JPH09147699A - Vacuum valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the breaking capacity of a vacuum valve by forming a pair of electrode, of which contact is formed of a disc-shaped center part and a ring-shaped peripheral part, so as to form vertical magnetic electrodes for separately generating an axial magnetic field. SOLUTION: When a current carrying shaft is driven by an external operating mechanism so as to open a contact of a vacuum valve so as to break the current, arc is firstly ignited in a ring-shaped contact 33. At this stage, the current is flowed to a tip of a coil electrode 31 of the peripheral part, and a coil electrode 32 of the center part is not operated. With an increase of the current, the arc is moved to a contact 34 of the center part by the self-pinching force. A magnetic field between the contacts at a sum of a first and a second coils is thereby formed, and it is effective in the dispersion of the arc. Consequently, in comparison with the conventional vertical magnetic field electrode, a current area for maintaining the arc in the dispersing condition is increased so as to improve the breaking performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum valve, and more particularly to an electrode structure for a vacuum valve that improves the breaking performance.

[0002]

2. Description of the Related Art The structure of a vacuum valve used in a conventional vacuum circuit breaker is shown in FIG. As shown in FIG. 1, a conventional vacuum valve 10 includes a fixed electrode 14 and a movable electrode 15 which can be brought into contact with and separated from each other in a vacuum container configured by closing both ends of an insulating cylinder 11 with a fixed flange 12 and a movable flange 13. Are arranged and configured. Here, the fixed electrode 14 is fixed to the tip of the fixed energizing shaft 16, and is electrically connected to the outside of the vacuum container by the fixed energizing shaft 16. The movable electrode 15 is fixed to the tip of the movable energizing shaft 17, and is electrically connected to the outside of the vacuum container by the movable energizing shaft 17. The movable energizing shaft 17 is fixed to the movable flange 13 via a bellows 18, and allows the electrodes 14 and 15 to be brought into and out of contact with each other by an operation mechanism portion (not shown) while maintaining the vacuum in the vacuum container. . Electrode 1
An arc shield 20 is attached to the inner surface of the insulating cylinder 11 around 4, and 15.

By the way, since the vacuum valve utilizes the excellent dielectric strength of vacuum, the distance between the electrodes can be made smaller and smaller than that of, for example, an SF ₆ gas circuit breaker using another insulating medium. it can. Further, the breaking capacity can be increased by improving the electrode structure. In order to improve the shutoff performance of the vacuum valve, the electrodes 14,
It is necessary to suppress the local heating of the electrode due to the arc generated during the period 15. As a result, the generation of abnormal charged particles and the generation of metal vapor due to local heating of the electrode can be suppressed, and the blocking performance can be improved. As an electrode structure for this purpose, a method of applying a force by a magnetic field to an arc generated between the electrodes when the current is cut off is generally used.

As one of the methods of applying a magnetic field, there is a method of applying a perpendicular magnetic field to an arc generated between electrodes. The electrode structure using this method is generally called a spiral electrode or a contact electrode. The magnetic field generated by such an electrode structure is a magnetic field in the radial direction from the center of the electrode. Therefore, since a perpendicular magnetic field is applied to the arc generated between the electrodes, a Lorentz force acts on the arc in the circumferential direction. Due to this force, the arc is rotationally driven in the circumferential direction and rotates on the electrode surface. By rotating the arc, it is possible to prevent local heat input and prevent melting of the electrodes.

However, with the progress of vacuum circuit breakers,
In recent years, it has come to be applied to high voltage circuits. In order to apply to a high voltage, it is necessary to increase the distance between the electrodes in order to improve the withstand voltage between the electrodes. In such a case, using an electrode structure that applies a magnetic field perpendicular to the arc generated between the electrodes described above, when the arc rotates on the electrode surface, the arc is extended in the circumferential direction and radiated from the electrodes. It may jump out in the direction. In such a case, the arc generated from the electrode ignites the arc shield mounted around the electrode. When the arc is ignited on the arc shield in this manner, the arc stays at that position and locally generates an excessive heat input. Due to this excessive heat input, the electrodes and the arc shield may be melted and the breaking performance may be deteriorated. Further, in the electrode structure of such a system, as described above, since the arc state is a high-temperature concentrated arc, the wear of the contacts is large, and the switching life at the time of breaking a large current may be shortened.

