JPS61121218A - Vacuum breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a vacuum breaker, and more particularly to an electrode material for a vacuum breaker having high withstand voltage and welding resistance.

[Background of the invention]

Traditionally, the electrical or physical properties that vacuum breaker electrodes should have are (1) high withstand voltage characteristics, (2) excellent custom welding resistance, and (3)
The following have been mentioned: (4) low generation of cutting current, (5) low amount of gas released, etc. In particular, the characteristics (1) to (8) are very important factors in increasing the capacity of a vacuum breaker.

Conventionally, various alloys based on Cu have been widely used as the above-mentioned electrodes. In order to improve the withstand voltage characteristics of (1), it is typical to use Cu containing pe, Co, etc. In addition, in order to improve the welding resistance characteristics, 1.
Products with trace amounts of low melting point, high vapor pressure elements such as 3i, pb, etc. that do not dissolve in solid form in Cu have been put into practical use, and Cu-
Co-13i.

The pb series is well known. On the other hand, in recent years, as the capacity of each single power receiving and substation equipment has increased, especially at high voltages, dog'r! There has been a growing demand to cut off the L-style. However, with the above-mentioned Cu-based alloy electrode, it has become very difficult to cut off a large current of 40 to 100 kA under a high voltage of 10 kV or higher. The reason for this is that Cu-based materials have a limit in the above-mentioned withstand voltage characteristics and also have problems in welding resistance.

Recently, C
In addition to those based on U, there are many patents disclosing electrodes made of composite metals.
No. 22 mentions a composite metal in which Cut Ag or the like is infiltrated into a sintered metal body having a melting point of 1600C or higher. Since this composite metal is made by infiltrating Cu and Cu alloy into a skeleton that is hard and brittle, such as a Cr sintered body, the contact part easily peels off even after cutting off the short circuit current. It has excellent welding resistance. In this respect, it can be said that it is a material suitable for interrupting large currents. However, this material has a drawback in that it is difficult to obtain a predetermined cutoff performance when a large current is cut off under high voltage. Generally W.

High melting point metals such as 'l'a and Mo have high thermionic emissivity and therefore have poor inter-electrode resistance and single pressure characteristics. Also C'r
Active elements such as , Zr, and Ti tend to evaporate when exposed to high temperatures in a vacuum, and therefore the withstand voltage characteristics between the electrodes are not very good.

In order to compensate for the drawbacks of conventional materials, a new material has already been developed that contains Ag or Ag in a sintered body of Fe group elements.
Electrode made of composite metal infiltrated with alloy, JP-A-57
It is known from the publication No.-9019. This invention uses a PE group element such as CO, which has high withstand voltage characteristics, as a skeleton, and a kg+ Ag with excellent low surge properties is placed in the gap between the skeletons.
It is an electrode made of a composite metal in which a Te+Ag-Se alloy is vacuum infiltrated, and has an extremely low cutting current and high breaking performance.

However, since this electrode mainly contains Ag, which has low withstand voltage characteristics, it has been found that it is unreasonable to apply it to a vacuum breaker having a higher voltage class. In contrast to the conventional technology described above, it was necessary to develop a new electrode for large capacity use that has high withstand voltage characteristics and high current breaking ability, excellent welding resistance, and preferably low surge characteristics. .

Against this background, the inventors of the present invention
We have developed an electrode shown in Publication No. 3726. The present invention, which will be described later, is an improvement on all pages.

[Purpose of the invention]

An object of the present invention is to provide a large-capacity vacuum breaker having electrodes with excellent withstand voltage and anti-welding properties and large current interrupting ability.

[Summary of the invention]

The present invention provides a vacuum breaker having a vacuum container and a pair of contact electrodes disposed in the vacuum container, in which at least one of the electrodes has CO as a main component in a void of a porous body containing CO as a main component. , is characterized in that it is obtained from a member infiltrated with an alloy containing low melting point and high vapor pressure elements with substantially no solid solution amount at room temperature for Ag, CO, and further Cu. It's in the vacuum breaker.

The inventors used Co powder, which has good conductivity among Fe group elements, excellent withstand voltage characteristics, and high current cutting ability, as a skeleton, and infiltrated each extra-conductive metal into this skeleton prototype. As conductive metals, Cu and various Cu
I was able to get the alloy.

