JPS63175308A - Vacuum valve - 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] [Purpose of the invention] (Industrial field of application) The present invention relates to the electrode structure of a vacuum valve, and in particular to a vacuum valve with excellent low surge performance, large current interruption performance, and large current carrying performance. Regarding.

(Prior Art) As a conventional vacuum valve considering low surge performance, for example, the one shown in Japanese Patent Application Laid-Open No. 58-38425@ is known. The electrode structure of this vacuum valve is as shown in Figs. 5, 6, and 7.
It is composed of an end plate 3a and a movable end plate 3b, and a fixed side electrode 4a and a movable side electrode 4b are fully supported in the vacuum vessel 1 by a fixed side energizing shaft 5a and a movable side energizing shaft 5b so as to be able to come and go. .

The fixed electrode 4a includes a fixed coil electrode 9a for generating an axial magnetic field fixed to the tip of the fixed current-carrying shaft 5a, and a fixed contact 8a disposed on the surface side of the fixed coil electrode 9a and electrically connected to the fixed coil electrode 9a. It consists of The movable electrode 4b includes a movable coil electrode 9b for generating an axial magnetic field fixed to the tip of the movable current-carrying shaft 5b, and a movable contact 8b electrically connected to the movable coil electrode 9b. Note that the end plate 3b of the movable current-carrying shaft 5b is received from the arc shield 7 on the inner surface of the vacuum vessel 1.
A bellows 6 is provided at the sliding contact portion.

The contacts 8a and 8b are formed from a silver-tungsten carbide (hereinafter referred to as Ag-WC) based sintered material, and coil electrodes 9a and 9b are electrically connected by a current-carrying part 10 on the back surface of the contacts 8a and 8b. is provided. In the coil electrodes 9a, 9b, the current from the current-carrying shafts 5a, 5b is shunted by the coil shunting arm portion 11 and flows into the circular arc portion 12. The current flowing through the arc portion 12 generates an axial magnetic field (longitudinal magnetic field) in the space between the electrodes 4a and 4b.

This axial magnetic field uniformly spreads the arc ignited between the contacts, causing the ! of the contacts 8a, 8b! Since i (I) can be made small, it is possible to interrupt large currents compared to flat plate electrodes or spiral electrodes.In addition, Ag-
Since 8a and 8b are formed of WC material, they also have low surge performance that can suppress the cutting current to 1A or less when a small current is interrupted. Note that 13 is a slit and 14 is a reinforcing material.

(Problem to be solved by the invention) However, since the contacts 8a, 8bG, and tA9-WC are made of a low-surge material, they generally have low thermal conductivity, and tungsten carbide (hereinafter referred to as tungsten carbide) W
It is brittle because it is a sintered material of fine powder of @ (hereinafter referred to as Cu) and copper-chromium (hereinafter referred to as Cu-Qr).
Compared to , it is more susceptible to thermal shock and has a smaller breaking limit current. Therefore, A g-Wc is used as the material for the contacts 8a and 8b.
It is possible to laminate the material and Cu-Cr material together, but
In this case, the arc ignited on the Ag-WC material does not migrate onto the CLI-Qr material due to local concentration of heat due to its low thermal conductivity and low arc voltage, resulting in low surge performance. It was not possible to create an electrode structure that also had large current interrupting performance.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vacuum valve that has excellent low surge performance, as well as large current interrupting performance and large current carrying performance.

[Structure of the invention] (Means for solving the problem) In order to achieve the above object, the first invention is as follows:
In a vacuum valve having an electrode in which a pair of contacts that can freely come into contact with and separate from the inside of the vacuum vessel are arranged on opposing surfaces, a large diameter and a small diameter electrode are provided on the opposing back surface of the electrode and extend in the circumferential direction with the same center as the electrode. a coil electrode having a circumference of
These two coil electrodes are electrically connected in parallel on the back surface of the electrode, and are arranged so that the direction of current flowing through the large-diameter and small-diameter coil electrodes is opposite, and the opposing electrodes are also connected in parallel. The electrodes have the same structure, and the directions of the electrodes flowing through the circumferential portions with the large diameter are the same, and the directions of the currents flowing through the circumferential portions with the small diameter are the same.

Further, the second invention provides a vacuum valve having an electrode in which a pair of contacts that can freely come into contact with and separate from the inside of the vacuum container are arranged on opposing surfaces, and an identical electrode having the same center as the above electrode is provided on the opposite back surface of the electrode. A coil electrode is provided having a plurality of circular arc parts with a large diameter extending on the circumference and a plurality of circular arc parts with a small diameter extending on the same circumference, and each of the circular arc parts of the two groups of coil electrodes is connected to the back surface of the electrode. are electrically connected in parallel, the direction of the current flowing through the group of large-diameter circular arc parts is the same, and the direction of the M flow flowing through the group of circular arc parts with a small diameter is the same.