As another method of applying a magnetic field to the arc generated when the current is cut off, there is a method of applying a magnetic field in the axial direction parallel to the arc generated between the electrodes.
The electrode structure adopting such a method is generally called a vertical magnetic field electrode. In this case, the arc generated between the electrodes uniformly spreads over the entire electrodes, a local excessive heat input of the electrodes can be prevented, and an electrode structure with excellent blocking performance can be obtained. Further, even when the distance between the electrodes is large with respect to the high voltage, it is possible to ignite a stable arc between the electrodes by improving the magnetic field strength and improve the breaking performance. Furthermore, since the arc form is a distributed arc, the contact wear is small even when a large current is interrupted, and the switching life can be extended.

A conventional vertical magnetic field electrode structure for generating a typical axial magnetic field will be described. A contact is arranged on the front surface of the plate-shaped electrode. On the back surface of the electrode, a coil electrode formed by an arm portion extending radially from the center and a coil portion extending from the tip of each arm portion in an arc shape is arranged.
A current flowing in the coil portion of the coil electrode can generate a magnetic field parallel to the arc between the electrodes. Further, the number of coil portions can be changed to change the strength of the magnetic field in the axial direction.

As another longitudinal magnetic field electrode structure for generating an axial magnetic field, a spiral slit is formed in the cylindrical portion of a cup-shaped electrode to generate an axial magnetic field as shown in Japanese Patent Publication No. 32007/2007. A structure that allows it is proposed. In this case, by making the current path of the cylindrical portion spiral, an arc-direction component of the current is generated, thereby generating an axial magnetic field between the electrodes. The magnetic field strength in the axial direction is
It can be changed by a method such as changing the inclination of the slit of the cylindrical portion.

[0009]

Recently, a vacuum circuit breaker using a vacuum valve has been widely used. Along with this, there are cases where it is applied even when the system is large. Therefore, it has become necessary to increase the breaking capacity and the conducting capacity.

In order to meet such demands, improvements in electrode structure and contact material are being made. A special alloy such as a CuCr alloy has been developed as a contact material for improving the breaking performance. On the other hand, as a result of investigating the relationship between the magnetic field strength and the arc voltage from a study of a longitudinal magnetic field electrode structure that generates a magnetic field in parallel with the arc generated between the contacts, it is clear that the arc voltage shows the minimum value at a certain magnetic field strength. It has become. By applying the magnetic field strength that the arc voltage shows the minimum value, the energy consumed between the contacts is minimized,
Maximum breaking performance.

The magnetic field strength at which the arc voltage is minimized varies depending on the electrode diameter, the breaking current, the contact material, and the like. In order to change the magnetic field strength, the magnetic field strength can be increased by reducing the number of arms. For example, by reducing the number of arms from four to three and two, the magnetic field strength increases by about 1.3 times and two times, and the optimum magnetic field strength can be obtained and the blocking performance can be improved. Can be improved.

However, the magnetic field distribution in the axial direction with respect to the radial direction is such that the central portion becomes higher. In the case of such a magnetic field distribution, the spread of the arc is such that the central part of the electrode has a slightly larger current density than the peripheral part of the electrode. In the vicinity of the normal rated breaking current, melting of the electrode is suppressed and it is possible to break. However, when the current to be interrupted further increases, the self-pinch force acts on the arc state which was a diffusion arc due to the effect of the magnetic field in the axial direction, and the arc is further concentrated in the central portion. When the arc concentrates in this way, the contact melts and the current interruption capability is limited. Therefore, an object of the present invention is to provide a vacuum valve provided with a contactor and an electrode structure capable of increasing the breaking capacity.

[0013]

According to a first aspect of the present invention, the electrodes of the vacuum valve are constituted by longitudinal magnetic field electrodes for independently generating an axial magnetic field in the central portion and the peripheral portion, and the central portion Disk-shaped contacts are arranged on the electrodes, and ring-shaped contacts are arranged on the peripheral electrodes. The invention according to claim 2 is further arranged so that the direction of the axial magnetic field generated by the central electrode is opposite to the direction of the axial magnetic field generated by the peripheral electrode.

According to a third aspect of the present invention, the electrode of the vacuum valve is a first coil electrode including an arm portion extending radially from the center of the shaft and a first coil portion extending in an arc shape from the tip of the arm portion. A second arm portion extending axially from the tip of the coil portion of the first coil electrode and a second coil electrode formed of a second coil portion extending in an arc shape from the second arm portion. The ring-shaped contactor is arranged on the front surface of the first coil electrode, and the ring-shaped contactor is electrically connected to the tip of the coil portion of the first coil electrode. The disk-shaped contactor is arranged inside, and the disk-shaped contactor is electrically connected to the tip of the coil portion of the second coil electrode. In the invention according to claim 4, the direction of the axial magnetic field generated by the current flowing through the first coil electrode is opposite to the direction of the axial magnetic field generated by the current flowing through the second coil electrode. It is arranged so that.

