JPH05190062A - Electrode for vacuum circuit-breaker - Google Patents

Abstract

PURPOSE:To improve breaking performance without increasing an electrode diameter by unifying axial magnetic field distribution. CONSTITUTION:An electrode is composed of an main electrode 11, a first coil 10a generating an axial magnetic field, a second coil 10b generating an axial magnetic field in the reversed direction to the first coil 10a and being provided inside the first coil 10a, a base electrode 13 and a rod 7. The axial magnetic field distribution can be uniformalized by a method wherein a current flowing at the time of current breaking is splitted into the first coil 10a and the second coil 10b, and the axial magnetic field generated by the second coil 10b weakens the axial magnetic field generated by the first coil 10a in the central part while conversely intensity it in the peripheral part. An arc can be uniformly dispersed on the electrode surface and the breaking performance can be improved without increasing an electrode diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an electrode of a vacuum circuit breaker, particularly a cylindrical coil electrode for generating an axial magnetic field, and more particularly to improvement of distribution of an axial magnetic field generated by the coil electrode.

[0002]

2. Description of the Related Art A conventional axial magnetic field type vacuum circuit breaker will be described with reference to FIGS. 15 to 16 by taking the vacuum circuit breaker disclosed in Japanese Patent Publication No. 62-103928 as an example.

As shown in FIG. 15, the vacuum circuit breaker includes a vacuum container 3 consisting of an insulating cylinder 1 and an end plate 2, a fixed electrode 4 and a movable electrode 5 arranged in the vacuum container 3, and a vacuum from the back surface of these electrodes. It comprises rods 7 and 8 extending to the outside of the container 3, a bellows 8 for operating the movable side while maintaining airtightness, and an arc shield 22 for protecting the inner edge surface of the insulating cylinder 3 from stains.

To cut off the electric current, the rod 7 is operated by an operating device.
When the electrode is moved, the movable electrode 5 including the main electrode 11, the coil electrode 10, the spacer 12 and the base electrode 13 is separated from the fixed electrode 4 similarly, and an arc 9 is generated between both electrodes. At this time, as shown in FIG. 16, a current flows from the main electrode 11 to the coil electrode 10 through the coil electrode upper protruding portion 15,
A current flows out to the base electrode 13 through the coil electrode lower protruding portion 14, and a magnetic field H is generated by the current 23 flowing through the coil electrode 10. When this magnetic field H is applied to the arc 9, the arc is dispersed into a filament-shaped arc and extinguished.

[0005]

The axial magnetic field generated in the above conventional technique will be described with reference to FIGS. FIG. 13 is a schematic vertical sectional view of an electrode for explaining the generation of an axial magnetic field, and also shows a reinforcing plate 19 and a coil connecting rib 21 which are not shown in the perspective view of the electrode of FIG.
As shown in the figure, in the conventional technique, a cylindrical coil electrode 10 is used.
Since a magnetic field having a single polarity is generated by the above, the distribution of the magnetic field 20 in the axial direction becomes a biased distribution in which the maximum in the vicinity of the axial center and decreases as the distance from the axial center decreases, as shown in FIG. As a result, the arc cannot be evenly distributed between the electrodes, and the electrode diameter needs to be increased to improve the breaking performance.

It is an object of the present invention to evenly distribute the arc between the electrodes by making the axial magnetic field distribution uniform and to improve the breaking performance without increasing the electrode diameter.

[0007]

In order to achieve the above object, a second cylindrical coil electrode for generating an axial magnetic field in a direction opposite to that of the cylindrical coil electrode is provided inside the cylindrical coil electrode. This makes the distribution of the axial magnetic field applied between the electrodes uniform.

[0008]

In the present invention, the magnetic field generated by the second cylindrical coil electrode weakens the magnetic field generated by the first cylindrical coil electrode near the center of the axis and strengthens it near the outer circumference to thereby distribute the axial magnetic field. The homogenization results in an even diffusion of the arc between the electrodes, thus improving the breaking performance without increasing the electrode diameter.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view of an electrode showing an embodiment of the present invention. The coil electrode, which is attached to the back surface of the main electrode 11 and generates an axial magnetic field, is the first coil 10 near the outer peripheral portion.
a and a second coil 10b provided inside thereof, each coil electrode includes a first coil to a second coil connecting rib 1
7 and the second coil connecting rib 18 are connected.

When an electrode is opened to cut off an electric current and an arc is generated, a current 9a is applied to the first coil 10a from the base electrode 13 through the first coil lower protrusion 14a.
Flows into the main electrode 11 through the coil electrode upper protrusion 15. In addition, a current 9b is applied to the second coil 10b from the base electrode 13 through the second coil lower protrusion 14b.
Flows into the main electrode 11 through the coil electrode upper protrusion 15.

