JP2007324038A - Circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further improve current-limiting performance by securing withstand voltage performance between a moving contact and a fixed contact. <P>SOLUTION: This circuit breaker is provided with: a fixed contact 5; a moving contact 3 opening/closing with respect to the fixed contact 5; and a pair of magnetic bodies 10 having the fixed contact 5 and the moving contact 3 incorporated therein, and movably arranged in a direction relatively approaching both sides of an opening/closing space 53ps permitting the opening/closing operations of the moving contact 3. The circuit breaker is structured such that, when a breaking current at which the moving contact 3 executes a breaking operation is set above a predetermined value, both the magnetic bodies 10 move in mutually-approaching directions by electromagnetic attraction force acting between both the magnetic bodies 10 to narrow the opening/closing space 53a in a range permitting the opening/closing operations of the moving contact 3; and when the breaking current is reduced by a current-limiting operation and the electromagnetic attraction force is reduced, both the magnetic bodies 10 are restored to the original positions thereof. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a circuit breaker having a current limiting performance.

  In order to provide a function of interrupting a large current such as a short circuit current, a conventional circuit breaker includes a fixed contact and a movable contact so as to form an electric circuit that repels the movable contact. The movable contact and the fixed contact of the fixed contact are arranged on the side surface in the vicinity of the fixed contact to increase the opening electromagnetic force of the movable contact and the arc driving force in the grid direction. It has become. (For example, see Patent Document 1)

JP 2002-8508 A (FIG. 1 and its description)

  In the conventional circuit breaker, the insulating cover is installed for the purpose of protecting the magnetic material from the arc and generating decomposition gas to increase the pressure near the contact and improve the current limiting performance. In consideration of the withstand voltage performance between the movable contact and the fixed contact at the time, it is arranged at a predetermined distance from a straight line connecting the movable contact and the fixed contact, that is, an arc generated at the time of interruption. In this type of circuit breaker, it is desirable to secure a withstand voltage performance between the movable contact and the fixed contact to further improve the current limiting performance.

  The present invention has been made in view of the above circumstances, and aims to further improve the current limiting performance by securing a withstand voltage performance between the movable contact and the fixed contact. .

  The circuit breaker according to the present invention includes a stationary contact, a movable contact that opens and closes with the stationary contact, and both sides of an open / close space that incorporates the stationary contact and the movable contact and allows the movable contact to open and close. A pair of magnetic bodies arranged so as to be movable in a relatively approaching direction, and an electromagnetic attraction force acting between the two magnetic bodies when the breaking current at which the movable contactor cuts off exceeds a predetermined value. The two magnetic bodies move in a relatively approaching direction to narrow the open / close space within a range that allows the movable contactor to open and close, and the current limiting operation reduces the breaking current and reduces the electromagnetic attractive force. If it becomes, it will be a circuit breaker which both said magnetic bodies return to an original position.

  The present invention relates to a fixed contact, a movable contact that opens and closes with the fixed contact, and a direction that approaches the both sides of the open / close space that incorporates the fixed contact and the movable contact and allows the movable contact to open and close. A pair of magnetic bodies movably disposed on the movable contactor, and when the breaking current at which the movable contactor cuts off exceeds a predetermined value, the two magnetic bodies are separated by an electromagnetic attractive force acting between the two magnetic bodies. When both the magnetic bodies move in a relatively approaching direction to narrow the open / close space within a range that allows the movable contactor to open and close, and the current-blocking operation reduces the cut-off current and the electromagnetic attractive force. Is returned to the original position, so that the withstand voltage performance between the movable contact of the movable contact and the fixed contact of the fixed contact can be secured, and the current limiting performance can be further improved.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view showing an example of the overall configuration of the circuit breaker, and FIG. 2 is a perspective view showing an example of the configuration of the main part of the arc extinguishing unit of the circuit breaker. FIG. 3 is a cross-sectional plan view of an essential part cross-section taken along line AA in FIG. 1 in the direction of the arrow, and shows a state in a case where the current is relatively small. FIG. 4 is a cross-sectional plan view of the cross section of the main part taken along the line AA in FIG. 1 in the direction of the arrow, and shows a state in a region where the current is relatively large. FIG. 5 is an exploded perspective view showing an example of the component configuration inside the arc extinguishing chamber. In addition, in each figure, the same code | symbol shows the same part.

  As shown in FIG. 1, the overall configuration of the circuit breaker includes a plurality of arc extinguishing units 23 connected by a cross bar 27 extending over the arc extinguishing unit 23, and will be described later via the cross bar 27. A mechanism unit 25 that opens and closes contacts; a relay unit 26 that has a connection terminal 26a on the load side and detects an abnormal current to operate the mechanism unit 25; a handle 29 that manually operates the mechanism unit 25; The plurality of arc extinguishing units 23 are accommodated by a base 30 and a cover 28 that is detachably mounted on the base 30.