Here, it has been found that it is extremely difficult to simply infiltrate pure Cut into the Co skeleton due to the small difference in melting point, or partial melting. That is, Co
As the molten Cu enters the gaps between the skeletons, they simultaneously dissolve and erode each other, causing the original shape of the skeleton to be lost. Therefore, the present inventors investigated various infiltration members that infiltrate the above-mentioned skeleton. As an infiltration alloy, Ag or an Ag alloy has excellent low surge properties, but is not suitable for high pressure applications, so we mainly focused on infiltration members made of various Cu alloys. Cu as an additive element in Cu alloy
We selected a material that can lower the melting point of the pulp and that itself will not abnormally deteriorate the internal pressure within the vacuum breaker pulp.

These elements include kt, Ag amount La+ Mg+
I tried to list Mn, Ni, so, etc. Various Cu alloys containing these elements are melted in vacuum, a Co skeleton is immersed in the molten metal, and each; f! Co ICU alloy
Infiltrated into the skeleton. The infiltration time is 3 to 5 minutes, and C
o Part of the skeleton was dissolved in copper alloy. As a result of the experiment, Co skeleton and Cu-A were found to be materials with high infiltration, dielectric strength, and high current breaking performance.
The material infiltrated with g-alloy was superior. This material is 25
It was found that it has a conductivity of IAC 8% or more and can have a large rated ti. The porosity of the Co skeleton of this Co-(Cu-8g) based infiltration alloy is 10 to 60% by volume (Cu-
If it is easy to manufacture a skeleton with an Ag alloy infiltration amount of 10 to 60% by weight, it becomes difficult to manufacture a skeleton with an infiltration amount of over 60%. Preferably it is 30 to 60% by weight. When the amount of Ag in the Cu-Ag infiltrated member is 5'i% or more relative to Cu, the infiltration property is improved, but the infiltration property is insufficient. Therefore, 10%
The above is preferable, and from the viewpoint of pressure resistance, 50% by weight is preferable.

It was found that a content in the range of 10 to 50% by weight facilitates infiltration and satisfies various electrical properties. In particular, when the Ag content is 15% or more, the production yield is good and the pressure resistance is high.
~20% is preferred, most preferably 17%. When λg is 15%, the yield is slightly inferior, and when λg is 20%, it is more than sufficient.

Furthermore, if the amount of Ag exceeds 50%, the withstand voltage characteristics will not be very good. The amount of Ag is preferably 2 to 20% by weight, particularly 4 to 12% by weight, based on the entire contact electrode.

The skeleton containing CO as a main component is preferably composed essentially of CO.

Furthermore, the present invention provides a co-(Cu-Ag) based infiltration alloy containing Bi, which has substantially no solid solution amount in solid state with respect to Cu.
It contains one of Pb, Te, and Se and cobalt, and provides excellent welding resistance and pressure resistance. These Bi, pb, etc. are prepared in advance by Cu-A
It is sufficient to add it when melting and manufacturing g-alloy. Bi
, -pb, etc. for the Cu-Ag infiltrated member.
It exhibits excellent welding resistance at a maximum of 3% by weight above the solid solubility limit of . If it is contained in an amount larger than this, the voltage resistance properties will deteriorate to the same level as conventional materials. Preferably Bi.

The amount of Pb is very small, 0.1% by weight or more and less than 1% by weight. In particular, O,OS~1% is preferable for the entire electrode,
Further, 0.05 to 0.3% by weight is preferable.

For CO children, the content is preferably 5% by weight or less, particularly 0.5 to 3% by weight. The CO may be incorporated by infiltrating a portion of the CO skeleton into the infiltrated alloy. Of course, it is better to include it in the infiltrated alloy from the beginning.

Such materials have not only poor electric radiation resistance but also high large current interruption performance and high contact characteristics. In addition, conventional electrodes containing ordinary Cu1 or 3% by weight or less of Bi or PB have a large cutting current of approximately 8 to 16 A when a small current is cut off, but the present invention has a low cutting current of 3 to 6 A. It has been found that it exhibits cutting current characteristics, and can also have low surge characteristics. In addition, in the present invention, pb, Bi, Te, S
Among e, Bi is most preferable and its amount is 0.05 to 0.
．． 3% by weight is preferred.

The material of the present invention can be applied only to the contact electrode or to the entire electrode. Preferably, the material of the present invention is applied only to the contact electrode.

