OA18899A

OA18899A - Contact system of circuit breaker and circuit breaker.

Info

Publication number: OA18899A
Application number: OA1201800386
Authority: OA
Inventors: Yin NAN; Chao Li; Qiang Zhang; Lei Liu
Original assignee: Svrui (Tianjin) Electrical Equipment Co., Ltd.
Priority date: 2016-04-29
Filing date: 2017-04-21
Publication date: 2019-09-30

Abstract

The present disclosure relates to a contact system of a circuit breaker and a circuit breaker. The contact system of a circuit breaker comprises: a contact support; a rotary support shaft; a busbar; a plurality of conductive sheet groups, each conductive sheet group comprising two or three conductive sheets, each conductive sheet being provided with a contact, and the plurality of conductive sheet groups being arranged in parallel and rotatably supported on the contact support by means of the rotary support shaft, so that the plurality of contacts form a contact surface that can contact an external conductor to achieve electric conduction; and a flexible connection member, two ends of which are respectively electrically connected with the plurality of conductive sheets and the busbar. A first gap is formed between two adjacent conductive sheet groups, a second gap is formed between two adjacent conductive sheets in each of the conductive sheet groups, and the first gap is larger than the second gap; contacts on the conductive sheets on two sides of the conductive sheet group are disposed distant from each other and deflected in the arrangement direction of the conductive sheets. A condition that a contact pressure between the conductive sheets and the external conductor is decreased due to overheated fusion welding of the contacts is avoided.

Description

CONTACT SYSTEM OF CIRCUIT BREAKER AND CIRCUIT BREAKER

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of electrical switches, and in particular relates to a contact System of a circuit breaker and a circuit breaker.

BACKGROUND

[0002] Circuit breakers are an important part of power distribution equipment, and are mainly used in industrial low-voltage power Systems to connect and disconnect current in grid circuits and protect lines and power equipment from being damaged by overload, undervoltage, short-circuit, single-phase grounding and other faults. With continuously improved requirements of power engineering for power sources and power transmission and distribution equipment, the requirement for the performance of circuit protection switches is also increasingly high. Miniaturization, high performance, modularization and high reliability are the main development direction of universal circuit breakers at the current stage.

[0003] The circuit breakers are divided into high-voltage circuit breakers and low-voltage circuit breakers according to their use range. The low-voltage circuit breaker, also known as an automatic switch, is commonly known as an “air switch”. It is an electric appliance having a manual opening and closing fonction and capable of automatically performing intelligent analysis and protection on faults of voltage loss, undervoltage, overload and short-circuit. In the actual use of the circuit breaker, when it is in a closed state, if a fault of short-circuit occurs in the circuit, it is required to hâve a protection characteristic of a delay action for the purpose of sélective protection. That is, it can withstand the impact caused by short-circuit current within a short time before a short-circuit current is eut off, thereby ensuring that the fault of a lower branch is removed by a lower circuit breaker as much as possible, reducing a power-off range and reducing loss.

[0004] The contact System is an important part of the circuit breaker. The design of contact spring parameters and final pressure values of contacts in the contact System is critical and directly related to short-time withstand performance of the circuit breaker. Improvement on the short-time withstand current value of the circuit breaker can increase a sélective protection range of a class B circuit breaker, effectively improve reliability of differential protection, and prevent override trip and other accidents. Under the impact of short-circuit current, huge electric repulsion will cause a contact pressure between contacts to decrease, resulting in overheat and even fusion welding, so that the circuit breaker cannot continue to work normally; and it may even cause dynamic and static contacts to be repulsed, causing strong arc to burn out the contacts and the circuit breaker.

[0005] It is well known that an increase of the number of contact fingers can effectively reduce the electric repulsion, and thus higher short-circuit withstand current can flow through the circuit breaker without improving the final pressure of the contacts. Chinese Patent No. 200710025637.6 discloses a dynamic contact structure of a circuit breaker, in which in order to improve the short-time withstand current, a scheme of increasing the number of contact sheets in a contact support is adopted, and a spécifie implémentation is to remove isolation grids of the conductive sheets integrated with the contact support and the contacts is isolated using a fixed support and grids. Use of thinned isolation grids increases accommodation space for the contacts and then increases the number of conductors. This method and the prior art hâve the following disadvantages.

[0006] On the one hand, the number of contacts in a limited space is increased, thereby certainly reducing thickness of the contacts. Excessive and too thin contacts cause the space for placing contact springs under the contacts to decrease greatly, resulting in too large aspect ratio of the springs, or the excessive contacts cause the isolation grids to become thin, resulting in tilting of the contacts during closing and inclining of the springs abutting against the contacts and the contact support. When the contact springs work continuously for a long time, the springs are always in an extreme pressure State and are easy to fail due to fatigue, causing the pressure of the contact springs on the contacts to decrease at the closing position and thus causing the final pressure of the contacts to decrease.

[0007] On the other hand, the final pressure of the contacts is reduced, surface contact résistance of the contacts contacting each other is increased, reliabilîty of electric connection is reduced, a température rise of the contacts is increased, and fuse welding résistance of the contacts is reduced, so that the température rise of the circuit breaker is too high, the service life of the circuit breaker is shortened, the reliabilîty is reduced, the short-time withstand current is reduced, the range of sélective protection is small, and the accuracy of range matching is reduced or învalid; and the structure is too compact due to the increase of parts, so that the circuit breaker is difficult to install and unlikely to automate.

