JPH01204322A - Vacuum valve - Google Patents

Abstract

PURPOSE:To maintain low chopping current characteristics, low surging performance and high amperage current cut-off performance as well by arranging plural numbers of contact elements in a disc form with an equal interval spaced on contacting surfaces in a disc form faced with each other wherein plural numbers of slits are provided, which are deep enough more than 75% of the outer diameter of electrodes in a closed end cup form, and thereby constituting the contact elements to be brought in contact with each other when the electrodes are closed. CONSTITUTION:Contacting plates 22 and 23 in a disc form are provided for the surfaces faced with each other of electrodes 14 and 15 in a closed end cup form, wherein the plates are provided with slits 24 and 25 deep enough more than 75% of the outer diameter, and are composed of material having high voltage resistance and high amperage current cut-off performance. In addition, plural numbers of contacting elements 26 and 27 in a disc form composed of material having low surging performance are provided in the surfaces faced with each other of the contact plates 22 and 23 in such a way as to be protruded out of the surfaces with an equal interval spaced so that the contact elements 26 and 27 are constituted to be brought in contact with each other when the electrodes are closed. By this constitution, the electrodes are improved in structure so that a vacuum valve the low chopped current characteristics and cut-off performance of which are improved, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION OBJECTS OF THE INVENTION Field of Industrial Application The present invention relates to vacuum valves, and particularly to improvements in magnetically driven electrode structures.

(Prior Art) Generally, a vacuum valve opens electrodes in a vacuum evacuated to 10-4 Torr or less, and interrupts current by utilizing the excellent arc-extinguishing and insulating properties of vacuum.

Its basic configuration is shown in FIG.

In FIG. 4, the vacuum valve 1 includes an airtight container whose openings at both ends of an insulating container 2 are sealed by end plates 3 and 4, respectively, and whose interior is evacuated to a high vacuum of 10-4 Torr or less. There is. Further, a fixed electrode support rod 6 supporting a fixed electrode 5 is supported and fixed on the end plate 3, and a movable electrode 7 is provided opposite to the fixed electrode 5. It is supported by a movable electrode support rod 8 that is connected to an operating mechanism. The movable electrode support rod 8 can operate while maintaining the degree of vacuum in the airtight container by means of metal bellows 9, each of which has an airtight connection to the open end of the end plate 4. Further, a bellows cover 10 is installed to surround the metal bellows 9 in order to protect the rose 9 from melted debris from between the electrodes. Further, a shield 11 is provided to protect the inner surface of the insulating container 2 from being contaminated by metal vapor generated from the electrodes and diffused by an arc during current interruption.

Next, the above fixed electrode 5. The detailed structure of the movable electrode 7 is shown in FIG. A cup-shaped electrode structure with a bottom is disclosed in Japanese Patent Application Laid-open No. 53
As is known from Japanese Patent No. 28270, the fixed electrode 5 and the movable electrode 7 are connected to each other by a ring-shaped contact electrode 1.
2.13 and a bottomed cup-shaped electrode 14.15, which are fixed to a fixed electrode support rod 6 and a movable electrode support rod 8, respectively. Grooves 16 and 17 are formed on the side surfaces of the bottomed cup-shaped electrodes 14 and 15, respectively, so that the arc generated between the ring-shaped contact electrodes 12 and 13 stagnates in a part. This makes it easy to magnetically rotate the ring-shaped contact electrodes 12 and 13 without having to do so.

When interrupting a large current of several KA or more using the vacuum valve configured as described above, the arc magnetically rotates on the ring-shaped contact electrodes 12 and 13, and the interruption is completed at the current zero point, but the current is less than several hundred. When the current is cut off, the arc plasma between the electrodes diffuses into a high vacuum, and furthermore, below the current zero point of several + A, the energy balance at the cathode spot, which is the source of metal vapor ejection, collapses and becomes unstable. Become,
A current interruption occurs, and the current is cut off several to several tens of times before reaching the natural current zero point. This phenomenon causes a surge voltage to be generated on the load side of the vacuum circuit breaker. This breaking current value varies depending on the circuit on the load side of the vacuum circuit breaker and the contact material, but in general, contact materials with high withstand voltage characteristics and large current breaking performance have higher arc extinguishing characteristics. Since the energy balance at the spot is disrupted by a relatively large current value and the cathode spot is likely to disappear, the cutting current value becomes as high as several A or more, generating a large surge voltage.

In order to reduce this cutting current value, in a cup-shaped electrode with a bottom as shown in Fig. 5, which magnetically drives the arc,
As a contact material for the ring-shaped contact electrode 12.13, a melt-based material containing 1% by weight or more of a high vapor pressure material such as bismuth, tin, or tellurium, or an arc maintenance material such as silver-tungsten carbide and more. Also used is a sintered material made of an arc-resistant material that has a high melting point and low vapor pressure, and has low breaking current characteristics.

