A molded case circuit breaker

Abstract

A molded case circuit breaker belongs to the technical field of low-voltage electrical appliances. It comprises a shell, a contact system, an arc extinguishing device and a release arranged in a cavity formed by the inside of the shell, an incoming terminal and an outgoing terminal; the arc extinguishing device is arranged corresponding to the contact system and is located at one end of the cavity close to the incoming terminal in the length direction of the molded case circuit breaker defined by the arrangement direction of the incoming terminal and the outgoing terminal; the excitation conductor of the release is electrically connected between the movable contact of the contact system and the outgoing terminal, and in the height direction of the molded case circuit breaker defined by the action direction of the movable contact, the excitation conductor extends along the length direction of the molded case circuit breaker at a position lower than the height of the outgoing terminal. Advantage: save copper resources and reduce cost, compact structure, save space and meet the requirement of flat design; create the required conditions for the available space of the operating mechanism, and the expansion of the operating mechanism in the length direction of the molded case circuit breaker is also conducive to reducing its height, embodying the flat design.

Description

Technical Field

[0001] This utility model belongs to the field of low-voltage electrical technology, specifically relating to a molded case circuit breaker. Background Technology

[0002] From the perspective of the current flow path inside the circuit breaker, the conductive circuit of a molded case circuit breaker mainly includes: incoming terminals, contact system, current-carrying conductor, and outgoing terminals. The aforementioned contact system includes stationary contacts and moving contacts. The moving contact is driven to rotatably separate or close relative to the stationary contact electrically connected to the incoming terminals, centered on a fixed pivot point. Under closing conditions, the current path is: from the power source, through the incoming terminals, stationary contacts, moving contacts, flexible connection, current-carrying conductor, outgoing terminals, and load. Molded case circuit breakers are typically designed as 2-pole, 3-pole, or 4-pole circuit breakers, with the number of contact systems corresponding to these specifications.

[0003] Figure 1 The diagram shown is a schematic diagram of the conductive circuit of a molded case circuit breaker in the prior art. Figure 2 This is a three-dimensional structural diagram of the yoke 41 and thermal trip unit of the magnetic trip unit in a prior art molded case circuit breaker. The applicant further details the following... Figure 1 and Figure 2 The following explanation is provided. Terminal 6 is electrically connected to a conductor, on which are mounted a bimetallic strip for a thermal trip and a yoke 41 and armature 42 for a magnetic trip. The conductor, in close contact with the bimetallic strip, serves as the thermal element of the thermal trip, transferring heat to the bimetallic strip. When an overload current occurs in the conductive circuit, the bimetallic strip slowly bends (also known in the industry as "deformation"). When it bends sufficiently to strike the operating mechanism, it acts on the mechanism, thus tripping the circuit breaker and separating the moving and stationary contacts, providing overload protection. The magnetic trip includes a U-shaped yoke 41 and an armature 42. A conductor passing through the cavity of the U-shaped yoke 41 serves as the excitation conductor for the magnetic trip, providing the excitation magnetomotive force to drive the magnetic trip. When a short circuit occurs in the conductive circuit, under the action of the excitation magnetomotive force, the armature 42 rotates rapidly, the magnetic trip activates, and the operating mechanism trips, separating the moving and stationary contacts, providing short-circuit protection.

[0004] Depend on Figure 1As shown, one end of the aforementioned conductor is connected to the flexible connection 213 of the contact system 2, while the other end of the conductor is electrically connected to the aforementioned outgoing terminal 6. Ideally, the distances from the incoming terminal 5 and the outgoing terminal to the bottom of the circuit breaker housing should be the same and fixed, and the direction from the incoming terminal to the outgoing terminal should be defined as the horizontal direction (the incoming and outgoing terminals are symmetrical in spatial height and have the same height). However, in the prior art, since the magnetic trip unit and the thermal trip unit are installed vertically, and the height of the U-shaped yoke 41 is much higher than that of the outgoing terminal 6, after the conductor is connected to the flexible connection 213 of the contact system 2, it is tightly fixed to the bottom of the bimetallic strip, then passes upward through the cavity of the yoke 41, and then needs to be bent downward to achieve electrical connection with the outgoing terminal 6. Therefore, the total length of the conductor is much greater than the horizontal distance from the flexible connection to the outgoing terminal, resulting in a significant increase in the amount of copper used in the circuit breaker and a significant increase in cost. Furthermore, according to the resistance formula R = ρ * L / S (ρ is resistivity, L is length, and S is cross-sectional area), an increase in the conductor length will correspondingly lead to an increase in the resistance of the entire conductive circuit R. An increase in the resistance of the conductive circuit will bring adverse factors such as increased energy loss and temperature rise.

[0005] In view of the above-mentioned existing technology, it is necessary to make substantial and reasonable improvements. To this end, the applicant has made beneficial designs, which have resulted in the technical solution that will be introduced below. Utility Model Content

[0006] The objective of this invention is to provide a molded case circuit breaker that helps to effectively reflect the rationality of the electrical connection of the excitation conductor, thereby saving the amount of copper resources (a non-ferrous metal) and reducing costs, while also achieving a compact structure, saving space, and meeting the requirements of flat design. This invention also helps to avoid energy loss and temperature rise caused by unreasonable structure and placement of the excitation conductor, thus improving product quality.

[0007] The present invention achieves its objective as follows: a molded case circuit breaker includes a housing, a contact system, an arc-extinguishing device, and a trip unit disposed within a cavity formed by the interior of the housing, as well as incoming and outgoing terminals; the arc-extinguishing device is disposed corresponding to the contact system and located at one end of the cavity near the incoming terminal in the length direction of the molded case circuit breaker defined by the arrangement direction of both the incoming and outgoing terminals; the excitation conductor of the trip unit is electrically connected between the moving contact of the contact system and the outgoing terminal; in the height direction of the molded case circuit breaker defined by the direction of action of the moving contact, the excitation conductor extends along the length direction of the molded case circuit breaker at a height position lower than that of the outgoing terminal.

[0008] In a specific embodiment of this utility model, the trip unit includes a magnetic trip unit and a thermal trip unit. In the magnetic trip unit, the excitation conductor is an excitation conductor, and in the thermal trip unit, the excitation conductor is a thermal element.

[0009] In another specific embodiment of this utility model, the trip unit includes a U-shaped yoke and an armature. The U-shaped yoke includes side plates and a bottom plate. The side plates are a pair that fold upwards from the front and rear sides of the bottom plate to form a face-to-face position. The pair of side plates and the bottom plate together constitute the U-shaped yoke with a yoke cavity. The armature includes a striking rod and a snap plate. The lower end of the striking rod forms a snap plate connecting seat, which is fixed to the upward-facing side of the snap plate. A pivot head is formed on the front and rear sides of the right end of the snap plate connecting seat. The pivot head is rotatably supported on the upper part of the end of the pair of side plates facing the output terminal. The upper end of the striking rod extends upwards, and the snap plate corresponds to the upper cavity opening of the yoke cavity. The excitation conductor is located at the bottom of the cavity and passes through the yoke cavity of the yoke while being fixed to the bottom plate.

[0010] In another specific embodiment of this utility model, the upper front part and the upper rear part of the pair of side plates facing the terminal outlet are each provided with a pivot head support groove, and the pivot head is rotatably supported in the pivot head support groove.

[0011] In another specific embodiment of the present invention, the moving contact of the contact system includes a rotating shaft, and an operating mechanism is also provided in the cavity for driving the rotating shaft to separate or close the moving contact connected to the rotating shaft from the stationary contact. The upper end of the striking rod extends upward to the extent that it cooperates with the operating mechanism.

[0012] In another specific embodiment of this utility model, a reaction spring hanging edge extends upward from the front and rear sides of the flapping plate connecting seat. In the use state, one end of a reaction spring is hung on any one of the two reaction spring hanging edges, while the other end of the reaction spring is hung on the U-shaped yoke.

[0013] In a further specific embodiment of the present invention, the trip unit further includes a conductor connection portion extending along the length direction of the molded case circuit breaker and a thermal actuation portion extending along the height direction of the molded case circuit breaker, wherein the conductor connection portion and the excitation conductor are fitted together and tightly fixed within the yoke cavity.

[0014] In a further specific embodiment of this utility model, the moving contact includes a moving contact guide rod that cooperates with the stationary contact and a flexible connection that is connected to the moving contact guide rod. The excitation conductor is connected to the flexible connection, and the connection point between the two constitutes a connection point located within the yoke cavity of the U-shaped yoke.

[0015] The technical advantages of the present invention are as follows: Since the excitation conductor extends along the length of the molded case circuit breaker at a height lower than the output terminals, the conductor length is significantly shortened. This saves copper resources (a non-ferrous metal) and reduces costs, while also making the structure compact, space-saving, and meeting the requirements of a flat design. Because the excitation conductor is arranged in this manner, the yoke of the magnetic trip unit can be horizontally installed, allowing the magnetic trip unit to be housed in the space below the operating mechanism without occupying the length of the molded case circuit breaker. This provides the necessary space for the operating mechanism to achieve improved reliability and functional expansion. The extension of the operating mechanism along the length of the molded case circuit breaker also helps to reduce its height, embodying the aforementioned flat design. Furthermore, it avoids energy losses and temperature rises caused by unreasonable structures and positions of the excitation conductor in existing technologies. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the conductive circuit of the structural system of a molded case circuit breaker in the prior art; Figure 2 A three-dimensional structural diagram of the yoke of the magnetic trip unit and the thermal trip unit in existing molded case circuit breakers; Figure 3 This is a schematic diagram of the incoming and outgoing terminals, contact system, excitation conductor, and trip unit of the molded case circuit breaker of this utility model. Figure 4 for Figure 3 The trip unit shown includes a detailed structural diagram of a magnetic trip unit and a thermal trip unit; Figure 5 for Figure 4 A detailed structural diagram of the trip unit revealed by removing the armature.

[0017] In the diagram: 1. Housing; 2. Contact system, 21. Moving contact, 211. Moving contact guide rod, 212. Rotating shaft, 213. Flexible connection, 2131. Connection point, 22. Stationary contact; 3. Arc extinguishing device; 4. Trip unit, 41. U-shaped yoke, 411. Side plate, 4111. Pivot shaft head support groove, 412. Base plate, 413. Yoke cavity, 42. Armature, 421. Strike rod, 4211. Clamping plate connecting seat, 42111. Pivot shaft head, 42112. Reaction spring hanging edge, 422. Clamping plate, 43. Conductor connection part, 44. Thermal actuation part; 5. Incoming terminal; 6. Outgoing terminal; 7. Excitation conductor; 8. Operating mechanism; 10. Cavity. Detailed Implementation

[0018] In order to better understand the technical essence and beneficial effects of this utility model, the applicant provides a detailed description below by way of embodiments. However, the description of the embodiments is not intended to limit the solution of this utility model. Any formal but not substantive equivalent transformations made based on the concept of this utility model should be considered within the scope of the technical solution of this utility model.

[0019] In the following description, all directional or positional concepts involving up, down, left, right, front, and back are based on the current position. Figure 3 The location and state are taken as a reference, and therefore should not be construed as a special limitation on the technical solution provided by this utility model.

[0020] Please see Figure 3 The diagram shows the outer casing 1, which, according to common knowledge, typically consists of a base and a cover, with the cover positioned above and joined to the base. It also shows the contact system 2, the arc-extinguishing device 3, and the trip unit 4, all housed within a cavity 10 formed by the interior of the outer casing 1. The diagram further shows the incoming terminal 5 and the outgoing terminal 6. The arc-extinguishing device 3 is positioned corresponding to the contact system 2 and, along the length of the molded case circuit breaker defined by the arrangement directions of the incoming and outgoing terminals 5, is located within the cavity 10 near the incoming terminal 5. The excitation conductor 7 of the trip unit 4 is electrically connected between the moving contact 21 of the contact system 2 and the outgoing terminal 6. Clearly, the cavity 10 is the space formed between the base and the cover. Of course, the aforementioned outer casing 1 can also be formed by splicing together a base, a middle cover, and a top cover. Its internal space is also configured as the cavity 10 for accommodating the components of the molded case circuit breaker, such as the arc extinguishing device 3, the contact system 2, the operating mechanism 8, the trip unit 4, and optional accessories such as shunt trip units and auxiliary modules, which may be configured as needed. The incoming terminal 5 is connected to the power supply, and the outgoing terminal 6 is connected to the load. Of course, if necessary, the incoming terminal 5 can also be connected to the load, and the outgoing terminal 6 can be connected to the power supply to achieve reverse wiring. The ends of the incoming and outgoing terminals 5 and 6 located in the cavity 10 are electrically connected to the contact system 2, thereby forming the main conductive circuit of the molded case circuit breaker.

[0021] In this embodiment, the arrangement direction of the incoming terminal 5, which serves as the first terminal, and the outgoing terminal 6, which serves as the second terminal, is defined as the length direction of the molded case circuit breaker, and normally the incoming and outgoing terminals 5 and 6 are at the same height of the molded case circuit breaker; the direction of the opening and closing movement of the moving contact 21 is defined as the height direction of the molded case circuit breaker; and the direction of the side-by-side positions of the various poles of the molded case circuit breaker is defined as the width direction of the molded case circuit breaker.

[0022] The key technical point of the technical solution provided by this utility model is that, in the height direction of the molded case circuit breaker defined by the operating direction of the aforementioned moving contact 21, the aforementioned excitation conductor 7 extends along the length direction of the aforementioned molded case circuit breaker at a height position lower than that of the aforementioned outgoing terminal 6.

[0023] Please see Figure 4 and Figure 5 And combined Figure 3 The aforementioned release device 4 includes a U-shaped yoke 41 and an armature 42. The U-shaped yoke 41 includes side plates 411 and a base plate 412. The side plates 411 have a pair that fold upwards from the front and rear sides of the base plate 412 to form a face-to-face position. The pair of side plates 411 and the base plate 412 together constitute the aforementioned U-shaped yoke 41 with a yoke cavity 413. The U-shaped yoke 41 is disposed within the aforementioned cavity 10. The aforementioned armature 42 includes a striking rod 421 and a snap-fit ​​plate 422. The lower end of the striking rod 421 forms a snap-fit ​​plate connecting seat 4211. The connecting seat 4211 is fixed to the upward-facing side of the striking plate 422. A pivot head 42111 is formed on the front and rear sides of the right end of the striking plate connecting seat 4211. This pivot head 42111 is rotatably supported on the upper part of the aforementioned pair of side plates 411 facing the aforementioned output terminal 6. The upper end of the striking rod 421 extends upward. The striking plate 422 corresponds to the upper cavity opening of the aforementioned yoke cavity 413. The excitation conductor 7 is located at the bottom of the cavity 10 and passes through the yoke cavity 413 of the yoke 41 while being fixed to the base plate 412. The excitation conductor 7, the U-shaped yoke 41, and the armature 42 constitute the magnetic trip unit in the trip unit. Of course, the yoke of this invention is not limited to the U-shaped structure given in the above embodiment; the striking plate of the armature can also be set in a U-shaped structure, while the yoke that cooperates with it can be set in a flat plate structure.

[0024] The aforementioned pair of side plates 411 each have a pivot head support groove 4111 on the upper front and upper rear sides facing the right end of the aforementioned output terminal 6, and the aforementioned pivot head 42111 is rotatably supported in the pivot head support groove 4111.

[0025] Depend on Figure 3 As shown, the aforementioned moving contact 21 of the aforementioned contact system 2 includes a rotating shaft 212, and an operating mechanism 8 is also provided in the aforementioned cavity 10 for driving the aforementioned rotating shaft 212, preferably made of plastic material, to separate or close the moving contact 21 connected to the rotating shaft 212 from the U-shaped stationary contact 22.

[0026] The upper end of the aforementioned striking lever 421 extends upward to the extent that it extends to the aforementioned operating mechanism 8 ( Figure 3The degree of coordination between the two is shown. The rotating shaft 212 is driven by the operating mechanism 8, which in turn drives the moving contact 21 to move, thereby separating or closing it from the stationary contact 22.

[0027] The aforementioned snap-fit ​​plate connecting seat 4211 has a reaction spring hanging edge 42112 extending upward from both its front and rear sides. In use, one end of a reaction spring is hung on either of the two reaction spring hanging edges 42112, while the other end of the reaction spring is hung on the aforementioned U-shaped yoke 41. Since the arrangement and function of the reaction spring are prior art, the applicant has not shown them in the figures.

[0028] The excitation conductor 7 in the aforementioned magnetic trip device refers to a straight conductor extending in the space enclosed by the U-shaped yoke 41 and the armature 42. In this invention, the excitation conductor 7 is lower than the height of the output terminal 6. Therefore, an upwardly extending rigid conductor is used as a connecting conductor on the right side of the excitation conductor 7 to achieve electrical connection with the output terminal 6.

[0029] Since the U-shaped yoke 41 can be directly fixed to the bottom wall of the cavity 10 of the outer shell 1 (or directly fixed to the bottom wall of the base), and the excitation conductor 7 is fixed to the base plate 412, it is very beneficial to the positioning of the magnetic trip device.

