JPS63259934A - 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 [Object of the Invention] (Industrial Field of Application) The present invention relates to a vacuum valve, and particularly to an electrode structure with excellent low surge performance and high current interrupting performance.

(Prior Art) Conventionally, as a vacuum valve considering low surge performance, for example, Japanese Patent Application Laid-Open No. 58-38425 is known. The structure of this vacuum valve is as shown in FIGS.
3 to form a vacuum container 4, and a pair of electrodes 5 and 6 which can be freely brought into and out of contact with each other are disposed inside the vacuum container 4. The movable energizing shaft 8 of the electrode 6 is movably attached to the end plate 3 via a bellows 9, the arc shield 10 surrounding the electrodes 5 and 6 is attached to the insulating cylinder 1, and the bellows cover 1
1 is attached to the current-carrying shaft 8.

Further, the structure of the electrodes 5 and 6 is such that the opposing contact surfaces are Ag-W.
Electrode body 14.15 formed from C-based sintered material and serving as a contact point
Coil electrodes 16 and 17 are provided on the back surface of the coil electrodes 16 and 17, which are electrically connected through current-carrying parts 16a and 17a.

Current from the fixed and movable energizing shafts 7, 8 is shunted into the coil electrodes 16, 17 by the coil shunt arms 16b, 17b, and flows into the coil arc parts 16c, 17c.

The current flowing through the coil arc portions 16c and 17c generates an axial magnetic field in the electrode space. This axial magnetic field uniformly spreads the arc ignited between the contacts, minimizing damage to the contacts, making it possible to interrupt larger currents than with flat plate electrodes or spiral electrodes. Moreover, the opposing contact surfaces of the electrode bodies 14 and 15 are made of low-surge contact material Ag-W.
Since it is made of C-based sintered material and also serves as a contact, it also has low surge performance that can suppress the cutting current to below IA.

(Problems to be Solved by the Invention) However, low-surge contact materials such as Ag-WC generally have low thermal conductivity and are brittle (such as Cu or Cu-WC) because they are sintered materials of fine powder. Compared to Cr, it is weaker against thermal WJ shock and has a relatively small breaking limit current, so it was not possible to create a structure that has both low surge performance and large current breaking performance.

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

[Structure of the invention]

(Means and effects for solving the problems) The present invention has the following features:
A vacuum valve in which a pair of electrodes having an electrode body and a coil electrode that generates an axial magnetic field is disposed in a vacuum container formed by closing both end openings of an insulating cylinder with end plates so as to be able to move toward and away from the vacuum chamber, A circular concave portion is provided on the surface of the electrode body, and an electrode face plate made of a Cu-Cr material is fixed thereto, and a contact made of a low-surge contact material fixed to this electrode face plate is fixed to the electrode face plate.
A coil arm part that extends in the radial direction and is connected to one side of the coil arc part of the coil electrode disposed on the back surface of the electrode body, and a coil that is connected to the other side of the coil arc part and extends in the radial direction. The structure is such that it is arranged between the folded parts and not separated from the electrode face plate, so that the axial magnetic field generated by the coil electrode is weaker on the low-surge contact material than on the Cu-Cr material. It has low breaking current characteristics, excellent low surge performance, and excellent large current breaking performance.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings. Note that the general structure of the vacuum valve of the present invention is the same as the conventional one, and the structure of the fixed side electrode and the movable side electrode is the same, so the movable side electrode will be explained, and the fixed side electrode will be explained. Explanation will be omitted. Fig. 1 is a plan view of a movable side electrode according to an embodiment of the present invention, and Fig. 2 is a cross-sectional view taken along the line A-0-A of Fig. 1 and viewed in the direction of the arrow. The movable side electrode 20 includes a coil electrode 22 which has one end fixed to the end of the movable current-carrying shaft 21 and generates an axial magnetic field (vertical magnetic field), and a coil electrode 22 which is fixed to the other end of this coil electrode 22 and is made of Cu material. The electrode body 23 has a circular concave portion on its surface (the surface facing the fixed electrode), and the circular concave portion of the electrode body 23 is fixed to the circular concave portion by brazing or the like, and has a height equal to or less than the surface of the electrode body 23. It protrudes slightly more than Cu-Cr.
An electrode face plate 24 formed from a material, and an Ag which is fixed to this electrode face plate 24 and whose main component is Ag-WC and which contains Co, Ti, Bi, To, B, etc. in an amount of 10 vt% or less of the total weight as an additive. -Radius 5-10m+ with WC type contact material
The contact point 25 is formed into a circular shape and protrudes from the electrode face plate 24 by 1 to 3 m.

