JP2007048610A - Circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit breaker equipped with an arc-extinguishing device which raises an arc voltage without coating an arc-extinguishing plate with an insulator. <P>SOLUTION: In the circuit breaker housing in a main body case 4: a fixed contact board 12 equipped with a fixed contact 2; a movable contact board 11 equipped with a movable contact 1; and an arc-extinguishing device 100 for extinguishing arc A generated between the contacts as the movable contact is driven in a direction separated from the fixed contact, the arc-extinguishing device 100 is provided with: a plurality of arc-extinguishing plates 6 made of a magnetic material equipped with notched parts at an arc entrance side; a platy insulating member 200; as well as side plates retaining the plurality of arc-extinguishing plates made of a magnetic material and the platy insulating member at a given interval, and the platy insulating member 200 is arranged in a position nearer toward the fixed contact side than the arc-extinguishing plates made of a magnetic material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a circuit breaker, and more particularly to a circuit breaker provided with an arc extinguishing device.

  A circuit breaker that cuts off an overcurrent caused by an accident or the like is used by being inserted into a power receiving end of a power distribution system or a circuit branching to each electric device (for example, see Patent Document 1). Further, these circuit breakers are provided with an arc extinguishing device for improving the breaking performance (see, for example, Patent Document 2).

  FIG. 5 is a diagram for explaining such a conventional circuit breaker. FIG. 5 is a partial cross-sectional view of the circuit breaker in the open circuit state as viewed from the side. In FIG. 5, 1 is a movable contact, 2 is a fixed contact, 3 is a body cover, and 4 is a body case. The movable contact 1 is attached to the movable contact base 11, and the fixed contact 2 is attached to the fixed contact base 12. An arc runner 16 is disposed at the other end of the fixed contact 2.

  5 is an exhaust port lid, 15 is an exhaust port, 6 is an arc extinguishing plate, 7 is a partition, and 8 is a blocking part. The arc extinguishing plate 6 is supported by the arc extinguishing plate side plate 13 and constitutes an arc extinguishing device 100. The partition 7 is provided to divide the space in which the arc A is generated from the space in which the rotational driving force transmission shaft 14 is stored.

  Accordingly, the portion surrounded by the main body cover 3, the main body case 4, the exhaust port lid 5, and the partition 7 becomes the blocking portion 8, and this space becomes the space where the arc A is generated.

  Next, the operation of this circuit breaker will be described. When the circuit breaker is in a closed state, the movable contact 1 is in contact with the fixed contact 2 while a predetermined force is applied to the movable contact 1 by the action of an opening / closing mechanism (not shown). For this reason, in a normal state, a current flows through the fixed contact base 12, the fixed contact 2, the movable contact 1, and the movable contact base 11 as a path.

  When an excessive current that needs to be interrupted flows, the movable contact base 11 rotates due to the electromagnetic repulsion caused by the current flowing through the fixed contact base 12 and the movable contact base 11, and the movable contact 1 opens and is fixed. An arc A is generated between the contacts 2. Moreover, the arc A is extended by the opening operation of the movable contact base 11, and the arc length is increased.

  At this time, the arc extinguishing plate 6 draws the arc A between the arc extinguishing plates 6 from the arc entrance side of the arc extinguishing plate 6 by the magnetic driving force, and cools the arc A. Thereby, the arc voltage is increased and arc extinguishing is performed. In order to increase the magnetic driving force acting on the arc A, the arc extinguishing plate 6 is generally made by processing a magnetic plate such as iron. Further, as shown in FIGS. 5 and 6, a cut portion 6 </ b> A is provided on the arc entrance side of the arc extinguishing plate 6. Furthermore, by arranging a plurality of such arc extinguishing plates 6 at intervals, the arc can be divided in the length direction. Thereby, the voltage drop with respect to an arc and the increase in a cooling effect | action are brought about, and an arc voltage can be raised.

  6 is a diagram for explaining the details of the arc extinguishing plate 6 of the arc extinguishing apparatus 100 shown in FIG. As shown in FIG. 6, the arc extinguishing plate 6 is covered with an insulator 20.

  As described above, when the arc A is drawn by the arc extinguishing plate 6, the insulator 20 is ablated by the heat of the drawn arc A, and pyrolysis gas is generated. While cooling the arc A with this gas, the pressure in the interruption | blocking part 8 can be raised and an arc voltage can be raised.

As described above, according to the circuit breaker of the prior art, the arc length is increased by the opening operation, the arc is divided and cooled by the arc extinguishing plate 6, and further, the heat from the insulator 20 constituting the arc extinguishing plate 6 is obtained. The current is limited by the cooling action by the cracked gas and the increase of the arc voltage due to the pressure increase in the interrupting section 8, and the circuit can be finally shut off.
JP 2001-176372 A JP 63-126135 A

  In the prior art, the effect on the current limiting by the pyrolysis gas generated from the insulator covering the arc extinguishing plate is from the time when the movable contact base reaches a position where the arc extinguishing plate is located. For this reason, it is difficult to concentrate the current limiting effect immediately after the start of the flow of the fault current that requires current limiting, that is, when the open distance of the movable contact base is short.

