JP2003208829A - Direct current breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a direct current breaker downsizable with a simple structure. <P>SOLUTION: An elastic electrode (plate spring 10) and a fixed electrode 20 are provided. These two electrodes are normally in contact with each other. Switching between interruption/continuity is effected by inserting/withdrawing an insulating plate between the two electrodes. Reliable interruption of a direct current is achieved by a simple configuration to insert/withdraw the insulating plate between the electrodes. There is no need for any hermetic structure for sealing a cooling gas or any space for extending arc by a magnetic field, which allows downsizing and low-cost fabrication. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC current circuit breaker. In particular, the present invention relates to a circuit breaker capable of reliably blocking DC current with a simple structure.

[0002]

2. Description of the Related Art As an electric power (AC) circuit breaker, an oil circuit breaker, a water circuit breaker, a magnetic circuit breaker, an air circuit breaker, a gas circuit breaker, and a vacuum circuit breaker can be classified according to the arc extinguishing medium and the arc extinguishing method used. There are circuit breakers. In the case of alternating current, since there is a current zero point, it is generally performed to interrupt the current using this zero point.

On the other hand, it is difficult to cut off a direct current because there is no zero current point. In general, extinguishing a DC arc is
The sudden change in the conductivity between the contacts. Ideally, it is desired to change the resistance value from 0 to infinity. Specific means include increasing the contact opening distance, increasing the contact opening speed, extending the arc with a magnetic field, and cooling with a cooling gas or an arc extinguishing chamber to increase the resistance.

[0004]

However, in the conventional DC circuit breaker, there is a problem that the size is inevitably increased and the cost is increased. For example, in order to interrupt the DC arc in the atmosphere, it is necessary to increase the distance between the contacts, and a space for that is essential. Further, in the case of cutting by opening the electric contact placed in the completely airtight structure, a gas sealed structure is required. In addition, when the arc is stretched by the action of the magnetic field, a space required for this stretching is required. As described above, it is difficult to reduce the size of the conventional DC circuit breaker in any configuration.

Therefore, a main object of the present invention is to provide a DC circuit breaker which can be downsized with a simple structure.

[0006]

SUMMARY OF THE INVENTION The present invention achieves the above object by constructing an insulating plate which can be inserted into and removed from a pair of electrodes which are normally in contact with each other.

That is, the DC circuit breaker of the present invention comprises at least one elastic electrode, a pair of electrodes which are normally in contact with each other, and an insulating plate which is inserted / removed between the electrodes to switch between interruption and conduction. Is characterized by.

At least one of the electrodes is an elastic electrode, and the insulating plate can be freely inserted and removed between the two electrodes, so that the direct current can be surely cut off by a simple structure such as a driving mechanism for the electrode, the insulating plate and the insulating plate. You can In addition, an airtight structure is not required, and it can be manufactured at low cost. Hereinafter, each component of the present invention will be described in detail.

(Electrodes) The electrodes of the circuit breaker of the present invention are always in contact with each other. When the insulating plate is inserted, the gap between the electrodes is opened, and when the insulating plate is removed, the gap between the electrodes is again formed. At least one of them is an elastic electrode so that they can contact each other.

As a concrete structure of the elastic electrode, a plate spring-like one is preferable. Particularly, a leaf spring having one end side as a fixed end and the other end side as a free end bent in an arc shape is preferable. This arcuate portion is brought into contact with the other electrode. Since the insulating plate is inserted into and removed from the arc-shaped portion, the inserting / removing operation can be smoothly performed.

In this elastic electrode, it is preferable that a plurality of leaf springs are arranged in parallel in the inserting / removing direction of the insulating plate. When the insulating plate is inserted between the electrodes, the melting loss of the electrode due to the arc current concentrates on the electrode portion that comes into contact with the insulating plate immediately before cutting, that is, at the end. Therefore, by providing a plurality of leaf springs, it is possible to function as an electrode by leaving another healthy leaf spring even if some leaf springs are melted.

Further, the elastic electrode may have a structure in which a plurality of leaf springs are arranged in parallel and an insulating plate is inserted between the electrodes to simultaneously shut off the plurality of leaf springs. For example, a plurality of leaf springs are arranged in parallel in a direction orthogonal to the inserting / removing direction of the insulating plate. here,
Part of these leaf springs is arranged so as to contact the anode side, and the remaining part is arranged so as to contact the cathode side. Then, by inserting an insulating plate between these elastic electrodes and the other electrode, a plurality of leaf springs,
That is, two or more points are simultaneously cut off.