Since the currents 9a and 9b flowing through the first coil and the second coil flow through a plurality of arcuate current paths, they equivalently form one turn of current and generate opposite axial magnetic fields.

FIG. 2 is a schematic vertical sectional view showing the coil current of the embodiment of the present invention shown in FIG. 1, and also shows the reinforcing plate 19 not shown in FIG. Currents 9a and 9b in opposite directions respectively flow in the first coil 10a and the second coil 10b.

FIG. 3 is an axial magnetic field strength distribution of the embodiment of the present invention shown in FIG. The axial magnetic field 20b generated by the second coil is the axial magnetic field generated by the first coil.
Since 20a is weakened near the center of the axis and strengthened in the peripheral part on the contrary, the axial magnetic field obtained by combining the two becomes more uniform than the distribution of the axial magnetic field 20a generated in the case of only the first coil 10a. Since the arc is uniformly dispersed on the surface of the main electrode, the current interruption performance can be improved without increasing the electrode diameter.

FIG. 4 is a schematic vertical cross-sectional view showing a path of a current flowing through each coil of the embodiment of the present invention shown in FIG. Since the spacer 12 is made of a high resistance material such as stainless steel, most of the current flowing through the rod flows into the coil electrode. That is, the current flowing through the rod 7 is the current 9a flowing from the base electrode 13 through the first coil lower protrusion 14a to the first coil 10a and the current 9a flowing through the second coil electrode lower protrusion 14b to the second coil 10b.
b to the main electrode 1 through the coil electrode upper protruding portion 15.
1 merges with each other and flows in to generate an axial magnetic field in each coil. In the present embodiment, by optimizing the structures of the second coil lower protrusion and the second coil, the current flowing through the second coil and the axial magnetic field generated by the second coil are controlled, and the axial magnetic field distribution is made uniform. ..

5 and 6 show an embodiment for controlling the current 9b flowing through the second coil 10b in the embodiment of the present invention shown in FIG. FIG. 5 shows a structure in which a flange portion is provided on a spacer made of a high resistance material such as stainless steel, and a current is passed through the flange portion to control the current 9b flowing to the second coil 10b. There is a feature that the current value can be controlled depending on the temperature. Figure 6
Is a gap provided between the lower protrusion 14b of the second coil and the base electrode 13, and the current 9b flowing through the second coil is
Flows from the base electrode 13 into the second coil 10b through the spacer 12. In this embodiment, the base electrode 13 and the second
By changing the gap of the coil lower protrusion 14b, the current flowing through the second coil can be controlled as in the case of FIG. By the way, in the coil electrode of the embodiment of the present invention shown in FIG. 1, since the slit for dividing the second coil and the first coil intersect in the radial direction, the slit of the second coil is changed in the radial direction. There is a working problem that it cannot be milled. This point is improved by another embodiment of the present invention shown in a perspective view in FIG. The present embodiment is characterized in that the slits for dividing the first coil and the slits for dividing the second coil can be milled at the same time in the radial direction, so that the number of working steps can be reduced. FIG. 8 is a vertical cross-sectional view for explaining a current path flowing through the coil of the embodiment shown in the perspective view of FIG. The current flowing through the rod 7 flows from the base electrode 13 into the first coil 10b through the first coil lower protruding portion 14b, into the first coil 10a through the first coil to second coil connecting ribs 17, and then the first coil. Upper protrusion 15
The main electrode 11 is reached via a. In the present embodiment, the structure of the second coil is optimized to control the magnetic field generated in the second coil and make the axial magnetic field distribution uniform.

Next, FIG. 9 shows a perspective view of still another embodiment of the present invention. In this embodiment, in order to improve the current carrying capacity of the embodiment shown in FIG. 7, the lower coil 1a is attached to the first coil 10a.
4a is provided, and the slits that divide the first coil and the second coil are arranged linearly in the radial direction, so that both slits can be milled at once from the radial direction. The coil has lower protrusions 14a, 14
Since it is connected to the base electrode 13 and the main electrode 11 by b and the upper protrusions 15a and 15b, it has an advantage of being excellent in mechanical strength. FIG. 10 is a schematic vertical sectional view for explaining a path of a current flowing through the coil of the embodiment shown in FIG.
The current flowing through the rod 7 flows from the base electrode 13 through the first coil lower protruding portion 14a through the first coil 10a and the current 9a flowing from the first coil upper protruding portion 15a into the main electrode 11.
And the second coil 10 through the second coil lower protruding portion 14b.
b from the second coil upper protrusion 15b to the main electrode 11
The current is diverted to the current 9b, and an axial magnetic field is generated by each coil. A current flows through the first coil to second coil connecting rib 17 shown in the figure in accordance with the difference between the first coil side potential and the second coil side potential. When positioned, the rib 17 eliminates the potential difference.
Almost no current flows in the
Can be omitted.