[0008] Therefore, an improved contact System of a circuit breaker and circuit breaker are needed.

SUMMARY

[0009] In order to effectively solve one or more of the above-mentioned defects in the prior art, the présent disclosure provides a contact system of a circuit breaker and a circuit breaker, which can achieve one or more purposes of increasing the final pressure value of the contact system of a circuit breaker, overcoming a larger electric repulsion caused by short-circuit current, optimizing the structure of the contact system of a circuit breaker and controlling the température rise of the contact System of a circuit breaker and the circuit breaker.

[0010] In order to achieve the above objects, the présent disclosure adopts the following technical solution.

[0011] According to an aspect of the présent disclosure, it is provided a contact system of a circuit breaker, including: a contact support; a rotary support shaft; a busbar; and a plurality of groups of conductive sheets, each group of conductive sheets including two or three conductive sheets, each conductive sheet being provided with a contact, and the plurality of groups of conductive sheets being arranged in parallel and rotatably supported on the contact support by means of the rotary support shaft, so that the plurality of contacts form a contact surface that can contact an external conductor to conduct electricity; and a flexible connection member, two ends of which are respectively electrically connected with the plurality of conductive sheets and the busbar; wherein a first gap is formed between two adjacent groups of conductive sheets, a second gap is formed between two adjacent conductive sheets in each group of the conductive sheets, the first gap is larger than the second gap, and contacts on the conductive sheets on two sides of the group of conductive sheets are disposed and offset from each other in an arrangement direction of the conductive sheets.

[0012] By changing the original same gap between the conductive sheets to the gap between the adjacent groups of conductive sheets being larger than the gap between the adjacent conductive sheets in each group of the conductive sheets, the number of the conductive sheets and the contacts can be effectively increased, the structure of the contact system of a circuit breaker is optimized to increase its current carrying capacity, the withstand capability of the contact system of a circuit breaker to rated short-time withstand current is improved, overall conductivity and current carrying capacity of the contact system of a circuit breaker are improved, and a problem of température rise of the contact system caused by the repulsion between the conductive sheets and the external conductor due to the short-time withstand current is avoîded.

[0013] Moreover, since the contacts on the conductive sheets on two sides of the group of conductive sheets are disposed distant and offset from each other in the arrangement direction of the conductive sheets, preset gaps are formed between the plurality of contacts in each group of the conductive sheets, which can increase the air gap in each group of the conductive sheets, improve flowability of air around each contact in the group of conductive sheets, facilitate heat dissipation of the contacts when the circuit breaker is in a working State, prevent a problem that the circuit breaker fails or fails to test because the actual number of the conductive sheets is reduced by adhesion thereof due to fuse welding and silver précipitation of the contacts in the presence of too small gaps between the contacts on the plurality of conductive sheets in one group of conductive sheets during a withstand voltage test of the circuit breaker, improve a non-deratîng index of the circuit breaker in a high température environment, and thus reduce the température rise of the circuit breaker.

[0014] According to an aspect of the présent disclosure, the conductive sheet has a contact setting surface for connecting the contact, and the contact setting surfaces of the conductive sheets on two sides of the group of conductive sheets are disposed distant and offset from each other in the arrangement direction of the conductive sheets. The contacts are offset by offset of the contact setting surfaces, so that the structures ofthe conductive sheets are ensured to be simple while fusion welding of the contacts is avoided.

[0015] According to an aspect of the présent disclosure, the contact System of a circuit breaker further includes first isolation portions and second isolation portions, the first isolation portions being located between the adjacent groups of conductive sheets to maintain the first gaps between the adjacent groups of conductive sheets, and the second isolation portions being located between the adjacent conductive sheets in the group of conductive sheets to maintain the second gaps between the adjacent conductive sheets. The first isolation portions and the second isolation portions are disposed to maintain the first gaps and the second gaps between the adjacent groups of conductive sheets and the adjacent conductive sheets respectively, thus providing a limiting and latéral supporting effect for the conductive sheets to ensure the structural stability of the conductive sheets during contact with the external conductor.

[0016] According to an aspect ofthe présent disclosure, the first isolation portions and/or the second isolation portions includes a boss formed on the conductive sheet or an isolator arranged separately. The first isolation portions and the second isolation portions are provided in various forms, and the conductive sheets are effectively supported while installation space for the conductive sheets in the contact System of a circuit breaker is increased, and do not tilt during contact with the external conductor.

[0017] According to an aspect of the présent disclosure, the busbar is provided with a current deflecting segment capable of deflecting the current flowlng through the busbar to generate an acting force causing the contacts ofthe conductive sheets to move toward the extemal conductor to the flexible connection member, The contact pressure between the conductive sheets and the external conductor is increased.

[0018] According to an aspect of the présent disclosure, the current deflecting segment is a tilting portion provided at a position of the busbar close to the flexible connection member. The tilting portion formed by the busbar body constitutes the current deflecting segment, so that the busbar is ensured to be simple in structure, convenient to process and cost is reduced while the busbargenerates an acting force causing the contacts ofthe conductive sheets to move toward the external conductor to the flexible connection member.