Since the plurality of leaf springs are cut off at the same time, the pressure for inserting the insulating plate can be reduced. In order to pass a large current with one leaf spring, it is necessary to increase the contact pressure between the leaf spring and the fixed electrode, and for that purpose it is also necessary to increase the insertion force of the insulating plate. On the contrary,
If a plurality of leaf springs are used, the contact pressure of each leaf spring with respect to the fixed electrode can be lowered, and the insertion force of the insulating plate can be reduced. Of course, in the elastic electrode, a plurality of leaf springs may be arranged in parallel both in the inserting / removing direction of the insulating plate and in the direction orthogonal thereto.

On the other hand, the fixed electrode is preferably composed of a block-shaped electrode. In particular, the elastic electrode is brought into contact with each electrode piece by using a fixed electrode divided into a plurality of electrode pieces, and each electrode piece, a DC power source, and a load are connected in series, whereby a plurality of leaf springs divides the voltage. Since the pressure is applied, damage to the electrode due to the arc current can be reduced.

Furthermore, an L-shaped block may be used, and a part thereof may be used as a fixed electrode. That is, an L-shaped block in which a thin plate portion and a thick plate portion are integrated, a thin plate block facing this thick plate portion, and a thick plate block facing the thin plate portion independently of the thin plate block are used. Here, one elastic electrode is fixed to the thin plate portion and brought into contact with the thick plate block. The other elastic electrode is fixed to the thin plate block and brought into contact with the thick plate portion. Then, the thin plate block, the thick plate block, the DC power supply and the load are connected in series. In this configuration, the thick plate portion and the thick plate block of the L-shaped block serve as fixed electrodes.

At this time, if the thin plate block is connected to the cathode side and the thick plate block is connected to the anode side, damage to the elastic electrode can be effectively suppressed. When a metal-phase arc is generated, metal vapor is generated between the electrodes and the anode side is consumed. Therefore, by connecting the thick plate and the thick block so that the thick plate and the thick block are on the anode side, the thick plate and the thick block can be consumed, and the elastic electrodes such as thin leaf springs are prevented from being consumed. it can.

(Insulating Plate) This insulating plate is interposed between the electrodes to electrically cut off the electrodes. The insulating plate may be entirely made of an insulating material, or may be an insulating plate partially made of a conductive material and composed of a conductive portion and an insulating portion. The insulating portion may be formed on at least a part of the insulating plate. In particular, it is preferable to form the insulating portion on the surface in contact with the elastic electrode.

The insulating material used for the insulating plate (insulating portion) is preferably at least one selected from plastic, ceramic and diamond. As the plastic, a general material as an electrically insulating material can be used. For example, epoxy resin, polyamide resin, fluororesin, silicone resin, polyethylene, polypropylene, polyvinyl chloride and the like are suitable. As a ceramic,
At least one selected from the group IVa, Va, and VIa elements of the periodic table, carbides, nitrides, borides, oxides of Al and Si, and solid solutions thereof is suitable. More specifically, W
C, TiC, TiN, TiCN, TiB ₂ , TiBN, ZrC, ZrN, SiN, Al
There are N, VC, TaC, HfC, Mo ₂ C, SiO, SiO ₂ and Al ₂ O ₃ .
In addition, vitreous substances such as quartz glass, soda-lime glass, borosilicate glass, lead glass, and crystallized glass can also be used. Diamond may be single crystal, polycrystal, natural or synthetic.

When the plastic is coated on the substrate, it is preferable to coat it by a method such as electrostatic coating or powder coating. When ceramic or diamond is coated on the substrate, it is desirable to form the coating by a vapor phase synthesis method. For example, the diamond film can be formed by a CVD (Chemical vapor deposition) method such as a hot filament method, a microwave plasma method, a high frequency plasma method, or an arc discharge plasma jet method.

The thickness of the insulating plate itself or the insulating portion depends on the material, but should be such that a desired control capacity can be secured. An example of the rated control capacity of a circuit breaker for an electric vehicle is 150A / 400V.

Further, it is preferable that the resistance value of the insulating plate is continuously changed in the inserting / removing direction. For example, the insulating plate itself or the insulating portion may be thinner at the front side in the insertion direction of the insulating plate, and the insulating plate itself or the insulating portion may be thicker toward the rear side. By making the front part of the insulating plate thin in the insertion direction, the insulating plate can be easily inserted.

Insulating plate having an inclined thickness (insulating part)
The plate may be formed by first forming a flat plate and then polishing it to form a slanted thickness, or using plastic or the like by forming a sheet having a slanted thickness in advance and adhering it to a substrate.

When an insulating plate having a conductive portion and an insulating portion is used, it is preferable that the boundary between the conductive portion and the insulating portion be as flush as possible. With this configuration, there is no step at the boundary between the conductive portion and the insulating portion, and the insulating plate can be smoothly inserted / removed between the electrodes.

(Insulating Plate Driving Mechanism) For driving the insulating plate,
A linear motion type actuator such as a solenoid and a rotary motion type actuator such as a motor are suitable. The driving operation is to reciprocate the insulating plate to insert and remove it between the electrodes, or to rotate the insulating plate consisting of the conductive part and the insulating part.
It is possible to change the position located between the electrodes between the conductive portion and the insulating portion.

(Insulation cover) By inserting an insulating plate between both electrodes, it can be electrically cut off, but depending on the size of the insulating plate and the current / voltage value between the electrodes, it may bypass the side of the insulating plate. Arcs may form between the electrodes. It is preferable to provide an insulating cover to block this arc.

The insulating cover is preferably formed so as to surround at least the periphery between both electrodes. By surrounding this range, the arc that bypasses the insulating plate can be effectively cut off. By using the insulating cover, it is not necessary to make the insulating plate excessively large, and it is possible to contribute to downsizing of the circuit breaker as a whole. It is preferable to use a plastic molded product as the insulating cover.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. (Embodiment 1) FIG. 1 is a schematic configuration diagram around electrodes in a circuit breaker of the present invention. FIG. 2 is a schematic configuration diagram of the entire circuit breaker of the present invention.

As shown in FIG. 1, the circuit breaker comprises a pair of leaf springs 10 (elastic electrodes) fixed to a conductive support plate 11 and a fixed electrode 20 which is always in contact with the leaf spring 10. Spring
By connecting / disconnecting the insulating plate 30 between the fixed electrode 20 and the fixed electrode 20, conduction / interruption is performed.

As the leaf spring 10, a J-shaped bent metal plate was used. One end of this leaf spring is fixed to the conductive support plate 11, and the other end is set as a free end so that the bent portion on the free end side abuts the fixed electrode 20. At that time, the leaf spring 10 is arranged so that the free end faces the insertion direction of the insulating plate 30, and the bending degree of the bent portion is adjusted so that the free end is slightly lifted above the fixed electrode 20, and the insulating plate 30 is inserted and removed. When the free end is an insulating plate
It was configured not to get caught in 30. On the other hand, fixed electrode 20
Has a block shape having an upper surface in contact with both the pair of leaf springs 10. As shown in FIG. 2, a power supply device 40 and a load 50 are connected in series to the conductive support plate 11 and the fixed electrode 20.

The insulating plate 30 is inserted and removed between the elastic electrode and the fixed electrode 20. Here, a polycrystalline diamond plate having a thickness of 200 μm was used as the insulating plate 30. This diamond plate was manufactured by synthesizing a diamond film on an appropriate base material by the CVD method and removing the base material.

The insulating plate 30 is inserted and removed by reciprocating the insulating plate 30 with a solenoid 60. As shown in FIG. 2, the support base 70 is fixed to the drive shaft of the solenoid 60, and the insulating plate 30 is fixed to the support base 70. The solenoid 60 energizes the exciting coil from the driving power supply 61, and the electromagnetic force thereof causes the driving shaft to move forward and backward in the axial direction. Then, the insulating plate 30 is inserted and removed between the elastic electrode and the fixed electrode 20 as the drive shaft moves back and forth.

With the circuit breaker having such a structure, the direct current can be surely cut off by a simple mechanism of driving only the insulating plate 30. Further, the circuit breaker can be miniaturized without the need for a cooling gas sealing structure.

In this embodiment, the leaf springs 10 are arranged side by side in a direction orthogonal to the inserting / removing direction of the insulating plate 30, but similar leaf springs may be arranged in parallel in the inserting / removing direction. That is, as shown in FIG. 3, it is also preferable that a plurality of leaf springs 10A, 10B, and 10C are arranged in a comb-like shape.

When an insulating plate is inserted between the electrodes, the melting loss of the electrode due to the arc current concentrates on the electrode portion (the leaf spring 10C in FIG. 3) that comes into contact with the insulating plate immediately before cutting, that is, at the end. Therefore, by providing a plurality of leaf springs 10A, 10B, 10C in a comb-teeth shape, even if some leaf springs are melted, another leaf spring that is sound can be left to function as an electrode.
As a result, the durability of the circuit breaker can be improved even when a large current is interrupted, especially in the case of an abnormality.