The present invention includes a vacuum container and a pair of electrodes disposed in the container, the electrodes including a contact electrode, an arc holding the contact electrode, a threat/excitation electrode, and an arc fan sb.
Coil that holds all the electrodes! ! The arc driving electrode and the coil electrode are arranged so as to generate a parallel magnetic field in the gap between the contact electrodes, and the contact electrode has a cobalt-based skeleton and a cobalt-based skeleton. The vacuum breaker is characterized in that it is infiltrated with a copper alloy containing a low melting point, high vapor pressure element that has no substantial solid solution amount at room temperature with respect to silver, cobalt and copper at room temperature.

By symmetrically providing a plurality of grooves at equal intervals on the arc driving electrode, the vortex 11 flow in the electrode can be reduced. This electrode has a lower arc generation voltage than the contact electrode. During energization, current is passed through the contact electrode, but a parallel magnetic field is formed in the gap between the contact electrodes so that the arc that occurs when the current is cut off is generated between the arc driving electrode and the contact electrode. A parallel magnetic field is obtained by the groove formed in the arc driving electrode and the shape of the coil electrode.

The arc driving electrode has a weight of C010-30%, Agl
It is preferable to use an ingot alloy in which the content of Cu is 0% or less and the balance is substantially made of Cu.

The coil electrode includes a ring-shaped ring part, an arm part passing through the axial center of a circle of the ring part, and a convex part connecting the arc driving electrode and the coil electrode provided on the ring part. and a connection portion having a connection portion, preferably made of copper. As a result, the current flowing through the electrodes flows in opposite directions on the left and right sides of the electrode, forming parallel magnetic fields.

Further, it is preferable that the axial center portion of the arm portion is ring-shaped.

The vacuum breaker of the present invention has a maximum breaking current of 6 A or less at 10 A, and an average of 4.5 A or less; an average withstand voltage of 55 kV or more in a 2-5 m gap; a diameter of 20 mm, and a radius of 10 +
An electrode made of a metal member having a breaking current of 9 kA or more due to the spherical surface of m is used. The electrode of the present invention is C
Compared to an electrode made of a u-1 wt % PB alloy, the cut-off current in the above shape is 130% or more. The cut-off current increases with the diameter of the electrode, but approximately 1 of the diameter
．． It increases to the third power. The metal member is preferably an alloy in which molten metal is infiltrated into the voids of which the metal skeleton is used.

The skeleton, whose main component is cobalt, is produced by filling a container with mechanically crushed powder and press-molding it, or by filling the powder into a container and applying vibrations to make them adhere without pressure-molding.
It can be manufactured by a method such as sintering. The porosity of the skeleton is preferably 10 to 60% by volume, so that the amount of copper alloy infiltration is 10 to 60% by weight. The sintering temperature is 9
00-1000C is preferable.

For infiltration of copper alloys, it is best to use an alloy obtained by pre-melting a copper alloy of the target composition prior to the infiltration step. In general, elements with low melting points and high vapor pressures are difficult to alloy when melting a copper-silver alloy, so it is better to use them as a mother alloy. The temperature of the molten metal and the immersion time are important factors in this infiltration. It is preferable to control the amount of cobalt in the skeleton to be 5% by weight or less in the infiltrated alloy. More preferably, it is 3% by weight or less. The gas contained in the electrode comes out during use, lowering the degree of vacuum in the vacuum container and reducing the shutoff ability, so it is desirable to carry out sufficient degassing treatment.

The skeleton containing cobalt as a main component is preferably composed essentially of cobalt. Cobalt is lAC325~
At 30%, the current interruption rate is the highest. Cobalt powder preferably has a diameter of 30 to 70 μm, particularly 40 to 50 μm.
Powders having the same diameter are preferred. The particle size of cobalt after being immersed in the copper alloy bath is preferably 10 to 50 μm in diameter. By using a powder having such a particle size, it is possible to easily infiltrate the powder and to obtain a powder having high withstand voltage and current cutoff characteristics.

[Embodiments of the invention]

Example 1 As a method for producing a Co skeleton serving as a matrix, mechanically crushed -250 to +325 mesh C
The O powder was annealed at a temperature of about 500 to 700 C in a hydrogen atmosphere, and then preformed using a hydraulic press to have a predetermined porosity.