(Function) With the above structure, when the current is interrupted, the contacts separate and the arc ignited in the electrode space is caused by the difference in the magnitude of the axial magnetic field. Since the current sharing in the arc ignited by the electrode member with a small arc voltage drop is increased compared to the contact with a large arc voltage drop, damage to the contact is reduced and current interrupting performance can be improved.

Furthermore, when a small current is interrupted, the axial magnetic field proportional to the interrupting current is small, and an arc is ignited on a contact point that protrudes from the others, making it possible to exhibit low surge performance.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings. Here, since both the movable side electrode and the fixed side electrode have the same structure, only the movable side electrode will be explained. In FIG. 1, on the opposite surface of the electrode 20 on the fixed side electrode side, there is an electrode member 21 formed in a donut shape on the outer periphery and made of Cu-0r material, and an electrode member 21 in the center thereof that protrudes from the others toward the fixed side electrode side. The contact points 22 formed from AQ-WC material are fixed concentrically by brazing or the like (X). A large diameter coil electrode 23 and a small diameter coil electrode 24 arranged inside the large diameter coil electrode 23 and slightly larger than the outer diameter of the contact 22 are provided. The electrodes 20 are electrically connected to each other by coil current-carrying parts 23c and 24G on the back surface thereof.The coil current-carrying parts 23c and 24c each have a circumferential part (hereinafter referred to as a coil part) that goes around the axis of the electrode 20 approximately once. ')23
b, 24b are connected, and the coil portions 23b, 24
The other end of b is electrically connected to an electrode base 26 and a current-carrying shaft 27 via coil current-carrying parts 23a and 24a, respectively. Note that the coil current-carrying parts 23c and 24c are arranged at axially symmetrical positions. Further, the coil current-carrying parts 23a and 24a are similarly arranged at axially symmetrical positions. The large diameter coil electrode 23 and the small diameter coil electrode 24 are connected to each coil portion 23.
The directions of the currents flowing through the electrodes 20 and 24b are opposite to each other around the axis of the current-carrying shaft 27, and the current flows through the electrodes 20 and 24b.
Between the electrode base 26 and the coil electrodes 23 and 24, thin ring-shaped reinforcing members 25a and 25b made of a low conductivity material such as stainless steel are provided at equal intervals in the circumferential direction. ．． Coil electrodes 23, 24, electrode base 26
are fixed to each other to prevent deformation of each part due to closing and opening operations. Furthermore, the contact 22 and the electrode member 21 are provided with a slit 28 that extends in a straight line toward the center of the contact 22 in the radial direction.

Furthermore, each coil electrode 23,24 has a cross-sectional area of 5ipS2.
and the center radius r1 and r2 are approximately equal.

In the electrode structure configured as described above, when a current ■ flows in the direction of the arrow as shown in FIG. 2, and the movable electrode (not shown), which has the same structure as in FIGS. Then, an arc 29 is ignited on the electrode member 21.

This arc 29 is diffused over the contact 22 by the axial magnetic field generated by the current flowing through the coil electrodes 23,24. Here 1. The axial magnetic field on contact 22 is
The direction of the current flowing through the coil electrodes 23 and 24 is opposite, and is weakened by the influence of the current I that flows through the large-diameter coil electrode 23. and has a magnetic field zero point near the inner circumference of the contact 22,
Furthermore, a strong upward magnetic field is generated radially outward. As the interrupting current increases, the absolute value of each axial magnetic field strength also increases in proportion to the current. Therefore, the magnetic field on the outside of the contact 22 in the radial direction becomes stronger, and the charged particles of the arc 29 generated in the space between the electrodes are reinforced by the lines of magnetic force of the strong magnetic field on the electrode member 21. It is also distributed. At this time, as shown in Figure 3, the arc voltage is reduced by the axial magnetic field (axial magnetic flux density), so the arc voltage drop under a weak downward axial magnetic field is lower than under a strong upward axial magnetic field. higher than the arc voltage of Therefore, the strength of the magnetic field (the share of the current of the arc 29 on one electrode member becomes large. Therefore, when the current value is large in the AC half wave of the breaking current, ignition occurs on the electrode member 21 made of Cu-Cr. The current sharing in the arc 29 increases, and the damage to the contact 22 made of low-surge material AQ-WC becomes slight, due to the high withstand voltage and large current breaking performance of the electrode member 21, and the effect of improving the breaking performance due to the axial magnetic field. It is possible to interrupt large currents.

