US3778573A - Vacuum circuit interrupter having improved contact structure - Google Patents

Vacuum circuit interrupter having improved contact structure Download PDF

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US3778573A
US3778573A US00265904A US3778573DA US3778573A US 3778573 A US3778573 A US 3778573A US 00265904 A US00265904 A US 00265904A US 3778573D A US3778573D A US 3778573DA US 3778573 A US3778573 A US 3778573A
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contact
contact structure
type circuit
circuit interrupter
engagement
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US00265904A
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R Harrold
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CBS Corp
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Westinghouse Electric Corp
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    • 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
    • H01H33/664—Contacts; Arc-extinguishing means, e.g. arcing rings
    • H01H33/6646—Contacts; Arc-extinguishing means, e.g. arcing rings having non flat disc-like contact surface
    • 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
    • H01H33/666—Operating arrangements
    • 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
    • H01H33/664—Contacts; Arc-extinguishing means, e.g. arcing rings
    • H01H2033/6648—Contacts containing flexible parts, e.g. to improve contact pressure
    • 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
    • H01H33/666—Operating arrangements
    • H01H33/6664—Operating arrangements with pivoting movable contact structure

Definitions

  • the present invention relates to vacuum type circuit interrupters and more particularly to the contact structure which is a part of such vacuum interrupters.
  • the contact structures disclosed utilize the principle of closing on a first material which has good closing characteristics, and resists welding, and opening on a second material which interrupts the circuit without current chopping for improved vacuum interrupter operation.
  • Vacuum type circuit interrupters generally comprise an evacuated insulatingenvelope with separable contacts disposed within the insulating envelope.
  • the contacts are movable between a closed position in which the contacts are engaged and an open position where the contacts are separated and an arcing gap is established therebetween. An arc is initiated between the contact surfaces when the contacts move into or out of engagement while the circuit in which the interrupter is used is energized.
  • welds may be formed between required to break the weld so that the contacts can-beopened, depends upon many factors including the arc voltage, the current, the contact area and the contact material. These welds are objectionable since they interfere with the easy movement of the separable contacts and may result in the failure of the vacuum interrupter to open.
  • Copper tungsten is ideal for weld free closing but poor on openings due to current chopping and also has undersirable electron emission. Chrome due to its vapor pressure properties is goodfor weld free closing, however, it has disadvantages of high contact resistance and is expensive. in the required oxygen-free form.
  • One of thebest materials for opening is copper, but this welds easily on contact closing. Thus some materials are best for closing, others best for opening and a compromise is made by using metal mixtures or alloys.
  • Contacts made from copper bismuth or chrome copper construction have reasonably good opening and closing characteristics, however, they still require an expensive contact release mechanism. It-is felt that the present invention has significant advantages over prior art contacts in that the contacts close on a-material that is weld free and open on a material that has good nonchopping characteristics.
  • This invention discloses contact constructions which effectively use closing on a first material which has good non-welding characteristics and opening on a second material which does not cause excessive current chopping, and which has good interrupting characteristics. This improves operation of the vacuum interrupter. An expensive release mechanism is not required to assist in weld breaking and also the interrupter in its final closed position how low contact resistance.
  • the contacts are brought together on a material which has good nonweld characteristics and then the contacts are moved to a final closed position where contact is made through a material having low resistance and good nonchopping characteristics.
  • the contact points are moved from the first material to the second material by moving the operating rod transverse to the longitudinal axis of the vacuum interrupter. On vacuum interrupter opening, the contacts separate on the second material which has good non-chopping properties.
  • the stationary contact is disposed within the vacuum interrupter.
  • a movable contact is attached to an operating rod which moves along the longitudinal axis of the vacuum interrupter.
  • the movable contact is pivotally attached to the operating rod so that when the vacuum interrupter is closed first contact is made on a material which has good non-weld characteristics and as the operating rod closes further the movable contact pivots around the operating rod and contact is made with a second material which has good opening characteristics.
  • the movable contact is returned to and held in position for another closing operation by ceramic magnets which are attached to the movable contact and the operating rod. Current is carried from the movable contact tothe operating rod by a flexible connection.
  • two identical semicircular contacts each made of two materials are disposed within the vacuum interrupter.
  • One of the contacts is pivotally attached to a stationary conducting rod.
