circuit breaker

Abstract

To provide an air circuit breaker capable of preventing breakage of a housing by ensuring a high pressure loss in a flow path where the inflow of blocking gas is assumed to flow into a mechanical portion.SOLUTION: In accordance with the rotation of a mover holder 14, an end portion 14b and a flow path restricting portion 2B1 are concentrically formed into an arcuate shape centered on a rotation shaft 14a, thereby narrowing a gap 20a and narrowing a protrusion 14c and a gap 20b in a flow path restricting portion 2B2. In particular, the flow path restricting portion 2B2 has a triangular shape such that the gap 20b in the open state extends toward the mechanism portion 52 side.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This disclosure relates to a circuit breaker (hereinafter referred to as an air circuit breaker) in which, for example, a handle is operated from outside a housing to charge a closing spring, and then a command is given to close a current-carrying part using the charged force, and more particularly to an improvement in circuit breaking capacity. [Background technology]

[0002] Air circuit breakers are generally often used as main circuit breakers in buildings, factories, etc. Therefore, as a switching device for an electric circuit, it is required to have a durable switching function, and since it is for main use, the rated current reaches several thousand amperes, and a contact pressure function based on the stored force described above is required between the movable and fixed contacts to accommodate this large current, so it is well known that not only the current-carrying parts but also the mechanism parts that control each of the above functions are complex and large.

[0003] Not only this air circuit breaker, but circuit breakers in general not only have the function of opening and closing, i.e., as a switch, but also have the important role of interrupting the electrical circuit to prevent damage to wires and load equipment in advance when an accident such as a ground fault or short circuit occurs. In addition, as the main circuit breaker mentioned above, air circuit breakers also have the function of ensuring the continuity of current flow throughout the entire system, that is, not interrupting until the circuit breaker directly involved in the accident has completed its interrupting operation, so that other healthy circuits continue to be energized, in order to minimize the impact of the accident (specified as the rated short-time withstand current). This is one of the reasons why the contact pressure mentioned above becomes large.

[0004] Of course, if an accident occurs directly below an air circuit breaker, the air circuit breaker itself will perform the breaking operation. Here, the fault current caused by a short circuit, i.e., the short-circuit current, becomes larger the shorter the distance from the transformer, and as mentioned above, because it is used as a main circuit breaker, an air circuit breaker installed directly below the transformer is required to be capable of breaking a current that is several hundred times the rated current, for example. Moreover, the larger the short-circuit current, the greater the arc energy generated during the breaking operation, and as a result, the higher the gas pressure generated between the two contacts.

[0005] This high-temperature, high-pressure gas (hereafter referred to as "breaking gas") is mainly discharged to the outside through an exhaust port located above the current-carrying part, but it is necessary to assume that some of it will remain inside the housing. For this reason, it is well known that, to prepare for the rise in internal pressure when the circuit is broken, the current-carrying part and the mechanism part are housed in their own strong units. However, as mentioned above, in order to transmit the stored energy to the current-carrying part, the two parts are connected, and it is also well known that the parts that make up this connection move in response to opening and closing.

[0006] For this reason, an opening inevitably occurs in a part of the unit body, and arc touch caused by the insulating gas flowing into the mechanical part through this opening, i.e., a rise in the potential of the metal parts that make up the mechanical part, must be avoided from the perspective of preventing electric shock. Therefore, in order to close the above-mentioned opening, it is known to incorporate a loose-fitting member (slide plate) that slides in response to the member that performs the connection (insulating link) (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Utility Model Application Publication No. 5-33433 Summary of the Invention [Problem to be solved by the invention]

[0008] Although incorporating a slide plate reduces the occurrence of arc touch, it is difficult to physically eliminate the gap between the outer periphery of the insulating link and the small opening in the slide plate, in order to avoid impeding the movement of the insulating link and to ensure mass production. Therefore, it is necessary to allow a certain amount of insulating gas to flow into the mechanical part, but the problem here is that, as mentioned above, this insulating gas is at "high temperature and high pressure," and therefore, if you try to increase its ability to interrupt short-circuit current, it could, in some cases, damage the housing itself.

[0009] This disclosure has been made to solve the above-mentioned problems, and further aims to provide an air circuit breaker with improved breaking capacity while suppressing the rise in potential of metal parts due to the incorporation of a slide plate. [Means for solving the problem]

[0010] The air circuit breaker according to this disclosure comprises a housing made of an insulating cover and a base portion, a mechanism portion fixed to the base portion and covered with the cover, a load-side conductor fixed to the base portion, and a movable contact which is electrically connected to the load-side conductor via a flexible conductor. Multiple a movable element and a rotation shaft supported by the base portion, Multiple a movable contact holder that holds a movable contact by a movable contact pin; and a power supply side conductor that has a fixed contact that repeatedly comes into contact with and separates from the movable contact and is fixed to the base portion, the mover holder has a width direction parallel to the rotation axis that is larger than the plurality of movers; At least one surface of the base portion facing the mover holder has a shape corresponding to the rotation locus of the mover holder. The shape has a size in the width direction that is larger than that of the plurality of movers. It is something that has been made into a reality. [Effects of the Invention]

[0011] As described above, this disclosure can provide an air circuit breaker that can interrupt a larger short-circuit current. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a side view of the air circuit breaker in a closed state according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a front view of FIG. 1 with the cover and mechanism removed. [Figure 3] 2 is a partially enlarged view of FIG. 1 showing a series of operations from contact closing to contact opening. [Figure 4] FIG. 4 is a perspective view showing the main components in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Embodiment 1 Fig. 1 is a side view of the air circuit breaker in the closed state according to the first embodiment of the present disclosure, with a portion cut away to show the interior. Fig. 2 is a front view of Fig. 1 with the cover and mechanism removed, corresponding to view A in Fig. 1. Fig. 3 is an enlarged view of the cutaway portion of Fig. 1, and more specifically shows the operation from the closed state to the open state, i.e., (a) the closed state, (b) the start of the open operation, (c) the occurrence of an arc, and (d) the open state. Fig. 4 is a perspective view focusing on the mover holder in Fig. 3(a).

[0014] In FIG. 1, the outer shell of the air circuit breaker 101, i.e., the housing 51, is made up of a cover 1 and a base 2, and the base 2 is further divided into a base 2A to which a power supply side conductor 3 and a load side conductor 6 are fixed, and a base 2B to which a unitized mechanism section 52 is fixed with a pair of opposing frame plates 7 as its foundation, and these bases 2A and 2B are fixed together, for example, by screws (not shown).

[0015] The load side conductor 6 is electrically connected to the mover 4 via the flexible conductor 5, and the movable contact 4a and the fixed contact 3a fixed to this mover 4 and the above-mentioned power supply side conductor 3, respectively, repeatedly make contact and separate, thereby opening and closing the electric circuit in which the air circuit breaker 101 is installed, that is, turning on and off the current that flows in the following order: outer conductor (not shown) connected to the power supply side conductor 3 → power supply side conductor 3 → fixed contact 3a → movable contact 4a → mover 4 → flexible conductor 5 → load side conductor 6 → outer conductor (not shown) connected to this load side conductor 6, as is well known.

[0016] The operation leading to the opening and closing of the electric circuit described above is also well known. That is, in the open-contact state (see FIG. 3(d) described later), pressure is accumulated in closing spring 8 by manually operating a handle (not shown). By pressing an ON operation button (also not shown), the accumulated force of closing spring 8 is transmitted to moving element 4. Specifically, this accumulated force rotates main shaft 10, to which arm 9 is fixed, counterclockwise. This causes lever 12, which is rotatably supported on arm 9 by arm pin 11, to be connected to lever 12 by lever pin 13. Moving element holder 14, which rotates around pivot 14a journaled in a recess (not shown) in base 2B, and moving element 4, which is held by moving element holder 14 by moving element pin 15, to rotate clockwise. As a result, as shown in FIG. 1, moving contact 4a contacts fixed contact 3a with an appropriate contact pressure exerted by a contact pressure spring (not shown), maintaining the closed-contact state, i.e., the electrical continuity of the electric circuit.

