Circuit breaker

Abstract

A circuit breaker (1) has a breaking unit (10), said breaking unit (10) comprises a case (100), an arc chamber (110), a busbar (120) having a first end portion (121) and a second end portion (122), and a conductor (160) for transferring a current to the busbar (120), the conductor (160) having a first end portion (161) and a second end portion (162). The busbar (120) is arranged in the case (100) such that the first end portion (121) is placed on a side of the arc chamber (110). The second end portion (122) of the busbar (120) is connected to the second end portion (162) of the conductor (160) by a form-fitted connection using a connection part or by a material-fitted connection.

Description

[0001] P2024, 1174 WO N / P24-1704W001 February 12, 2026

[0002] 1

[0003] Description

[0004] CIRCUIT BREAKER

[0005] Technical Field

[0006] The disclosure relates to a circuit breaker for protecting electrical circuits from short circuits and overload currents .

[0007] Background

[0008] A circuit breaker is used as an electrical switch for protecting an electrical circuit in electrical systems from damage caused by the occurrence of a short circuit or by a large current that is lower than the current in the case of a short circuit but large enough to damage the electrical circuit .

[0009] The circuit breaker comprises a breaking unit to interrupt a current flow in the event of a short circuit or in an overcurrent situation. The breaking unit comprises a movable contact and a stationary contact . The movable contact may be moved in a closed and open state . In the closed state of the circuit breaker, the movable contact is in electrical connection with the stationary contact so that the circuit breaker allows a current flow from an input terminal to an output terminal of the circuit breaker . In an open state of the circuit breaker, the movable contact is separated from the stationary contact so that the flow of current between the input and output terminals of the circuit breaker is interrupted .P2024, 1174 WO N / P24-1704W001 February 12, 2026

[0010] 2

[0011] The stationary contact is located at the end of a busbar, which is arranged inside a case / cassette of the breaking unit . To monitor a current flow in a current-carrying cable and to switch off in the event of a fault, for example in the event of a short circuit, by the circuit breaker, the current-carrying cable is connected to an outer terminal of the circuit breaker . From the outer terminal, the applied current is conducted via a conductor, also referred to as a primary conductor, into the interior of the housing of the circuit breaker to the breaking unit .

[0012] In the housing of the circuit breaker, the (primary) conductor is electrically connected to the busbar of the breaking unit . Usually, the (primary) conductor inside the circuit breaker is connected to the busbar via a screw connection. However, the screw connection between the two current-carrying conductors, i . e the (primary) conductor and the busbar of the breaking unit, has some disadvantages .

[0013] The screw connection between the (primary) conductor and the busbar is associated with a large effort in manufacturing since the screw connection must be made inside the housing of the circuit breaker . In addition, the screw connection needs a lot of space inside the housing of the circuit breaker .

[0014] The screw connection also has a negative impact on electrical performance . In particular, an increased resistance occurs at the screw connection between the two current-carrying conductors . Furthermore, there is a risk of voltage flashovers to neighboring components within the circuit breaker in the area of the screw connection.

[0015] There is a desire to provide a circuit breaker with an improved assembly to overcome at least the above-mentionedP2024, 1174 WO N / P24-1704W001 February 12, 2026

[0016] 3

[0017] disadvantages of a screw connection between the (primary) conductor of the circuit breaker and the busbar of the breaking unit of the circuit breaker .

[0018] Summary

[0019] An embodiment of a circuit breaker with an improved assembly with respect to the connection between the (primary) conductor of the circuit breaker and the busbar of the breaking unit of the circuit breaker is specified in claim 1.

[0020] According to the proposed approach of a circuit breaker, the circuit breaker has a breaking unit which comprises a case, an arc chamber, and a busbar . The busbar has a first end portion and a second end portion. The busbar is arranged in the case of the breaking unit such that the first end portion is placed on a side of the arc chamber . The breaking unit further comprises a conductor for transferring a current to the busbar . The conductor has a first end portion and a second end portion. The second end portion of the busbar is connected to the second end portion of the conductor by a form-fitted connection using a connection part or by a material-fitted connection.