Thus, the coil electrode 22 is integrally fixed to the movable energizing shaft 11 [121 by brazing or the like, and is connected to the coil mounting portion 22a, which extends in the radial direction and directs the current flowing through the energizing shaft in the radial direction. One end is connected to the tip of the coil arm 22b and extends in the circumferential direction, so that an axial magnetic field is generated in the electrode space when a current flows through the coil arm 22b. Coil arc part 2
2c, a coil folded part 22d at the other end of this coil arc part 22c for changing the current flowing in the circumferential direction in the radial direction, and further, a coil folded part 22d for connecting to the electrode body 23 at the end of this folded part 22d. It has a coil connecting portion 22e.

In addition, the above-mentioned contact point 25 is located between the side surface 22f to which the coil arc portion 22c of the coil arm portion 22b is not connected, and the side surface 22f when viewed from the plane of the electrode body 23, as shown in FIG.
2f and between the side surfaces 22g of the coil folded portion 22d, which are in contact with or slightly separated from both sides, II!
The electrode plate 24 should not protrude more than 1/2 of the radius of the pole body 23, and the plurality of pieces should be arranged concentrically with the electrode body 23. In addition, the movable side electrode 2
Both electrodes are arranged so that when the electrode 0 moves and contacts the fixed electrode, the two electrodes have contact points with each other.

Next, the operation of the electrodes of the vacuum valve configured as described above will be explained. When a short circuit or ground fault occurs and a rated breaking current flows through the vacuum valve, and the movable electrode 20 is separated from the fixed electrode by an operating mechanism (not shown), a cathode is placed on the contact 25 of the electrode that has become a cathode. The spots are ignited and the metal vapor plasma they produce maintains an arc in the interelectrode space. At this time, an axial magnetic field is generated in the space between the electrodes due to the current flowing through the coil arc portions 22c of the coil electrodes 22 of both electrodes. However, the coil arc portion 22c of the coil electrode 22 does not exist near the back surface of the contact 25 of both electrodes, and it passes through the coil folded portion 22d to reach the coil connecting portion 22e, and passes through the electrode body 23 to the contact 2.
5, the current flowing near the contact point 25 of both electrodes does not have a circumferential component, that is, the strength of the axial magnetic field at the contact point 25 and its vicinity is weaker than that around it. An arc ignited on an electrode with a weak axial magnetic field becomes unstable when the instantaneous value of the arc current becomes large, as shown in Figure 3, because the arc voltage is large in a weak magnetic field, and the arc only occurs on the contact 25. Stable ignition is no longer possible, and the cathode spot also partially moves onto the surrounding electrode face plate 24 made of Cu-Cr material. Electrode face plate 2
When the arc is ignited on 4, the axial magnetic field strength there is strong enough to produce an arc voltage near the minimum value in FIG. 3, and the arc voltage is sufficiently low to stabilize the arc. At this time,
In order to keep the voltage between the electrodes balanced, the current share is increased in the area where the arc voltage is low.

Most of the arc moves onto the electrode face plate 24, reducing contact wear to maintain a high current arc on the contact 25 and reducing contact damage. Since the Cu-Cr material has large current interrupting performance and is a high withstand voltage contact material, the interrupting performance is further improved by combining it with a vertical magnetic field electrode. Therefore, the electrode structure of the above-described embodiment has a large-capacity breaking performance in addition to the damage reduction effect of the low-surge contact material.