Inside each arc-extinguishing chamber unit 23 having the exhaust hole 23b, a stationary contact 5 having a connection terminal 5a is disposed.
As described in Patent Document 1, the fixed contact 5 is formed with a parallel conductor 7 for reversing the movable contact 3 by electromagnetic force when a large current is applied.
A fixed contact 6 is formed at the end of the parallel conductor 7. The movable contact 2 is disposed on the surface of the movable contact 3 that faces the fixed contact 6.
The movable contact 3 is held by a rotor 19 interlocked with the cross bar 27, and the movable contact 2 is rotated about a rotation shaft 19a of the rotor 19 so that the movable contact 2 becomes the fixed contact. 6 is configured to be close to and away from 6.
An insulator 11 is disposed on the upper surface of the stationary contact 5 to protect against arc heat, and a plurality of arc-extinguishing side plates 15 are held between the arc-extinguishing side plates 15 on the upper portion thereof. The magnetic material arc extinguishing plate 16 is arranged. The pair of arc extinguishing side plates 15 and the plurality of magnetic material arc extinguishing plates 16 constitute an arc extinguishing plate unit 156.

A pair of magnetic bodies 10 is disposed in the vicinity of the contact in the arc extinguishing unit 23. The magnetic body 10 has an electromagnetic force that repels the movable contact 3 in order to separate the movable contact 2 from the fixed contact 6 and a fixed contact 6 and an arc runner 9 when a large current is generated. The electromagnetic force that guides the arc between the contact 5 and the movable contact 3 in the direction of the magnetic arc extinguishing plate 16 is strengthened.
The magnetic body 10 is covered with an insulating cover 13 that is an insulating material that protects the magnetic body 10 from the arc. The insulating cover 13, which is an insulating material, generates decomposition gas by arc heat and increases the pressure in the vicinity of the contact point, thereby improving the current limiting performance. The insulating cover 13 is away from the contact in order to keep the insulation cover 13 at a distance that does not cause dielectric breakdown between the movable contact 2 and the fixed contact 6 when the movable contact 2 and the fixed contact 6 are opened. The spring 14 that is urged to the right is installed between the spring receiving portion 13a of the insulating cover 13 and the spring receiving portion 23a of the arc extinguishing unit 23.

In the above configuration, in the case of a relatively small current region, the force Fb of the spring 14 is superior to the electromagnetic attractive force Fa acting between the pair of magnetic bodies 10 due to the current.
Therefore, as shown in FIG. 3, the insulating cover 13 is moved away from the fixed contact 5 by the force Fb of the spring 14, and the inner width B of the insulating cover 13 is The distance between the movable contact 2 and the fixed contact 6 during the opening is maintained at a distance that does not cause dielectric breakdown.
Since the inner width of the insulating cover 13 is maintained at the inner width B, the movable contact 3 with respect to the fixed contact 5 can be compared with the case of the inner width C (described later) (C <B). The open / close space 53 ps allowing the open / close operation is in a wide state.

When the electromagnetic attraction force Fa acting on the magnetic body 10 is increased due to a large current and the electromagnetic attraction force Fa acting on the magnetic body 10 is larger than the spring force Fb, as shown in FIG. The magnetic body 10 and the insulating cover 13 are moved in a direction approaching the fixed contact 5 by Fa, and the inner width of the insulating cover 13 becomes an inner width C that is smaller than the inner width B. That is, the open / close space 53ps that allows the movable contact 3 to open / close with respect to the fixed contact 5 is narrower than the state in which the inner width of the insulating cover 13 is maintained at the inner width B (see FIG. 3). .
When the magnetic body 10 and the insulating cover 13 move in a direction approaching the fixed contact 5 and the inner width of the insulating cover 13 becomes the inner width C, the insulating cover 13 is connected to an arc generated between the contacts. Since the opening / closing space 53ps is narrower than the case of the inner width B because the distance is short, a larger amount of decomposition gas is generated when the arc is exposed to the insulating case 13, resulting in a sudden contact The current limiting performance can be greatly improved by increasing the pressure in the vicinity and restricting the arc.

When the interruption of the current is completed, the magnetic body 10 and the insulating cover 13 are returned to the position of the distance B by the spring force Fb.
Further, even when a large current flows, if the sum of the spring force Fb and the pressing force Fc due to the contact pressure is larger than the electromagnetic force Fa, that is, if Fa <Fb + Fc, the magnetic body 10 and The insulating cover 13 moves from the distance C in the distance B direction. In this case, since the effect of suppressing excessive pressure generation due to generation of cracked gas can be expected, the material strength of the arc extinguishing chamber unit 23 can be kept low, and inexpensive materials can be used.

