JPS59119626A - Electrode for vacuum interrupter - 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] The present invention relates to electrodes for vacuum interrupters.

In general, the electrodes of a vacuum interrupter must (1) have a high ability to interrupt large currents, (2) have high dielectric strength, (3) have good welding resistance, and (4) effectively interrupt small currents. You are required to meet the following conditions:

Conventionally, in order to satisfy the above-mentioned conditions, electrodes made of alloy materials made of copper containing a high vapor pressure material (low melting point material), for example, U.S. Pat.
1-12181) containing α6 weight of bismuth (hereinafter referred to as “Ou-, 0,5B
8.596.027) and U.S. Patent No. 8.596.027
The one described in No. (Hyouko Sho 48-88071) is known.

However, Cu-05Bi electrodes etc. have a large current cutting ability,
Although it has excellent welding resistance and electrical conductivity, its dielectric strength and
In particular, the dielectric strength after cutting off is markedly reduced, the current cutting value is as high as IOA, and a cutting surge may occur when cutting off. There are problems such as the risk of causing insulation breakdown of equipment.

In addition, in order to eliminate the drawbacks of 0u-0,5Bi electrodes, etc., electrodes made of alloy materials of copper and low vapor pressure materials (high melting point materials), such as U.S. Pat. 86121) consisting of 80% by weight of tungsten and 20% by weight of copper (hereinafter referred to as "200u-8").
0W Electrode) and British Published Patent No. 2,024,
Known examples include those described in No. 257 (4? 157284/1984). However, 20. Ou-80
Although W[poles, etc.] have a high dielectric strength, they have problems such as difficulty in interrupting large currents such as accident currents.

The present invention was made in view of the above-mentioned problems, and its purpose is to provide excellent dielectric strength and to effectively interrupt small currents while maintaining good large current interrupting ability and welding resistance. The next step is to provide the electrodes of the vacuum interrupter. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The figure is a longitudinal cross-sectional view of a vacuum interrupter equipped with an N pole according to the present invention. A thin annular sealing fitting made of a metal such as Kovar is attached to each end of a plurality of insulating tubes (two in this example) made of an insulating material such as 1.2°... 2. are joined together coaxially to form a single insulating tube through one of the sealing fittings, 2. and 2. A vacuum vessel 11&: is formed by closing the Jt with disk-shaped metal end plates J, J made of metal such as stainless steel, and evacuating the inside to a high vacuum. Disk-shaped electrode j,! f, each metal end plate J,
Through T, a pair of electrode rods were introduced from the center of J into the vacuum container L so that they could be relatively approached and separated while maintaining airtightness.
It is roughly configured so that it can be brought into contact and separated (contacted and separated) freely.

In the figure, 7 is a metal bellows, and t is a shield concentrically surrounding each electrode 3 and the like.

Each of the electrodes 3 is made of an alloy of 20-70% by weight copper, 6-40% tungsten, 5-70% molybdenum and 5-70% chromium.

That is, each electrode j is -100 mesh (147μ
5 to 40% by weight of tungsten powder (J lower) and -10
0 mesh molybdenum powder 5-70 weight - [1%,
- A porous base material is formed by diffusion bonding a mixed powder of 100 mesh with 5 to 70 weight percent of chromium powder at a temperature below its melting point, and 20 to 70 weights of copper are added to this base material. It is provided by infiltrating it.

The first method for manufacturing such an electrode is to first mechanically mix a predetermined amount of tungsten, molybdenum, and chromium powders with a grain size of 1i-100 mesh to enable mutual diffusion at a temperature below the melting point. . Next, the mixed powder of tungsten, molybdenum, and r6"""?->\ chromium is stored in a container made of alumina, etc., which does not react with any of chromium, tungsten, and copper, and placed in a vacuum atmosphere at a pressure of 5XlO-6 Torr or less, or 800-i in a non-oxidizing atmosphere such as hydrogen gas, nitrogen gas and argon gas,
They are heated at a temperature of 00° C. for 10 minutes or more to form a porous base material by mutual diffusion bonding. Finally, this porous base material and the copper are heated to 1,100°C or the melting point of copper (1,088°C
) and above for about 6 to 20 minutes to infiltrate a predetermined amount of copper into the base material to complete the desired electrode j.

Similarly to the first manufacturing method, the second method for manufacturing electrode j is to first prepare tungsten, molybdenum, and chromium with a mesh of 1100 to enable mutual diffusion at temperatures below the melting point. A predetermined amount of powder is mechanically mixed, and this mixed powder of tungsten, molybdenum, and chromium is stored in a container made of alumina, etc., which does not react with any of tungsten, molybdenum, chromium, and copper. Place a predetermined amount of copper blocks on top. Next, the mixed powder and the copper block are placed in a vacuum furnace that can maintain a pressure of 5×10″″1 ITor or less. And vacuum furnace 'e600
℃ for 60 minutes to degas the mixed powder etc., then the vacuum furnace was operated for 80 minutes at a temperature of 800℃, and the temperature was increased to 3,000℃.
The vacuum furnace was operated for 0 minutes to diffusely bond the tungsten, molybdenum and chromium powders to each other to form a porous substrate, and finally the vacuum furnace was operated for 20 minutes at a temperature of 1,100°C to bond the copper to the substrate. After infiltration, the desired electrode S is completed.

Furthermore, the eighth method for manufacturing the left electrode is to first manufacture an alloy of tungsten, molybdenum, and chromium with a predetermined composition ratio, and then crush this alloy of tungsten, molybdenum, and chromium to form a -100 mesh powder. . Next, the alloy powder of tungsten, molybdenum, and chromium is stored in a container made of alumina or the like that does not react with any of tungsten, molybdenum, chromium, and copper, and placed in a vacuum atmosphere or hydrogen gas at a pressure of 5 x 10 Torr or less. , heated in a non-oxidizing atmosphere such as argon gas at a temperature below its melting point for a predetermined time to form a porous base material that is bonded to each other.

Finally, apply 5X10'-'Tort to this porous substrate.
A desired electrode 5 is completed by infiltrating a predetermined amount of @ in a vacuum atmosphere at the following pressure.

Here, the tungsten, molybdenum,
The composition ratios of chromium and copper are 20% by weight and 20% by weight, respectively.
% by weight, 20% by weight and 40% by weight, materials with a composition of 9; 40 in.

A vacuum interrupter having a pair of electrodes j made of a material with a composition of 10% by weight and 40% by weight, and a material with a composition of The performance verification results are as shown below.

0 1) Large current interrupting ability Each composition was able to interrupt a current of 1 2 KA (EMS).

11) When a shock wave withstand voltage test was conducted with the dielectric strength gap ``f'' maintained at 8%, the product with the composition ■ was +120 KV.

-IIOKV, the one with the ■ composition shows ±120■, and the one with the yellow composition +110! ! V, -120W, and those of composition (■) show ±110W;
The variation was ±10W. Also, large current (12K
A similar test was conducted after A) was cut off, but there was no change in dielectric strength. Furthermore, similar tests were conducted after switching on and off with a small advance current (80A), but the dielectric strength hardly changed.

111) Welding resistance 1 Each composition was 25KA (FIMS) under a pressure of 180KP.
) for 3 seconds (KO short-time current standard), and after 9 seconds, the contact resistance could be removed without any problem with a static removal force of 200 KP, and the increase in contact resistance after that was only 2 to 8 inches. . In addition, under a pressure of 1,000) lP,
The tripping after applying current (MS) for 3 seconds was also problematic, and the subsequent increase in contact resistance remained at θ~5ch.

Carefully, each composition has sufficient welding resistance.

IV) Delayed and advanced small current cutting ability■Delayed small current (
The average breaking capacity current cutting value of the rm component (inductive load) is 3.9, A (fn=1.1. n=100
), and those with 11 compositions showed an average of 4.21 (fn=
1.8. n=100)? Furthermore, those with a seal composition have an average of 4.8 μm (ry).

2 = 1.1. n = 100) k, and those with composition ■ average 8.5 A (fn = 0.9. n = LOo) k
Indicated.

■ Breaking capacity voltage for small leading current (capacitive load); 8
4 KV

V conductivity The conductivity (TE AO8) of each composition showed a V conductivity of 20 to 50 inches.

vl) Hardness For each composition, cirrhosis is 106 to L 82 av (LKp)
showed that.

Further, a vacuum interrupter having an electrode according to the present invention,
A comparison of various performances with a conventional vacuum interrupter with 0u-05Bi electrodes resulted in the following results.

1) Large current breaking ability Both are at the same level.

11) Dielectric strength The dielectric strength of the conventional one at a gap of 10% is equal to the dielectric strength of the one of the present invention at a gap of 3%. Therefore, the vacuum interrupter having the electrodes according to the present invention had a dielectric strength about eight times that of the conventional one.

1ll) Welding resistance The welding resistance of the electrode according to the present invention is 801 compared to the conventional electrode, but there is almost no problem in practical use.

1. Delayed and advanced small current cutting ability ■ Delayed small current cutting ability The current cutting value of the electrode according to the present invention is as small as 40 times compared to the conventional 4, so cutting surge hardly becomes a problem and Its value does not change even after opening and closing.

(2) Advanced small current cutting ability The electrode according to the present invention can cut off a load with twice the capacitance compared to the conventional electrode.

When the tungsten content was less than 5%, the dielectric strength decreased rapidly, and when it exceeded 404%, the large current breaking ability decreased rapidly.

In addition, if molybdenum is less than 5 folds, the dielectric strength will decrease rapidly, and if it exceeds 70 folds, VC
The large current interrupting ability suddenly decreased.

In addition, if the content of chromium is less than 5% by weight, the current cutting value will increase significantly, and the current will be delayed and the cutting capacity will decrease, and if it exceeds 70% by weight,
The large current cutting ability suddenly decreased.

Furthermore, if the copper content is less than 20% by weight, the electrical conductivity will decrease rapidly, the contact resistance after a short-time current test will increase rapidly, and the generation of Joule heat will be large when the rated current is applied. Practicality decreased, and when it exceeded 70% by weight, dielectric strength decreased and welding resistance rapidly deteriorated.

As described above, the present invention uses copper of 20 to 70 weight weight, 5 to 40 weight of copper,
Since the vacuum interrupter electrode is made of an alloy of tungsten (wt%), molybdenum (6~70wt%), and chromium (5~70wt%), the dielectric strength of the vacuum interrupter is significantly improved compared to the conventional 0u-05Bi electrode. It is possible to increase the effectiveness.

6 Both provide vacuum interrupters with excellent large current interrupting ability.
It is possible to obtain a product that is fast, slow, and has excellent ability to cut off small currents.

Also, tungsten powder with a weight of 5 to 40, 5 to 70
20 to 70% by weight of molybdenum powder and 5 to 70% by weight of chromium powder are bonded to each other by diffusion bonding to a porous base material.
Since the vacuum interrupter electrode is infiltrated with 70% by weight of copper, in addition to the above-mentioned effects, mechanical strength and electrical conductivity can be increased.

[Brief explanation of drawings]

The figure is a longitudinal sectional view of a six-vacuum interrupter with electrodes according to the invention. ≠...vacuum container, 5...electrode. 7

Claims (2)

[Claims] (1) 20~700~70wt%~40wt-%4 glue/
guste/, 5-70 F-is molybdenum and 6-7
Vacuum interrupter electrode made of 0% chromium alloy (2) 5-40% by weight tungsten powder, 5-70%
2% by weight of molybdenum powder and 5 to 70% by weight chromium powder are diffusion bonded to each other on a porous base material.
An electrode for a vacuum interrupter which is immersed in an amount of 0 to 700 to 70% by weight.