In the case of interrupting a small current such as a steady load current, the axial magnetic field strength in the entire interelectrode space is weak, the arc voltage difference between the contacts 25 and the electrode face plate 24 is small, and there is no contact between the contacts 25. Since the contact point has a contact point, the arc mainly ignites on the contact point until the load current is cut off at the current zero point. Here, the contact 25 is made of Ag-WC or a small amount of Ss, Bit B
Since the metal material is mainly composed of Ag-WC containing low melting point materials such as , To, etc., the average cutting current is approximately 0.
．． The electrode structure exhibits low cutoff characteristics of 8 amperes or less and can realize a low-surge vacuum valve.

By containing 10vt% or less of Co or T1 in the contact 25, the bonding force between fine particles of the WC compound in the metallographic structure of the contact 25 is strengthened, suppressing arc damage to the contact and interrupting large currents. advantageous to

According to the above configuration, due to the effect of having a contact point between the Cu-Cr material, the axial magnetic field and its strength distribution, and the contact whose main component is Ag-WC, when a large current is interrupted, the Cu-Cr
By increasing the current sharing on the electrode face plate of the material, A g −W
Damage caused by breaking large currents to the C contact can be minimized, and when the current is small, an arc can be ignited in the A g -W C material, improving breaking performance and reducing the average severance. A vacuum valve having low surge performance with a current of 0.8 A or less can be provided.

Note that the present invention is not limited to the above-described embodiments, and the contact 25 is made of a low-surge material made of an alloy containing a high vapor pressure, low melting point material based on Ag or Cu, and Similar effects can be achieved in a vertical magnetic field electrode in which the electrode face plate 24 is made of a Cu-Cr material, and a vacuum valve with improved cutoff performance and low surge performance can be provided.

〔Effect of the invention〕

The present invention is configured as described above.

It combines low-surge contact material and Cu-Cr with good breaking performance, and has a contact point between the low-surge contact and the Cu-Cr material, as well as a vertical magnetic field electrode, so it has low surge performance and high current breaking performance. Due to the arc diffusion effect on Cu-Cr, a vacuum valve with low surge and large interrupting capacity can be provided.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a movable side electrode according to an embodiment of the present invention;
FIG. 2 is a cross-sectional view taken along the A-0-A line in FIG. A diagram showing the relationship between directional magnetic flux density, FIG. 4 is a sectional view showing the configuration of a conventional vacuum valve, FIG. 5 is a plan view showing the electrodes of the conventional vacuum valve, and FIG. FIG. 2 is a cross-sectional view taken along line 0-A and viewed in the direction of the arrow. 1... Vacuum container 20... Movable side electrode 22.
...Coil electrode 22b...Coil arm portion 22c.
...Coil arc part 22d...Coil folding part 23...
・Electrode body 24...Electrode face plate 25...Contact agent Patent attorney Norihiko Ken Yudo Daishimaru Ken Figure 1 Figure 2 Figure 3 Figure 4 A Figure 5 Figure 6

Claims (3)

[Claims] (1) A vacuum in which a pair of electrodes having an electrode body and a coil electrode that generates an axial magnetic field is arranged so as to be able to be moved toward and away from the inside of a vacuum container formed by closing the openings at both ends of an insulating cylinder with end plates. In the bulb, a circular recess is provided on the surface of the electrode body to which an electrode face plate made of a Cu-Cr material is fixed, and a contact formed in a disc shape from a low-surge contact material fixed to this electrode face plate is attached with a diameter of 1 to 3 mm. a coil arm that protrudes and extends in a radial direction and is connected to one side of a coil arc portion of the coil electrode disposed on the back surface of the electrode body;
A vacuum valve characterized in that the vacuum valve is arranged between coil folded parts connected to the other side of the coil arc part and extending in the radial direction so as not to come off from the electrode face plate. (2) The low-surge contact material contains sintered Ag-WC as the main component, and contains Co, Ti, Se, Bi, Te, etc. at a weight ratio of 10 wt% or less without impairing its low breaking current characteristics.
The vacuum valve according to claim 1, which contains B or the like. (3) The vacuum valve according to claims 1 and 2, wherein the vacuum valve is equipped with an electrode having contacts, an electrode face plate, and a coil electrode, and is subjected to current aging.