JPH0527935U - Arc extinguishing device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an arc extinguishing device with excellent current limiting characteristics. [Structure] A magnetic member 25 wider than the arc traveling plate 8 along the inclined portion 8c of the arc traveling plate 8 is provided.
It is provided so as to close the gap between the recirculation side plate 14. [Effect] By closing the gap, the turbulence of the hot gas flow is prevented, and the magnetic member enhances the magnetic field involved in the driving of the arc to promote the arc running, thereby improving the current limiting characteristics.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to improvement of an arc extinguishing device such as a circuit breaker.

[0002]

[Prior Art]

 FIG. 4 is a side sectional view showing a circuit breaker including a conventional arc-extinguishing device disclosed in, for example, Japanese Patent Application Laid-Open No. 55-46487. In the figure, the mover 3 having the movable contact 2 is configured to rotate in the direction indicated by the arrow A by the operation of the operation lever 20 and come into contact with the fixed contact 4 provided on the stator 5. The lower case 21 of the circuit breaker is provided with an arc traveling plate 8 whose one end is bent at about 45 °. The left end portion 8b of the arc traveling plate 8 in the figure is arranged so as to be close to the tip end portion 3a of the mover 3, while the straight portion 8a is composed of a plurality of metal plates arranged at predetermined intervals. The arc-extinguishing grid 10 is located near the bottom of the grid. The central portion of the stator 5 is formed in a U shape, and one end thereof is connected to the terminal 23 via the trip coil 19. Further, the straight line portion 5c is arranged close to the upper portion of the arc extinguishing grid 10. An exhaust plate 11 having a plurality of exhaust holes 11a is provided at the right end of the grid 10. FIG. 5 is a partial plan view of the vicinity of the arc traveling plate 8 shown in FIG. In the figure, a pair of return side plates 14 are provided on both side surfaces of the arc traveling plate 8. The return side plate 14 is arranged so that a minute predetermined gap is formed between the return side plate 14 and the arc traveling plate 8.

Next, the operation of this conventional example will be described. When the movable contact 2 is separated from the fixed contact 4 by the breaking operation, an arc is generated between both contacts. This arc moves between the tip portion 3a of the mover 3 and the bent portion 5a of the stator 5, and then moves to the position of the arc 22 shown via the arc traveling plate 8 and the straight portion 5b of the stator 5. The arc 22 further shifts to the right between the straight line portion 8a of the arc traveling plate 8 and the straight line portion 5c of the stator 5, enters the inside of the arc extinguishing grid 10, and is divided by the many arc extinguishing grids 10 to extinguish the arc. To be done. Gas is generated by the high-temperature arc until the arc generated between the movable contact 2 and the fixed contact 4 enters the arc extinguishing grid 10 and is extinguished, and the gas progresses in the right direction of the arc. It moves and is discharged from the exhaust port 11a of the exhaust plate 11.

In the plan view shown in FIG. 5, when the arc X moves in the direction indicated by the arrow B on the arc traveling plate 8, the gas pressure at the position P 2 in the traveling direction of the arc X is generally at the position P 1 behind the arc X. The pressure becomes higher than the gas pressure, and the arc X cannot be immediately transferred to the arc extinguishing grid, and the current limiting effect decreases. In order to solve this problem, in the prior art, the gas existing at the position P2 is caused to flow back to the position P1 behind the arc X by causing the gas existing at the position P2 to flow back to the position P2. As a result, the gas pressure at the position P2 decreases and the gas pressure at the position P1 increases, and the arc X easily moves toward the arc extinguishing grid 10.

FIG. 6 shows an actual measurement example of the interruption characteristic in this conventional example. The horizontal axis represents time, and the vertical axis represents arc voltage and arc current. In the figure, when the contacts open at time t ₁ , the arc current increases and the arc voltage gradually increases. Next, when the arc contacts the arc extinguishing grid at time t ₂ , the arc enters the arc extinguishing grid and is divided, so that the arc current sharply decreases.