  In other words, the circuit breaker of the first embodiment described above includes a fixed contact, a movable contact that opens and closes with the fixed contact, and the fixed contact and the movable contact are built in to allow the opening and closing operation of the movable contact. A pair of magnetic bodies arranged so as to be able to move relatively closer to both sides of the open / closed space, and acting between the two magnetic bodies when the breaking current at which the movable contactor cuts off exceeds a predetermined value The electromagnetic attracting force moves the two magnetic bodies in a relatively approaching direction to narrow the open / close space within a range allowing the movable contactor to open and close, and the current limiting operation reduces the breaking current. When the electromagnetic attractive force is reduced, the magnetic breaker returns to the original position.

  Further, it can be said that the insulating material 13 that generates decomposition gas by arc heat is interposed between the magnetic bodies 10 and the open / close space 53ps.

  Further, it can be said that the fixed contact 5, the movable contact 3, and the open / close space 53 ps are built in the extinguishing unit 23, and the magnetic body 10 is disposed on both side walls of the extinguishing unit 23. .

  Further, it can be said that the magnetic body 10 is incorporated in the magnetic body incorporation holes 23sr on both side walls of the extinguishing unit 23 so as not to protrude from both side wall surfaces 23ss.

  Further, the fault current is not less than the predetermined value, and the overload current is less than the predetermined value. That is, the magnetic body 10 and the insulating material 13 are moved when an accident current flows between the contacts 3 and 5, the current limiting is effectively performed, and an overload current flows. In such a case, the movement is not performed and a sufficient withstand voltage is maintained.

  As described above, Embodiment 1 of the present invention can realize a circuit breaker having excellent current limiting performance by rapidly increasing the pressure in the vicinity of the contact when a large current is interrupted.

  In addition, as described above, the first embodiment of the present invention can move the insulating cover closer to the arc only when the circuit breaker interrupts a relatively large current, and can greatly improve the current limiting performance. It is what.

  In Embodiment 1 of the present invention, as described above, the insulating cover that covers the magnetic body is attached to the arc extinguishing unit so that the magnetic body and the insulating cover can be moved together, and when a large current is cut off, Using the electromagnetic attractive force generated in the magnetic body, the insulating cover can be brought close to the arc, the pressure in the vicinity of the contact can be rapidly increased to obtain a good current limiting performance, and in the region where the current is small, the spring force In this configuration, the distance between the insulating cover and the arc can be secured as much as necessary.

  In addition, since the insulating cover 13 covering the magnetic body of the circuit breaker can approach the arc when a large current is interrupted, the current limiting performance can be greatly improved. In other cases, the distance between the insulating cover 13 and the arc Therefore, the withstand voltage performance can be sufficiently satisfied.

Embodiment 2. FIG.
FIG. 6 shows that the current near the arc and the vicinity of the arc indicate that a large current starts flowing at time T0 and that the pressure near the arc starts to increase due to the decomposition gas generated from the insulating case 13 by the arc at time T1. It is an example of the waveform of a pressure. If the time at which the magnetic body 10 and the insulating case 13 start operating exceeds the time T1, the operation of the magnetic body 10 and the insulating case 13 is delayed due to a sudden increase in the pressing force Fc due to the pressure near the contact. Or may not move. Therefore, if the spring force Fb and the electromagnetic attractive force Fa are designed so that the magnetic body 10 and the insulating case 13 move to the inner width C between time T0 and time T1, that is, from TO to T1. If Fb <Fa in the meantime, the above operation can be performed reliably.

Embodiment 3 FIG.
FIG. 7 shows trip characteristics of the circuit breaker, in which the horizontal axis represents current and the vertical axis represents tripping operation time. The spring 14 for urging the magnetic body 10 and the insulating cover 13 away from the contact point needs to be appropriately strong so as not to lose its function due to the biting of the melt at the time of interruption. is there. Further, the current limiting performance is affected by the pressure in the vicinity of the arc at least in an area exceeding the circuit breaker instantaneous trip shown in FIG. Therefore, if the spring force Fb and the electromagnetic attraction force Fa are designed so that the magnetic body 10 and the insulating cover 13 do not operate below the instantaneous tripping region, that is, the current increases up to the region exceeding the instantaneous tripping. If Fb <Fa, a spring having a relatively strong spring force to resist a large current can be obtained, so that a configuration with high operational reliability can be obtained.