These were further pre-sintered at a high temperature of 900 to 1000C in a hydrogen atmosphere. After sintering, further 1000~1100
Vacuum degassing was performed at a high temperature of C to thoroughly remove the occluded gas. A Cu-Ag-Co-low melting point, high vapor pressure elemental infiltration alloy was manufactured as follows. Oxygen-free copper (OFC) and 99.99 wt% pure Ag shot with an inner diameter of 60rrrr
x Set it in a carbon crucible, and set it in a 1 to 5 x 110
-5IIIIIIH high frequency melting in vacuum, Cu-A
After confirming that g was melted, 1 atm of high-purity Ar gas was sealed, and then a predetermined amount of a low-melting-point, high-vapor-pressure element was added.

In this way, evaporation loss of 13i etc. can be prevented and an infiltrated alloy that is considerably gas-free can be obtained.

Next, using the Co skeleton and infiltrated alloy described above,
I will explain how to obtain it. The Co skeleton is placed on a carbon holder and preheated by high frequency heating. At the same time, the above-mentioned infiltrated alloy is placed in a master alloy melting crucible in the lower part, and is empty-melted. After preheating the Co skeleton to about 1000C and confirming that the master alloy has completely melted, the skeleton is immersed in the molten infiltrated alloy. After soaking for 3 to 5 minutes in a predetermined direct position to dissolve a part of the Co skeleton into the infiltrated alloy, the skeleton?
Raise it to the top and let it cool in the furnace. By the above operations, an excellent infiltrated alloy with a filling density of 97 to 99% can be obtained. As an example of the alloy according to the present invention obtained in this way, 70
%Co-30% (84%Cu-15%Ag-3%C0-
Microstructure of an infiltrated alloy with a composition of 1% (13i)
00 times), it was found that it consisted of large gray particles and a Cu-Ag-Co-Bi alloy in the white part of the base.

By the above manufacturing method, various infiltration alloys with i>, Co as a base were produced, and electrodes finished with a spherical surface with a diameter of 20 mm and a radius of each electrode contact surface of Low were collected from these alloys, and an assembled type exhaust gas was used. Various electrical performances were investigated using a set of vacuum pulp breaker test equipment.

Table 1 shows the composition of the electrode materials.

Table 1: For the withstand voltage cutoff test, first cut off AC300A for 1° to clean the electrodes, then reduce the impulse voltage to 5°.
The discharge voltage was measured by applying it in kV steps. The electrode gap at this time was 2.5 m. ACIO for cutting current measurement
The cutting current that occurs when the current of A is cut off is 10
Measurement was performed 0 times, and the maximum and average values were determined. Current breaking performance is so.

Cu-1, which is commonly used as the current when the A step is repeatedly cut off and becomes impossible to cut off.
The maximum breaking current of the weight% PB alloy is assumed to be 100%, and the comparison value (%) is shown.

In addition, both the inventive material and the conventional material have good electrode surface conditions when cut off at the maximum cutoff current, and have good welding resistance, especially when Co contains 30 to 60% by weight of Cu-A.
Materials infiltrated with g-Co-Bi alloy are superior.

Note that the cutoff current of the Cu-lPb alloy is approximately 7 kA, and the alloy is located at grain boundaries.

It is a molten alloy with Pb.

FIG. 4 is a diagram showing the relationship between the amount of infiltration of an infiltrated alloy containing 30% by weight of Ag and the average withstand pressure. The numbers in the diagram are alloy tombs. As shown in the figure, as the amount of infiltrated alloy in the Co skeleton increases, the average withstand pressure decreases rapidly. From the viewpoint of pressure resistance characteristics, the content of the infiltrated alloy is preferably 40% by weight or less. 8.9 to no
It is clear that the conventional alloy has a lower pressure resistance even with the same amount of infiltration.

FIG. 5 is a diagram showing the relationship between the amount of infiltration and the current interrupting performance of the same infiltrated alloy with <30% Ag by weight.

As shown in the figure, it can be seen that the current interrupting performance of the alloy of the present invention is significantly superior to that of the conventional alloy, which is 48.9, even with the same infiltration amount. In particular, when the amount of infiltration is 10 to 60% by weight, a current interrupting performance of 130% or more can be obtained.