[0006]

[Problems to be solved by the device]

 In the conventional arc-extinguishing device as described above, when the current to be interrupted becomes large, hot gas is discharged to the lower part of the arc traveling plate 8 from a minute gap between the 45 ° inclined portion 8c of the arc traveling plate 8 and the annular side plate 14. Leak. As a result, the hot gas is disturbed by the air flow and is less likely to turn rightward in FIG. 4, and the grid 10 is not filled, so that dielectric breakdown between grid plates is less likely to occur. Therefore, the arc is less likely to enter the grid 10, and the arc is delayed to be divided. As described above, the conventional arc-extinguishing device has a problem that the arc is not immediately divided when the current to be interrupted increases, and thus the current limiting characteristic cannot be improved.

The present invention has been made to solve the above problems, and an object thereof is to provide an arc extinguishing device having excellent current limiting characteristics.

[0008]

[Means for Solving the Problems]

 An arc-extinguishing device according to the present invention has a fixed contact, one end of which is disposed in the vicinity of an arc-extinguishing grid, a mover having a movable contact that comes in contact with and separates from the fixed contact, and one end of which is the mover And an arc traveling plate having the other end disposed in proximity to the arc extinguishing grid, and a magnetic member provided along the arc traveling plate. Also, a stator having fixed contacts, one end of which is arranged in proximity to the arc-extinguishing grid, a mover having movable contacts that come in contact with and separated from the fixed contacts, and one end of which is arranged close to the mover. , An arc traveling plate whose other end is arranged in the vicinity of the arc extinguishing grid, a pair of arc-displacement plates sandwiching the stator and the arc traveling plate from the side and maintaining a gap with the arc traveling plate. It may be provided with a reflux side plate and a closing member which is provided along the arc traveling plate and has a width wider than that of the arc traveling plate to substantially close the gap.

[0009]

[Action]

 The magnetic member according to the present invention enhances the magnetic field by the electric current flowing through the arc traveling plate and increases the driving force applied to the arc to accelerate the traveling of the arc in a predetermined direction. The closing member (also used as a magnetic member in the following embodiments) closes a minute gap between the arc traveling plate and the reflux side plate and directs the hot gas in a predetermined direction without disturbing the flow.

[0010]

【Example】

 1 is a side sectional view of a circuit breaker including an arc extinguishing device according to an embodiment of the present invention, and FIG. 2 is a partial plan view of the vicinity of an arc traveling plate 8. The same parts as those of the conventional example (FIGS. 4 and 5) are designated by the same reference numerals, and the description thereof will be omitted. The difference from the conventional example is that the magnetic member 25 is provided so as to extend from the 45 ° inclined portion 8c of the arc traveling plate 8 to the left end portion 8b from below. The magnetic member 25 is made of, for example, iron and has a width wider than that of the arc traveling plate 8. As shown in FIG. 2, the magnetic member 25 is provided so that the clearance between the magnetic member 25 and the return side plate 14 is minimized, that is, substantially closed. There is.

Next, the operation of the above embodiment will be described. The arc generated between the movable contact 2 and the fixed contact 4 due to the short-circuit accident moves between the tip 3a of the mover 3 and the bent portion 5a of the stator 5 due to the effect of the return side plate 14 described above. . The hot gas generated at this time is blown out in the downward direction of FIG. 1, and is further blown onto the 45 ° inclined portion 8c of the arc traveling plate 8. At this time, the hot gas hitting the arc traveling plate 8 is turned rightward in FIG. In addition, hot gas that tries to enter below the arc traveling plate 8 through the gap between the arc traveling plate 8 and the reflux side plate 14 hits against the magnetic member 25 that closes the gap from the rear side and is repelled. Turns right. In this way, the hot gas is redirected with almost no scattering in the air flow and proceeds to the right in FIG. 1 to fill the space between the grid plates of the grid 10. In this way, since the dielectric breakdown in the grid 10 is promoted, the arc quickly moves between the straight line portion 5c of the stator 5 and the straight line portion 8a of the arc traveling plate 8, is attracted into the grid 10 and is divided, It is extinguished. On the other hand, when the arc travels on the arc traveling plate 8, the magnetic field due to the current flowing through the arc traveling plate 8 is strengthened by the magnetic member 25, and the driving force applied to the arc is increased by a known action. The arc on the plate 8 rapidly travels toward the grid 10.

