JP5940225B1 - Switchgear - Google Patents

Abstract

An opening / closing device capable of ensuring shutoff reliability is obtained. The switching device (100) generates a magnetic field for extending an arc generated between the fixed contact (1) and the movable contact (2) when the fixed contact (1a) and the movable contact (2a) are separated. The magnet (4) to be moved is disposed so that one end thereof is close to the arc generation region (20) between the fixed contact (1) and the movable contact (2), and the other end is a magnet (4). ) Protects the magnetic body (3), the magnet (4), and the magnetic body (3) arranged so as to be in contact with one of the magnetic pole surfaces, and isolates the arc extension space (21) in which the direction of the energization of the arc is different. An insulating cover (3c), and the magnet (4) is disposed in a region other than the arc generation region (20).

Description

  The present invention relates to a switching device such as a switch, a switch, a circuit breaker, an electromagnetic contactor, a relay, and the like for cutting off current.

In the switchgear, the arc generated between the contacts is stretched to increase the arc resistance, and the arc voltage is increased to cut off the current. In particular, in the DC switchgear, it is necessary to make the arc voltage higher than the power supply voltage and generate a current zero point to cut off, so the technique of extending the arc is important.
Conventionally, in general, in order to extend an arc, the arc length is extended by linking a magnetic field line of a permanent magnet to the arc and applying a Lorentz force to the arc (for example, Patent Document 1).

JP 2009-87918 A

However, the conventional switchgear disclosed in Patent Document 1 is a switchgear in which a magnet is mounted in the arc extinguishing chamber in order to extinguish the arc. There was a problem that the shut-off reliability was lowered.
In addition, there is a means for expanding the arc extinguishing space so that the arc can be cut off even when the arc is driven in the opposite direction. However, this means has a problem that the apparatus becomes large. In addition, the arc that is driven and extended to the outside of the surface facing the magnetic pole surface of the magnet not only makes the magnetic drive action difficult, but also causes the magnetic field lines generated from the magnet to cause an unexpected electromagnetic force. , The reliability of the interruption is reduced.
In such a switchgear, in order to apply a desired Lorentz force to the arc, it is necessary to apply a magnetic force line in a uniform direction to the working surface of the Lorentz force. In order to link magnetic field lines in a uniform direction to the arc, the magnetic pole surface of the permanent magnet must be made larger than the working surface of the Lorentz force, resulting in a high-cost configuration and securing an arrangement space. It becomes difficult.

In addition, for arcs located at locations that do not oppose the magnetic pole surface of the permanent magnet, the magnetic lines of force generated from the permanent magnet cause an unexpected Lorentz force, which reduces the reliability of interruption, and in the worst case It will cause an accident that cannot be shut off. In a conventional switchgear equipped with a permanent magnet, the arc is almost always extended to the outside of the opposing surface of the permanent magnet, and such a switchgear is poor in reliability of interruption.
Furthermore, a magnetic yoke is sometimes used to form the magnetic lines of force from the permanent magnet outside the opposing surface of the permanent magnet, but the Lorentz force generated by the magnetic lines of force from the permanent magnet reverses when the current direction changes. In this case, the reverse connection makes it difficult to cut off and causes an accident. In order to avoid this accident, it is necessary to install an arc extension space and a magnetic yoke that can sufficiently extend even if the direction of the current is reversed and the arc moves in the opposite direction, and the size of the switchgear is increased. there were.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a switchgear that can ensure sufficient shutoff reliability even when a small magnet is used regardless of the direction of current. Yes.

The switchgear according to the present invention is configured to open and close the fixed contact having a fixed contact, the movable contact having a movable contact, the movable contact having a movable contact, and the fixed contact and the movable contact. An opening / closing mechanism, a magnet for generating a magnetic field for extending an arc generated between the fixed contact and the movable contact, and one end of the fixed contact when the fixed contact and the movable contact are separated; A magnetic body arranged so as to be close to an arc generation region between a child and the movable contact and having the other end in contact with one magnetic pole surface of the magnet, the magnet and the magnetic An insulating cover serving as a wall that protects the body and isolates the arc extension space in which the arc extends into two spaces corresponding to the energization direction of the arc, and the magnet is provided in a region other than the arc generation region. In the area And it is characterized in that it is location.