  • the other contact is pivotally attached to the movable operating rod.
  • the movable operating rod moves along the longitudinal axis of the vacuum interrupter to move the contacts into and out of engagement.
  • the arrangement is such that when the two contacts are in the open position, they are held in position by coil springs. When brought together, under' pressure, they make contact on a first material then revolve around the respective pivots continuously making electrical contact until a final closed position is reached in which contact is made on a second material.
  • the contacts close on a weld free material and under increasing pressure the contacts roll over each other to the final closed position.
  • This embodiment of the invention can prevent welding of contacts even if the contacts are made of a material having poor weld characteristics, such as copper, by virtue of the contact rolling motion on closing which prevents welding. The current which flows when contact motion has ceased being insufficient for contact welding.
  • two sets of contacts are used in the vacuum interrupter, one for closing and one for opening.
  • the first set of contacts are located in the center of the second set of contacts so that the second set of contacts form an annular contact ring surrounding the first set of contacts.
  • a weld free material can be used for the closing contacts and a material without current chopping properties can be used for the opening contacts.
  • An expensive release mechanism is not required, and also the interrupter in its final closed position has low contact resistance.
  • the contact structure first closes on the centrally located contacts which are made of a weld free material.
  • the surrounding second set of contacts of high conductivity material with good opening characteristics then close. After a slight time delay, the first set of contacts open and the vacuum interrupter is in the fully closed position. On opening, the second set of contacts interrupt the current flow without chopping.
  • Devices utilizing the teaching of the present invention have several advantages over the prior art. For example, there is no contact welding on vacuum interrupter closing. Another advantage of the present invention is that there is minimal current chopping on contact opening and the contacts separate on a material having good current interrupting characteristics. Another advantage is that there is reduced contact wear since the contacts close on a non-welding noneroding material. Another advantage of the present invention is that when the vacuum interrupter is in the fully closed position, the contacts are closed on a material which has low contact resistance. Still another advantage of the present invention is that an expensive mechanism to release welded contacts is not required.
  • FIG. 1 is a vertical sectional view of a vacuum type circuit interrupter with the contacts in the open position embodying a contact construction of the present invention
  • FIG. 2 is a side view partially in section of the vacuum interrupter shown in FIG. 1 with the contacts in the fully closed position;
  • FIG. 3 is a side view partially in section of another embodiment of the invention with the contacts in the open position;
  • FIG. 4 is similar to FIG. 3 but with the contacts in the closed position
  • FIG. 5 is a side view of a pair of contacts illustrating another embodiment of the invention.
  • FIG. 6 is a view of the contacts shown in FIG. 5 with the contacts in the closed position;
  • FIG. 7 is a vertical sectional view of still another embodiment of the invention with the contacts in the open position
  • FIG. 8 is a view of a portion of the vacuum interrupter shown in FIG. 7 with the contacts in an intermediate closed position;
  • FIG; 9 is a side view partially in section of the vacuum interrupter shown in FIG. 7 with the contacts in the fully closed position.
  • the vacuum type circuit interrupter 10 comprises a highly evacuated envelope 12 formed of glass or suitable ceramic material and a pair of metallic end caps 14 and 16 and the insulating envelope 12 to render the envelope l2 vacuum tight.
  • the vacuum in the envelope 12 under normal operating conditions is lower than 10 Torr so that mean free path of electrons will be longer than the potential breakdown distance within the tubular envelope l2.
  • a pair of relatively movable electrodes or contacts 20 and 22 Disposed within the envelope 12 are a pair of relatively movable electrodes or contacts 20 and 22 embodying the teaching of the present invention. As shown in FIG. 1, when these contacts 20 and 22 are separated there is an arcing gap 24 formed therebetween.
  • the upper contact 20 is stationary and is secured to a conducting rod 26 by a suitable means such as welding or brazing.
  • the conducting rod 26 is secured at its upper end to the stationary end cap 14 by suitable means such as welding or brazing.
  • the lower contact 22 is movable and is joined to a conducting operating rod 28.
  • the conducting operating rod 28 is suitably mounted for movement along the longitudinal axis of the tubular insulating envelope 12 and for a slight motion transverse to the longitudinal axis of the tubular insulating envelope 12.
  • the movable operating rod 28 projects through an opening 30 in the bellows end cap 16.
  • a flexible metal bellows 32 is secured in sealing relationship at its respective opposite ends to movable operating rod 28 and the opening 30 in the bellows end cap 16.
  • the flexible metal bellows 32 provides a seal about the rod 28 to allow for movement of the rod 28 without impairing the vacuum inside the insulating envelope l2.
  • actuating means (not shown) is provided for driving the movable contact 22 upward into engagement with the stationary contact 20 so as to close the interrupter 10.
  • the actuating means is also capable of returning the contacts 22 to its open position so as to open the interrupter 10.
  • the circuit opening operation will for example entail a typical gap length when the contacts are fully separated of approximately one-half inch.
  • a metallic arc initiates between the separated contacts 20 and 22 and serves as a vehicle for current conduction until the arc is extinguished.
  • the arc In an alternating current circuit the arc is usually extinguished near the first current zero of the alternating current wave.
  • The are that is established across the arcing gap 24 between the contacts 20 and 22 when they are opened, and also when they are closed, vaporizes and melts some of the contact material.
  • the vapors are dispersed from the arcing gap 24 toward the inside of the insulating envelope 12.-The internal surfaces of the insulating envelope 12 are protected from the condensation of the arc generated metallic vapor and particles thereon by means of a tubular metallic shield 36.
  • the tubular metallic shield 36 is supported on the insulating envelope l2 and preferably electrically isolated from both end caps 14 and 16. This shield 36 acts to intercept and condense arc generated .metallic vapors before they can reach the internal surfaces of the insulating envelope 12. To reduce the possibility that metallic vapors or particles can bypass the main shield 36 and coat the internal surface of the insulating envelope 12 a pair of end shields 38 and 40 are provided at opposite ends of the central shield 36.
  • the contacts 20 and 22 comprise two portions, a first portion of a non-welding material 52 such as chrome, copper tungsten, or the like, and the second portion 54 comprises a material having low resistance and nonchopping properties such as copper or the like.
  • a non-welding material 52 such as chrome, copper tungsten, or the like
  • the second portion 54 comprises a material having low resistance and nonchopping properties such as copper or the like.
  • the movable contact 22 is pivotally attached to the operating rod 28.
  • the operating rod 28 is supported for movement along the longitudinal axis of the interrupter 10.
  • the contacts are comprises of a first material 52 having non-welding characteristics and a second material 54 having low resistance, nonchopping characteristics.
  • FIG. 3 when the vacuum interrupter is in the open position, the movable contact 22 is held in position by a magnet 56 attached to contact 22 and a magnet 58 attached to the movable operating rod 28.
  • the movable contact 22 is attached to the operating rod 28 through a ceramic bearing 60. Current flows from the movable contact 22 to the operating rod 28 through a flexible connection 62.
  • FIGS. 5 and 6 there are shown a pair of vacuum interrupter contacts illustrating another embodiment of the present invention.
  • the first contact 64 is pivotally attached to the stationary conducting rod 26.
  • a second contact 66 is pivotally attached to the movable operating rod 28.
  • Each contact 64 and 66 is made from a first material 52 having good non-welding characteristics and a second material 54 having good circuit opening characteristics.
  • the contact arrangement is such that when the contacts 64 and 66 are brought together under pressure, engagement is first made between the first material 52 which is weld free and then the two contacts revolve around their respective pivots 68 and continuously making a good electrical contact until when the contacts are fully closed, contact is made between the second material 54 having good opening characteristics. Opening of the contacts will occur between the materials 54 having good opening characteristics with minimum current chopping.
  • Contacts 64 and 66 are identical and semicircular in construction.
  • the contacts 64 and 66 pivot on ceramic bearings 68 and 70, respectively.
  • the contacts 64 and 66 are held in the open position by flat spiral springs 72 and 74, respectively, when the contacts are disengaged, as shown in FIG. 5.
  • the contacts 64 and 66 are brought together under pressure, they revolve around the respective pivot bearings 68 and 70 continuously making electrical contact until in the final closed position, as shown in FIG. 6, contact is made between the second material 54 having good opening characteristics.
  • the movable operating rod 28 moves rapidly to the open position, before the flat spiral springs 72 and 74 can rotate the contacts 64 and 66, so that opening occurs on the second material 54.
  • a flexible connection 76 electrically connects contact 64 to conducting rod 26.
  • a flexible connection 78 connects contacts 66 with the movable operating rod 28.
  • a continuous current path extends from the conducting rod 26, through the flexible connection 76, through the second material 54 of contact 64, through the second material 54 of contact 66, through the flexible connection 78, to the movable operating rod 28.
  • This design is such that on closing any metallic vapor formed due to arcing between the closing contacts 64 and 66, will be directed away from the final closing surfaces. Likewise, during an opening operation, any metallic vapor expelled from the contacts will be directed away from the point where initial contact engagement is made.
  • FIGS. 5 and 6 will prevent contact welding even if the contacts 64 and 66 are made of one material such as copper, since the contact rolling motion on closing prevents welding. When contact motion has ceased the current then flowing is insufficient for welding of the contacts 64 and 66.
  • Many variations and improvements are possible with this construction of contact. For example, by suitably grading the resistivity of the contact area used for closing and opening, and by controlling the motions of contacts 64 and 66 the are initially formed between the low contacts resistance material 54 would experience an increasing resistive path as it continued between the high resistance material while finally extinguished as the contacts separate further. This would be a type of resistive opening.
  • FIGS. 7, 8 and 9 there is shown a movable contact structure 80 and a stationary contact structure 82 disposed within a vacuum interrupter 10.
  • two sets of contacts are used in a vacuum interrupter.
  • the lower contact structure 82 which is relatively stationary comprises a central contact made of non-welding material 52, an outer contact 92 made of a non-chopping material 54, an outer housing 94, a compression spring 96 to resilv iently support contacts 90 and 92, and flexible connections 98 to electrically connect the contacts 90 and 92 to end'cap 14.
  • Movable contact structure 80 comprises, a central contact 81 made of a nonwelding material 52, an annular surrounding contact 83 made of a non-chopping material 54, a compression spring 84 for moving contact 81 relative to contact 83, and an operating means (not shown) for moving contact structure 80 into and out of engagement with contact structure 82.
  • a cup-shaped shield 85 surrounds the flexible metallic bellows 32 to prevent the bellows 32 from being bombarded by particles expelled during contact arcing.
  • a metal bellows 33 is attached to reset rod 86 to permit movement of the reset rod 86 to return contact 81 to its normal open position upon opening of vacuum interrupter 10.
  • vacuum interrupter is shown in its normal open position.
  • the first step in the closing operation of vacuum interrupter 10 is shown by dashed lines 87 in FIG. 7.
  • the contact structure 80 moves toward the contact structure 82 and the central contacts 81 and 90 engage as shown by the dashed lines 87 in FIG. 7.
  • the outer contacts 83 of contact structure 80 begins to move relative to the stationary contact 81.
  • contact 81 is held stationary with respect to contact 83 by spring loaded ball bearings 102 engaging a circular depression 104 in supporting rod 106.
  • the rod 106 is disengaged from the position shown in FIG.
  • contacts 81 and 90 remain engaged until after contacts 83 and 92 are engaged.
  • rod 106 continues to move from the position where it was held stationary by bearings 102 to the position as shown in FIG. 9 where it is held stationary by spring loaded bearings 108.
  • the centrally located contacts 81 and 90 separate so that the final closed position is as shown in FIG. 9.
  • the vacuum interrupter 10 is now closed on contacts 83 and 92 which are made from a material 54 having good opening characteristics. When the vacuum interrupter 10 opens contacts 83 and 92 separate with little current chopping.
  • a reset means (not shown) operates the reset rod 86 to move the rod 106 from the position where it is held stationary by spring loaded bearings 108 to the position where it is held stationary by spring loaded bearings 102.
  • the interrupter 10 is then in fully opened position as shown in FIG. 7 and ready for another closing operation.
  • This invention has advantages over prior art contacts in that there is no contact welding on closing and there is little current chopping on opening. Another advantage is that there is reduced contact wear because of closing on a non-welding material. Other advantages are that when the contacts are in the fully closed position, they are closed on contact material having low contact resistance, also no expensive release mechanism to break welded contact is required.
  • a vacuumtype circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first portion constructed from a material having good nonwelding characteristics and a second portion constructed from a material having low resistivity and good opening characteristics, said second contact structure comprising a first portion having good non-weld characteristics and a second portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure, when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said
  • a vacuum type circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first portion constructed from a material having good nonwelding characteristics and a second portion constructed from a material having low resistivity and good opening characteristics, said second contact structure comprising a first portion having good non-weld characteristics and asecond portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure, when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion
  • a vacuum type circuit interrupter as claimed in claim 2 wherein said first portion of said first contact and said second portion of said first contact are rigidly joined, and said first portion of said second contact and said second portion of said second contact are rigidly joined.
  • a vacuum type circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first portion constructed from a material having good nonwelding characteristics and a second portion constructed from a material having low resistivity and good opening characteristics, said second contact structure comprising a first portion having good non-weld characteristics and a second portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion of
  • a vacuum interrupter as claimed in claim 4 including a first magnetic means attached to said second contact structure, a second magnetic means attached to said movable operating rod, said first magnetic means and said second magnetic means cooperating to retain said second contact structure in predetermined position when said vacuum type circuit interrupter is open.
  • a vacuum type circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first portion constructed from a material having good nonwelding characteristics and a second portion constructed from a material having low resistivity and good opening characteristics, said second contact structure comprising a first portion having good non-weld characteristics and a second portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure, when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion
  • a vacuum type circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first I portion constructed from a material having good nonacteristics and a second portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure, when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion of said first contact are disengaged, when said vacuum type circuit interrupter is operated from a closed position to an open position separation of said first contact from said second

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Abstract

A vacuum type circuit interrupter is provided having a contact structure comprising separable mating contacts. The contact structure is constructed so that the mating contacts close on a first material and open on a second material. The first material on which the mating contacts close is made from weld free material so that contact welding does not occur when the vacuum interrupter is closed. The second material on which the contacts open, possesses good contact opening characteristics and interrupting that is, opening of the contacts will occur without excess current chopping.

Description

United States Patent [191 Harrold Dec. 11, 1973 VACUUM CIRCUIT INTERRUPTER HAVING IMPROVED CONTACT STRUCTURE Inventor: Ronald T. Harrold, Murrysville, Pa.
Westinghouse Electric Corporation, Pittsburgh, Pa.
Filed: June 23, 1972 Appl. No.: 265,904
Assignee:
US. Cl 200/144 B, 200/146 R Int. Cl. H011! 33/66 Field of Search 200/144 B, 146 R,
References Cited UNITED STATES PATENTS 7/1943 Thumim 200/146 R 7/1959 Reece 200/144 B X 3,017,480 1/1962 Klaassen 200/146 R Primary ExaminerRobert S. Macon Attorney-A. T. Stratton et al.
[ ABSTRACT 9 Claims, 9 Drawing Figures I /l I g q I 4 l v I I 32 \\/IB VACUUM CIRCUIT INTERRUITER HAVING IMPROVED CONTACT STRUCTURE BACKGROUND OF THE INVENTION The present invention relates to vacuum type circuit interrupters and more particularly to the contact structure which is a part of such vacuum interrupters. The contact structures disclosed utilize the principle of closing on a first material which has good closing characteristics, and resists welding, and opening on a second material which interrupts the circuit without current chopping for improved vacuum interrupter operation. Vacuum type circuit interrupters generally comprise an evacuated insulatingenvelope with separable contacts disposed within the insulating envelope. The contacts are movable between a closed position in which the contacts are engaged and an open position where the contacts are separated and an arcing gap is established therebetween. An arc is initiated between the contact surfaces when the contacts move into or out of engagement while the circuit in which the interrupter is used is energized.
When the contacts are brought together the are that is formed -melts some of the metallic contact material. After the contacts are brought together under high pressure engagement welds may be formed between required to break the weld so that the contacts can-beopened, depends upon many factors including the arc voltage, the current, the contact area and the contact material. These welds are objectionable since they interfere with the easy movement of the separable contacts and may result in the failure of the vacuum interrupter to open.
Another difficulty that is encountered with some prior art contacts in vacuum interrupters is that the materials used have an excessive tendency to chop under low current conditions. Thissharp chop in' current can induce extremely high voltages acrossinductive devices connected in the circuit beinginterrupted, and such overvoltages can lead'to destruction of the circuit components. For an effective vacuum interrupter, there should not be an excessive current chop on circuit opening.
Copper tungsten is ideal for weld free closing but poor on openings due to current chopping and also has undersirable electron emission. Chrome due to its vapor pressure properties is goodfor weld free closing, however, it has disadvantages of high contact resistance and is expensive. in the required oxygen-free form. One of thebest materials for opening is copper, but this welds easily on contact closing. Thus some materials are best for closing, others best for opening and a compromise is made by using metal mixtures or alloys. Contacts made from copper bismuth or chrome copper construction have reasonably good opening and closing characteristics, however, they still require an expensive contact release mechanism. It-is felt that the present invention has significant advantages over prior art contacts in that the contacts close on a-material that is weld free and open on a material that has good nonchopping characteristics.
SUMMARY OF THE INVENTION This invention discloses contact constructions which effectively use closing on a first material which has good non-welding characteristics and opening on a second material which does not cause excessive current chopping, and which has good interrupting characteristics. This improves operation of the vacuum interrupter. An expensive release mechanism is not required to assist in weld breaking and also the interrupter in its final closed position how low contact resistance.
In one embodiment of the invention, the contacts are brought together on a material which has good nonweld characteristics and then the contacts are moved to a final closed position where contact is made through a material having low resistance and good nonchopping characteristics. The contact points are moved from the first material to the second material by moving the operating rod transverse to the longitudinal axis of the vacuum interrupter. On vacuum interrupter opening, the contacts separate on the second material which has good non-chopping properties.
In another embodiment of the invention, the stationary contact is disposed within the vacuum interrupter. A movable contact is attached to an operating rod which moves along the longitudinal axis of the vacuum interrupter. The movable contact is pivotally attached to the operating rod so that when the vacuum interrupter is closed first contact is made on a material which has good non-weld characteristics and as the operating rod closes further the movable contact pivots around the operating rod and contact is made with a second material which has good opening characteristics. When the vacuum interrupter is opened, the movable contact is returned to and held in position for another closing operation by ceramic magnets which are attached to the movable contact and the operating rod. Current is carried from the movable contact tothe operating rod by a flexible connection.
In another embodiment of the invention two identical semicircular contacts each made of two materials are disposed within the vacuum interrupter. One of the contacts is pivotally attached to a stationary conducting rod. The other contact is pivotally attached to the movable operating rod. The movable operating rod moves along the longitudinal axis of the vacuum interrupter to move the contacts into and out of engagement. The arrangement is such that when the two contacts are in the open position, they are held in position by coil springs. When brought together, under' pressure, they make contact on a first material then revolve around the respective pivots continuously making electrical contact until a final closed position is reached in which contact is made on a second material. The contacts close on a weld free material and under increasing pressure the contacts roll over each other to the final closed position. Surge current flows initially through'this weld free material while the contacts roll over each other, until, by the time normal current is flowing contact is made on a second material which has good conductivity and desirable opening characteristics. On opening, the arc is formed between this second material and minimum current chopping is experienced. This embodiment of the invention can prevent welding of contacts even if the contacts are made of a material having poor weld characteristics, such as copper, by virtue of the contact rolling motion on closing which prevents welding. The current which flows when contact motion has ceased being insufficient for contact welding.
In anotherembodiment of the invention, two sets of contacts are used in the vacuum interrupter, one for closing and one for opening. The first set of contacts are located in the center of the second set of contacts so that the second set of contacts form an annular contact ring surrounding the first set of contacts. In this way, a weld free material can be used for the closing contacts and a material without current chopping properties can be used for the opening contacts. An expensive release mechanism is not required, and also the interrupter in its final closed position has low contact resistance. In a closing operation, the contact structure first closes on the centrally located contacts which are made of a weld free material. The surrounding second set of contacts of high conductivity material with good opening characteristics then close. After a slight time delay, the first set of contacts open and the vacuum interrupter is in the fully closed position. On opening, the second set of contacts interrupt the current flow without chopping.
Devices utilizing the teaching of the present invention have several advantages over the prior art. For example, there is no contact welding on vacuum interrupter closing. Another advantage of the present invention is that there is minimal current chopping on contact opening and the contacts separate on a material having good current interrupting characteristics. Another advantage is that there is reduced contact wear since the contacts close on a non-welding noneroding material. Another advantage of the present invention is that when the vacuum interrupter is in the fully closed position, the contacts are closed on a material which has low contact resistance. Still another advantage of the present invention is that an expensive mechanism to release welded contacts is not required.
