US3805000A - Vacuum interrupter and methods of making contacts therefor - Google Patents
Vacuum interrupter and methods of making contacts therefor Download PDFInfo
- Publication number
- US3805000A US3805000A US00234204A US23420472A US3805000A US 3805000 A US3805000 A US 3805000A US 00234204 A US00234204 A US 00234204A US 23420472 A US23420472 A US 23420472A US 3805000 A US3805000 A US 3805000A
- Authority
- US
- United States
- Prior art keywords
- copper
- boron
- bismuth
- vacuum interrupter
- contact
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/02—Contacts characterised by the material thereof
- H01H1/0203—Contacts characterised by the material thereof specially adapted for vacuum switches
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
- H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
- H01H33/66—Vacuum switches
- H01H33/668—Means for obtaining or monitoring the vacuum
- H01H33/6683—Means for obtaining or monitoring the vacuum by gettering
Definitions
- This invention relates to vacuum switches and methods of making the same, and more particularly, to vacuum interrupters and vacuum interrupter contact fabrication methods.
- bismuth can be added to the boron containing copper.
- the boron solubility in copper is very low, i.e., about 0.02 percent at 1,000 C. This solubility drops off rapidly so that practically none is leftin solution at room temperature. For this reason, boron containing copper is highly conductive. However, the boron does an excellent job of reducing the copper oxides.
- OFHC copper oxygen-free, high conductivity copper
- OFHC copper does not contain boron.
- bismuth in OFHC copper prevents contacts from welding.
- a further improvement is made by using boron containing copper with bismuth. This composition resists welding better than presently known contacts. It is believed that copper crystals in boron containing copper are as little as one-eighth the size of conventional OFHC copper. The smaller crys- .tals allow a more uniform distribution of the bismuth or other similar additives and the smaller crystals are more easily pulled apart in case of welding.
- the uniform distribution of bismuth between the smaller crystals of boron containing copper also provides a smooth contact surface which is less likely to induce or support an arc.
- the present invention is essentially concerned with the improved performance obtained in vacuum interrupters when copper contact electrodes contain lower percentages of boron.
- boron containing copper electrodes provide a superior host for bismuth addition over OFHC copper.
- the basis for this superiority is the small uniformly distributed copper grains which are characteristic of boron containing copper. Grain growth is inhibited by the presence of boron.
- bismuth may be diffused into the grain boundaries merely by heating the boron containing copper electrodes in contact with bismuth in a nonoxidizing atmosphere.
- boron containing copper contact electrodes may be functionally enhanced by the addition of bismuth by diffusion, a superior contact system is obtained with the copper boron system without the introduction of bismuth.
- the main function of bismuth is to provide sufficient metal vapor between opening electrodes to allow a plasma to be maintained to sustain an arc to current zero, thereby preventing high voltage spikes to occur as a result of premature arc quenching.
- a second contribution of bismuth is to reduce welding of contacts.
- boron also provides an arc sustaining plasma to prevent premature arc quenching as well as an anti-welding function. Additionally, however, the presence of boron in the arc plasmacontributes a most important gettering" function. There is always a minor amount of gas occluded or dissolved in practical electrode materials. These gases may be evolved during the melting of the electrode surfaces due to are action. Boron vapor has a strong tendency to react with these evolving gases to form oxides, nitrides, carbides, etc., removing not only the evolved gases but improving the quality of the vacuum ambient by a gettering action.
- BD copper boron deoxidized copper
- BD copper costs less than OFHC copper.
- the copper electrodes of a vacuum interrupter when fabricated from BD copper, do not require separate contacts to be brazed on. This provides a major cost saving. Should it be desired to include bismuth in the contact system, the bismuth may be diffused into the contacting ends of such electrodes.
- FIG. 1 is a longitudinal sectional view of a vacuum interrupter
- FIG. 2 is a diagrammatic view of a prior art method of making a vacuum interrupter
- FIG. 3 is a diagrammatic view of an alternate method of the invention which may be employed in making a vacuum interrupter.