In addition, in FIG. 3, for example, Cu-CrlOKArms
1 is a diagram showing the relationship between the axial magnetic field strength and the arc voltage when the material is Qu-Cr and a 10 KA (effective value) interrupting current is passed. Furthermore, when the current exceeds its peak and becomes smaller, or in the case of normal switching of current, the axial magnetic field weakens and stands out from the others, and because the thermal conductivity is small, the cathode spot on the contact 22 reaches the current zero point. It easily lingers and exhibits low surge performance.

Since the product of the center radius and cross-sectional area of each of the large-diameter coil electrode 23 and the small-diameter coil electrode 24 is approximately equal, the current divided into both is approximately equal, and a stable axial magnetic field proportional to the current is generated. It is possible.

Furthermore, since the reinforcing members 25a and 25b are provided as shown in FIGS. 1 and 2, deformation during opening and closing operations is thereby prevented. Contact point 22. Since the electrode member 21 and the electrode 20 are provided with a plurality of slits 28 extending linearly in the radial direction, there is no influence of disturbance of the axial magnetic field due to eddy currents.

By subjecting the electrode constructed in this manner to current aging, a thin film layer of ultrafine particles of A9°Cu and Qr is formed on the facing surface of the electrode 20, which reduces the melt removal force.
It is possible to obtain effects such as lower pressure resistance.

According to the embodiment of the present invention described above, when a large current is interrupted due to the axial magnetic field distribution, the current share of the arc 29 on the electrode member 21 is increased, and the damage caused by the large current interruption on the contact 22 is minimized. Moreover, since it is possible to ignite an arc on the contact 22 when the current is small, a vacuum valve having improved large current interrupting performance and low surge performance can be obtained.

The present invention is not limited to the embodiments described above, and for example, as shown in FIG. 4, the large-diameter coil electrode 33 and the small-diameter coil electrode 34 are divided into a plurality of large-diameter circular arc parts 33b and small-diameter circular arc parts 34b, respectively. The large-diameter arcuate portion 33b and the small-diameter arcuate portion 34b are electrically connected in parallel to the current-carrying shaft 27. Electrode 22
The current flowing through the large diameter coil electrode group 33 is arranged so that the direction of the current flowing through the small diameter coil electrode 34 is opposite to each other. It is also possible to provide a vacuum valve with electrodes configured to strengthen the axial magnetic fields generated by the coil electrodes 33 and 34. FIG. 4 shows an example in which it is divided into two parts, for example. By dividing the large-diameter coil electrode 33 and the small-diameter coil electrode 34 into a plurality of circular arc parts 33b and 34b, the impedance of the vacuum valve is lowered, so that in addition to the effect of the above-mentioned embodiment, a larger amount of current can be passed. things become possible.

[Effect of the Invention J] The present invention is constructed as follows. The first invention provides a vacuum valve having an electrode in which a pair of contacts that can freely come into contact with and separate from the interior of a vacuum container are arranged on opposing surfaces, and a circumferential direction having the same center as the electrode on the opposite back surface of the electrode. A coil electrode is provided which has a large-diameter and a small-diameter circumferential part that extend to .The two coil electrodes are electrically connected in parallel on the back surface of the electrode, and the current flowing through the large-diameter and small-diameter coil electrodes is The electrodes are arranged so that the directions are opposite, the opposing electrodes have the same structure, and the direction of the electrodes flowing through the circumferential portion of each large diameter is the same, and the direction of the current flowing through the circumferential portion of each small diameter is the same. That's what I did. Further, the second invention is a vacuum valve having an electrode in which a pair of contacts that can freely come into contact with and be separated from the inside of a vacuum container are arranged on opposing surfaces, and a pair of contacts that are arranged at the same center as the electrode on the opposite back surface of the electrode. A coil electrode is provided having a plurality of circular arc parts with a large diameter extending on the same circumference and a plurality of circular arc parts with a small diameter extending on the same circumference, and each of the circular arc parts of the two groups of coil electrodes is connected to the electrode. They are electrically connected in parallel on the back surface, and the direction of current flowing through the group of large-diameter circular arc portions is the same, and the direction of the current flowing through the group of circular arc portions with small diameter is the same. With this configuration, it is possible to provide a vacuum valve that has excellent low surge performance and improved large current interruption performance and large current conduction performance.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the electrode structure of an embodiment of the vacuum valve of the present invention, Fig. 2 is a sectional view taken along line II-II in Fig. 1 and viewed in the direction of the arrow, and Fig. 3. FIG. 1 is a diagram showing the relationship between the arc voltage, axial magnetic field, and breaking current of the contact material used, FIG. 4 is a plan view showing the electrode structure of another embodiment of the vacuum valve of the present invention, and FIG. FIG. 6 is a plan view of a conventional vertical magnetic field type electrode, and FIG. 7 is a cross-sectional view taken along line -■ in FIG. 6 and viewed in the direction of the arrow. DESCRIPTION OF SYMBOLS 1... Vacuum valve, 2... Insulating container, 3... End plate, 5a... Fixed side current-carrying shaft, 5b... Movable side current-carrying shaft,
7... Arc shield, 20... Electrode, 21...
Electrode member, 22...Contact, 23.33...Large diameter coil electrode, 24°34...Small diameter coil electrode. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 4 = Figure 5