[0019] According to an aspect ofthe présent disclosure, the current deflecting segment is formed by a through slot formed in the busbar, and an extension direction of the through slot is parallel to the contact surface. By forming the through slot, the current deflecting segment of the busbar forms a proper tilt angle, so that the deflected current generates strong electric repulsion on the flexible connection member to force the conductive sheets and the contacts to move toward the external conductor.

[0020] According to an aspect of the présent disclosure, the cross section of the through slot is V-shaped or U-shaped. The tilt of the current deflecting segment thus formed is more advantageous for the deflected current to generate strong electric repulsion to the flexible connection member.

[0021] According to an aspect of the présent disclosure, the depth of the through slot is 1/2 to 2/3 of the thickness of the busbar area. The deflected current generates strong electric repulsion in the through slot area of the busbar to the flexible connection member, thereby providing a large electric repulsion for the flexible connection member.

[0022] According to an aspect of the présent disclosure, the through slots includes a plurality of through slots disposed on the busbar in the current direction, and the two adjacent through slots are located on opposite sides of the busbar and staggered from each other. The flexible connection member is subjected to multiple superposed electric repulsions, so that the contact pressure between the conductive sheets and the external conductor is increased.

[0023] According to an aspect of the présent disclosure, the contact System of a circuit breaker further includes: elastic members correspondingly disposed between each group of conductive sheets and the contact support. One group of conductive sheets share one elastic member, so that the installation space for the elastic members is enlarged, a spring index of the elastic members is reduced, the performance of the elastic members is improved, and early fatigue faiiure ofthe elastic members is avoided.

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[0024] According to another aspect of the present disclosure, it is provided a circuit breaker, including the contact system of a circuit breaker.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The following drawings of the present disclosure hereby constitute a part of the present disclosure and are used for understanding the present disclosure. Embodiments shown in the drawings and the descriptions thereof are to interpret the principle of the present disclosure. In which:

[0026] FIG. 1 is a schematic view of an overall structure of a contact system of a circuit breaker according to an embodiment of the present disclosure;

[0027] FIG. 2 is a schematic view of an exploded structure of the contact system of a circuit breaker;

[0028] FIG. 3 is a schematic view of a partial structure of the contact system of a circuit breaker;

[0029] FIG. 4 is a front schematic view of a structure of a group of conductive sheets of the contact system of a circuit breaker;

[0030] FIG. 5 is a three-dimensional structure view of a clamping sheet sandwiched in the group of conductive sheets of Fig. 4;

[0031] FIG. 6 is a schematic view of a latéral structure of the conductive sheet of FIG. 5;

[0032] FIG. 7 is a structure view of a busbar of the contact System of a circuit breaker;

[0033] FIG. 8 is a structure view of another busbar of the contact system of a circuit breaker;

[0034] FIG. 9 is a structure view of another busbar of the contact system of a circuit breaker;

[0035] FIG. 10 is a cross-sectional view of a partial structure of the contact system of a circuit breaker in an open state;

[0036] FIG. 11 is a cross-sectional view of a partial structure of the contact system of a circuit breaker în a closed state;

[0037] FIG. 12 is a working principle view of the contact System of a circuit breaker.

DETAILED DESCRIPTION

[0038] Features and exemplaryembodiments ofvarious aspects ofthe presentdisclosure are described in detail below. In the following detailed description, numerous spécifie details are illustrated to provide a comprehensive understanding on the present disclosure. However, it will be apparent to those skilled in the art that the present disclosure may be practiced without some of these spécifie details. The following descriptions of the embodiments are merely to provide a better understanding on the present disclosure by describing the examples of the present disclosure. The present disclosure is not limited to any spécifie configuration presented below, but covers any modification, substitution and improvement made to the structure and components of the present disclosure without departing from the spirit of the present disclosure. In the drawings and the following descriptions, well-known structures and techniques are not shown to avoid unnecessarily obscuring the technical solutions of the present disclosure.

[0039] In order to better understand the present disclosure, a contact System of a circuit breaker and a circuit breaker of the illustrated embodiments of the present disclosure are described in detail below in combination with FIGS. 1-12.

[0040] Referring to FIG. 1, which is a schematic view of an overall structure of a contact System of a circuit breaker according to an embodiment of the present disclosure, the contact System of a circuit breaker 100 is disposed in a circuit breaker to control a voltage/current of opening/closed circuit in the circuit breaker, and has a protection characteristic of a delay action. That is, it can withstand the impact caused by short-circuit current within the short time before the short-circuit current is eut off, thereby ensuring that a fault of a lower branch is removed by a lower circuit breaker as much as possible, narrowing a power-off range and reducing loss.

[0041] Specifically, the contact system of a circuit breaker 100 is provided with a plurality of conductive sheets 20 (commonly referred to as contacts or contact fingers) that are electrically connected with a busbar 40 by a flexible connection member 30, and the plurality of conductive sheets 20 are arranged in parallel and rotatably disposed on a contact support 10 via a rotary support shaft 80 (shown in FIG. 2). Each conductive sheet 20 is provided with a contact 21 (commonly referred to as a dynamic contact or a silver contact). The contact surface formed by a plurality of contacts 21 can contact an external conductor to conduct electricity or separate from the external conductor to eut off electricity, so that the circuit breaker can be in a turn-on or turn-off State.