Embodiment 4 FIG.
In the above-described embodiment, the configuration in which the plurality of springs 14 have different spring forces is not described. For example, the spring force on the connection terminal 5a side is made stronger than the spring force on the mover rotating shaft 19a side. For example, since the insulating case 13 on the inner width D side operates with a smaller current than the inner width E side, the inner width D <the inner width E, and the exhaust efficiency toward the exhaust hole 23b side is unlikely to be impaired. The arc-extinguishing unit strength can be kept low. On the contrary, if the spring force on the side of the mover rotating shaft 19a is made stronger than the spring force on the side of the connection terminal 5a, the insulation case 13 on the inner width E side has a smaller current than the inner width D side. Operate. As a result, the inner width D> the inner width E, and the contact vicinity pressure can be maintained in a high state, so that a high current limiting performance can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Embodiment 1 of this invention, and is a perspective view which shows an example of the whole structure of a circuit breaker. It is a figure which shows Embodiment 1 of this invention, and is a perspective view which shows an example of a structure of the principal part of the arc-extinguishing unit of a circuit breaker. It is a figure which shows Embodiment 1 of this invention, and is a figure which shows the state in the case of the area | region where a current is comparatively small in the cross-sectional top view which looked at the principal part cross section in the AA line of FIG. FIG. 2 is a diagram illustrating the first embodiment of the present invention, and is a cross-sectional plan view of the main part cross-section taken along line AA in FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Embodiment 1 of this invention, and is a perspective view which shows an example of the component structure of an arc extinguishing chamber inside with an exploded view. It is a figure which shows Embodiment 2 of this invention, and is a figure which shows the example of a waveform of the electric current at the time of interruption | blocking, and an arc vicinity pressure. It is a figure which shows Embodiment 3 of this invention, and is the figure which showed the trip characteristic of the circuit breaker.

Explanation of symbols

2 movable contact, 3 movable contact, 5 fixed contact,
5a connection terminal, 6 fixed contact, 7 parallel conductor,
9 Arc Runner 10 Magnetic material, 11 Insulator,
13 Insulating cover, 13a Spring receiving part, 14 Spring,
15 arc extinguishing side plate, 16 magnetic material arc extinguishing plate, 156 arc extinguishing plate unit,
19 rotor, 19a rotating shaft, 23 arc extinguishing unit,
23a Spring receiving part, 23b Exhaust hole, 23sr Magnetic body incorporation hole,
23ss wall on both sides, 25 mechanism, 26 relay,
26a connection terminal, 27 crossbar, 28 cover,
29 handle, 30 base, 53 arc extinguishing plate unit,
53ps open / close space.

Claims (8)

  The fixed contact, the movable contact that opens and closes with the fixed contact, and the fixed contact and the movable contact are built in, and can move in a direction relatively approaching both sides of the open / close space that allows the movable contact to open and close A pair of arranged magnetic bodies, and when both of the magnetic contacts are relatively close to each other by an electromagnetic attractive force acting between the two magnetic bodies when the breaking current at which the movable contactor is cut off exceeds a predetermined value The opening and closing space is narrowed within a range allowing the opening and closing operation of the movable contact, and when the current is reduced by the current limiting operation and the electromagnetic attractive force is reduced, the two magnetic bodies are returned to their original positions. Circuit breaker back to   2. The circuit breaker according to claim 1, wherein the movement in the direction in which the two magnetic bodies are relatively approached is performed before an arc is generated between the fixed contact and the movable contact. A circuit breaker.   3. The circuit breaker according to claim 1 or 2, wherein the two magnetic bodies relatively approach each other if a current flowing across the fixed contact and the movable contact exceeds a circuit breaker instantaneous trip region. A circuit breaker that performs said movement in direction.   The circuit breaker according to any one of claims 1 to 3, wherein a movement amount of the relative movement of the two magnetic bodies is different between an arc starting point side and an arc extending side. Circuit breaker.   5. The circuit breaker according to claim 1, wherein an insulating material that generates a decomposition gas by arc heat is interposed between each of the magnetic bodies and the switching space. A circuit breaker.   The circuit breaker according to any one of claims 1 to 5, wherein the fixed contact, the movable contact, and the open / close space are built in an extinguishing unit, and the magnetic body is the extinguishing unit. A circuit breaker arranged on both side walls of the circuit board.   7. The circuit breaker according to claim 6, wherein the magnetic body is incorporated in the magnetic body incorporation holes on both side walls of the extinguishing unit so as not to protrude from both side wall surfaces. Circuit breaker.   2. The circuit breaker according to claim 1, wherein the fault current is not less than the predetermined value and the overload current is less than the predetermined value.

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