(Problem to be Solved by the Invention) However, materials such as melt systems containing 1% by weight or more of high vapor pressure materials such as bismuth, tin, and tellurium, or arc maintenance materials such as silver-tungsten carbide,・A low-surge contact material with low rupture current characteristics, such as a sintered material made of an arc-resistant material that has a higher melting point and lower vapor pressure than other materials, is used in the rings of the magnetically driven bottomed cup-shaped electrodes 5 and 7. When used as a shaped contact material, the height direction of the bottomed cup-shaped electrode 14.15 is Even if you make the ring-shaped contact larger, or change the cutting angle of the grooves 16 and 17 on the side surface, lengthen the distance through which the current flows on the electrode, and increase the strength of the magnetic field in the radial direction, the ring-shaped contact 1
The arc ignited during 2.13 has no more than three revolutions during the breaking current half cycle, and the ring contact 12.13
The arc that was ignited during this period cannot be rotated at high speed,
A part of the arc is the inner bottom 1 of the bottomed cup-shaped electrode 14.15
8. Since the arc diffuses to the 19 part or stays at one place on the ring-shaped contacts 12 and 13 for a relatively long time, the contact material is severely worn out and damaged, making it easy to fail to shut off. It is difficult to interrupt the above current.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vacuum valve with improved electrode structure, low breaking current characteristics, and improved breaking performance.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a plurality of slanted slits symmetrically on the side surfaces of both the fixed side and movable side electrodes in the shape of a bottomed cup. In a vacuum valve with an electrode structure that generates a radial magnetic field in the space between the electrodes when shut off, a cap of approximately the same outer diameter and 75 mm of the outer diameter is placed on the opposing surface of the bottomed cup-shaped electrode.
A disc-shaped contact is provided with a slit to a depth of % or more, and is made of a material with high withstand voltage and large current breaking performance. Disc-shaped contacts made of a material having low surge properties are provided at equal intervals and protrude from the surface, and the disc-shaped contacts are configured to come into contact with each other when the contact is closed.

(Function) When interrupting a current of several hundred A or less, such as a load current, an arc ignited between the disc-shaped contacts will occur between the disc-shaped contacts because the interrupting current is relatively small. Since the radial magnetic field generated by the arc is small and the magnetic driving force is also small, there is no rotational movement, so the arc continues to ignite. Since the disc-shaped contact is made of a low-surge material, it exhibits low susceptibility and suppresses the generated surge voltage.

In addition, when interrupting a large current, if the gap length between the disc-shaped contacts is opened at a sufficient interval, the arc in the radial direction is sufficient to drive the arc on the disc-shaped contacts. The magnetic field acts on the arc and is spread beyond the disc-shaped contact, so
An arc is also ignited on the disc-shaped contact. Since this arc rotates and moves at high speed on the disc-shaped contact due to the radial magnetic field, wear and damage to the disc-shaped contact is minimized, and a large current can be interrupted.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. The overall structure of the vacuum valve except for the electrode portion is the same as that of the conventional vacuum valve shown in FIG. 4, so a description thereof will be omitted.

FIG. 1 is a side view showing the electrode part, and FIG. 2 is a side view showing the electrode part.
It is a top view seen along the AA line of a figure in the direction of an arrow.

In FIGS. 1 and 2, the fixed electrode 20 and the movable electrode 21 are each configured as follows.

That is, the bottomed cup-shaped electrodes 14.15 are usually made of degassed pure steel or disc-shaped contacts 22, 2, which will be described later.
The same material as that used for 3 is used. This bottomed cup-shaped electrode 14.15 has an inner bottom part 18.19, and a side surface of the cup-shaped electrode 14.15 has an inner bottom part 18.19. Grooves 18.17 are provided in order to generate a radial magnetic field between them. A slit 2 is formed on the opposite surface of the bottomed cup-shaped electrode 14, 15, which has approximately the same outer diameter as the bottomed cup-shaped electrode 14, 15, and has a depth of 75% or more of the outer diameter.
4.25 is extended, and a disc-shaped contact 22.23 made of a contact material having high withstand voltage and large current interrupting performance, such as copper-chromium or copper-tellurium-selenium, is fixed by brazing or the like. . On the opposing surface of this disk-shaped contact 22.23, it is arranged so that it does not protrude beyond the side surface of the bottomed cup-shaped electrode 14.15, and slightly in the axial direction than the disk-shaped contact 22.23. The protruding disk-shaped contacts 26 and 27 are 3
They are fixed by brazing or the like in an evenly spaced arrangement, and when the contact is closed, the opposing contacts come into contact with each other. This contact26.
No. 27 is arc-resistant with materials such as melt systems containing 1% by weight or more of high vapor pressure materials such as bismuth, tin, and tellurium, or with arc sustaining materials and high melting point, low vapor pressure materials such as silver-tungsten carbide. The contact material is made of a sintered material and is formed from a low surge contact material that exhibits low shatterability.