[0017] To interrupt the conduction of the electric circuit, that is, to transition from this closed state to an open state, the off operation button (not shown) is pressed, causing the main shaft 10 to rotate clockwise, and then, in the reverse order of the above-mentioned "open contact → closed contact," the lever 12, the moving piece holder 14, and the moving piece 4 each rotate counterclockwise, causing the moving contact 4a to separate from the fixed contact 3a. Note that, during this separation, an arc (see FIG. 3(c) below, reference numeral 17) is generated between the moving contact 4a and the fixed contact 3a, and this arc is guided by an arc runner 18 fixed to the power supply side conductor 3 and is cut off and extinguished in the arc extinguishing chamber 19, as is well known.

[0018] The movement of the main shaft 10 in response to the operation of the mechanism 52, which is the key to the series of opening and closing operations, is not essential to this disclosure and will not be described in further detail. However, as is clear from the above description, the arm 9 fixed to the main shaft 10 is located on the base 2B side, while the mover holder 14 is located on the base 2A side. Therefore, the lever 12, which transmits the rotation of the arm 9 to the mover holder 14, is disposed across the bases 2A and 2B. In addition, during the clockwise and counterclockwise rotations described above, the lever 12 moves significantly in the vertical direction on the paper (see FIG. 3, which will be described later). In addition, to ensure a certain degree of rigidity, the width corresponding to the horizontal direction on the paper also increases, as shown in FIG. 2. Therefore, an opening corresponding to the rotation of the lever 12 must be provided in both the bases 2A and 2B.

[0019] 2, the arms 9 are fixed to the main shaft 10 at equal intervals, the number of which corresponds to the number of poles (four poles in this embodiment 1), and needless to say, the lever 12 and the movable piece holder 14, not shown in this Fig. 2, are also provided for four poles. In other words, since the openings described above also cover the number of poles, as described in paragraph 0006, in order to prevent the inflow of the shutoff gas into the mechanism part 52 during shutoff, slide plates 16 are also attached to these openings for the number of poles, as in Patent Document 1.

[0020] For example, the slide plate 16 is preferably made by attaching a fluororesin fabric sheet with a cut for allowing the lever 12 to pass between two opposing general-purpose engineering plastic sheets each having a small opening through which the lever 12 passes, as this provides both strength sufficient to withstand opening and closing operations and the ability to prevent the inflow of shutoff gas.

[0021] Next, the essence of this disclosure, i.e., the differences from Patent Document 1, will be explained with reference to Figure 3. The sliding plate 16 is loosely fitted into grooves 2B3 provided on the top and bottom of the base 2B in the plane of the paper, so that the small opening provided in this sliding plate 16 and the lever 12 are perpendicular to each other (see also Figure 4), which is the same as in Patent Document 1. Therefore, the sliding plate 16 moves upward and downward in the plane of the paper like a shutter in accordance with the series of operations from (a) to (d), i.e., the counterclockwise rotation of the lever 12, the mover holder 14, and the mover 4 in response to the clockwise rotation of the main shaft 10 (arm 9). However, the difference from Patent Document 1 is that the thickness of the sliding plate 16 and the dimensions of the groove 2B3 are determined so that the gap 20c generated by the loose fit is as narrow as possible.

[0022] As shown in (c), when the contacts are opened, an arc 17 is generated between the contacts 3a and 4a. As mentioned in paragraph 0008, when a large current such as a short-circuit current is interrupted, the arc generates a breaking gas with high temperature and pressure. If an attempt is made to increase the breaking capacity, which is one of the performance improvements required of this air circuit breaker 101, it is unavoidable to consider how to prevent damage to the housing 51, and in particular the cover 1, from this breaking gas.

[0023] As shown in (c), there are three possible routes for the circuit breaker gas to flow leftward on the page, i.e., into the mechanical part 52 (not shown): "Q1 → Q4" near the occurrence of the arc 17, and "Q2 → Q3" and "Q2 → Q4" which are routes that detour from below on the page due to the weight of the arc 17, since the air circuit breaker 101 is installed facing roughly upward on the page.

[0024] Therefore, the flow paths for Q1 and Q2 are narrowed. That is, flow path suppressing portions 2B1 and 2B2 are provided on base 2B according to the rotation locus of end portion 14b and protrusion portion 14c of moving piece holder 14, and the gaps between end portion 14b and flow path suppressing portion 2B1 and between protrusion portion 14c and flow path suppressing portion 2B2, i.e., gaps 20a and 20b, are made as narrow as possible.