[0021] In conclusion, according to the proposed approach, the screw connection that is usually provided between the (primary) conductor and the busbar is no longer required. The separate parts of the (primary) conductor and the busbar which have been designed as separate parts in the conventional circuit breaker, as described above, are combined in the new design into a single part .P2024, 1174 WO N / P24-1704W001 February 12, 2026

[0022] 4

[0023] In terms of the form-fitting connection using a connection part, this means that the connection between the (primary) conductor and the busbar can no longer be released without destroying the connection part .

[0024] In the case of the form-fitted connection using the connection part, the connection part can be configured, for example, as a rivet . According to this form-fitted connection, the second end portion of the busbar is connected to the second end portion of the conductor by a riveted connection .

[0025] In terms of the material-fitted connection, the now singlepiece combination of the (primary) conductor and the busbar means that the connection cannot be released without destroying at least one of the (primary) conductor and the busbar .

[0026] There are various possibilities for the material-fitted connection or the material bond. According to a first possible embodiment of the material-fitted connection, the second end portion of the busbar is welded to the second end portion of the (primary) conductor . According to another possible embodiment of the material-fitted connection, the second end portion of the busbar is soldered to the second end portion of the conductor . Another option for the material-fitted connection is to glue the second end portion of the busbar to the second end portion of the conductor, for example by using a conductive adhesive .

[0027] According to a possible embodiment, the circuit breaker comprises a sensor unit for measuring a current flow in the conductor . The sensor unit is enclosed in the case of theP2024, 1174 WO N / P24-1704W001 February 12, 2026

[0028] 5

[0029] breaking unit . This means that the sensor unit is capsulated by the case of the breaking unit .

[0030] According to a possible embodiment of the circuit breaker, the conductor comprises a middle portion between the first end portion and the second end portion. The sensor unit is arranged to surround the middle portion of the conductor .

[0031] In this embodiment, both the sensor unit and the (primary) conductor are enclosed in the case of the breaking unit and thus encapsulated from the outside . This also means that the form-fitted connection using the connection part or the material-fitted connection between the (primary) conductor and the busbar is encapsulated in the case of the breaking unit .

[0032] The proposed embodiment of a circuit breaker thus helps to prevent flashovers in the area of the connection of the current-carrying (primary) conductor and the busbar to adj acent parts within the housing of the circuit breaker .

[0033] Additional features and advantages are set forth in the detailed description that follows . It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework for understanding the nature and character of the claims .

[0034] Brief Description of the Drawing

[0035] The accompanying figures are included to provide further understanding, and are incorporated in, and constitute a part of the specification. As such, the proposed configuration ofP2024, 1174 WO N / P24-1704W001 February 12, 2026

[0036] 6

[0037] a circuit breaker will be more fully understood from the following detailed description, taken in conjunction with the accompanying figures of which

[0038] Figure 1 shows a circuit breaker comprising a breaking unit with improved assembly of current-carrying parts; and

[0039] Figure 2 shows a perspective view of a breaking unit of a circuit breaker with improved assembly of current-carrying parts and with an encapsulation of a sensor unit within a case of the breaking unit .

[0040] Detailed Description

[0041] Figure 1 shows a circuit breaker 1 which is configured for interrupting a current flow in the event of a short circuit or when an overcurrent is detected. The circuit breaker 1 may be configured as a molded case circuit breaker (MCCB) . The circuit breaker comprises a breaking unit 10 being arranged inside a housing 20 of the circuit breaker . The breaking unit 10 comprises a breaking mechanism which allows the circuit breaker 1 to be operated in a closed state in which a movable contact and a stationary contact located in the breaking unit 10 are electrically connected, and in an open state in which the movable contact and the stationary contact of the breaking unit are separated so that a current flow is interrupted by the circuit breaker .