  Furthermore, in recent years, demands for increasing the breaking capacity of circuit breakers and the number of times that current can be interrupted have increased. Moreover, the pressure in the breaker has increased with the downsizing of the breaker. Although this pressure increase causes an increase in arc voltage, it is advantageous from the viewpoint of extinguishing the arc. However, on the other hand, a high-strength material must be used to prevent the casing from being damaged, and the cost increases.

  For example, in order to suppress the pressure rise, it is necessary to adjust the amount of pyrolysis gas from the insulator, but in the conventional technology, the arc extinguishing plate and the insulator are integrated, so the amount of the insulator is adjusted. Difficult to do. When the insulating coating is thinned to suppress the pressure rise, the damage of the insulating material per current interruption becomes large, and the demands for increasing the breaking capacity and the number of current interruptions cannot be satisfied.

  The present invention has been made in view of these problems, and it is an object of the present invention to provide a circuit breaker including an arc extinguishing device capable of increasing an arc voltage without covering an arc extinguishing plate with an insulator.

  In order to solve the above problems, the present invention employs the following means.

  A main body case having a fixed contact base having a fixed contact, a movable contact base having a movable contact, and an arc extinguishing device that extinguishes an arc generated between the contacts when the movable contact is driven in a direction away from the fixed contact. In the circuit breaker housed in the arc breaker, the arc extinguishing device includes a plurality of magnetic arc extinguishing plates each having a notch on the arc inlet side, a plate-like insulating member, and the plurality of magnetic substance A side plate for holding the arc extinguishing plate and the plate-like insulating member at a predetermined interval is provided, and the plate-like insulating member is arranged on the fixed contact side with respect to the magnetic arc-extinguishing plate.

  Since this invention is provided with the above structure, the circuit breaker provided with the arc-extinguishing apparatus which can raise an arc voltage, without coat | covering an arc-extinguishing board with an insulator can be provided.

  Hereinafter, the best embodiment will be described with reference to the accompanying drawings. FIG. 1 is a diagram illustrating a circuit breaker according to an embodiment of the present invention. In the figure, the same parts as those shown in FIG.

  As described above, when an excessive current that needs to be interrupted flows through the circuit breaker, the movable contact base 11 rotates by the electromagnetic repulsive force due to the current flowing through the fixed contact base 12 and the movable contact base 11, The movable contact 1 is pulled away from the fixed contact 2. For this reason, an arc A is generated between the fixed contact 2 and the movable contact. The arc A is stretched by the opening operation of the movable contact base 11, and the arc length gradually increases.

  As described above, the arc extinguishing plate 6 is made of a magnetic material, and the arc extinguishing plate 6 is provided with a cut portion 6A in order to increase the magnetic driving force acting on the arc A. By arranging a plurality of arc extinguishing plates 6 formed in this manner at intervals, the arc can be divided in the length direction. Thereby, the voltage drop with respect to an arc and the increase in a cooling effect | action are brought about, and an arc voltage can be raised.

  By the way, in this embodiment, the arc-extinguishing plate side plate 13 of the arc-extinguishing device 100 is provided with a plate-like insulating member 200 separately from the arc-extinguishing plate 6. In this respect, the circuit breaker of this embodiment is greatly different from the conventional circuit breaker. The plate-like insulating member 200 is preferably arranged closer to the fixed contact 2 than the magnetic arc extinguishing plate 6 is. With this arrangement, the insulating member 200 is ablated by the heat of the arc A generated between the fixed contact 2 and the movable contact, and pyrolysis gas is generated. While cooling the arc A with this gas, the pressure in the interruption | blocking part 8 can be raised and an arc voltage can be raised.

  By forming the insulating member 200 separately from the arc-extinguishing plate 6, the position where the insulating member 200 is arranged can be set regardless of the number and arrangement of the arc-extinguishing plates 6. For this reason, by disposing the magnetic arc-extinguishing plate 6 on the fixed contact 2 side, the insulating member 200 is generated by the arc A generated when the open distance of the movable contact base immediately after the start of the flow of the accident current is short. Can be heated. Further, the pyrolysis gas generated by the heating can provide a high current limiting effect even when the open circuit distance between the contacts is short.

  The insulating member 200 needs to have heat resistance sufficient to generate pyrolysis gas by the arc A and maintain its shape against a plurality of accident currents. As the insulating member 200, a thermoplastic resin such as a polyamide resin or some kind of insulating paper can be used. When a thermoplastic resin such as a polyamide resin is used, it is easier to ablate than insulating paper, and a pyrolysis gas can be generated with a relatively small interruption current. When insulating paper is used, the heat resistance is higher than that of a thermoplastic resin, and there is an advantage that the shape is less deformed particularly when current is interrupted a plurality of times. As an example of the insulating paper, there is a cellulose-based insulating paper, so-called vulcanized fiber. The vulcanized fiber is made of natural fiber and has good insulation, heat resistance and processability, and is also used for the arc extinguishing plate side plate 13 in some circuit breakers.