11 and 12 show one embodiment for controlling the current 9b flowing through the second coil 10b in the embodiment shown in FIG. In FIG. 11, for example, a reinforcing plate made of a high resistance material such as stainless steel is used as the second coil 10b and the main electrode 11.
Inserted between them, and an electric current is passed through this reinforcing plate 19,
It controls the current 9b passing through the second coil 10b, and has a feature that the current value can be controlled by the thickness of the reinforcing plate 19. In FIG. 12, a gap is provided between the second coil lower protruding portion 14b and the base electrode 13, and the current 9b flowing through the second coil flows from the base electrode 13 into the second coil 10b through the spacer 12. In this embodiment, by changing the gap between the base electrode 13 and the second coil electrode lower protrusion 14b, the current flowing through the second coil can be controlled as in the embodiment shown in FIG. Also, as shown in FIG. 5, a spacer 12 is provided with a flange portion, and the current flowing through the second coil 10b is similarly controlled by causing a current to flow through the flange portion,
That is, the axial magnetic field generated by the second coil 10b can be controlled.

[0019]

The present invention comprises a first coil for generating an axial magnetic field and a coil provided inside thereof for generating an axial magnetic field in the opposite direction. for that reason,
The current flowing through the electrode when the current is cut off is divided into the first coil electrode and the coil electrode inside the first coil electrode, and the axial magnetic field generated by the coil inside the first coil electrode is centered on the axial magnetic field generated by the first coil electrode. The magnetic field distribution in the axial direction can be made uniform by weakening the strength in the portion and strengthening it in the peripheral portion.

As a result, since the arc can be uniformly dispersed on the electrode surface, there is an effect that the breaking performance can be improved without increasing the electrode diameter.

[Brief description of drawings]

FIG. 1 is a perspective view of an electrode showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view for explaining a coil current of the embodiment of FIG.

3 is an axial magnetic field distribution diagram of the embodiment of FIG.

FIG. 4 is a vertical sectional view for explaining a current path of the embodiment of FIG.

5 is a vertical cross-sectional view of an example of a method of controlling the current flowing through the second coil electrode of the embodiment of FIG.

6 is a vertical cross-sectional view of another example of the method for controlling the current flowing through the second coil of the embodiment of FIG.

FIG. 7 is a perspective view of an electrode showing another embodiment of the present invention.

8 is a vertical sectional view for explaining a current path of the embodiment shown in FIG.

FIG. 9 is a perspective view of an electrode showing still another embodiment of the present invention.

10 is a vertical cross-sectional view for explaining a current path of the embodiment shown in FIG.

11 is a vertical cross-sectional view of an example of a method of controlling the current flowing through the second coil of the embodiment of FIG.

12 is a vertical cross-sectional view of another example of the method for controlling the current flowing through the second coil of the embodiment of FIG.

FIG. 13 is a vertical sectional view for explaining a conventional coil current.

FIG. 14 is a conventional axial magnetic field distribution diagram.

FIG. 15 is a vertical cross-sectional view of a vacuum circuit breaker of a conventional electrode embodiment.

FIG. 16 is a perspective view of a conventional electrode.

[Explanation of symbols]

7 ... Rod, 10a ... 1st coil, 10b ... 2nd coil, 11 ... Main electrode, 13 ... Base electrode.

Front Page Continuation (72) Inventor Shunkichi Endo 4026 Kuji-machi, Hitachi City, Hitachi, Ibaraki Prefecture Hitachi Research Laboratory, Inc. (72) Inventor Yukio Kurosawa 4026 Kuji-cho, Hitachi City, Ibaraki Institute Hitachi Research Laboratory, Hitachi

Claims (3)

[Claims] 1. At least a pair of main electrodes that are arranged in a vacuum container and are freely contactable and separable, a rod extending from the back surface of the main electrode to the outside of the vacuum container, a back surface of at least one of the main electrodes, and the rod. A cylindrical coil electrode divided into a plurality of arc-shaped electric passages between, one end of the arc-shaped electric passage is electrically connected to the main electrode and the other is electrically connected to the rod, the arc-shaped electric passage An electrode for generating a magnetic field in an axial direction by a flowing current, wherein at least one coil electrode is provided inside the cylindrical coil electrode. 2. The vacuum circuit breaker electrode according to claim 1, wherein the cylindrical coil electrode and the coil electrode provided inside the cylindrical coil are connected by a rib. 3. The current control method for a coil electrode according to claim 1, wherein an axial magnetic field generated by the coil electrode is controlled by passing a current through the coil electrode through a high resistance material.