FIG. 6 is a diagram showing the relationship between the amount of infiltration of an infiltrated alloy containing 30% by weight of Ag and the cutting current. The infiltration amount of the present invention material is 10
%, the maximum breaking current is clearly less than 6A,
The average cutting current is 4.5A or less.

FIG. 7 is a diagram showing the relationship between the amount of Ag in an infiltrated alloy with an infiltrated amount of 30 to 60% by weight, average withstand voltage, current breaking performance, and cutting current. These properties are greatly influenced by the content of Ag. As shown in the figure, Ag significantly lowers the breakdown voltage characteristics. In particular, in order to achieve a breakdown voltage of 55 kV or more, the Ag amount should be 12% or less. Furthermore, the current interrupting performance is significantly reduced depending on the amount of Ag. In order to obtain a current interrupting performance of 130% or more, it is 12% or less. The cutting current decreases rapidly as the amount of Ag increases, resulting in a low cutting current.

Example 2 An electrode using the material of the present invention was built into a vacuum pulp for a vacuum breaker shown in FIG. Such a vacuum pulp has an insulating cylinder 11 made of ceramics or crystallized glass, both ends of which are sealed by metal terminal plates 12, 12'. Its interior is designed to maintain a pressure of 10''mHg or less. A fixed electrode 10 and a movable electrode 10'', which can be opened and closed via a bellows 16, are incorporated in the terminal board 12 as a pair of electrodes. After evacuation to a pressure of The fixed electrode 10 and the movable electrode 10' each have a contact electrode 13.
14 are provided, both of which are joined to auxiliary electrode members 18, 18' made of Cu and Cu alloy. An example of the material of the present invention for the auxiliary electrode is 70% or 40%c.

A contact electrode made of -30 or 60% by weight (84.5% by weight Cu - 17% by weight Ag - 0.25% by weight Bi) alloy is brazed, and an auxiliary electrode is made of Cu.

19.19'. As in Example 1, these one-point electrodes are made of Co skeleton-'Cu-A.
g-Bi gold alloy was infiltrated for about 4 minutes. Part of the skeleton CO is dissolved in the infiltrated alloy after infiltration, and approximately 3
It contained % by weight. The amount of Bi in the entire electrode is 0.
075% by weight and 0.15% by weight. FIG. 2 is a detailed structural diagram of the electrode 10, 10', and FIG. 3 is an assembled perspective view thereof. Both electrodes have the same structure. The contact electrodes 13.14 are joined to the arc driving electrodes 21.21', and are made of a material with a lower shear arc voltage than the contact electrodes 13.14. The arc driving electrode 21°21' has a third
As shown in the figure, the eddy current reduction groove 2 is
2.22' is provided.

The arc driving electrode 21.21' is made of a copper-20 weight % cobalt-3 coulometric % iron alloy.The arc driving electrode 21.21' is further joined to the coil electrode 20.20'. The coil electrode 20.20' has a ring portion 26.26',
It consists of an arm part 24.24', a shaft center part 27.27, and a connecting part 25.25' with an arc driving electrode 21.21' provided symmetrically on the shaft part 26.26'. The coil electrodes 20 and 20' are made of highly conductive pure copper.

Similarly, pure copper is used for the holders 19 and 19'.

As shown in FIG. 2, the contact electrode 13.14 is embedded and joined to the arc driving electrode 21.21'. Each current is connected to an arc generated when the current is cut off to the contact electrode 13.
14 and the arc drive electrodes 21, 21', so that a parallel magnetic field is generated in the gap between the electrodes. As shown in FIG. 3, the electrodes are arranged 90 degrees symmetrically to each other. The directions of the arc drive electrodes 21 and 21' are shifted by 90 degrees from the eddy current reduction grooves 22 and 22', and similarly, the arm parts 24 and 24' of the coil electrodes 20 and 20' are arranged orthogonally to each other. be done. With this arrangement, o~90' and 180~270°
The magnetic field direction of 90° to 180° and 270° to 360° are completely opposite to each other, resulting in parallel magnetic fields. Due to the generation of such a magnetic field, the arc that occurs when it is cut off is
It is controlled so that it is generated from the entire contact electrode and arc drive electrode.

