JPS63269430A - Vacuum interrupter - Google Patents

Abstract

PURPOSE:To improve the breaking performance and withstand voltage characteristic by specifying the relationship between the gap size between the outer periphery sides of a pair of electrodes in an opened state and the axial length of a main shield. CONSTITUTION:An electrode 2 is formed with a composite metal material containing copper and a hard metal with the melting point higher than that of copper. The relationship between a metal shield 3 and the outer periphery side of the electrode 2 is set to (l)/G=0.5-1.0. The metal shield 3 is formed with a main shield 18 with the thickness of 2mm and auxiliary shields 19, 20 with the thickness less than 2mm at both ends of this main shield 18, and the relationship between the axial length L of the main shield 18 and the gap size G is set to L/G>=2. The breaking performance, withstand voltage characteristic, durability, and workability can be thereby improved.

Description

[Detailed description of the invention] ^ Industrial field of application The present invention relates to a vacuum incluctor equipped with an arc magnetic rotation drive type electrode such as a spiral electrode or a contrato electrode, and particularly relates to a vacuum incluctor equipped with an electrode of an arc magnetic rotation drive type such as a spiral electrode or a contrast electrode, and in particular, This invention relates to a vacuum interrupter with improved performance.

B. Summary of the Invention The vacuum interrupter of the present invention is provided with a pair of electrodes of an arc magnetic rotation drive type made of a composite metal material containing copper and a metal that has a higher melting point than copper and is harder. The relationship between the gap size I between the metal shield surrounding the electrode and the outer peripheral side surface of the electrode and the gap size G in the open state between the outer peripheral side surfaces of the pair of electrodes is expressed as j/G=0.5 to 1. 0,
In addition, the metal shield is formed of a main shield with a plate thickness of 2 mm or more and auxiliary shields with a plate thickness of less than 2 mm at both ends of the main shield, and the axial length of the main shield and the gap dimension G are The relationship is L/G≧2.

C. Prior Art FIG. 10 shows a schematic structure of the area around the electrodes of a vacuum ink club equipped with electrodes driven by arc magnetic rotation.

In FIG. 10, electrodes 2, 2 are integrally provided on the opposing inner end surfaces of a pair of lead rods 1a, lb that are in a straight line. Further, a cylindrical metal shield 3 is provided to surround the pair of electrodes 2, 2. As electric 112,
Typical examples are spiral electrodes and contrast electrodes.

In the cutting operation, the arc 4 is rotated by magnetic force between the pair of electrodes 2, 2 to move it to the periphery of the electrodes 2, 2, and the cutting is completed when the arc 4 reaches the zero point of the current.

D Problems to be Solved by the Invention Now, considering the rotation of the arc 4, the pair of electrodes 2, 2 are surrounded by the metal shield 3, and since the arc 4 swells, the arc 4 is It will rotate with a part of it in contact with the metal shield 3.

Therefore, if the gap size l between the outer circumferential side surface 5 of the ga electrode and the metal shield 3 is too small, the portion of the metal shield 3 that the arc 4 comes into contact with will be localized, and the metal There is a problem that the shield 3 has a hole, which reduces its durability.

Methods for avoiding this include increasing the plate thickness of the metal shield 3 and increasing the gap size l, but the method of increasing the plate thickness has the problem of increasing costs.

That is, both ends of the metal shield 30 need to be rounded by drawing as an electric field relaxation process. However, the thicker the plate, the more difficult it is to draw, and this tendency is especially noticeable in the case of commonly used stainless steel, resulting in extremely poor productivity◇ On the other hand, if the gap size l is large, the arc 4 There is a problem in that the total length of the wire becomes long, and the breaking performance and W4 voltage characteristics deteriorate.

The reason for this is that when the total length of the arc is long, ■ the arc voltage increases, ■ the arc energy increases, ■ the vapor density of the arc increases, and ■ the arc running part of the electrode wears out significantly, resulting in severe surface roughness. It is.

The present invention provides a vacuum interrupter that solves the problems of the prior art described above.

E, F, ``Means for Solving Problem 1'' The inventors therefore attempted to improve the cutting performance by optimizing the gap between the electrode and the metal shield, and also An attempt was made to see if it was possible to improve the workability of electric field relaxation treatment by reducing the plate thickness only at both ends.