[0042] Figure 2 shows a perspective view of the breaking unit 10. The breaking unit 10 comprises a case / cassette 100 in which an arc chamber 110 and an arc chamber 130 are arranged onP2024, 1174 WO N / P24-1704W001 February 12, 2026

[0043] opposite sides of a rotary unit 150 for interrupting a single phase or interrupting a current flow through the breaking unit 10. The breaking unit 10 comprises a busbar 120 having a first end portion 121 and a second end portion 122. The busbar 120 is arranged in the case 100 such that the first end portion 121 is placed on a side of the arc chamber 110. As shown in Figure 2, the busbar 120 may be formed inside the case 100 in a reverse loop .

[0044] Referring to Figure 2, the rotary unit 150 is configured as a double breaking contact system. The breaking unit 10 comprises a busbar 140 having a first end portion 141 and a second end portion 142. The busbar 140 is arranged in the case 100 such that the first end portion 141 is placed on a side of the arc chamber 130, and the second end portion 142 protrudes out of the case 100 of the breaking unit 10.

[0045] The rotary unit 150 comprises a movable contact bridge having respective movable contacts at each end of the contact bridge . The rotary unit 150 allows the breaking unit 10 or the circuit breaker 1 to be operated in an open state and a closed state / current flow state . In the open state of the circuit breaker, stationary contacts arranged at the end portions 121, 141 of the busbars 120, 140 are separated from the movable contacts of the movable contact bridge of the rotary unit 150. In the closed state / current flow state of the circuit breaker, the movable contacts of the movable contact bridge of the rotary unit 150 are in electrical connection with the stationary contacts of the busbars 120, 140 .

[0046] Referring to Figure 2, the breaking unit 10 comprises a (primary) conductor 160 for transferring a current to theP2024, 1174 WO N / P24-1704W001 February 12, 2026

[0047] busbar 120. The (primary) conductor 160 has a first end portion 161 and a second end portion 162. The circuit breaker comprises an outer terminal 170 to apply a current to the (primary) conductor 160. The first end portion 161 of the (primary) conductor 160 is connected to the outer terminal 170 .

[0048] According to the proposed approach of the breaking unit 10 of the circuit breaker 1, the second end portion 122 of the busbar 120 is connected to the second end portion 162 of the (primary) conductor 160 by a form-fitted connection using a connection part or by a material-fitted connection.

[0049] In the case of the form-fitted connection using the connection part, the second end portion 122 of the busbar 120 is connected to the second end portion 162 of the conductor 160 such that the connection part is destroyed when the formfitted connection is released. According to an embodiment of the form-fitted connection using the connection part, the second end portion 122 of the busbar 120 is connected to the second end portion 162 of the conductor 160 by a riveted connection. In this case, the connection part of the from-fitted connection is a rivet .

[0050] In the case of the material-fitted connection between the busbar 120 and the (primary) conductor 160, the second end portion 122 of the busbar 120 is connected to the second end portion 162 of the (primary) conductor 160 such that the busbar 120 and / or the (primary) conductor 160 is destroyed if an attempt is made to disconnect the material-fitted connection between the busbar 120 and the (primary) conductor 160 .P2024, 1174 WO N / P24-1704W001 February 12, 2026

[0051] In the case of a material-fitted connection between the busbar 120 and the (primary) conductor 160, the second end portion 122 of the busbar 120 is firmly bonded to the second end portion 162 of the (primary) conductor 160 which means that the busbar 120 is integral with or solidly connected to the (primary) conductor 160.

[0052] In the case of the material-fitted connection, the second end portion 122 of the busbar 120 is metallurgically bonded to the second end portion 162 of the (primary) conductor 160. For example, the second end portion 122 of the busbar 120 can be welded to the second end portion 162 of the (primary) conductor 160. According to another possible embodiment of the material-fitted connection between the busbar 120 and the (primary) conductor 160, the second end portion 122 of the busbar 120 is soldered to the second end portion 162 of the (primary) conductor 160. According to another possible realization of the material-fitted connection between the busbar 120 and the (primary) conductor 160, the second end portion 122 of the busbar 120 is glued to the second end portion 162 of the (primary) conductor 160, for example, by using a conductive adhesive .