- FIGS. 4 and 5 are plan views of the faces of vacuum interrupter contacts made in accordance with the methods of FIGS. 2 and 3, respectively.
- Vacuum interrupter 10 may be entirely conventional except for switching contact surfaces 11 and 12.
- Vacuum interrupter 10 includes an evacuated enve lope 13 having rigid metal plates 14 and 15 brazed to a ceramic cylinder 16.
- a cylindrical shield 17 is brazed to the end of plate 14 to keep metal vapor from short circuiting plates 14 and 15 by coating cylinder 16 internally.
- a bellows 18 is fixed at one end to plate 15 and at its other end to a cylindrical copper rod '19.
- Rod 19 may, thus, be moved toward a cylindrical copper rod 20 fixed to plate 14.
- Rods l9 and 20 may be copper containing boron.
- rods 19 and 20 may be boron deoxidized copper.
- surfaces 19 and 20 may be boron deoxidized copper with bismuth added by furnace diffusion, as illustrated in FIG. 3.
- a relatively pure copper is reduced to the molten state and boron is added to the copper at a proportion of 0.0l percent by weight.
- the copper may be a common commercial grade of relatively pure copper. It preferably is a highly refined electrolytic grade.
- the boron goes into solution in the melted copper, but approximately 0.003 percent is required to deoxidize the copper to produce oxygen free copper. When allowed to cool, the excess boron becomes approximately 0.007 percent. The excess boron is essentially precipitated out of the copper solution when the copper is allowed to cool to room temperature. This leaves what is conventionally called boron deoxidized copper (BD copper).
- BD copper boron deoxidized copper
- the boron containing copper can be reheated to a molten state in a vacuum and bismuth added.
- the boroncopper-bismuth mixture is then cooled to room temperature.
- the vacuum interrupter is then processed in a conventional manner;
- boron 0.003 to 0.50 percent.
- a typical range for the bismuth is 0.1 to 1.0 percent, although 0.2 percent is preferred. All percentages herein are given by weight.
- the copper to be used to make contacts preferably should have an electrical conductivity of 100 percent IACS (International Annealed Copper Standard) and would have a typical analysis as follows:
- boron deoxidized copper is hereby defined for use herein and in the claims to be strictly limited to copper containing boron in which elemental boron is mixed with the copper while the copper is in a molten state.
- the present invention eliminates:
- the present invention may be practiced by usingcontacts separately brazed to electrodes 19 and 20, it is an advantage of the invention that they need not be made separately. That is, the contacts of electrodes l9 and 20 may be made integral therewith.
- Two distinct methods disclosed herein are: (1) Melting BD copper and bismuth together, and (2) Diffusing bismuth powder into the surface of an end portion of a BD copper rod to provide an electrical contact surface thereat.
- the copper grain size in the contact surface shown in FIG. 5 is much smaller than that in the contact surface shown in FIG. 4.
- the aforementioned advantages are believed to be attributable to this difference in grain structure.
- the gain of OFHC copper size is believed to be about eight times that of BD copper.
- bismuth powder is diffused into the end 21 of a BD copper rod 22 in a hydrogen (or other inert gas-argon, nitrogen, etc.) furnace.
- the method illustrated in FIG. 3 may be performed by standing rod 22 on end in a vertical position, as shown, on a layer of bismuth powder.
- the rod 22 and the bismuth powder are then heated in an inert gas while the rod 22 is resting on the bismuth powder.
- the temperature may then be raised to a predetermined diffusion temperature above ambient but below the melting point of copper or to a lower temperature including, but not limited to, for example, between about 500 to 1,082 C. However, this temperature range is not critical.
- the contact pressure between rod 22 and the his muth powder due to the weight of the rod is sufficient to assure an even penetration of bismuth at the said predetermined diffusion temperature.