[0030] Please see Figure 5 And combined Figures 3 to 4 The trip unit 4 further includes a conductor connection portion 43 extending along the length direction of the molded case circuit breaker and a thermal actuation portion 44 extending along the height direction of the molded case circuit breaker. The aforementioned conductor connection portion 43 and the aforementioned excitation conductor 7 are fitted together and tightly fixed within the aforementioned yoke cavity 413. The excitation conductor 7, the conductor connection portion 43, and the thermal actuation portion 44 constitute the thermal trip unit in the trip unit.

[0031] Depend on Figure 3 As shown, the aforementioned moving contact 21 includes a moving contact guide rod 211 that cooperates with the aforementioned stationary contact 22 (one end of the moving contact guide rod 211 is connected to the rotating shaft 212) and a flexible connection 213 connected to the moving contact guide rod 211. The aforementioned excitation conductor 7 is connected to the flexible connection 213, and the connection point of the two constitutes a connection point 2131. This connection point 2131 (also referred to as the "connection position" or "connection part") is located in the aforementioned yoke cavity 413 of the aforementioned U-shaped yoke 41.

[0032] from Figure 3The schematic diagram clearly shows that the aforementioned operating mechanism 8 is located in the upper part of the cavity 10, and has a handle on the upper surface of a cover protruding from the outer shell 1. The operator can perform opening, closing, and re-tethering operations on the molded case circuit breaker by moving the handle. In this embodiment, the trip unit 4 includes a magnetic trip unit composed of an excitation conductor 7, a yoke 41, and an armature 42, and a thermal trip unit composed of an excitation conductor 7, a conductor connection part 43, and a thermal actuation part 44. When a fault occurs in the conductive circuit of the molded case circuit breaker, the magnetic trip unit or the trip unit senses the fault current and operates. For example, the magnetic trip unit operates as follows: the excitation conductor 7 is the excitation conductor of the magnetic trip unit; the fault current flowing through the excitation conductor 7 generates a magnetic field around the excitation conductor 7, such that... Figure 3 The armature 42, which is separated from the U-shaped yoke 41, rotates counterclockwise until the armature 42 and yoke 41 are attracted together, as shown. Figure 4 As shown. The striking lever 421 pushes the traction lever of the operating mechanism 8, causing the operating mechanism 8 to trip. Under the action of the main spring inside the operating mechanism 8, the connecting mechanism inside the operating mechanism 8 is driven to move, and finally the rotating shaft 212 connected to the operating mechanism 8 is driven to move. Then, the rotating shaft 212 drives the moving contact 21 to separate from the stationary contact 22, realizing the tripping of the circuit breaker. The operation of the thermal trip unit is as follows: the excitation conductor 7 is the thermal element of the thermal trip unit. The fault current flows through the excitation conductor 7, causing the excitation conductor 7 to generate heat, which is transferred to the conductor connection part 43 that is close to the excitation conductor 7. This causes the thermal actuation part 44 to bend due to heat, pushing the traction lever of the operating mechanism 8, causing the operating mechanism 8 to trip.

[0033] The arc-extinguishing device 3 is used to extinguish the electric arc generated between the moving and stationary contacts 21 and 22 when they separate. Therefore, the arc-extinguishing device 3 is arranged corresponding to the moving and stationary contacts 21 and 22. Generally, the arc-extinguishing device 3 includes several arc-extinguishing grid plates stacked at intervals, with the grid plates stacked along the height direction of the molded case circuit breaker. The arc-extinguishing device 3 is housed within the cavity 10 and located at one end of the molded case circuit breaker along its length. It is positioned above the stationary contact 22. The end of the rigid guide rod of the moving contact 21 extends into the arc-extinguishing device 3 and can operate within it, so that the arc-burning area of ​​the electric arc generated between the moving and stationary contacts 21 and 22 is located inside the arc-extinguishing device 3, which is beneficial for the movement, elongation, and extinguishing of the arc.

[0034] In summary, the key design feature of this utility model is that, in the height direction of the molded case circuit breaker, the excitation conductor 7 extends along the length direction of the molded case circuit breaker at a position lower than the height of the outgoing terminal 6. This can be understood as the excitation conductor 7 being located below the height plane of the molded case circuit breaker formed by the incoming terminal 5 and the outgoing terminal 6. In the prior art, the excitation conductor 7 first extends upwards in the height direction of the molded case circuit breaker to a height higher than the outgoing terminal 6, and then another conductor extending in the height direction of the molded case circuit breaker (the connecting conductor mentioned in the background section) connects the top end of the excitation conductor 7 to the outgoing terminal 6. That is, the conductor between the flexible connection 213 and the outgoing terminal 6 undergoes several upward extensions, bends, and downward extensions, thus significantly shortening the conductor length compared to the prior art. Based on this, the technical solution provided by this utility model overcomes this drawback and accurately realizes the technical effects described in the above-mentioned technical effects section.