(Embodiment 2) Next, a circuit breaker of the present invention using an insulating plate having a conductive portion and an insulating portion will be described with reference to FIGS. FIG. 4 is a schematic configuration diagram in the vicinity of the electrodes of Example 2, FIG.
[Fig. 3] is a schematic configuration diagram of an entire circuit breaker of a second embodiment.

The present example is the same as the first embodiment except for the configuration of the insulating plate 30 which is different from that of the first embodiment. This insulating plate was coated with an epoxy resin by electrostatic coating only on about half the area on one side of the metal plate.
The thickness of the epoxy resin is 200 μm. The part covered with the epoxy resin is the insulating part 31, and the exposed part of the metal plate is the conductive part 32.

The insulating plate 30 is arranged with respect to the electrodes by the conductive portion 32.
Was connected to the solenoid 60 so that the insulating part 31 was on the rear side in the insertion direction. Usually elastic and fixed electrodes
A conductive portion 32 is interposed between the electrodes 20, and the electrodes are electrically connected to each other. On the other hand, when shutting off, the solenoid 60 is driven to further insert the insulating plate 30 and
Make sure that 31 is sandwiched between both electrodes. As a result, the insulating portion 31 is interposed between the elastic electrode and the fixed electrode, and the insulation is performed.

In the above example, the case where the epoxy resin coating has a substantially uniform thickness over the entire surface has been described. However, as shown in FIG. 6, an inclination such that the front side in the insertion direction is thin and the rear side is thick. It may be a coating. If such an insulating portion 31 is formed, the step between the conductive portion 32 and the insulating portion 31 can be made as small as possible, and the insulating plate 30 can be inserted more smoothly.

(Embodiment 3) Next, a circuit breaker of the present invention using a split type fixed electrode will be described with reference to FIGS. Figure 7
8 is a schematic configuration diagram of the vicinity of an electrode of Example 3, and FIG. 8 is a schematic configuration diagram of the circuit breaker of Example 3 as a whole.

In this example, a pair of leaf springs 10 are attached to the conductive support plate 11.
Are fixed in parallel in a direction orthogonal to the inserting / removing direction of the insulating plate 30. The arrangement itself of the leaf spring 10 with respect to the conductive support plate 11 is the same as that in the first embodiment. On the other hand, the fixed electrode 20 is composed of two conductive blocks 21 and 22 so as to come into contact with each leaf spring 10. In each block that constitutes the fixed electrode,
As shown in FIG. 8, the power supply device 40 and the load 50 are connected in series. Therefore, one conductive block 21 serves as an anode and the other conductive block 22 serves as a cathode.

When the insulating plate 30 is inserted between the elastic electrode and the fixed electrode 20, the leaf springs 10 and the conductive blocks 21, 22 are inserted.
It is possible to cut off between and simultaneously. At that time, each of the pair of leaf springs 10 divides the voltage, and by lowering the voltage generated in one leaf spring, damage to the electrodes due to the arc current can be suppressed.

(Embodiment 4) Next, a circuit breaker of the present invention in which a part of an L-shaped block is used as a fixed electrode will be described with reference to FIGS. FIG. 9 is a schematic configuration diagram in the vicinity of the electrodes of Example 4, FIG.
[Fig. 8] is a schematic configuration diagram of an entire circuit breaker of a fourth embodiment.

This example is different from Example 1 mainly in the shape of the fixed electrode, the arrangement of the elastic electrode, and the way of connecting the power source and the load. This circuit breaker uses a conductive L-shaped block 25, and a thick plate block 26A and a thin plate block 26B obtained by dividing the L-shaped block. In the L-shaped block 25, a thick plate portion 25A and a thin plate portion 25B are integrated. On the other hand, the thin plate block 26A and the thick plate block 26B are independent of each other. Thin block 2
6B faces the thick plate portion 25A of the L-shaped block, and the thick plate block 26
A is opposed to the thick plate portion 25B of the L-shaped block.

Here, one leaf spring is fixed to the thin plate portion 25B and brought into contact with the thick plate block 26A. The other leaf spring is fixed to the thin plate block 26B and brought into contact with the thick plate portion 25A. Then, the thick plate block 26A, the thin plate block 26B, the DC power source and the load are connected in series. In this configuration, the thick plate portion 25A of the L-shaped block and the thick plate block 26A serve as fixed electrodes.

At this time, if the thin plate block 26B is connected to the cathode side and the thick plate block 26A is connected to the anode side, damage to the leaf spring can be effectively suppressed. When a metal-phase arc is generated, metal vapor is generated between the electrodes and the anode side is consumed. Therefore, if the thick plate portion 25A and the thick plate block 26A having a large thickness are connected so as to be on the anode side, the thick plate portion 25A and the thick plate block 26A can be consumed, and the elastic electrode of the thin leaf spring is consumed. Can be prevented.

Also in this circuit breaker, by inserting and removing the insulating plate 30 between the elastic electrode and the fixed electrode 20, it is possible to reliably cut off the direct current.

(Embodiment 5) Next, a circuit breaker of the present invention using an insulating cover will be described with reference to FIGS. FIG. 11 is a schematic configuration diagram in the vicinity of the electrodes of the fifth embodiment, and FIG. 12 is a schematic configuration diagram of the circuit breaker of the fifth embodiment.

In this circuit breaker, a single leaf spring 10 is used as an elastic electrode, and a single conductive block in contact with this is used as a fixed electrode 20.
I am trying. An insulating cover 80 is formed so as to surround the contact surface between the leaf spring 10 and the fixed electrode 20.
The cover 80 may be a plastic molded product.

Although the direct current can be cut off with a sufficient certainty even with the configuration of the first embodiment, depending on the size of the insulating plate and the current / voltage value between the electrodes, the arc may be generated between the electrodes bypassing the side of the insulating plate. There is. Since the insulating cover 80 is formed so as to surround the periphery of the contact surface between both electrodes, the arc that bypasses the insulating plate 30 can be effectively blocked. As a result, it is not necessary to oversize the insulating plate 30, and the circuit breaker as a whole can be downsized. By using a polycrystalline diamond plate with a thickness of 200 μm as the insulating plate 30 and an insulating cover together, 150A / 400
V control capacity can be secured.

(Embodiment 6) Next, a circuit breaker of the present invention having a single elastic electrode using a rotary insulating plate will be described with reference to FIGS. FIG. 13 is a schematic configuration diagram around the electrodes of Example 6,
FIG. 14 is a schematic configuration diagram of the entire circuit breaker of the sixth embodiment.

In this circuit breaker, a single leaf spring 10 is used as the elastic electrode, and a single conductive block is used as the fixed electrode. A power supply device 40 and a load 50 are connected in series to the leaf spring 10 and the fixed electrode 20. The insulating plate 30 has a semicircle on one surface as a conductive portion 32 and the remaining semicircle as an insulating portion 31. As shown in FIG. 14, the insulating plate 30 rotates by rotating a rotary drive device 90 such as a motor with a drive power supply 91.

In this structure, when the insulating plate 30 is rotated, the leaf spring 10 is energized when it is in contact with the conductive portion 32, and is cut off when the leaf spring 10 is in contact with the insulating portion 31.

(Embodiment 7) Next, a circuit breaker of the present invention having a plurality of elastic electrodes using a rotary insulating plate will be described with reference to FIGS. FIG. 15 is a schematic configuration diagram around the electrodes of Example 7,
FIG. 16 is a schematic configuration diagram of the entire circuit breaker of the seventh embodiment.

In this circuit breaker, the leaf spring 10 bent in a J shape is used.
Are arranged in parallel with each other on the conductive support plate 11 in opposite directions to form elastic electrodes. With this arrangement direction,
When the insulating plate 30 described later is rotated, the leaf spring 10
Prevents the rotation of 30 from becoming an obstacle. On the other hand, fixed electrode
Reference numeral 20 denotes a pair of conductive blocks 21, 22 that come into contact with each leaf spring 10.
Is. Each conductive block 21, 22 has a power supply 40 and a load.
50 and 50 are connected in series. The insulating plate 30 is a disk having a rotating shaft disposed between the conductive blocks 21 and 22 and sandwiched between the elastic electrode and the fixed electrode 20. This insulating plate is divided into four fan-shaped parts each having a central angle of 90 ° on one surface side, and fan-shaped parts symmetrical with respect to the center are divided into conductive parts 32 and insulating parts 31. The insulating portion 31 is formed with an epoxy resin film having a thickness of 200 μm.

The insulating plate 30 is a rotary drive device 90 and a drive power source 91.
Is the same as that in the sixth embodiment.