- the method of making vacuum interrupter contact material comprising the steps of: heating a quantity of elemental boron and a quantity of elemental copper together until the copper melts and dissolves a portion of the boron, the boron quantity being beof the sum of both quantities; allowing the boron and copper to cool to form an ingot; placing a quantity of bismuth powder on top of an approximately horizontal surface of fixture means in a furnace; standing said ingot upright on top of said powder; filling the furnace with an inert gas; and raising the temperature inside the furnace in a manner to cause said powder to adhere to said ingot.
Landscapes
- High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
Abstract
Description
Claims (1)
- 2. The method of making a vacuum interrupter contact said method comprising the steps of: heating a contact, of elemental boron and a quantity of elemental copper together until the copper melts and dissolves a portion of the boron, the boron quantity being between about 0.003 percent and about 0.5 percent, by weight, of the sum of both quantities; allowing the boron and copper to cool to form an ingot; placing a quantity of bismuth powder on top of an approximately horizontal surface of fixture means in a furnace; standing said ingot upright on top of said powder; filling the furnace with an inert gas; and raising the temperature inside the furnace in a manner to cause said powder to adhere to said ingot.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US00234204A US3805000A (en) | 1970-03-23 | 1972-03-13 | Vacuum interrupter and methods of making contacts therefor |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US2191970A | 1970-03-23 | 1970-03-23 | |
US00234204A US3805000A (en) | 1970-03-23 | 1972-03-13 | Vacuum interrupter and methods of making contacts therefor |
Publications (1)
Publication Number | Publication Date |
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US3805000A true US3805000A (en) | 1974-04-16 |
Family
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US00234204A Expired - Lifetime US3805000A (en) | 1970-03-23 | 1972-03-13 | Vacuum interrupter and methods of making contacts therefor |
Country Status (1)
Country | Link |
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US (1) | US3805000A (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4231814A (en) * | 1978-02-22 | 1980-11-04 | Hitachi, Ltd. | Method of producing a vacuum circuit breaker |
US5288458A (en) * | 1991-03-01 | 1994-02-22 | Olin Corporation | Machinable copper alloys having reduced lead content |
US5360591A (en) * | 1993-05-17 | 1994-11-01 | Kohler Co. | Reduced lead bismuth yellow brass |
US5441555A (en) * | 1990-03-06 | 1995-08-15 | United States Bronze Powders, Inc. | Powder metallurgy compositions |
US5653827A (en) * | 1995-06-06 | 1997-08-05 | Starline Mfg. Co., Inc. | Brass alloys |
US5879477A (en) * | 1993-05-17 | 1999-03-09 | Kohler Co. | Reduced lead bismuth yellow brass |
EP1437751A1 (en) * | 2003-01-09 | 2004-07-14 | Hitachi, Ltd. | Electrode for vacuum interrupter, vacuum interrupter using the same and vacuum circuit-breaker |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2183592A (en) * | 1939-12-19 | Electrical conductor | ||
US2479311A (en) * | 1945-07-11 | 1949-08-16 | Int Smelting & Refining Co | Production of oxygen-free copper |
US3246979A (en) * | 1961-11-10 | 1966-04-19 | Gen Electric | Vacuum circuit interrupter contacts |
US3450573A (en) * | 1965-06-30 | 1969-06-17 | Ass Elect Ind | Grain refinement process for copper-bismuth alloys |
US3502465A (en) * | 1967-05-24 | 1970-03-24 | Mitsubishi Electric Corp | Contact alloys for vacuum circuit interrupters |
US3514559A (en) * | 1967-03-27 | 1970-05-26 | Mc Graw Edison Co | Vacuum type circuit interrupter |
US3596025A (en) * | 1968-09-27 | 1971-07-27 | Gen Electric | Vacuum-type circuit interrupter with contacts containing a refractory metal |
US3627963A (en) * | 1971-03-18 | 1971-12-14 | Wesley N Lindsay | Vacuum interrupter contacts |
US3670129A (en) * | 1970-08-17 | 1972-06-13 | Westinghouse Electric Corp | Electrical contact members |
-
1972
- 1972-03-13 US US00234204A patent/US3805000A/en not_active Expired - Lifetime
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2183592A (en) * | 1939-12-19 | Electrical conductor | ||
US2479311A (en) * | 1945-07-11 | 1949-08-16 | Int Smelting & Refining Co | Production of oxygen-free copper |
US3246979A (en) * | 1961-11-10 | 1966-04-19 | Gen Electric | Vacuum circuit interrupter contacts |
US3450573A (en) * | 1965-06-30 | 1969-06-17 | Ass Elect Ind | Grain refinement process for copper-bismuth alloys |
US3514559A (en) * | 1967-03-27 | 1970-05-26 | Mc Graw Edison Co | Vacuum type circuit interrupter |
US3502465A (en) * | 1967-05-24 | 1970-03-24 | Mitsubishi Electric Corp | Contact alloys for vacuum circuit interrupters |
US3596025A (en) * | 1968-09-27 | 1971-07-27 | Gen Electric | Vacuum-type circuit interrupter with contacts containing a refractory metal |
US3670129A (en) * | 1970-08-17 | 1972-06-13 | Westinghouse Electric Corp | Electrical contact members |
US3627963A (en) * | 1971-03-18 | 1971-12-14 | Wesley N Lindsay | Vacuum interrupter contacts |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4231814A (en) * | 1978-02-22 | 1980-11-04 | Hitachi, Ltd. | Method of producing a vacuum circuit breaker |
US5441555A (en) * | 1990-03-06 | 1995-08-15 | United States Bronze Powders, Inc. | Powder metallurgy compositions |
US5637132A (en) * | 1990-03-06 | 1997-06-10 | United States Bronze Powders, Inc. | Powder metallurgy compositions |
US5288458A (en) * | 1991-03-01 | 1994-02-22 | Olin Corporation | Machinable copper alloys having reduced lead content |
US5409552A (en) * | 1991-03-01 | 1995-04-25 | Olin Corporation | Machinable copper alloys having reduced lead content |
US5360591A (en) * | 1993-05-17 | 1994-11-01 | Kohler Co. | Reduced lead bismuth yellow brass |
US5879477A (en) * | 1993-05-17 | 1999-03-09 | Kohler Co. | Reduced lead bismuth yellow brass |
US5653827A (en) * | 1995-06-06 | 1997-08-05 | Starline Mfg. Co., Inc. | Brass alloys |
EP1437751A1 (en) * | 2003-01-09 | 2004-07-14 | Hitachi, Ltd. | Electrode for vacuum interrupter, vacuum interrupter using the same and vacuum circuit-breaker |
US20040141271A1 (en) * | 2003-01-09 | 2004-07-22 | Shigeru Kikuchi | Electrode for vacuum interrupter, vacuum interrupter using the same and vaccum circuit-breaker |
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Date | Code | Title | Description |
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AS | Assignment |
Owner name: ITT CORPORATION Free format text: CHANGE OF NAME;ASSIGNOR:INTERNATIONAL TELEPHONE AND TELEGRAPH CORPORATION;REEL/FRAME:004389/0606 Effective date: 19831122 |
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AS | Assignment |
Owner name: FL INDUSTRIES, INC., 220 SUTH ORANGE AVENUE, LIVIN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ITT CORPORATION, 320 PARK AVENUE, NEW YORK, NY 10022, ACORP. OF DE.;REEL/FRAME:004453/0578 Effective date: 19850629 |
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AS | Assignment |
Owner name: BANGOR PUNTA INTERNATIONAL CAPITAL HOLDING CORP., Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:FL INDUSTRIES, INC.,;REEL/FRAME:004899/0615 Effective date: 19880425 Owner name: BANGOR PUNTA INTERNATIONAL CAPITAL HOLDING CORP., Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:FL INDUSTRIES, INC.,;REEL/FRAME:004899/0615 Effective date: 19880425 |
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AS | Assignment |
Owner name: LEAR SIEGLER JENNINGS CORP. Free format text: CHANGE OF NAME;ASSIGNOR:BANGER PUNTA INTERNATIONAL CAPITAL HOLDING CORP.;REEL/FRAME:005270/0960 Effective date: 19880420 |