Experiment 1> The breaking performance of the vacuum incretor equipped with the contrast-type electrode 2 shown in FIG. 3 was investigated by changing the gap dimension I between the outer circumferential side surface 5 of the electrode 2 and the metal shield 3. However, the gap size Gl between the opposing electrodes 2, 2! G=20g
It was kept constant at mm. Other conditions are as shown in Table 1 and FIG. In addition, in this experiment and subsequent Experiments 2 and 3, for convenience, the thickness of the metal shield 3 is the same as that of the main shield 18, auxiliary shields 19, 20 shown in FIG.
Both had the same plate thickness of 1 (1,=12=1).

The experimental results in Table 1 show the characteristics fsA shown in FIG. 4, and the material is Cu-M, which has good withstand voltage characteristics.

-Cr, Cu-Fe-Cr has a gap size 4 between the outer peripheral side surface 5 of the electrode 2 and the metal shield 3.
= approximately 35 kAr in the range of 10 to 20 m,
A wide range of breaking performance of m, s or more was obtained. That is, f
! When ai12 is formed by containing a hard material such as Mo, Fe, or Cr, wear due to arcing is extremely small.
Since the material itself also has good withstand voltage characteristics, it has been found that changes in the gap size 4 greatly contribute to the breaking performance.

Note that the characteristic line B in FIG. 4 shows the contact portion 6 as a reference example.
The experimental results are shown under the same conditions when the u-0,5Bi gold alloy is used and the arc portion 8 is made of Cu. Since all of these materials are soft materials, they are subject to relatively large wear due to arcing, and therefore it has been found that even if the gap size 4 is changed, the breaking performance is hardly improved.

Experiment 2> When the vacuum interrupters used in Experiment 1 were divided into groups and investigated, traces of arc travel were found on the inner wall of the metal shield 3 and around the opposing surface 21 of the arc portion 8.

From this, the inventors have determined that there is a correlation between the gap size G between the outer circumferential sides 5, 5 of the opposing electric currents 2°2 and the gap size I between the metal shield 3 and the outer circumferential side 5 of the electrode 2. I surmised that there might be.

Therefore, the gap dimension l is set constant at 1 = 15 mm,
The breaking performance was investigated by changing the gap dimension G. Other conditions were the same as in Table 1. However, as shown in FIG. 5, the facing surface 21 of the arc portion 8 is a flat surface, and the step between the arc portion 8 and the contact portion 6 is 11 to facilitate the movement of the arc.
It was set as IIIl. Therefore, the gap size G between the pair of arc parts changes according to the relationship G = g + 2 (+ms) (g is the contact opening gap).

The experimental results are shown in Figure 6, 4=15+++n
+ for G = 15 to 30 ■ range, i.e. j/G = 0
．． In the range of 5 to 1.0, the breaking performance is approximately 35 kAr,
It was found that the performance was good, with a value of m, s, or higher.

That is, regarding the breaking performance, in the relationship between the pair of electric current ws2 and the metal shield 3, the gap size between the electrode 2 and the metal shield 3! It was found that B is more closely related to the dimension G between the pair of arc parts 8 and 8 than to the same dimension G of the pair of contacts,
The metal shield 3 is effectively used during arc rotation, and the reasons for the above-mentioned problems are as follows: increase in arc voltage, increase in arc energy, increase in arc vapor density, and wear and tear of the arc running part of the electrode and surface. It can be cut off without causing roughness. In this way, it has been found that by optimizing the relationship between the members involved in shutoff, the shutoff performance can be improved without waste.

From the results of experiments 1 and 2 above, j/G=0.5~1.0
In addition, by making the Ti electrode material a material with good withstand voltage characteristics, the metal shield 3 can be utilized to improve the breaking performance.

Experiment 3 From the above results, it was found that the metal shield 3 could be used effectively to improve the breaking performance, but next we investigated its durability.

Therefore, the relationship between the plate thickness 1 (1, = 12 = 1) of the metal shield 3 and the durability is determined by the gap size j = 10 mm between the arc portion 8 and the metal shield 3.

Two cases of 15 mm were investigated. The structure and conditions are the same as shown in FIG. 3 and Table 1.

The experimental results are shown in Figure 7. Durability was evaluated by the number of times the device was shut off until the point where the shutoff performance suddenly decreased, and the upper and lower limits of the results of examining the number of times for each of three samples are shown in FIG.

From FIG. 7, it was found that if the plate thickness t was at least 2IIIm, the durability would be extremely good. In practice, t
= 2 to 3 strands, and if the cutoff current is large, the thickness may be further increased as necessary.