[0053] The proposed form-fitted connection between the busbar 120 and the (primary) conductor 160 using a connection part or the material-fitted connection / material-to-material connection between the busbar 120 and the (primary) conductor has advantages over a screw connection in terms of the manufacturing, design and electrical performance of the circuit breaker .

[0054] The form-fitted connection using a connection part or the material-fitted connection between the busbar 120 and theP2024, 1174 WO N / P24-1704W001 February 12, 2026

[0055] - 10 -

[0056] (primary) conductor 160 results in less assembly work as less screw connections are required. Moreover, the available space in the housing 20 of the circuit breaker 1 is increased because the space-wasting screw connection between the busbar 120 and the (primary) conductor 160 is no longer necessary. In terms of electrical performance, the form-fit connection using a connection part or the material-fit connection between the busbar 120 and the (primary) conductor 160 leads to reduced current path resistance because of the avoidance of screw connections .

[0057] Referring again to Figure 2, the breaking unit 10 comprises a sensor unit 180 for measuring a current flow in the (primary) conductor 160. If the sensor unit 180 detects an increased current flow in the (primary) conductor 160 in the event of a fault, such as a short circuit, a trip device (not shown in Figure 2 ) is triggered to separate the movable and stationary contacts from each other to interrupt the current flow through the circuit breaker .

[0058] According to the proposed approach of the breaking unit 10, the sensor unit 180 is enclosed or encased in the case 100 of the circuit breaker . This means that the sensor unit 180 is capsulated by the case 100 so that the sensor unit 180 is a part of the breaking unit 10. As a result, the assembly of the breaking unit 10 or the circuit breaker 1 has a compact design .

[0059] The (primary) conductor 160 comprises a middle portion 163 between the first end portion 161 and the second end portion 162. The sensor unit 180 is arranged to surround the middle portion 163 of the (primary) conductor 160. The sensor unit 180 may comprise at least one coil 181 that surrounds theP2024, 1174 WO N / P24-1704W001 February 12, 2026

[0060] - 11 -

[0061] middle portion 163 of the (primary) conductor 160. The second end portion 162 and the middle portion 163 of the (primary) conductor 160 are enclosed in case 100 of the breaking unit 10 .

[0062] Thus, the connection between the busbar 120 and the (primary) conductor 160 is located inside the case / cassette 100 of the breaking unit 10 and is thus no longer freely accessible inside the housing 20 of the circuit breaker . The compact arrangement of the connection point between the busbar 120 and the (primary) conductor 160 inside the case / cassette 100 of the breaking unit 10 results in improved creepage and clearance between the current interrupting mechanism and the current paths .

[0063] The embodiments of the proposed circuit breaker disclosed herein have been discussed for the purpose of familiarizing the reader with novel aspects of the circuit breaker .

[0064] Although preferred embodiments have been shown and described, many changes, modifications, equivalents and substitutions of the disclosed concept may be made by one having skill in the art without unnecessarily departing from the scope of the claims .

[0065] In particular, the design of the proposed circuit breaker is not limited to the disclosed embodiments, and gives examples of many alternatives as possible for the features included in the embodiments discussed.

[0066] Furthermore, features recited in separate dependent claims may be advantageously combined. Moreover, reference signs used in the claims are not limited to be construed as limiting the scope of the claims .P2024, 1174 WO N / P24-1704W001 February 12, 2026

[0067] - 12 -

[0068] Moreover, as used herein, the term "comprising" does not exclude other elements . In addition, as used herein, the article "a" is intended to include one or more than one component or element, and is not limited to be construed as meaning only one .P2024, 1174 WO N / P24-1704W001 February 12, 2026