[0042] The contact support 10 has a frame-type structure, is made of an insulating material, and can insulate and support the plurality of conductive sheets 20 fixed thereon. Two ends of the contact support 10 are respectively connected with a pair of auxiliary fixing plates 51, 52 via side plates in a screw fixing manner. Of course, the auxiliary fixing plates 51, 52 can also be connected with the contact support 10 by other ways, or other structures serve as the auxiliary fixing plates 51, 52. The two ends of the rotary support shaft 80 sandwich the plurality of conductive sheets 20 penetrating it between the two auxiliary fixing plates 51, 52 via preset shaft holes 13 in the two auxiliary fixing plates 51 and 52 respectively, so that the auxiliary fixing plates 51, 52 cooperate with the contact support 10 to provide a supporting and limiting effect for the plurality of conductive sheets 20.

[0043] The busbar 40 and the contact support 10 are also fixed in the circuit breaker by a fixing rack 60, and the fixing rack 60 is rotatably connected with the contact support 10 by a rotating shaft 53. The plurality of conductive sheets 20 are electrically connected with the busbar 40 by the flexible connection member 30. The flexible connection member 30 has a soft connecting structure, preferably a copper connecting wire or other soft connecting structure formed by the same. To ensure good conductivity, the two ends of the flexible connection member 30 are preferably respectively connected with the plurality of conductive sheets 20 and the busbar 40 by welding to realize transition conduction by soft connection between the plurality of conductive sheets 20 and the busbar 40.

[0044] Of course, the present disclosure does not limit the connection method between the flexible connection member 30 and the conductive sheets 20 and the busbar 40, and the shape of the flexible connection member 30. For example, the flexible connection member 30 may be provided with connecting holes, connecting pins corresponding to the connecting holes are disposed on the busbar 40 and the conductive sheets 20, and the busbar 40 and the conductive sheets 20 are connected and fixed via engagement of the connecting pins and the connecting hole by threaded fastening.

[0045] The contact system of a circuit breaker further includes a contact shield 70. The contact shield 70 has a U-shaped plate structure, and surrounds a position below the contact surface formed by the contacts 21 of the plurality of conductive sheets 20 in order not to hinder the operation of the conductive sheets 20. The contact shield 70 is fixedly fixed by screws via preset threaded holes in the auxilîary fixing plates 51, 52 to further provide an insulating and protecting effect for the plurality of conductive sheets 20. Of course, there may be one or more contact shields 70, which is not limited.

[0046] Referring to FIG. 2, which is a schematic view of an exploded structure of the contact system of a circuit breaker according to an embodiment of the present disclosure. As shown în FIG. 2, the conductive sheet 20 is of a sheet structure, and its head bends toward the contact support 10 to form a recess. The contact position of the contact 21 with the extemal conductor is disposed at an end surface below the head of the conductive sheet 20. The plurality of contacts 21 are arranged in parallel to form a contact surface, and the conductive sheets 20 contact with an extemal conductor to conduct electricity or separate from the extemal conductor to eut off electricity via the contact surface formed by the contacts 21.

[0047] A shaft hole 24 allowing the rotary support shaft 80 to pass penetrates a middle lower position of each conductive sheet 20. After the plurality of conductive sheets 20 are %

disposée! on the contact support 10 via the rotary support shaft 80, the heads thereof are received in a U-shaped space formed by the contact support 10 and the two side plates connected thereto, and can rotate around the rotary support shaft 80. Of course, the number and shape of the conductive sheets 20 are not limited in the présent disclosure, and can be correspondingly adjusted according to a use requirement and an installation 10 position.

[0048] Referring to FIG. 3, which is a schematic view of a partial structure of the contact system of a circuit breaker according to an embodiment of the présent disclosure. As shown in FIG. 3, the plurality of conductive sheets 20 are configured as a plurality of groupe of conductive sheets 201. It is exemplarily shown in this embodiment that each 15 group of conductive sheets 201 includes two conductive sheets 20, a first gap is formed between two adjacent groups of conductive sheets 201, a second gap is formed between two adjacent conductive sheets 20 in each group of conductive sheets 201, and the first gap is larger than the second gap. Of course, the number of the conductive sheets 20 in each group of conductive sheets 201 is not limited thereto, and may be adaptively 20 increased or decreased according to actual application needs. For example, when the number of the conductive sheets in the contact system is singular, the plurality of conductive sheets may also be configured such that two conductive sheets constitute one group of conductive sheets and/or three conductive sheets constitute a group of conductive sheets, or be in a combined form of a single conductive sheet and a plurality of 25 groups of conductive sheets.

[0049] The contact System of a circuit breaker 100 further includes first isolation portions and second isolation portions, wherein the first isolation portions are disposed between two adjacent groups of conductive sheets 201 to maintain the first gaps between the adjacent groups of conductive sheets 201 ; and the second isolation portions are disposed 30 between two adjacent conductive sheets 20 in a group of the conductive sheets 201 to maintain the second gaps therebetween. Through the first isolation portions and the second isolation portions, the adjacent conductive sheets 20 and the adjacent groups of conductive sheets 201 are isolated from each other to support the structure of the conductive sheets 20 so as to prevent tilting thereof and prevent heat at the conductive 35 sheets 20 from being accumulated. Exemplarily, the first isolation portions are partition plates 11, the second isolation portions are clamping sheets 22, and the partition plates 11 are made of thermosetting plastic resisting high température and arc and having high structural strength.

[0050] The clamping sheet 22 is disposed between two conductive sheets 20 in each 40 group of the conductive sheets 201. The clamping sheets 22 are in the same shape as the conductive sheets 20 and thinner than the partition plates 11, and are used together with the partition plates 11 to prevent ta problem that a contact force of the conductive sheets 20 with the external conductor decreases as the conductive sheets 20 tilt due to continuous température rise during operation.

[0051] The plurality of conductive sheets 20 are configured as a plurality of groups of conductive sheets 201, the partition plate between adjacent conductive sheets 20 in each group of the conductive sheets 201 is replaced with a thinner clamping sheet 22, and the partition plate 11 between every two groups of conductive sheets 201 is reserved, thereby increasing the installation space for the conductive sheets 20 and increasing the number of the conductive sheets 20. The contact system of a circuit breaker is optimized, so that the conductive sheets can overcome large electric repulsion during contact with the external conductor to effectively improve the short-time withstand performance of the contact system of a circuit breaker. In addition, by replacing the partition plates 11 with the clamping sheets 22, the plurality of conductive sheets 20 in the group of conductive sheets 201 hâve a smaller total thickness, and a separate elastic member is not needed for each conductive sheet 20, instead the plurality of conductive sheets 20 in each group of conductive sheets 201 share one elastic member. For example, in this embodiment, one spring or one group of springs provides elastic force for each group of conductive sheets 201.

[0052] The partition plates 11 between the adjacent groups of conductive sheets 201 are reserved, thus it can be assisted by the clamping sheets 22 to provide a firm and reliable fixing and limiting effect in a latéral direction for the conductive sheets 20 arranged in parallel, thereby ensuring stability of the plurality of conductive sheets, solving the problem that the contact force decreases during contact conduction between the conductive sheets and the external conductor due to tilting of the conductive sheets, and improving reliability of the contact system of a circuit breaker. Further, in order to optimize the space, the structure of the contact system of a circuit breaker is simplified, and the conductive sheets 20 are effectively supported. Preferably, the partition plates 11 of an integrated structure are arranged on the contact support 10.

[0053] The first isolation portions and the second isolation portions in the contact system of a circuit breaker hâve a function of limiting and supporting the conductive sheets. In the illustrated embodiment of the présent disclosure, the first isolation portions are partition plates 11 and the second isolation portions are clamping sheets 22. However, it should be noted that structures of the first isolation portions and the second isolation portions are not limited thereto. For example, the first isolation portions and the second isolation portions may also be bosses formed on the conductive sheets 20 or other isolating members separately arranged in the contact System of a circuit breaker. The plurality of conductive sheets can also be laterally supported to ensure stability of the plurality of conductive sheets, and to avoid a problem that the contact force decreases during contact conduction of the conductive sheets with the external conductor.

[0054] Further, referring to FIG. 4 which is a structure view of a group of conductive sheets 201 according to an embodiment of the present disclosure, and FIG. 5 which is a three-dimensional structure view of the group of conductive sheets according to an embodiment of the present disclosure, the conductive sheets 20 are connected with the contacts 21 through a contact setting surface 25 formed thereon, and the contacts on the conductive sheets 20 on two sides of the group of conductive sheets 201 are disposed distant and offset from each other in an arrangement direction of the plurality of conductive sheets 20. In this embodiment, the contacts 21 on the two conductive sheets 20 in each group of the conductive sheets 201 are respectively offset by a preset distance toward the partition plates 11 on the two sides. Referring to FIG. 6 which is a latéral structure view of a conductive sheet according to an embodiment of the present disclosure, the contact setting surface 25 of the two conductive sheets 20 in each group of the conductive sheets 201 is offset by a preset distance (shown in FIG. 3) toward the partition plates 11 on the two sides (distant from each other) by impact molding, and the contacts 21 formed on the contact setting surface 25 are offset together, so that preset gaps are formed between the adjacent contacts 21. In order to achieve better flowability of air around the contacts and simpler structure of the conductive sheets, the contacts 21 are preferably uniformly distributed at the contact surface formed on the plurality of conductive sheets 20. The preset distance may be set according to gaps that need to be retained between the contacts of the contact System of a circuit breaker in actual operation, and the contacts are offset by the preset distance to maintain preset gaps between the adjacent contacts. In this embodiment, the contact setting surface 25 of the conductive sheets 20 is offset by the preset distance toward each other, so that a gap is formed between the contacts 21 in each group of the conductive sheets 201 to facilitate air flow. In other embodiments, the plurality of contacts in each group of the conductive sheets may be offset in other ways to maintain good air circulation between them.

[0055] The uniform distribution of the contacts can enlarge the air gap at the contacts 21 of each group of conductive sheets 201 and improve the flowability of air, thereby controlling a température rise in the operation of the contact system of a circuit breaker, facilitating dissipation of heat at the contacts 21 and then improving a non-derating index of the circuit breaker in a high température environment. In addition, when the circuit breaker is subjected to a short-time withstand test, the uniform distribution of the contacts

U avoids a problem of adhesion of two conductive sheets 20 during silver précipitation due to fuse welding at the contacts 21 when the gap between the two conductive sheets 20 in one group of conductive sheets 201 is too small, avoids test termination due to decrease of a relative number of the conductive sheets 20, and improves the short-time withstand performance of the contact system of a circuit breaker.