<Experiment 4> From the above results, the thickness of the metal shield 3 is t≧2 mm.
It was found that the durability was good, but next, we investigated whether it was possible to increase the thickness of the central part of the metal shield 3 to 2 mm or more, and make it thinner (about 1 mm) so that only both ends could be easily rounded. .

Therefore, as in the metal shield 3 shown in FIG. 1, the thickness of the plate j The relationship between axial length and durability was investigated.

Here, t1=2 cabinets, t2=1 barrel, and 1=15 barrels.

Other structures and conditions are the same as shown in FIG. 3 and Table 1.

The experimental results are shown in Figure 8. As in Experiment 3, durability was evaluated by the number of interruptions until the interruption performance suddenly decreased. Also, the area that the arc touches is the pair of electrodes 2, 2.
Considering that it depends on the gap size G between the outer circumferential side surfaces 5, 5, experiments were conducted at four points of L/G=1.2 and 3°4 for G=20 order.

From Figure 8, if L/G≧2, all the metal shields 3 should have a thickness of 2+ms, and as in the case of 4=15 mm in Experiment 3, a stable number of interruptions could be obtained and the durability would be extremely good. I found out something.

That is, if L/G≧2, even if the auxiliary shield 19.20 is thin, the arc will not move there, so there will be no hole there, and there will be no decrease in durability due to this.

Therefore, when the metal shield 3 is made of stainless steel or the like,
Since the main shield 18 is cylindrical, t1≧2 mm, and in practice there is no problem in manufacturing even if t1 = 2 to 3 mm, and the tips of the auxiliary shields 19 and 20 are rounded as an electric field mitigation process. , this is also thin (t (2 mm, for example, about II), which makes drawing process easier and productivity improved.

Although the above description relates to a vacuum incluctor equipped with a spiral electrode, the same applies to a vacuum incluctor equipped with a contrast electrode.

FIG. 9 shows an example of a contrast electrode.

In FIG. 9, a ring-shaped contact portion 24 is joined to a cup-shaped main body 23 having an inclined groove 22 on the outer surface for driving the arc in magnetic rotation.

In the case of a contrast electrode, since most of the arc is processed on the contact portion 24, it is sufficient to form the contact portion with a composite metal material having good withstand voltage characteristics. Of course, if the arc wraps around the cup-shaped main body 23, the main body 23 is also made of a composite metal material with good voltage resistance characteristics.

The present invention has been made based on the above experimental results, and the configuration of the vacuum interrupter according to the present invention includes a pair of electrodes that magnetically rotationally drive a generated arc, and an intermediate potential surrounding the pair of electrodes. In the vacuum interrupter equipped with a metal shield, the electrode is formed of a composite metal material containing copper and a metal having a higher melting point than copper and is harder, and the metal shield and the outer peripheral side surface of the electrode are connected to each other. The relationship between the gap size 4 between the two electrodes and the gap size G in the open state between the outer peripheral sides of the pair of electrodes is expressed as 1
7G=0.5 to 1.0, and the metal shield is formed of a main shield with a plate thickness of 2 mm or more and auxiliary shields with a plate thickness of less than 2 mm at both ends of the main shield, and the main shield It is characterized in that the relationship between the axial length of and the gap size G is set to L/G≧2.

F. By finding the optimal relationship between the gap dimensions between the working electrode and the metal shield, it is possible to effectively utilize the metal shield for disconnection, and also to remove the metal shield from the center where a thick plate is required. By finding the optimal condition for the axial length of the main shield at the end, we were able to make the auxiliary shield at both ends, which require rounding, thinner, which improved the breaking performance, withstand voltage characteristics, durability, and workability. An improved vacuum interrupter can be obtained.

C example Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 shows an embodiment of the vacuum ink cleaner of the present invention.

In Fig. 1, a pair of lead rods 1 are mutually linear.
Arc magnetic rotation drive type electrodes 2, 2 are integrally provided on the opposing inner end surfaces of a and lb.

The electrode 2 in FIG. 1 is a spiral electrode, and the electrode 2 in FIG.
, As shown in (b), an arc portion 8 having a large number of spiral grooves 7 is bonded to the back surface of the ring-shaped contact portion 6. 9 is a petal.

The material of the electrode 2 is a composite metal material containing copper and a metal that has a higher melting point than copper and is harder, and in this embodiment, the contact portion 6 is made of Cu-M.