According to the vacuum valve configured in this way, when interrupting a current of several hundred A or less, such as a load current, the contactor 2
Since the breaking current is relatively small, the arc ignited between 6.27 and 16.17 of the bottomed cup-shaped electrode 14.
Since the radial magnetic field generated between the contacts 26 and 27 by the current passing through is small, the magnetic driving force is also small, and since there is no rotational movement, the arc continues to ignite on the contacts 26 and 27. Therefore, since the contacts 26 and 27 are made of a low-surge contact material, they exhibit low susceptibility and can suppress the generated surge voltage.

In addition, when interrupting a current of several KA or more, contact 2
6. When the gap length between 27 and 27 is opened at a sufficient interval,
A radial magnetic field sufficient to drive the arc on contact 26.27 acts on the arc between contacts 26.27, and at high currents the diameter of the arc column also exceeds that of contact 26.27. Therefore, the arc is spread to areas other than the contacts 26 and 27, and the arc is also ignited on the disc-shaped contacts 22 and 23. The arc ignited on the low-surge contact material is difficult to rotate, but the disk-shaped contact 22 is made of a contact material that has high withstand voltage and large current interrupting performance, such as copper-chromium or copper-tellurium-selenium. The arc ignited on the disc-shaped contacts 22.
A disk-shaped contact to rotate at high speed on 23? ? .

Since consumption and damage to the material 23 are relatively small, the incoming current can be cut off.

Furthermore, with conventional bottomed cup-shaped electrodes, when the inter-electrode gap length is not sufficiently opened or when a larger current is interrupted, the arc transfers to the inner bottom part 18, 19 of the bottomed cup-shaped electrode and is interrupted. However, in the structure of the present invention, the inner bottom 18° 19 of the bottomed cup-shaped electrode is connected to the disc-shaped contact 22, 23.
Since it is covered with , the current interrupting performance is also improved. A plurality of slits 24, 25 are provided to a depth of 75% or more of the outer diameter of the disc-shaped contacts 22, 23 to prevent the generation of a magnetic field from being weakened by eddy currents generated within the disc-shaped contacts 22, 23.

Incidentally, the present invention is not limited to the above-described embodiments, but the disc-shaped contacts 22 and 23 having high withstand voltage and large current interrupting performance made of copper-chromium or copper-tellurium-selenium, etc.
As shown in FIG. 3, a plurality of arc-shaped slits 28.
29 may be provided to a depth of 75% or more of the outer diameter. Moreover, the shape of this slit may be a curved line other than an arcuate shape.

[Effects of the Invention] The present invention provides a disc-shaped contact with a plurality of slits provided to a depth of 75% or more of the outer diameter of the bottomed cup-shaped electrode on the opposing surface.
A plurality of disc-shaped contacts that do not protrude from the side surfaces and protrude beyond the disc-shaped contacts are provided at equal intervals, and the contacts are configured to come into contact with each other when closing, and The disc-shaped contact uses a contact material with high withstand voltage and large current breaking performance such as copper-chromium or copper-tellurium-selenium.
In addition, the electrode structure includes a disc-shaped contact with a sintered material consisting of an arc sustaining material and an arc-resistant material, or a low-surge material containing a high vapor pressure material, resulting in low surge performance and large current due to low rupture current characteristics. It is possible to provide a vacuum valve that also has shutoff performance.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an electrode portion of one embodiment of the present invention, FIG. 2 is a plan view taken along line A-A in FIG. 1 in the direction of the arrow, and FIG. FIG. 4 is a plan view of the electrode portion of the embodiment, FIG. 4 is a sectional view of a vacuum valve having a conventional cup-shaped electrode with a bottom, and FIG. 5 is a sectional view of the conventional cup-shaped electrode with a bottom. 14, 15...Bottomed cup-shaped electrode 20...Fixed electrode 21...Movable electrode 22, 23...Disc-shaped contact 24, 25...Slit 26, 27...Contactor (8733 ) Agent Patent Attorney Yoshiaki Inomata (Baka
1 person) Figure 4

Claims (1)

[Claims] On the sides of the bottomed cup-shaped fixed and movable electrodes,
In a vacuum valve having an electrode structure in which a plurality of symmetrical oblique slits are provided and a radial magnetic field is generated in the space between the electrodes when current is cut off, approximately 200 slits are provided on the opposing surface of the bottomed cup-shaped electrode. A disc-shaped contact with the same outer diameter and a slit extending to a depth of 75% or more of the outer diameter and made of a material with high withstand voltage and large current interrupting performance is provided, and on the opposite surface of the disc-shaped contact A plurality of disc-shaped contacts made of a material having low surge properties are provided, a plurality of which are equally spaced within the plane and protrude from the plane, so that the disc-shaped contacts come into contact with each other when closing. A vacuum valve characterized by comprising: