterized in that, The housing includes a base and a cover fixed to the top of the base. The cover is provided with a partition receiving groove for the insulating partition to slide into and for the insulating partition to be guided up and down. The distance between the opening of the partition receiving groove for the insulating partition to slide into and the top opening of the guide gap is less than the maximum dimension of the insulating partition in the up and down direction.

6. The molded case circuit breaker according to any one of claims 1-3, characterized in that, The housing includes a base and a cover fixed to the top of the base. The cover is provided with a partition receiving groove for the insulating partition to slide into and to guide the insulating partition up and down.

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