Claims (14)

[Claims] (1) In a vacuum valve having an electrode in which a pair of contacts that can freely come into contact with and separate from the inside of the vacuum container are arranged on opposing surfaces, a large diameter extending in the circumferential direction with the same center as the electrode is provided on the opposite back surface of the electrode. and a coil electrode having a circumferential portion with a small diameter are provided, and these two coil electrodes are electrically connected in parallel on the back surface of the electrode, and the direction of the current flowing through the large diameter and small diameter coil electrodes is opposite. A vacuum valve in which the electrodes facing each other have the same structure, the direction of the electrodes flowing through the circumferential portion of each large diameter is the same, and the direction of the current flowing through the circumferential portion of each small diameter is the same. . (2) If the center radius of the circumferential part of the small-diameter coil electrode is r_1 and the cross-sectional area is s_1, and the center radius of the circumferential part of the large-diameter coil electrode is r_2 and the cross-sectional area is s_2, then r_1/s_1
The vacuum valve according to claim 1, wherein the vacuum valve satisfies the relationship ≧r_2/s_2. (3) A pair of electrodes with movable contacts on opposing surfaces have a diameter equal to or smaller than the outer diameter of the small diameter coil electrode. 2. The vacuum valve according to claim 1, wherein a contact material consisting of: ) is provided protrudingly on the opposing surface of the electrode. (4) An electrode member made of copper (Cu)-chromium (Cr) material and having an outer diameter equal to or smaller than the outer diameter of the electrode is arranged around the contact member provided protruding from the opposing surface of the electrode. The vacuum valve according to claim 3, characterized in that: (5) The vacuum valve according to claim 1, wherein a plurality of slits extending linearly in the radial direction are provided at equal intervals in the contact, the electrode member, and the electrode. (6) A patent claim characterized in that a ring-shaped reinforcing material made of a low conductivity material such as stainless steel is provided between the back surface of the electrode and each coil electrode, and between each coil electrode and the current-carrying shaft. The vacuum valve according to item 1. (7) The contact material is subjected to current aging to form a thin film layer made of fine particles of copper (Cu), chromium (Cr), and silver (Ag) on the opposing surface of the electrode. Vacuum valve as described in section. (8) In a vacuum valve having an electrode in which a pair of contacts that can freely come into contact with and separate from the inside of the vacuum vessel are arranged on opposing surfaces, a pair of contacts that can be freely connected and separated from each other are provided on the opposite back surface of the electrode, and extend on the same circumference with the same center as the electrode. A coil electrode is provided which has a plurality of circular arc parts with a large diameter and a plurality of circular arc parts with a small diameter extending on the same circumference, and each of the circular arc parts of the two groups of coil electrodes are electrically parallel to each other on the back surface of the electrode. A vacuum valve that is connected to a vacuum valve in which the direction of current flowing through a group of large-diameter circular arc parts is the same, and the direction of current flowing through a group of small-diameter circular arc parts is the same. (9) If the center radius of the circumferential portion of the small-diameter coil electrode is r_1 and the cross-sectional area is s_1, and the center radius of the circumferential portion of the large-diameter coil electrode is r_2 and the cross-sectional area is s_2, then r_1/s_
Claim 8, characterized by satisfying the relationship: 1≧r_2/s_2
Vacuum valve as described in section. (10) A pair of electrodes with movable contacts on opposing surfaces have a diameter equal to or smaller than the outer diameter of the small diameter coil electrode. 9. The vacuum valve according to claim 8, characterized in that the contact material is provided protrudingly on the opposing surface of the electrode. (11) A contact material made of copper (Cu)-chromium (Cr) material is formed around the contact material protruding from the opposing surface of the electrode.
11. The vacuum valve according to claim 10, further comprising an electrode member having an outer diameter equal to or smaller than the outer diameter of the electrode. (12) The vacuum valve according to claim 8, wherein a plurality of slits extending linearly in the radial direction are provided at equal intervals in the contact, the electrode member, and the electrode. (13) A patent claim characterized in that a ring-shaped reinforcing material made of a low conductivity material such as stainless steel is provided between the back surface of the electrode and each coil electrode, and between each coil electrode and the current-carrying shaft. The vacuum valve according to item 8. (14) Claim 11, characterized in that the contact material is subjected to current aging to form a thin film layer made of fine particles of copper (Cu), chromium (Cr), and silver (Ag) on the opposing surfaces of the electrodes. Vacuum valve as described in section.