According to the structure described in claims 1 to 4, when an arc is ignited between the contactors, the magnetic field generated depending on the position of the arc can be distributed differently. Since the arc generated in the interval can be efficiently and stably controlled in the diffused state, the breaking performance can be improved.

Further, according to the invention of claim 5, the surface height of the disk-shaped contactor is set to 1 from the surface height of the ring-shaped contactor.
The invention according to claim 6 is
When the outer diameter of the electrode portion is D1 and the outer diameter of the disk-shaped contactor is D2, the outer diameter D2 of the disk-shaped contactor satisfies 0.1 × D1 ≦ D2 ≦ 0.7 × D1. According to a seventh aspect of the present invention, in the axial direction, the center position of the axial section of the second coil electrode is set to the axial center of the second coil electrode from the central position of the axial section of the first coil electrode. It is arranged at a position on the opposite surface side.

According to the structure described in claims 5 to 7, it is possible to divide the arc and optimize the generated magnetic field, and it is possible to improve the breaking performance. Further, according to the invention of claim 8, a plurality of contacts are arranged on each electrode of the vacuum valve, and a longitudinal magnetic field electrode for independently generating an axial magnetic field is arranged corresponding to each of the contacts to make contact. The magnetic field generated by the longitudinal magnetic field electrode is distributed differently depending on the position of the arc ignited between the children. With this configuration, when the arc is ignited between the contacts, the magnetic field generated depending on the position can be distributed differently, and the arc generated between the contacts can be efficiently diffused. Since the state can be stably controlled, the breaking performance can be improved.

Further, in the invention according to claim 9, the material of the contactor is mainly composed of Cu or Ag, and Co, C
An alloy containing at least one or more of r, Fe, Mo, W or a compound thereof and having a total content of 20 to 70% by weight. The invention according to claim 10 uses a ring-shaped contact material. The disc contactor is selected so that the arc voltage of the disc contactor is higher than that of the contactor. According to the invention of claim 11, Cu is used for the disc contactor.

When the contactor is made of the materials described in claims 8 to 11, the contactor can be restrained from being consumed. According to a twelfth aspect of the present invention, the electrode of the vacuum valve includes a first arm portion that extends radially from the center of the shaft, and a first coil portion that extends in an arc shape from the tip of the first arm portion.
A second arm portion and a second arm portion extending from the first coil portion toward the center.
A second coil electrode is formed from a second coil portion that extends in an arc shape from the tip of the arm portion of the arm, and a disk-shaped contactor is arranged on the entire surface of the coil electrode. The electrode is electrically connected to the tip of the first coil portion and the tip of the second coil portion, and the surface of the disk-shaped contactor has a central portion that is concave from the outer peripheral portion.

With this structure, when the arc is ignited between the contacts, the magnetic field generated depending on the position can be distributed differently, and the arc generated between the contacts can be efficiently generated. Since the diffusion state can be controlled stably, the breaking performance can be improved.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The structure of the entire vacuum valve is the same as the conventional one shown in FIG. An embodiment of the electrode portion according to the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment corresponding to the invention described in claims 1 and 2. Energizing shaft 30
At the tip of each of the
And the coil electrode 32 at the center is connected. The outer diameter of the central coil electrode 32 is smaller than the inner diameter of the coil of the peripheral coil electrode 33. Contacts are independently electrically connected to the front surfaces of the respective electrodes, a hollow annular contact 33 is arranged in the coil electrode 31 in the peripheral portion, and a coil electrode 32 in the central portion is
The plate-shaped contactor 34 is electrically connected.

The operation and effect of the embodiment having such a configuration will be described below. When the electric current is opened and closed by the vacuum valve, the energizing shaft is driven by the operation mechanism connected to the outside of the vacuum valve to open and close the contact of the vacuum valve.

Here, the magnetic field generated in the vicinity of the contactor when the current is cut off when the first coil and the second coil are oriented in opposite directions will be described with reference to FIG. Contactor 3 with arc-shaped arc when current is cut off
Fire at 3 first. At this time, the current flows to the tip of the coil electrode 31 in the peripheral portion and reaches the contact 33, so that the coil electrode 32 in the central portion does not work. Therefore, when the arc is ignited on the ring-shaped contactor 33, a magnetic field (FIG. 2A) equivalent to that of the conventional longitudinal magnetic field electrode is generated,
Applied to the arc.

However, as the current increases, the self-pinch force acts on the arc, and the concentration at the center starts.
When the arc is concentrated, the arc that had been ignited by the ring-shaped contactor until then is transferred to the contactor 34 at the center. When the arc is ignited to the contactor 34, the current flows through the second coil portion, so a magnetic field is also generated by the second coil portion, and the magnetic field between the contactors is the same as the magnetic field by the first coil and the second magnetic field.
2 and the magnetic field generated by the coil of FIG.

It has been clarified by our research that it is effective for diffusing an arc by such a magnetic field distribution. Therefore, the current region in which the arc can be kept in a diffused state is increased as compared with the conventional longitudinal magnetic field electrode, so that the breaking performance can be improved.

FIG. 3 is a front view of an embodiment corresponding to the invention described in claims 3 and 4, and FIG. 4 is a sectional view thereof. A coil electrode 35 is electrically connected to the tip of the energizing shaft 30. The coil electrode 35 includes a first arm portion 35a extending radially from the center and a first arm portion 35.
A first coil portion 35b extending from a in an arc shape, and a second arm portion 35 extending from the tip end 35c of the first coil portion toward the shaft side.
d, a second coil portion 35e extending in an arc shape from the second arm portion 35d, and a tip 35f of the second coil portion. A ring-shaped contactor 3 is provided on the front surface of the first coil.
3 are connected via the tip 35c of the first coil portion. The tip 35c of the first coil portion and the tip 35f of the second coil portion project toward the contacts 33, 34. The tip 35 of the second coil is provided on the front surface of the second coil portion 35e.
A disk-shaped contactor 34 is connected via f.

Regarding the height of each contact, the surface height of the plate contact 34 is lower than the height of the ring contact 33 by 1 mm or more. As a result, at the moment when the contactor is opened to cut off the current, the contact point is formed only on the ring-shaped contactor 33, and thus the contact point is dispersed into three or more points. By distributing the contact points, the current density at each contact point can be reduced.

Therefore, when the three points are in uniform contact with each other, the shared current flowing in the contact portions is 1 as compared with the case where the contact point is the central one point like the conventional plate contactor. / 3. Furthermore, since the energy is proportional to the square of the current, it becomes 1/9 in each part, and the total of 3 parts becomes 1/3 as compared with the conventional case. From this, the momentary energy of opening the current may damage the electrode and shorten the switching life, but since the energy can be reduced in the present invention, damage at the time of opening the electrode can be reduced,
The switching life can be extended.

The size of the disk-shaped contactor 34 is as follows. When the arc is concentrated on the center of the electrode, the concentration is rapidly promoted when the central portion reaches a current density of 20 A / mm ^{2 to} 30 A / mm ² or more. Such current concentration occurs within 10% or more of the center of the arc in the entire electrode. Therefore, the diameter of the hollow part of the contact (D2)
Is preferably 10% or more of the outer diameter (D1) of the electrode portion. Further, if the hollow portion of the contactor is enlarged, the area of the entire contactor is reduced. Therefore, if the area of the contact is reduced too much, the current density increases and local melting occurs.
On the other hand, when the total area is ½ or less, the effect of suppressing the melting of the central part and effectively using the whole is offset by the factor of the decrease in the blocking performance due to the decrease in the contactor surface area, and the effect of the present invention is lost. . Therefore, the diameter of the hollow portion of the contactor must be 70% or less of the outer diameter of the electrode portion. From the above results, the outer diameter (D2) of the hollow portion of the ring-shaped contactor and the outer diameter (D1) of the electrode portion satisfy the relationship of 0.1 × D1 ≦ D2 ≦ 0.7 × D1. The blocking performance can be improved.

Further, regarding the positional relationship between the electrode and the contactor, the position of the second coil portion is set to be greater than that of the first coil portion.
By approaching the contactor side, it is possible to increase the magnetic field strength by the second coil when the arc ignites on the disk-shaped contactor at the center.

Therefore, when the arc is concentrated, the magnetic field at the central portion can be made smaller than that at the electrode end portion, so that the breaking performance can be improved. Further, as the material used for the contact, Cu or Ag as a main component, Co,
At least 1 of Cr, Fe, Mo, W or a compound thereof
The total content is 20 to 70 wt% including at least one kind, and the electrode contains Cu or Cu as a main component and its content is 90 wt%.
It is preferable to use an alloy containing the above.

That is, in the case of a material in which a high vapor pressure material is added to Cu or a material which forms an intermetallic compound with Cu is added to the contactor, the consumption amount is larger than that of the above material. When the amount of wear is large as described above, opening and closing the load current may cause wear of a portion of the contact protruding from the electrode surface, and the height may be the same as that of the electrode. Then, since the arc starts to be generated at the electrode portion at the instant when the current is cut off, the spread of the arc is significantly reduced. on the other hand,
When the above-mentioned materials other than the present invention are used, it is necessary to increase the height of the contact in order to prevent arcing from occurring in the electrode portion. The distance between the vertical magnetic field generating electrodes is increased, and the effect of the magnetic field is reduced. From this, by using the above-mentioned materials, even if a current is opened and closed, arcing does not start at the central electrode, and the opening and closing life can be extended. further,
By using a material whose main part is mainly composed of Cu, some arc is ignited on the electrode part, and a part of electric current is processed by the electrode part, so that the breaking performance can be improved. it can.

Further, when the contactor whose material is selected so that the arc voltage of the disc contactor 34 is higher than the arc voltage of the ring contactor 33, the arc voltage becomes higher when the arc is concentrated. . Therefore, since a force that lowers the arc voltage acts on the arc, the concentration of the arc is suppressed and the breaking performance can be improved. For example, when a copper material is used for the disk-shaped contactor and the ring-shaped contactor is made of a copper-chromium alloy, the arc voltage of the ring-shaped contactor becomes high and the breaking performance can be improved.

FIG. 5 shows a sectional view of an embodiment relating to the twelfth aspect of the invention. The coil electrode 35 shown in FIG. 5 is the same as that shown in FIG. 3, and a contactor 36 having a recess at the center is connected to the front surface thereof. The coil electrode 35 and the contact 36 are connected to each other via the coil portion tips 35c and 35f.

When the contactor 36 is opened, the central portion of the contactor 36 is more concave than the outer peripheral portion, and therefore only the outer peripheral portion is in contact. Therefore, when the contact 36 is opened, the outer peripheral portion is first ignited. Contact 36
When the arc is ignited at the outer peripheral portion of, the current flows through the end portion 35c of the first coil. Therefore, the coil produces a magnetic field equivalent to that of a conventional longitudinal magnetic field electrode. Then, when the arc concentrates on the central portion, the tip 35f of the second coil becomes closer, so that the current is also shunted to the second coil. Therefore, the magnetic field has a strong distribution in the peripheral portion and a weak distribution in the central portion. Due to this change in the magnetic field distribution, the concentration of the arc can be suppressed and the breaking performance can be improved.

[0037]

According to the present invention described above, in the electrode structure inside the vacuum valve, the arc generated between the contacts is changed by changing the distribution of the axial magnetic field applied to the arc depending on the ignition position of the arc. Since the arc can be efficiently and stably controlled in a diffused state without being concentrated in the central portion of the electrode, the breaking performance can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a change in magnetic field distribution depending on an arc firing position.

FIG. 3 is a front view of an embodiment corresponding to claim 3 and claim 4;

FIG. 4 is a sectional view of an embodiment corresponding to claim 3 and claim 4;

FIG. 5 is a sectional view of an embodiment corresponding to claim 12.

FIG. 6 is a diagram showing a conventional vacuum valve.

[Explanation of symbols]

11 ... Insulating cylinder, 14 ... Fixed electrode, 15 ... Movable electrode, 16 ... Fixed energizing shaft, 17 ... Movable energizing shaft, 18 ...
Bellows, 30 ... Energizing shaft, 31 ... First longitudinal magnetic field electrode,
32 ... Second longitudinal magnetic field electrode, 33 ... Ring-shaped contactor,
34 ... Disc contactor, 35 ... Coil electrode, 36 ... Contactor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Sato No. 1 in Toshiba Fuchu factory, Fuchu-shi, Tokyo (72) Inventor Yoshinori Kagecho No. 1 Toshiba-cho, Fuchu, Tokyo Toshiba Fuchu factory, Co., Ltd. (72) Inventor Eiji Kaneko 1 Toshiba Town, Fuchu-shi, Tokyo Inside Toshiba Fuchu Factory (72) Inventor Kumi Uchiyama 1 Fushima-cho, Fuchu City, Tokyo Inside Toshiba Fuchu Factory (72) Inventor Seki The 1st place in Toshiba Town, Fuchu-shi, Tokyo Tokyo (72) Inventor Atsushi Yamamoto Atsushi Yamamoto 1st Toshiba Town, Fuchu-shi, Tokyo In-house Toshiba Fuchu Plant (72) Inventor Takashi Kusano 1 Address inside Toshiba Fuchu factory

Claims (12)

[Claims] 1. A vacuum valve comprising a pair of electrodes, which are attached to and detachable from each other via a conductive rod in a vacuum container, and a contactor is provided on each of these electrodes, wherein the pair of electrodes includes a central portion and a peripheral portion. And a vertical magnetic field electrode for independently generating an axial magnetic field, wherein a disk-shaped contactor is arranged in the central electrode and a ring-shaped contactor is arranged in the peripheral electrode. valve. 2. The arrangement is such that the direction of the axial magnetic field generated by the central electrode and the direction of the axial magnetic field generated by the peripheral electrode are opposite to each other.
A vacuum valve according to claim 1. 3. A vacuum valve in which a pair of electrodes are provided in a vacuum container so as to be able to come into contact with and separate from each other via a conductive rod, and each of these electrodes is provided with a contact, the electrodes extending radially from the center of an axis. A first coil electrode including a first arm portion and a first coil portion that extends in an arc shape from a tip of the first arm portion, and a coil portion of the first coil electrode closer to the energizing shaft than the tip of the coil portion. The second coil electrode formed by a second arm portion extending and a second coil portion extending in an arc shape from the second arm portion;
A ring-shaped contactor is arranged on the front surface of the coil electrode, and the ring-shaped contactor and the tip of the coil portion of the first coil electrode are electrically connected, and a circle is formed inside the ring-shaped contactor. A vacuum valve characterized in that a plate-shaped contactor is arranged and the disk-shaped contactor is electrically connected to the tip of the coil portion of the second coil electrode. 4. The arrangement is such that the direction of the axial magnetic field generated by the current flowing through the first coil electrode is opposite to the direction of the axial magnetic field generated by the current flowing through the second coil electrode. The vacuum valve according to claim 3, wherein the vacuum valve is formed. 5. The vacuum valve according to claim 1, wherein the surface height of the disk-shaped contactor is lower than the surface height of the ring-shaped contactor by 1 mm or more. 6. When the outer diameter of the electrode portion is D1 and the outer diameter of the disk-shaped contactor is D2, 0.1 × D1 ≦ D2 ≦ 0.7 × D1 is satisfied. The vacuum valve according to any one of claims 1 to 5. 7. The center position of the axial cross section of the second coil electrode is arranged at a position on the opposite surface side of the electrode in the axial direction from the center position of the axial cross section of the first coil electrode. The vacuum valve according to any one of claims 1 to 6, wherein the vacuum valve is formed. 8. A vacuum valve comprising a pair of electrodes, which are attached to and detachable from each other via a conductive rod in a vacuum container, and each of which has a contactor. A vacuum valve characterized in that a vertical magnetic field electrode for independently generating an axial magnetic field is arranged corresponding to each contact, and the generated magnetic field is distributed differently depending on the position of an arc ignited between the contacts. 9. An alloy containing Cu or Ag as a main component and containing at least one of Co, Cr, Fe, Mo, W or a compound thereof in a total amount of 20 to 70% by weight is used for the contact. The vacuum valve according to any one of claims 1 to 8, wherein the vacuum valve is formed. 10. The vacuum valve according to claim 9, wherein a contactor made of a material whose arc voltage of the disk-shaped contactor is higher than that of the ring-shaped contactor is arranged. 11. The vacuum valve according to claim 9, wherein Cu is used for the disk-shaped contactor. 12. A vacuum valve in which a pair of electrodes are provided in a vacuum container so as to be able to come into contact with and separate from each other through a conductive rod, and each of these electrodes is provided with a contact, the electrodes extending radially from the center of an axis. The first arm portion, the first coil portion extending in an arc shape from the tip of the first arm portion, the second arm portion extending in the center direction from the first coil portion, and the second arm portion A coil electrode is formed from a second coil portion that extends in an arc shape from the tip, and a disk-shaped contactor whose surface has a concave center portion from the outer peripheral portion is arranged on the front surface of the coil electrode. -Shaped contactor is electrically connected to the tip of the first coil portion and the tip of the second coil portion.