[0056] Of course, the uniform distribution of the contacts is not absolute. In this embodiment, the conductive sheets 20 on two sides of the group of conductive sheets 201 are offset such that a preset gap is formed between the adjacent contacts 21 in each group of the conductive sheets 201 to ensure the flowability of air around the contacts 21. This embodiment only schematically illustrâtes two conductive sheets 20 in one group of conductive sheets 201. In other embodiments, for example, when there are three conductive sheets in each group of conductive sheets, only the contacts on the conductive sheets on two sides of the group of conductive sheets are offset by a preset distance toward the isolation portions on the two sides thereof, but the conductive sheet in the middle of the group of conductive sheets is not offset, the object of the present disclosure can also be achieved, and a preset gap is maintained between the adjacent contacts in the group of conductive sheets. Of course, when each group of the conductive sheets includes three conductive sheets, the preset gaps between the adjacent contacts may be the same or different.

[0057] The busbar 40 (shown in FIG. 2) may be a copper bar or an aluminum bar that provides electrical connection between the circuit breaker and a switch in each shunt circuit, one end of the busbar is cylindrical and connected with an external terminal to conduct electricity, and the other end is plate-like or block-like. Of course, the shape ofthe busbar 40 is not limited thereto. In other embodiments, the busbar 40 may also be of an overall block structure.

[0058] A current deflectîng segment44 is disposed at the busbar 40 to deflect the current flowing through it, the deflected current can produce a force allowing the flexible connection member 30 to move away from the busbar 40, and the flexible connection member 30 can drive the plurality of conductive sheets 20 to move, thereby increasing the contact force between the plurality of conductive sheets 20 and the external conductor, that is, increasing a final pressure between the contacts, overcoming large electric repulsion during the contact between the plurality of conductive sheets 20 and the external conductor, and improving the short-time withstand current value of the circuit breaker.

[0059] Specifically, referring to FIG. 7 which is a structure view ofthe busbar ofthe contact system of a circuit breaker according to an embodiment of the present disclosure, as shown in FIG. 7, in this embodiment, the current deflectîng segment 44 is a tiltîng portion ib provided on a body of the busbar 40, the tilting portion is disposed at a position of the busbar 40 close to the flexible connection member 30, and an angle between the tilting portion and the flexible connection member 30 is less than 90 degrees, so that the eurent flowing into the busbar 40 from the flexible connection member 30 is deflected at the tilting portion to generate an electric repulsion to allow the flexible connection member 30 to move away from the busbar 40, and the contacts of the plurality of conductive sheets 20 are driven to rotate around the rotary support shaft 80 (shown in FIG. 12) toward a side close to the busbar 40.

[0060] Further, refer to FIG. 8, which shows another structure of a busbar according to an embodiment of the présent disclosure. As shown in FIG. 8, a through slot 41 is formed in a bottom surface of the busbar 40 close to the flexible connection member 30 to form a current deflecting segment 44, the cross section of the through slot 41 is in an inverted V shape, and an extension direction of the through slot 41 is parallel to the contact surface formed by the plurality of contacts 21, so that the current flowing into the busbar 40 from the flexible connection member 30 deflects at the through slot 41 to generate an electric repulsion to the flexible connection member 30, causing the flexible connection member 30 to move away from the busbar 40. Since the plurality of conductive sheets 20 are connected with the flexible connection member 30 and rotatably fixed on the contact support 10, the flexible connection member 30 connected to the lower ends of the plurality of conductive sheets 20 enables, through a leverage, the contacts of the plurality of conductive sheets 20 to rotate around the rotary support shaft 80 toward a side close to the busbar 40, thereby increasing the contact force (i.e., the final pressure of the contacts) between the plurality of conductive sheets 20 and the external conductor. Of course, the form of the through slot 41 is not limited thereto. In other embodiments of the présent disclosure, the cross section of the through slot 42 may be in an inverted U shape or other shape for forming a current deflecting segment at the busbar 40. The through slot 41 may not be formed in the bottom surface of the busbar 40, and a setting that the current deflecting segment 44 formed at the busbar 40 enables an acting force forcing the flexible connection member 30 to move away from the busbar 40 can be used.

[0061] Refer to FIG. 9, which is a structure view of another busbar according to an embodiment of the présent disclosure. As shown in FIG. 9, in another embodiment of the présent disclosure, the busbar 40 is provided with a plurality of through slots. Specifically, the busbar 40 is provided with one or more through slots behind in the flow direction of current therein, and the through slots are staggered oppositely. FIG. 9 shows the opposite staggered situation. The through slot 43 is formed in the upper end surface of the busbar 40, the cross sections of the through slot 41 and the through slot 43 are opposite, and the adjacent walls of the through slot 43 and the through slot 41 are parallel to facilîtate better flow of current in the busbar. Through such a structure, the flexible connection member 30 can be subjected to multiple superimposed electric repulsions, increasing the amplitude of movement of the flexible connection member 30 away from the busbar 40, further increasing the rotating force of the plurality of conductive sheets 20 connected thereto along the rotary support shaft 80 toward the busbar 40, and thus increasing the contact force between the plurality of conductive sheets 20 and the external conductor.

[0062] FIG. 9 only shows one through slot 43 is provided behind the through slot 41. Of course, a plurality of through slots may be provided behind the through slot 41 to form a plurality of current deflecting segments 44 for deflecting the current flowing through the busbar 40, which can further increase the contact force between the plurality of conductive sheets 20 and the external conductor.