  Next, the shape of the insulating member 200 will be described in more detail with reference to FIGS. Here, FIG. 2 is a front view showing an example of the arc extinguishing device 100 of the present invention, FIG. 3 is a plan view showing an example of the insulating member 200, and FIG. 3 (a) shows the notch 200A in the insulating member. The provided example, FIG.3 (b), shows the example which comprised the insulating member with two insulating members.

  In the case of the example shown in FIG. 3A, the insulating member 200 includes a cut portion 200 </ b> A similar to the cut portion 6 </ b> A of the arc extinguishing plate 6. Thus, by providing the incision 200A in the insulating member 200, the drawing of the arc A by the arc extinguishing plate 6 is not hindered. In order to increase the arc voltage, it is necessary to cool the arc extinguishing plate 6 by directly touching the arc A, and at the same time, it is necessary to reduce the mixing of the metal vapor into the arc A.

  For example, by changing the size of the cut portion 200A of the insulating member 200, the area where the arc A and the cut portion 6A of the arc extinguishing plate 6 directly touch can be changed. In this case, mixing of the metal vapor generated from the arc extinguishing plate 6 into the arc A can be suppressed while taking advantage of the cooling effect of the arc extinguishing plate 6. Further, as shown in FIG. 3B, the insulating member 200 may be configured by dividing the insulating member 200 into two insulating members 200a and 200b in order to take advantage of the cooling effect of the arc extinguishing plate 6. good.

  In addition, as shown in FIG. 2, when the insulating member 200 is composed of a plurality of insulating papers, a sheet-like insulating paper can be used. For this reason, since the thickness of one sheet of insulating paper can be reduced, workability is improved. In addition, since the amount of pyrolysis gas generated can be adjusted by changing the thickness and number of sheets of insulating paper, it is easy to manufacture an arc extinguishing device that matches the breaking capacity of the circuit breaker.

  FIG. 4 is a diagram for explaining the effect of the present invention. The figure shows the magnitude of the arc voltage at the time of short-circuit interruption in the case where a fiber material which is insulating paper is used as the insulating member 200 of the arc extinguishing device and in the case where the insulating member 200 is not used, with the horizontal axis as time. It is shown. As shown in the figure, the arc voltage in the structure using the insulating member is higher than the arc voltage in the structure not using the insulating member 200, and according to this embodiment, the interruption performance can be improved. I understand.

  As described above, according to the present embodiment, an arc extinguishing device structure in which an arc extinguishing plate and an insulating member are provided separately from a conventional arc extinguishing device composed of an arc extinguishing plate coated with an insulating material. Thereby, pyrolysis gas can be concentrated and generated at the timing when the opening distance of the movable contact base is short. For this reason, since the current limiting performance with respect to the magnitude of the pressure increase is improved, a circuit breaker having a high breaking capacity can be provided at a low cost.

It is a figure explaining the circuit breaker which concerns on embodiment of this invention. 1 is a front view showing an example of an arc extinguishing device 100. FIG. 4 is a plan view showing an example of an insulating member 200. FIG. It is a figure explaining the effect by this invention. It is a figure explaining the conventional circuit breaker. It is a figure explaining the detail of the arc-extinguishing board 6 of the arc-extinguishing apparatus 100 shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Movable contact 2 Fixed contact 3 Main body cover 4 Main body case 5 Exhaust port cover 6 Arc-extinguishing plate 6A Notch part 7 Partition 8 Blocking part 11 Movable contact stand 12 Fixed contact point base 13 Arc-extinguishing plate side plate 14 Exhaust port 16 Exhaust port 16 20 Insulator 100 Arc-extinguishing device 200, 200a, 200b Insulating member 200A Insulating member notch
A arc

Claims (5)

A main body case having a fixed contact base having a fixed contact, a movable contact base having a movable contact, and an arc extinguishing device that extinguishes an arc generated between the contacts when the movable contact is driven in a direction away from the fixed contact. In the circuit breaker stored in
The arc extinguishing device includes a plurality of magnetic arc extinguishing plates, a plate-like insulating member, and a plurality of magnetic arc-extinguishing plates and the plate-like insulation, each having a notch on the arc entrance side. A side plate for holding the sex member at a predetermined interval;
The circuit breaker, wherein the plate-like insulating member is disposed on a fixed contact side with respect to the magnetic arc extinguishing plate. The circuit breaker according to claim 1,
The circuit breaker according to claim 1, wherein the plate-like insulating member is a plate-like insulating member having a cut portion on an arc entrance side. The circuit breaker according to claim 1,
The circuit breaker according to claim 1, wherein the plate-like insulating members are two insulating members respectively attached to both side plates so as to form an arc passage between the side plates. The circuit breaker according to claim 1,
The circuit breaker, wherein the plate-like insulating member is an organic material. The circuit breaker according to claim 1,
The circuit breaker, wherein the plate-like insulating member is a cellulose-based insulating paper.

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