Claims

1. A molded case circuit breaker, comprising a housing (1), a contact system (2), an arc-extinguishing device (3), and a trip unit (4) disposed within a cavity (10) formed by the interior of the housing (1), an incoming terminal (5), and an outgoing terminal (6); the arc-extinguishing device (3) is disposed corresponding to the contact system (2) and located in the cavity (10) near the incoming terminal (5) in the length direction of the molded case circuit breaker defined by the arrangement direction of both the incoming terminal (5) and the outgoing terminal (6); the excitation conductor (7) of the trip unit (4) is electrically connected between the moving contact (21) of the contact system (2) and the outgoing terminal (6), characterized in that: In the height direction of the molded case circuit breaker defined by the direction of action of the moving contact (21), the excitation conductor (7) extends along the length direction of the molded case circuit breaker at a height position lower than the output terminal (6); the trip unit (4) includes a U-shaped yoke (41) and an armature (42), the U-shaped yoke (41) includes a side plate (411) and a bottom plate (412), the side plate (411) has a pair of side plates that are folded upward from the front and rear sides of the bottom plate (412) to form a face-to-face position relationship, and the pair of side plates (411) and the bottom plate (412) together constitute the U-shaped yoke (41) with a yoke cavity (413); the excitation conductor (7) is located at the bottom of the cavity (10) and passes through the yoke cavity (413) of the yoke (41) in a fixed state with the bottom plate (412).

2. A molded case circuit breaker according to claim 1, characterized in that: The trip unit (4) includes a magnetic trip unit and a thermal trip unit. In the magnetic trip unit, the excitation conductor (7) is an excitation conductor, and in the thermal trip unit, the excitation conductor (7) is a thermal element.

3. A molded case circuit breaker according to claim 2, characterized in that: The armature (42) includes a striking rod (421) and a snap plate (422). The lower end of the striking rod (421) forms a snap plate connecting seat (4211), which is fixed to the upward-facing side of the snap plate (422). A pivot head (42111) is formed on the front and rear sides of the right end of the snap plate connecting seat (4211). The pivot head (42111) is rotatably supported on the upper part of the end of the pair of side plates (411) facing the output terminal (6). The upper end of the striking rod (421) extends upward, and the snap plate (422) corresponds to the upper cavity opening of the yoke cavity (413).

4. A molded case circuit breaker according to claim 3, characterized in that: The pair of side plates (411) each have a pivot head support groove (4111) on the upper front and upper rear sides facing the terminal (6), and the pivot head (42111) is rotatably supported in the pivot head support groove (4111).

5. A molded case circuit breaker according to claim 3, characterized in that: The moving contact (21) of the contact system (2) includes a rotating shaft (212). An operating mechanism (8) is also provided in the cavity (10) for driving the rotating shaft (212) to separate or close the moving contact (21) connected to the rotating shaft (212) from the stationary contact (22). The upper end of the striking rod (421) extends upward to the extent that it cooperates with the operating mechanism (8).

6. A molded case circuit breaker according to claim 3, characterized in that: The front and rear sides of the flapping plate connecting seat (4211) each extend upward with a reaction spring hanging edge (42112). In use, one end of a reaction spring is hung on one of the two reaction spring hanging edges (42112), while the other end of the reaction spring is hung on the U-shaped yoke (41).

7. A molded case circuit breaker according to claim 1, characterized in that: The trip unit (4) further includes a conductor connection portion (43) extending along the length direction of the molded case circuit breaker and a thermal actuation portion (44) extending along the height direction of the molded case circuit breaker. The conductor connection portion (43) and the excitation conductor (7) are fitted together and tightly fixed in the yoke cavity (413).

8. A molded case circuit breaker according to claim 5, characterized in that: The moving contact (21) includes a moving contact guide rod (211) that cooperates with the stationary contact (22) and a flexible connection (213) that is connected to the moving contact guide rod (211). The excitation conductor (7) is connected to the flexible connection (213), and the connection point between the two constitutes a connection point (2131). The connection point (2131) is located in the yoke cavity (413) of the U-shaped yoke (41).

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