[0063] Further, in order to increase the electric repulsion generated by the current flowing through the current deflecting segment 44 to the flexible connection member 30 as much as possible, the depth of the through slot 41 is set to 1/2 to 2/3 of the thickness of the busbar 40 where it is located, as shown in FIG. 8. When the contact system is subjected to the short-circuit current and the current flows through the busbar 40, the current flows throughout the busbar 40 and flows toward the flexible conductive member 30 (the current which is alternating current has positive and négative flow directions, that is, flows from the flexible conductive member 30 to the busbar 40 or from the busbar 40 to the flexible conductive member 30, but the directions of the electric repulsions generated to the flexible conductive member 30 in the two directions are the same). When the current flows through the front end 46 of the busbar, the current line formed is initially compressed. In order to produce a better electric repulsion, a through slot 41 is additionally provided atthe busbar 40 to reduce the thickness of the busbar 40 where it is located, causing the current line to be compressed again and the magnetic line to be strengthened again. The depth of the through slot 41 is set to be 1/2 or more of the thickness of the busbar 40 where it is located, causing the current line to be compressed again.

[0064] By controlling the thickness of the busbar 40 where the through slot 41 is located, that is, by controlling the depth of the through slot 41, the maximum current carrying capacity of the busbar 40 where the through slot 41 is located is smaller than the maximum current circulating at the front end 46 of the busbar, thus preventing too large current carrying capacity at the front end 46 of the busbar from increasing the heat of the busbar to increase the heat of the body of the circuit breaker, and ensuring that no severe heat is emitted when current carrying capacity of the busbar 40 is small to affect the overall performance of the circuit breaker.

-lif

[0065] Since the depth of the through slot 41 is set withîn the range, the angle formed between the current defiecting segment 44 and the flexible conductive member 30 allows the current to flow in the busbar 40. When the current flows through the area where the through slot 41 is located, its horizontal flow direction is effectively changed to flow in the oblique direction of two parallel slopes of the current defiecting segment 44, and the current defiecting can generate a large electric repulsion to the flexible connection member 30, so that the flexible connection member 30 can provide a larger rotating force for the plurality of conductive sheets, and the plurality of conductive sheets 20 can overcome a larger electric repulsion during the contact with the external conductor.

[0066] Further, the current defiecting segment 44 is equally thick in order to ensure the circulation of the current in the busbar 40, achieve a better defiecting direction of the current and increase the electric repulsion generated by the current flowing through the current defiecting segment 44 to the flexible connection member 30. By setting the current defiecting segment 44 with an equal thickness, the deflected current flowing through the current defiecting segment 44 can maintain good flow performance without excessive loss, while the electric repulsion generated by the deflected current to the flexible connection member 30 is attenuated.

[0067] Further, in order that the current generates a large enough electric repulsion to the flexible connection member at the current defiecting segment 44, the thickness of the current defiecting segment 44 may also be set to be smaller than or equal to the thickness of the connecting portion 45 of the busbar 40 close to the flexible connection member 30, and a small distance is maintained between the through slot 41 and the flexible connection member 30. When high current flows through the current defiecting segment 44, the strength of the magnetic field generated on the surface of the busbar 40 is inversely proportional to the distance between the through slot 41 and the flexible connection member 30. Therefore, in order to generate a large repulsion to the flexible connection member 30, the initial position of the current defiecting segment 44 can be set to overlap the end of the flexible connection member 30 on the busbar 40, thus generating a large electric repulsion to the flexible connection member 30.

[0068] Referring to FIG. 10, which is a cross-sectional view of a partial structure of the contact system of a circuit breaker in an open state according to an embodiment of the présent disclosure, the contact system of a circuit breaker 100 is provided with elastic members corresponding to the plurality of groups of conductive sheets 201, and the elastic members abut between the group of conductive sheets 201 and the contact support 10, and are used for providing a contact force for the conductive sheets 20 during contact conduction between the plurality of conductive sheets 20 and the external «

conductor.

[0069] The elastic members are preferably coil springs 90. Specifically, the recess jointly formed by the two conductive sheets 20 in each group of the conductive sheets 201 and the clamping sheet 22 sandwiched between the two conductive sheets 20 is provided with a support slot 23 for accommodating the coil spring 90 (see FIG. 5 together), one end of the coil spring 90 abuts against the support slot 23, the other end abuts against a groove 12 provided in the contact support 10 corresponding to the support slot 23, and the portion plates 11 on two sides of each group of conductive sheets 201 limît the coil spring 90 therebetween from two sides. Each group of conductive sheets 201 shares one elastic member to increase the installation space for the elastic member, so that the spring index ofthe elastic member is within a preferred range.

[0070] The above structure doubles the installation space of the coil springs 90 in the contact System of a circuit breaker 100, so that the spring index of the coil springs 90 is half of that of the springs in the prier art, the structural strength of the coil springs 90 can be improved, the service life is greatly prolonged and the fatigue résistance is greatly improved.

[0071] Further, the elastic member at each group of the conductive sheets 201 can also be disposed as two coil springs 90 having different diameters are sleeved with each other or arranged in parallel to further prolong the service life ofthe elastic member and improve the withstand fatigue, so that the contact System of a circuit breaker can overcome a larger electric repulsion.

[0072] At the same time, each group of the conductive sheets 201 abuts against the contact support 10 through one elastic member to lift the setting position of the support slot 23 upward on the whole, so that the coil spring 90 is centered on the rotary support shaft 80 to lengthen the acting force arm on the conductive sheets 20. Thus, the contact pressure between the conductive sheet 20 and the external conductor is increased by increasing the moment of the force provided by the coil spring 90 without increasing the final pressure, so that the contact System of a circuit breaker 100 can overcome a larger electric repulsion.

[0073] Of course, the structure of the elastic members is not limited thereto. For example, the elastic members may be provided as torsion springs or other elastic structural members capable of providing force to the plurality of conductive sheets 20.

[0074] When the contact System of a circuit breaker 100 is in the open state, the two ends of the coil spring 90 abut against the support slot 23 and the groove 12 and are in a micro-compression state, and the plurality of conductive sheets 20 and the external conductor are in a separated power-off state. Refer to FIG. 11, which is a cross-sectional ^6 view of a partial structure of the contact system of a circuit breaker in a closed state according to an embodiment of the present disclosure. As shown in FIG. 11, when the contact system of a circuit breaker 100 needs current in operation, the contact support 10 can rotate about the rotating shaft 53 (shown in FIG. 1) as a central axis by a closing operation, and the two ends of the coil springs 90 abut against the support slots 23 and the grooves 12 and are completely compressed to apply elasticity to the plurality of conductive sheets 20, thereby maintaining good contact between the plurality of conductive sheets 20 and the external conductor.

[0075] Refer to FIG. 12, which is a working principle view of the contact system of a circuit breaker according to an embodiment of the present disclosure. The working principle and effect of the through slot 41 are described below in conjunction with the working principle view.

[0076] After closing, the flow direction of the current in the contact system of a circuit breaker 100 is as shown in the figure. When the contact system of a circuit breaker 100 encounters a short-circuit current (or called an abnormal high current), the current enters the busbar 40 and then flows through the current deflecting segment 44, the current is deflected, the flow direction of the current becomes a parabolic bottom-up flow direction at the current deflecting segment 44, and the current flowing through the current deflecting segment 44 generates an electric repulsion (Lorentz force) to the flexible connection member 30.

[0077] At the same time, an electric compensation force (Lorentz force) is also generated when the current flows through the flexible connection member 30 itself. The electric compensation force and the electric repulsion generated to the flexible connection member 30 are identical in direction, and the forces borne by the flexible connection member 30 can be superposed to cause the flexible connection member 30 to move away from the busbar 40. Since the busbar 40 and the contact support 10 are fixed by the fixing rack 60, the flexible connection member 30 generates a pulling force for the lower ends of the plurality of conductive sheets 20, and the plurality of conductive sheets 20 can penetrate the rotary support shaft 80. Due to the principle of a lever, the portions of the plurality of conductive sheets 20 disposed above the rotary support shaft 80 rotate around the rotary support shaft 80 toward the busbar 40, thereby increasing the contact force between the plurality of contacts 21 thereon and the external conductor, increasing the final pressure of the contact system of a circuit breaker, and enabling the contact System of a circuit breaker 100 to overcome the large electric repulsion generated by the short-circuit current at the contact surface of the external conductor and the conductive sheets 20.

[0078] A circuit breaker is also provided according to another embodiment of the present disclosure, including the contact System of a circuit breaker 100 described above, The structure and advantages thereof hâve been described above and will not be described again.

Claims

WHAT IS CLAIMED IS:

1. A contact system of a circuit breaker, comprising:

a contact support;

a rotary support shaft;

a busbar; and a plurality of groups of conductive sheets, each group of conductive sheets comprising two or three conductive sheets, each conductive sheet being provided with a contact, and the plurality of groups of conductive sheets being arranged in parallel and rotatably supported on the contact support by means of the rotary support shaft, so that the plurality of contacts form a contact surface that can contact an external conductor to conduct electricity; and a flexible connection member, two ends of which are respectively electrîcally connected with the plurality of conductive sheets and the busbar;

wherein a first gap is formed between two adjacent groups of conductive sheets, a second gap is formed between two adjacent conductive sheets in each group of conductive sheets, the first gap is larger than the second gap, and contacts on the conductive sheets on two sides ofthe group of conductive sheets are disposed distant and offset from each other in an arrangement direction of the conductive sheets,
2. The contact system of a circuit breaker according to claim 1, wherein the conductive sheet has a contact setting surface for connecting the contact, and the contact setting surfaces of the conductive sheets on two sides of the group of conductive sheets are disposed distant and offset from each other in the arrangement direction of the conductive sheets.
3. The contact system of a circuit breaker according to claim 1, further comprising first isolation portions and second isolation portions, the first isolation portions being located between the adjacent groups of conductive sheets to maintain the first gaps between the adjacent groups of conductive sheets, and the second isolation portions being located between the adjacent conductive sheets in the group of conductive sheets to maintain the second gaps between the adjacent conductive sheets.
4. The contact system of a circuit breaker according to claim 3, wherein the first isolation portions and/or the second isolation portions comprises a boss formed on the conductive sheet or an isolator arranged separately.

1¾
5. The contact System of a circuit breaker according to claim 1, further comprising: elastic members correspondingly disposed between each group of conductive sheets and the contact support.
6. A circuit breaker, comprising the contact System of a circuit breaker according to one of daims 1 to 5.