According to the switchgear according to the present invention, the arc generated between the contacts can be driven in the direction of the magnet along the side surface of the attracting rod, which is a magnetic body, regardless of the direction of the current. At this time, the arc travels and expands in the direction of the magnet while being driven along the side surface of the attracting rod, which is a magnetic material, so that the arc is rapidly cooled. As a result, an inexpensive and small switchgear can be obtained while maintaining high shutoff reliability even when a reverse polarity current flows. In addition, by providing an insulating cover that separates the arc extension space into two spaces corresponding to the direction of energization of the arc, the arc wraps around from one arc extension space to the other arc extension space. This makes it possible to prevent the arc from extending stably.

It is a sectional side view which shows the opening state of the switchgear in Embodiment 1 of this invention. It is sectional drawing in the AA 'line of FIG. It is explanatory drawing for demonstrating the arc-extinguishing operation | movement of the switchgear in Embodiment 1 of this invention. It is a sectional side view which shows the opening state of the switchgear in Embodiment 2 of this invention. It is a sectional side view which shows the opening state of the switchgear in Embodiment 3 of this invention. It is sectional drawing in the AA 'line of FIG. It is a sectional side view which shows the opening state of the switchgear in Embodiment 4 of this invention. It is sectional drawing in the AA 'line of FIG.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings. In the drawings, the same reference numerals denote the same or corresponding parts.
1 is a side cross-sectional view schematically showing an opening state of a switchgear according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. As shown in FIG. 1, a switching device 100 according to Embodiment 1 of the present invention includes a fixed contact 1 having a fixed contact 1a, a movable contact 2 having a movable contact 2a, a fixed contact 1a, and a movable contact 2a. And an opening / closing mechanism 103 for performing the opening / closing operation. Further, the switchgear 100 includes a magnet 4 that generates a magnetic field for extending the arc A generated between the fixed contact 1 and the movable contact 2 when the fixed contact 1a and the movable contact 2a are separated. . Furthermore, the opening / closing device 100 is arranged so that one end thereof is close to the arc generation region 20 between the fixed contact 1 and the movable contact 2, and the other end is on one magnetic pole surface of the magnet 4. A suction rod 3 made of a long magnetic material is provided so as to be in contact therewith. The magnet 4 is disposed in a region other than the arc generation region 20. The opening / closing device 100 includes an insulating cover 3c that protects the magnet 4 and the suction rod 3 made of a long magnetic body. The insulating cover 3c is made of a resin material such as nylon, for example. Here, the arc generation region 20 indicates a space between the fixed contact 1 and the movable contact 2 surrounded by a dotted line in FIG.

  In addition, the switchgear 100 according to Embodiment 1 of the present invention includes a fixed-side terminal portion 11 and a movable-side terminal portion that are connected to an external power circuit at both ends of a casing formed by a case 101 made of an insulator. 12 is provided, and an arc extinguishing chamber 102 for extinguishing the arc is provided in the lower part. The arc extinguishing chamber 102 has a fixed contact 1 formed integrally with the fixed terminal portion 11 and provided with a fixed contact 1a at a predetermined portion, and a movable contact 2a contacting and separating from the fixed contact 1a. An elongated magnetic element whose one end is disposed in the vicinity of the arc generation region 20 so as to face a space sandwiched between the movable contact 2 provided to move, and the fixed contact 1 and the movable contact 2. A suction bar 3 made of a body and a magnet 4 that is disposed in contact with the suction bar 3 and generates a magnetic field for extending the arc A generated between the fixed contact 1 and the movable contact 2 are disposed. .

As described above, in the switchgear 100 according to Embodiment 1 of the present invention, the magnet 4 that controls and extends the arc A generated between the two contacts when the two contacts are separated, and one end of the arc is generated. The basic structure is a suction rod 3 made of a long magnetic body, which is disposed in the vicinity of the region 20 and whose other end is disposed in contact with one magnetic pole surface of the magnet 4. With this structure, the arc A is extended along the longitudinal side surface of the suction bar 3 made of a long magnetic material by the magnetic field generated by the magnet 4. Here, a space between the side surface of the suction bar 3 located on the right side of the arc generation region 20 in FIG. 1 and the magnetic reinforcing plate 6 is defined as an arc extension space 21.
It should be noted that the same effect can be obtained even if the attracting rod 3 made of a long magnetic material is in the form of a round bar, a rectangular parallelepiped, or a cylindrical or polygonal bar. Further, as will be described later, the suction bar 3 made of a long magnetic material is protected by an insulating cover 3c for magnetic material provided so as to face the generation area of the arc A having a conduction direction in front of the paper surface. Yes. A magnetic reinforcing plate 6 described later is attached to the magnet 4.

FIG. 3 is an explanatory diagram for explaining an arc extinguishing operation of the switchgear according to Embodiment 1 of the present invention. An attracting rod 3 made of a long magnetic material protected by an insulating cover 3c for magnetic material is disposed, and the end surface of the attracting rod 3 opposite to the arc generation position is disposed on the end of the permanent magnet 41 having an N pole. The arc extinguishing principle will be described with reference to the model shown in FIG. 3 arranged so as to be in contact with the surface, divided into five stages of FIG. 3A to FIG.
In FIG. 3, first, in FIG. 3A, which is a progressing stage of arc extinction, the magnetic field lines M generated from the permanent magnet 41 are induced by the attracting rod 3, and the linkage to the arc from the tip of the attracting rod 3 toward the arc. A magnetic field is generated. The Lorentz force acts on the arc by the interlinkage magnetic field, and the arc is driven in the lower direction in FIG. 3A. In FIG. 3A, the code | symbol 8 shows an arc and its electric current direction, and the code | symbol 9 shows the action direction of Lorentz force.

Next, in FIG. 3B, which is an arc extinguishing progress stage, the magnetic field lines M formed so as to wrap around the arc driven at the stage of FIG. 3A from the tip of the attracting rod 3 to the S pole side of the permanent magnet 41 are chained. Come to fuck. By this interlinkage magnetic field, the arc is drawn into the arc extension space 21 that extends to the side surface portion of the suction bar 3 in the longitudinal direction. In FIG. 3B, the code | symbol 10 shows the arc in case a current direction is reverse.
Next, in FIG. 3C, which is the arc extinguishing progress stage, the arc drawn into the arc extension space 21 is drawn further to the back by the magnetic force lines M generated on the normal line from the side surface of the suction bar 3. As the arc is drawn deeper, the strength of the magnetic field generated from the side surface of the suction bar 3 increases, so that it becomes difficult for the arc to be detached from the suction bar 3, and the arc is stably transferred to the rear side (right side) of the suction bar 3. Can be stretched. Further, the magnetic field lines interlinking with the arc drawn in the back include many magnetic lines that circulate to the south pole side of the permanent magnet 41, and the interlinkage magnetic field by the magnetic field lines in this direction (right side in the figure) is A force for attracting the arc to the inside of the suction rod 3 is caused.

Next, in FIG. 3D, which is a progress stage of arc extinction, Lorentz force that pushes into the inside of the suction bar 3 with a stronger force acts on the arc in the vicinity of the magnetic insulating cover 3 c that protects the suction bar 3. It becomes like this. As a result, the arc is compressed toward the magnetic insulating cover 3c, and the resistance inside the arc increases rapidly. Then, the ablated gas generated by the arc heat from the arc exposed surface of the magnetic insulating cover 3c is blown toward the arc, thereby cooling the arc and further increasing the resistance inside the arc. Become.
Finally, in FIG. 3E, which is an advanced stage of arc extinction, when a concave slit 3e as shown in FIG. 3 is provided in a part of the insulating cover 3c for magnetic material, it is pushed into the inside of the suction bar 3. The arc is drawn into the slit 3e by the Lorentz force, and the arc contracts thinly. Further, the ablated gas from the insulating cover 3c for magnetic material is blown from around the contracted arc, and the resistance increases until the electrical conductivity cannot be maintained inside the arc, resulting in extinction.

According to the above structure, the same effect can be obtained even when the energization direction is reversed. In each arc extinguishing stage, the arc extends so as to be symmetric with respect to the axis of the suction bar 3 as shown in FIG. I will do it. Further, the same effect can be obtained even when the direction of the magnetic pole surface of the permanent magnet 41 (or the magnet 4) is reversed, and the arc is extended to be the target on the axis of the suction bar 3 in each arc extinguishing stage. I will do it.
In this way, by using the suction rod 3 and the permanent magnet 41 (or the magnet 4), the arc can be driven and extended in the same direction, and the reliability of interruption can be increased without increasing the size of the switchgear 100. Can increase the sex.

Moreover, in this Embodiment 1, it has the further effect by adding the following members other than said basic structure.
First, the switchgear 100 is provided with an arc extension space 21, and by arranging the permanent magnet 41 (or magnet 4) in the arc extension space 21, it is possible to extend the length that can extend the arc and further increase the arc resistance. Can do.
Further, by providing a magnetic reinforcing plate 6 made of a magnetic material on the opposite (non-attracting bar side) magnetic pole surface of the permanent magnet 41 (or magnet 4) adjacent to (disposed in contact with) the attracting bar 3. Since the magnetic resistance of the magnetic circuit formed by the magnetic lines of force that circulate around the permanent magnet 41 (or the magnet 4) via the attraction bar 3 decreases, the magnetic field intensity generated from the surface of the attraction bar 3 increases, and the arc extinguishing performance Can be further enhanced.

As shown in FIG. 2, in the first embodiment, the insulating cover 3c is provided with a wall that separates the two arc extension spaces 21 (spaces on both side surfaces of the suction bar 3). The insulating cover 3c forms a wall that separates two arc extension spaces 21 having different arc energization directions, thereby preventing the arc from flowing from one arc extension space 21 to the other arc extension space 21. This makes it possible to prevent the arc from extending stably.
Furthermore, in Embodiment 1 of the present invention, since the magnet 4 is composed of the permanent magnet 41, a constant magnetic flux can be applied to the arc, so that the magnetic flux generated from the current-carrying conductor is in a current region (eg, 1 kA). Less), stable blocking can be performed.
In the above description of the arc extinguishing principle, the permanent magnet 41 is used as a magnet to be used. However, a coiled conductor electrically connected to either one of the contacts or an external power source is used as a suction rod. The arc can be extinguished by the same phenomenon as described above even if it is wound around a part of the periphery of 3 and a part of the suction rod 3 is configured as an electromagnet (not shown).

When the permanent magnet 41 is used for the magnet 4 and when an electromagnet (not shown) is used, the current range in which the effect can be exhibited most is different. When the permanent magnet 41 is used, the current region is relatively weak. The effect is exhibited (for example, less than 1 kA), and when an electromagnet (not shown) is used, the effect is exhibited in a relatively large current region (for example, 1 kA or more) where the magnetic flux generated from the current flowing through the conductor is large.
As described above, by adopting the basic configuration of the present invention, the arc A generated regardless of the energization direction can be drawn into the back of the suction bar 3, the arc can be extended, and then cooled and extinguished. That is, the arc can be extended and cooled in the permanent magnet arrangement direction regardless of the direction of the current, so that the interruption reliability can be ensured and the switchgear 100 can be downsized even when the current flows backward. Further, the isolation wall formed by the insulating cover 3c can prevent the arc from entering the other arc extension space 21 and stabilize the interruption performance.

Embodiment 2. FIG.
FIG. 4 is a side cross-sectional view showing the opening state of the switchgear according to Embodiment 2 of the present invention. In the first embodiment, the suction rod 3 is made of a long magnetic material. However, in the second embodiment, as shown in FIG. 4, the shape of the suction rod 3 varies depending on the energization direction. The arc is extended and arranged so as to separate the space where the arc extends. As a result, magnetic saturation in the vicinity of the surface in contact with the magnet 4 in the attraction bar 3 can be suppressed, and an arc generated between the contacts can be efficiently drawn into the arc extension space 21. Further, as the suction bar 3 is enlarged, the region in the arc extension space 21 where the magnetic field strength is increased is also expanded, so that the extension state of the arc is easily maintained and the interruption reliability is improved.

Embodiment 3 FIG.
FIG. 5 is a side sectional view showing an open state of the switchgear according to Embodiment 3 of the present invention. FIG. 6 is a cross-sectional view taken along line AA ′ of FIG. As shown in FIG. 5, in the third embodiment, the insulating cover 3 c forms a wall that separates two arc extension spaces 21 having different arc energization directions, and surrounds the arc at the time of extension. Insulating cover 3c is arranged like this. In general, since the case 101 of the switchgear 100 is made of a material that does not easily ablate so as not to be worn even when exposed to the generated arc heat, the efficiency of spraying the ablated gas onto the arc is low.
According to the third embodiment of the present invention, the insulating cover 3c can be formed of a material that is easily ablated, and therefore, the arc at the time of expansion is disposed so as to be surrounded by the insulating cover 3c, thereby spraying the ablated gas onto the arc. Efficiency can be improved and shut-off reliability can be increased. Note that the third embodiment may be combined with the shape of the suction rod 3 of the second embodiment, and the combination further improves the blocking reliability.

Embodiment 4
FIG. 7 is a side sectional view showing an open state of the switchgear according to Embodiment 4 of the present invention. FIG. 8 is a cross-sectional view taken along the line AA ′ of FIG. As shown in FIGS. 7 and 8, in the fourth embodiment, in addition to forming a wall that separates two arc extension spaces 21 having different arc energization directions by the insulating cover 3c, The protrusion 7 is provided at the center of the arc (the center of the arc extension space 21) so that the arc can collide or compress. The protrusion 7 is made of the same material as the insulating cover 3 c and has a shape protruding from the side surface of the case 101.
According to the fourth embodiment of the present invention, the arc collides or compresses at the projecting portion 7 and the arc is stretched around the projecting portion 7 to further improve the cooling efficiency of the arc.
It should be noted that within the scope of the present invention, the embodiments can be freely combined, or the embodiments can be appropriately modified or omitted.

  DESCRIPTION OF SYMBOLS 1 Fixed contact, 1a Fixed contact, 2 Movable contact, 2a Movable contact, 3 Suction stick, 3c Insulation cover, 4 Magnet, 6 Magnetic reinforcement board, 7 Protrusion part, 11 Fixed side terminal part, 12 Movable side terminal part, DESCRIPTION OF SYMBOLS 15 Flexible conductor, 20 Arc generation | occurrence | production area | region, 21 Arc extension space, 41 Permanent magnet, 100 Switchgear, 101 Case, 102 Arc extinguishing chamber, 103 Opening / closing mechanism part.

Claims (5)

A stationary contact having a stationary contact;
A movable contact that is installed opposite the fixed contact and has a movable contact;
An opening / closing mechanism for performing an opening / closing operation between the fixed contact and the movable contact;
A magnet that generates a magnetic field for extending an arc generated between the fixed contact and the movable contact when the fixed contact and the movable contact are separated;
A magnetic body disposed so that one end thereof is close to an arc generation region between the fixed contact and the movable contact, and the other end is in contact with one magnetic pole surface of the magnet; ,
An insulating cover serving as a wall that protects the magnet and the magnetic body and that separates the arc extension space in which the arc extends into two spaces corresponding to the energization direction of the arc;
The magnet is arranged in a region other than the arc generation region.   2. The switchgear according to claim 1, wherein the magnetic body has the other end portion enlarged so as to separate the arc extension space into two spaces corresponding to the energization direction of the arc.   The switchgear according to claim 1 or 2, wherein the insulating cover is disposed so as to surround the arc when extended. The insulating cover is such that the arc at the time of expansion can be collision or compression, any one of claims 1 to 3, characterized in that is provided with a protrusion in the center of the arc extension space The switchgear described in 1.   The switchgear according to any one of claims 1 to 4, wherein the insulating cover is made of a resin material.

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