-Cr (e.g., 38Mo 13Cr-remaining Cu) sintered-infiltrated composite metal is used in the arc part 8 with Cu-F
e -Cr (e.g. 20Fe-20Cr-1 remaining)
A sintered-infiltrated composite metal of Cu) is used.

One lead rod 1a among the pair of lead rods 1a and Ib
is a fixed lead rod, which penetrates and is fixed to the metal end plate 11 joined to one end of the insulating cylinder 10. Other lead rod 1
b is a movable lead rod, which is connected via a metal bellows 13 to a metal end plate 12 joined to the other end of the insulating cylinder 10. The movable lead rod 1b is reciprocated in the axial direction by a drive device (not shown), and as a result, the pair of electrodes 2, 2 are opened and closed.

The insulating tube 10 is divided into two parts in the axial direction and connected by a metal tube 14, and a cylindrical metal shield 3 with an intermediate potential surrounding the pair of electrodes 2 is placed in a vacuum chamber 15 inside the insulating tube 10. It is fixed to the tube 14. In addition, in the vacuum chamber 15, there are 5U, which surround the base ends of the lead rods 1a and lb, respectively.
The shields 16 and 17 made of S304 are connected to the metal end plate 11,
It is fixedly provided at 12.

The intermediate potential metal shield 3 is formed by a central main shield 18 made of 5U3304, and auxiliary shields 19, 20 joined to both ends thereof.

The main shield 18 is a two-cylinder cylinder with a plate thickness t1, and the auxiliary shields 19 and 20 are cylindrical tiles with a plate thickness of 1 mm and rounded tips by drawing, and both are made of stainless steel fisUs304.

In addition, the axial length of the main shield 18 is
2. L/G= for the gap dimension G between the outer peripheral sides 5, 5 in 2.
3, G-20+nm1L=60 cylinders is set.

A metal shield 3 surrounding the outer peripheral side surface 5 of the electrode 2 and the electrode 2
The gap size 4 between the two is 15 mm.

The gap dimension G between the outer peripheral side surfaces 5, 5 of the pair of electrodes 2, 2 is 2
It is set to 0+nm.

When an experiment was conducted with the above configuration under other conditions shown in Table 1, the result was 42 kAr, ms.

It was confirmed that the large current could be interrupted more than 70 times, and results similar to those in the previous experiment could be obtained.

■3 Effects of the Invention According to the vacuum interrupter of the present invention, the electrodes are formed of a composite metal material containing copper and a metal that has a higher melting point than copper and is harder, and a pair of electrodes that magnetically rotationally drive the generated arc are provided. The relationship between the gap size G between the outer circumferential surfaces of the electrodes and the gap size 4 between the outer circumferential side surface of the f4 pole and the metal shield is expressed as 17
By setting G to 0.5 to 1.0, it was possible to effectively utilize the metal shield to perform the cutoff, and the cutoff performance and withstand voltage characteristics were improved.

Furthermore, the thickness of the metal shield does not need to be unnecessarily thick;
If only the main shield at the center had two or more shields, durability would be extremely good, and the plate thickness of the auxiliary shields at both ends could be made thinner, improving the productivity of processing for electric field relaxation processing.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a vacuum interrupter as an embodiment of the present invention, FIGS. 5
The figures are cross-sectional views of the vacuum interrupter electrodes used in the experiments, Figures 4, 6, 7, and 8 are graphs showing the experimental results, and Figure 9 is a cross-sectional view of the contrast electrode. FIG. 10 is a schematic diagram of the vicinity of the electrodes of a vacuum interrupter equipped with arc magnetic rotation driven electrodes. In the drawing, 2 is an electrode, 3 is a metal shield, 18 is a main shield, and 19 and 20 are auxiliary shields.

Claims (1)

[Claims] A device comprising a pair of electrodes that magnetically rotationally drive a generated arc,
Further, in the vacuum interrupter equipped with a metal shield having an intermediate potential that surrounds the pair of electrodes, the electrodes are formed of a composite metal material containing copper and a metal that has a higher melting point than copper and is harder. , the relationship between the gap size l between the metal shield and the outer peripheral side surface of the electrode and the gap size G in the open state between the outer peripheral side surfaces of the pair of electrodes is expressed as l
/G=0.5 to 1.0, and the metal shield is formed of a main shield with a plate thickness of 2 mm or more and auxiliary shields with a plate thickness of less than 2 mm at both ends of the main shield, A vacuum interrupter characterized in that the relationship between the axial length L and the gap size G is L/G≧2.