[0069] List of reference signs

[0070] circuit breaker

[0071] 10 breaking unit

[0072] 20 housing

[0073] 100 case

[0074] 110 arc chamber

[0075] 120 busbar

[0076] 121, 122 portions of busbar

[0077] 130 arc chamber

[0078] 140 busbar

[0079] 141, 142 portions of busbar

[0080] 150 rotary unit

[0081] 160 (primary) conductor

[0082] 161, 162, 163 portions of (primary) conductor 170 outer terminal

[0083] 180 sensor unit

[0084] 181 coil

Claims

P2024 , 1174 WO N / P24- 1704W001 February 12 , 2026- 14 -Claims1 . A circuit breaker having a breaking unit ( 10 ) , said breaking unit ( 10 ) comprising :- a case ( 100 ) ,- an arc chamber ( 110 ) ,- a busbar ( 120 ) having a first end portion ( 121 ) and a second end portion ( 122 ) ,- wherein the busbar ( 120 ) is arranged in the case ( 100 ) such that the first end portion ( 121 ) is placed on a side of the arc chamber ( 110 ) ,- a conductor ( 160 ) for trans ferring a current to the busbar ( 120 ) , the conductor ( 160 ) having a first end portion ( 161 ) and a second end portion ( 162 ) ,- wherein the second end portion ( 122 ) of the busbar ( 120 ) is connected to the second end portion ( 162 ) of the conductor ( 160 ) by a form- fitted connection using a connection part or by a material- fitted connection .2 . The circuit breaker of claim 1 ,wherein, in the case of the form- fitted connection using the connection part , the second end portion ( 122 ) of the busbar ( 120 ) is connected to the second end portion ( 162 ) of the conductor ( 160 ) such that the connection part is destroyed, when the form- fitted connection is released .3 . The circuit breaker of claim 1 or 2 ,wherein, in the case of the form- fitted connection using the connection part , the second end portion ( 122 ) of the busbar ( 120 ) is connected to the second end portion ( 162 ) of the conductor ( 160 ) by a riveted connection .4 . The circuit breaker of any of the claims 1 to 3 ,P2024 , 1174 WO N / P24- 1704W001 February 12 , 2026wherein, in the case of the material- fitted connection, the second end portion ( 122 ) of the busbar ( 120 ) is welded to the second end portion ( 162 ) of the conductor ( 160 ) .5 . The circuit breaker of any of the claims 1 to 3 , wherein, in the case of the material- fitted connection, the second end portion ( 122 ) of the busbar ( 120 ) is soldered to the second end portion ( 162 ) of the conductor ( 160 ) .6 . The circuit breaker of any of the claims 1 to 3 , wherein, in the case of the material- fitted connection, the second end portion ( 122 ) of the busbar ( 120 ) is glued to the second end portion ( 162 ) of the conductor ( 160 ) .7 . The circuit breaker of any of the claims 1 to 6 ,- wherein the breaking unit ( 10 ) comprises a sensor unit ( 180 ) for measuring a current flow in the conductor ( 160 ) , - wherein the sensor unit ( 180 ) is enclosed in the case ( 100 ) .8 . The circuit breaker of claim 7 ,- wherein the conductor ( 160 ) comprises a middle portion ( 163 ) between the first end portion ( 161 ) and the second end portion ( 162 ) ,- wherein the sensor unit ( 180 ) is arranged to surround the middle portion ( 163 ) of the conductor ( 160 ) .9 . The circuit breaker of claim 7 or 8 ,wherein the sensor unit ( 180 ) comprises at least one coil ( 181 ) that surrounds the middle portion ( 163 ) of the conductor ( 160 ) .10 . The circuit breaker of claim 8 or 9 ,P2024 , 1174 WO N / P24- 1704W001 February 12 , 2026wherein the second end portion ( 162 ) and the middle portion ( 163 ) of the conductor are enclosed in the case ( 100 ) .11 . The circuit breaker of any of the claims 1 to 10 , comprising :- an outer terminal ( 170 ) to apply a current to the conductor ( 160 ) ,- wherein the first end portion ( 161 ) of the conductor ( 160 ) is connected to the outer terminal ( 170 ) .12 . The circuit breaker of any of the claims 1 to 11 , wherein the busbar ( 120 ) is formed inside the case ( 100 ) in a reverse loop .13 . The circuit breaker of any of the claims 1 to 12 , wherein the circuit breaker ( 1 ) is configured as a molded case circuit breaker .

Images