Also in this configuration, when the insulating plate 30 rotates, the plate spring 10 is energized when it is in contact with the conductive portion 32, and is cut off when the plate spring 10 is in contact with the insulating portion 31.

[0057]

As described above, according to the circuit breaker of the present invention, it is possible to reliably cut off the direct current with a simple structure in which only the insulating plate is driven. Further, an airtight structure is not required, and a small DC circuit breaker can be obtained at low cost.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram around an electrode using a pair of leaf springs and a single fixed electrode.

FIG. 2 is a schematic configuration diagram of a circuit breaker of the present invention using the electrode of FIG.

FIG. 3 is an explanatory diagram showing a comb-blade type elastic electrode.

FIG. 4 is a schematic configuration diagram around an electrode in which a part of an insulating plate is a conductive portion.

5 is a schematic configuration diagram of a circuit breaker of the present invention using the electrode of FIG.

FIG. 6 is a schematic view of an insulating plate whose resistance continuously changes.

FIG. 7 is a schematic configuration diagram around an electrode using a split fixed electrode.

8 is a schematic configuration diagram of a circuit breaker of the present invention using the electrode of FIG. 7.

FIG. 9 is a schematic configuration diagram around an electrode using an L-shaped fixed electrode.

10 is a schematic configuration diagram of a circuit breaker of the present invention using the electrode of FIG.

FIG. 11 is a schematic configuration diagram around an electrode using an insulating cover.

12 is a schematic configuration diagram of a circuit breaker of the present invention using the electrodes of FIG.

FIG. 13 is a schematic configuration diagram around an electrode using a pair of electrodes and a rotary insulating plate.

14 is a schematic configuration diagram of a circuit breaker of the present invention using the electrode of FIG.

FIG. 15 is a schematic configuration diagram around an electrode using two pairs of electrodes and a rotary insulating plate.

16 is a schematic configuration diagram of a circuit breaker of the present invention using the electrode of FIG.

[Explanation of symbols]

10 leaf spring 11 Conductive support plate 20 Fixed electrode 21 Conductive block 22 Conductive block 25 L type block 25A thick plate 25B thin plate 26A thick plate block 26B thin plate block 30 insulating plate 31 Insulation part 32 Conductor 40 power supply 50 load 60 solenoid 61 Drive power supply 70 Support 80 insulation cover 90 rotary drive 91 Drive power supply

Claims (10)

[Claims] 1. A direct current circuit breaker, at least one of which is an elastic electrode, comprising a pair of electrodes which are normally in contact with each other, and an insulating plate which is inserted and removed between the electrodes to switch between interruption and conduction. . 2. The direct current circuit breaker according to claim 1, wherein the elastic electrode has a configuration in which a plurality of leaf springs are arranged in parallel in the insertion / removal direction of the insulating plate. 3. The elastic electrode has a structure in which a plurality of leaf springs are arranged in parallel, and has a structure in which a plurality of leaf springs are simultaneously cut off by inserting an insulating plate between the electrodes. DC circuit breaker described in. 4. A fixed electrode is divided into a plurality of electrode pieces, a plurality of elastic electrodes are in contact with each electrode piece, and each electrode piece, a DC power source and a load are connected in series. The DC circuit breaker according to any one of 1 to 3. 5. An L-shaped block in which a thin plate portion and a thick plate portion are integrated, a thin plate block facing the thick plate portion, and a thick plate block facing the thin plate portion independently of the thin plate block, Elastic electrode is fixed to the thin plate portion and contacts the thick plate block, the other elastic electrode is fixed to the thin plate block and contacts the thick plate portion, and the thin plate block, the thick plate block, the DC power source and the load are connected in series. 4. The DC circuit breaker according to claim 1, wherein the thin plate block is connected to the cathode side and the thick plate block is connected to the anode side. 6. The insulating cover according to claim 1, further comprising an insulating cover that, when the insulating plate is inserted, blocks an arc that bypasses the insulating plate and goes around from one electrode to the other electrode. DC circuit breaker. 7. The DC circuit breaker according to claim 1, wherein the insulating plate has a conductive portion and an insulating portion. 8. The resistance value of the insulating plate is configured to continuously change in the insertion / removal direction.
The DC circuit breaker according to any one of 1 to 7. 9. The DC circuit breaker according to claim 7, wherein the insulating plate is a disk having a conductive portion and an insulating portion, and a rotating mechanism for the insulating plate is provided. 10. The DC circuit breaker according to claim 1, wherein at least one selected from plastic, ceramic and diamond is used for the insulating plate.