FIG. 3 shows an example of actual measurement of the breaking characteristic in this embodiment. The horizontal axis represents time, and the vertical axis represents arc voltage and arc current. In the figure, when the contacts open at time t ₁ , the arc current increases and the arc voltage gradually increases. Next, when the arc contacts the arc extinguishing grid at time t ₂ , the arc enters the arc extinguishing grid and is divided, so that the arc current sharply decreases. It is clear from this figure that the arc current decreases more rapidly than in the measurement example under the same conditions of the circuit breaker using the conventional arc extinguishing device shown in FIG. .

In the above embodiment, the magnetic member 25 is configured to substantially close the gap between the arc traveling plate 8 and the reflux side plate 14, but the closing of the gap and the installation of the magnetic member are respectively performed. It is a different concept, and as described above, the different actions promote the traveling of the arc. Therefore, both of them are not necessarily required to have both of them, and even if the arc-extinguishing device has the respective requirements alone (for example, a magnetic member that does not necessarily close or a closing member that does not have magnetism), the intended purpose is limited. Improved flow performance can be achieved.

[0014]

[Effect of the device]

 Since the present invention is configured as described above, it has the following effects. In the arc-extinguishing device according to the first aspect of the present invention, the magnetic member is provided along the arc traveling plate so as to strengthen the magnetic field involved in driving the arc. Therefore, there is an effect that the vehicle can be driven at any time and therefore the current limiting performance can be improved. In the arc-extinguishing device according to claim 2, by providing a closing member having a width wider than that of the arc traveling plate, a minute gap between the arc traveling plate and the reflux side plate is closed to prevent turbulence of the hot gas flow. Therefore, the same effect as that of claim 1 can be obtained.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a circuit breaker having an arc extinguishing device according to an embodiment of the present invention.

FIG. 2 is a plan view of the vicinity of the arc traveling plate 8 of FIG.

FIG. 3 is a graph showing an example of actually measured breaking characteristics of the circuit breaker shown in FIG.

FIG. 4 is a side sectional view showing a circuit breaker having a conventional arc extinguishing device.

FIG. 5 is a plan view of the vicinity of the arc traveling plate 8 of FIG.

FIG. 6 is a graph showing an example of actual measurement of breaking characteristics in a conventional circuit breaker.

[Explanation of symbols]

 2 movable contact 3 movable element 4 fixed contact 5 stator 8 arc traveling plate 10 arc extinguishing grid 14 return side plate 25 magnetic member

Claims (2)

[Scope of utility model registration request] 1. A stator having fixed contacts, one end of which is disposed in the vicinity of an arc extinguishing grid, a mover having a movable contact which is brought into contact with and separated from the fixed contacts, and one end of which is brought closer to the mover. An arc extinguishing device comprising: an arc traveling plate, the other end of which is disposed in proximity to the arc extinguishing grid, and a magnetic member provided along the arc traveling plate. 2. A stator having fixed contacts, one end of which is disposed in the vicinity of an arc extinguishing grid, a mover having a movable contact which is brought into contact with and separated from the fixed contacts, and one end of which is brought closer to the mover. An arc traveling plate whose other end is disposed in the vicinity of the arc extinguishing grid, and is arranged so as to sandwich the stator and the arc traveling plate from the side and maintain a gap with the arc traveling plate. An arc extinguishing device comprising: a pair of return side plates, and a closing member which is provided along the arc traveling plate and has a width wider than the arc traveling plates to substantially close the gap.