[0025] More specifically, in accordance with the rotation of the movable piece holder 14, the end portion 14b and the flow path suppression portion 2B1 are formed in a concentric arc shape centered on the rotation axis 14a, and the flow path suppression portion 2B2 is formed in a triangular shape so that the gap 20b between the protrusion 14c and the flow path suppression portion 2B2 is always kept narrow, and as shown in (d), the gap 20b in the open contact state is extended toward the mechanism portion 52 side.

[0026] As described in paragraph 0002 and as is clear from Figure 4, since there are multiple movers 4, gaps 20a and 20b are large in the width direction, i.e., range B, and so as described above, by making gaps 20a and 20b as narrow as possible, it is possible to ensure a large amount of so-called flow path loss and reduce the blocking gas that flows into mechanism unit 52. Note that it is preferable to provide flow path suppression units 2B1 and 2B2 to base 2B by integral molding, as this reduces the number of parts.

[0027] Additionally, as explained above, for Q3 and Q4, gaps 20c and 20d are made as narrow as possible so as not to impede the movement of slide plate 16 and the rotation of lever 12. In particular, for gap 20d, the structure of slide plate 16 is devised so that a fluororesin fabric sheet with cuts is brought into contact with lever 12, thereby realizing a reduction in the inflow of shutoff gas without impeding the rotation of lever 12, as described above.

[0028] Thus, according to this disclosure, a high pressure loss is ensured in the flow path into which the inflow of the interrupter gas into the mechanism section 52 is expected, thereby reducing the amount of inflow of this interrupter gas and preventing damage to the cover 1. Of course, when upgrading the breaking capacity of the air circuit breaker 101, there are many different issues to be resolved, such as the contact opening speed of the moving piece 4 and the arc extinguishing performance of the arc extinguishing chamber 19, and this disclosure has also made a significant contribution.

[0029] In this disclosure, as stated in paragraph 0016, the closing (open contact → close contact) is dependent on the stored force of the closing spring 8 (so-called spring charge method), but the present invention is not limited to this method. For example, the same effect can be obtained by using a so-called electromagnetic solenoid method in which the plunger is moved by passing current through the coil of an electromagnet, thereby rotating the movable element 4. [Explanation of symbols]

[0030] 1 cover, 2 base, 3 power supply conductor, 3a fixed contact, 4 moving element, 4a moving contact, 5 flexible conductor, 6 load side conductor, 12 lever, 14: mover holder; 14a: rotation shaft; 14b: end portion; 14c: protrusion; 15. Movable pin, 16. Slide plate, 51 Housing, 52 Mechanism, 101 Air circuit breaker.

Claims

1. a housing including a cover and a base portion formed of an insulating material; a mechanism portion fixed to the base portion and covered with the cover; a load side conductor fixed to the base portion; a plurality of movers each having a movable contact and electrically connected to the load-side conductor via a flexible conductor; a mover holder having a rotation shaft pivotally supported on the base portion and holding the plurality of movers by mover pins; a power supply side conductor fixed to the base portion and having a fixed contact that repeatedly makes contact and separates with the movable contact, the mover holder has a width direction parallel to the rotation axis that is larger than the plurality of movers; the base portion has at least one surface facing the mover holder that has a shape corresponding to a rotation locus of the mover holder; The circuit breaker is characterized in that the shape has a size in the width direction that is larger than that of the plurality of movable elements.

2. 2. The circuit breaker according to claim 1, wherein the shape is provided on a surface of the mover holder that faces an end portion farther from the rotation shaft.

3. 3. The circuit breaker according to claim 2, wherein the shape and the end are arc-shaped with the rotation axis as the center in the direction of rotation of the mover holder.

4. 4. The circuit breaker according to claim 1, wherein the shape is provided so as to face a protrusion provided in the vicinity of the rotation shaft.

5. 5. The circuit breaker according to claim 1, wherein the shape is integrally formed with the base portion.

6. a lever connecting the mechanism and the mover holder; a slide plate that is loosely fitted to the base portion and has a small opening through which the lever passes; The circuit breaker according to any one of claims 1 to 5, characterized in that it comprises:

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