Rated 12 using vacuum pulp with the above structure.
When a short circuit current of kV/50 kA was cut off, it was confirmed that good cut-off properties were obtained, and the withstand voltage characteristics and welding resistance were also excellent. In addition, the cutting current generated when cutting off a small current of 2 to 6 A in a 12 kV circuit is as low as about 3 to 5 people, and it also has conventional low surge properties.

〔Effect of the invention〕

As described above, according to the present invention, a large capacity vacuum breaker with excellent voltage resistance and welding resistance can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram showing an example of a vacuum breaker according to the present invention, FIG. 2 is a front view showing an example of a vacuum breaker electrode according to the present invention, and FIG. 3 is an example of a vacuum breaker electrode according to the present invention. Figure 4 is a diagram showing the relationship between the average withstand pressure and the amount of infiltration alloy, and Figure 5 is a diagram showing the relationship between current interrupting performance and the amount of infiltration alloy. , Figure 6 is a diagram showing the relationship between the cutting flow and the amount of infiltrated alloy, and Figure 7 is a diagram showing the relationship between the average withstand voltage and cutting current and the amount of Ag in all electrodes. Figure 1,000'1

Claims (1)

[Scope of Claims] 1. A device having a vacuum container and a pair of contact electrodes disposed within the container, in which at least one of the pair of electrodes has silver 10 in the void of a skeleton substantially made of cobalt. ~50% by weight, 0.1 to 3% by weight of one or more of bismuth, lead, tellurium and selenium, cobalt 5
A vacuum shear breaker characterized in that it is constituted by a member in which 10 to 50% by weight of a copper alloy is infiltrated based on the total weight of the electrode, with the remainder being substantially copper. 2. A device having a vacuum container and a pair of electrodes arranged in the container, wherein the electrodes include a contact electrode, an arc drive electrode that holds the contact electrode, and a coil electrode that holds the arc drive electrode. the arc driving electrode and the coil electrode are arranged so that a parallel magnetic field is generated in the gap between the contact electrodes, and at least one of the contact electrodes is
In the voids of a skeleton mainly composed of cobalt, copper is the main component, 10 to 50% by weight of silver, 5% by weight or less of cobalt, and 0.1 to 3% of one or more of lead, tellurium, bismuth, and selenium.
1. A vacuum shear disconnector characterized in that it is constituted by a member infiltrated with a copper alloy containing % by weight. 3. The arc driving electrode contains 10 to 30% by weight of cobalt;
The vacuum shear disconnector according to claim 2, characterized in that it is made of a molten alloy consisting of 10% by weight or less of silver and the remainder substantially of copper. 4. The vacuum shear breaker according to claim 2, wherein the coil electrode is made of copper. 5. The vacuum chamber according to claim 2, wherein the arc driving electrode is symmetrical and provided with a plurality of grooves at approximately equal intervals, thereby reducing eddy current. Or disconnection. 6. The coil electrode connects a ring-shaped ring part, one arm part passing through the axial center of the circle of the ring part, and the arc driving electrode provided on the ring part and the coil electrode. 3. The vacuum shear breaker according to claim 2, further comprising a connecting portion having a convex portion. 7. In a device having a vacuum container and a pair of electrodes arranged in the container, both of the electrodes are contact electrodes,
The arc driving electrode has an arc driving electrode that holds the contact electrode, a coil electrode that holds the arc driving electrode, and a holder that holds the coil electrode, and the arc driving electrode has a plurality of grooves provided at equal intervals. , has a bilaterally symmetrical shape, and is made of a melted alloy consisting of 10 to 30% by weight of cobalt, 10% by weight or less of silver, and the remainder substantially copper;
In the voids of the skeleton consisting essentially of cobalt, silver 10
~50% by weight, 0.1 to 3% by weight of one or more of bismuth, lead, tellurium, and selenium, 5% by weight of cobalt or less, and the remainder substantially copper, making up 10% of the entire contact electrode. Consisting of ~50% by weight infiltrated members,
The coil electrode includes a ring-shaped ring part, one arm part passing through the axial center of the circle of the ring part, and a convex part provided on the ring part and connecting the arc driving electrode and the coil electrode. and a connecting portion having a connecting portion made of copper, the direction of the groove of the arc driving electrode and the arm portion of the coil electrode so as to generate a parallel magnetic field in the gap formed between the contact electrodes. A vacuum shield and disconnector characterized in that the directions thereof are arranged to intersect with each other at 90 degrees.