BRIEF DESCRIPTION OF THE DRAWINGS Further advantages of the present invention will be readily apparent upon reading the following description taken in conjunction with the drawings, in which:
FIG. 1 is a vertical sectional view of a vacuum type circuit interrupter with the contacts in the open position embodying a contact construction of the present invention;
FIG. 2 is a side view partially in section of the vacuum interrupter shown in FIG. 1 with the contacts in the fully closed position;
FIG. 3 is a side view partially in section of another embodiment of the invention with the contacts in the open position;
FIG. 4 is similar to FIG. 3 but with the contacts in the closed position;
FIG. 5 is a side view of a pair of contacts illustrating another embodiment of the invention;
FIG. 6 is a view of the contacts shown in FIG. 5 with the contacts in the closed position; I
FIG. 7 is a vertical sectional view of still another embodiment of the invention with the contacts in the open position;
FIG. 8 is a view of a portion of the vacuum interrupter shown in FIG. 7 with the contacts in an intermediate closed position; and
FIG; 9 is a side view partially in section of the vacuum interrupter shown in FIG. 7 with the contacts in the fully closed position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and more particularly to FIGS. 1 and 2, there is shown a vacuum type circuit interrupter l0 embodying the teaching of the present invention. The vacuum type circuit interrupter 10 comprises a highly evacuated envelope 12 formed of glass or suitable ceramic material and a pair of metallic end caps 14 and 16 and the insulating envelope 12 to render the envelope l2 vacuum tight. The vacuum in the envelope 12 under normal operating conditions is lower than 10 Torr so that mean free path of electrons will be longer than the potential breakdown distance within the tubular envelope l2.
Disposed within the envelope 12 are a pair of relatively movable electrodes or contacts 20 and 22 embodying the teaching of the present invention. As shown in FIG. 1, when these contacts 20 and 22 are separated there is an arcing gap 24 formed therebetween. The upper contact 20 is stationary and is secured to a conducting rod 26 by a suitable means such as welding or brazing. The conducting rod 26 is secured at its upper end to the stationary end cap 14 by suitable means such as welding or brazing. The lower contact 22 is movable and is joined to a conducting operating rod 28. The conducting operating rod 28 is suitably mounted for movement along the longitudinal axis of the tubular insulating envelope 12 and for a slight motion transverse to the longitudinal axis of the tubular insulating envelope 12. The movable operating rod 28 projects through an opening 30 in the bellows end cap 16.
As shown in FIGS. 1 and 2, a flexible metal bellows 32 is secured in sealing relationship at its respective opposite ends to movable operating rod 28 and the opening 30 in the bellows end cap 16. The flexible metal bellows 32 provides a seal about the rod 28 to allow for movement of the rod 28 without impairing the vacuum inside the insulating envelope l2.
Coupled to the lower end of the operating rod 28 suitable actuating means (not shown) is provided for driving the movable contact 22 upward into engagement with the stationary contact 20 so as to close the interrupter 10. The actuating means is also capable of returning the contacts 22 to its open position so as to open the interrupter 10. The circuit opening operation will for example entail a typical gap length when the contacts are fully separated of approximately one-half inch.
When contacts 20 and 22 ofa vacuum interrupter 10 are opened, at the beginning of circuit interruption, a metallic arc initiates between the separated contacts 20 and 22 and serves as a vehicle for current conduction until the arc is extinguished. In an alternating current circuit the arc is usually extinguished near the first current zero of the alternating current wave. The are that is established across the arcing gap 24 between the contacts 20 and 22 when they are opened, and also when they are closed, vaporizes and melts some of the contact material. The vapors are dispersed from the arcing gap 24 toward the inside of the insulating envelope 12.-The internal surfaces of the insulating envelope 12 are protected from the condensation of the arc generated metallic vapor and particles thereon by means of a tubular metallic shield 36. The tubular metallic shield 36 is supported on the insulating envelope l2 and preferably electrically isolated from both end caps 14 and 16. This shield 36 acts to intercept and condense arc generated .metallic vapors before they can reach the internal surfaces of the insulating envelope 12. To reduce the possibility that metallic vapors or particles can bypass the main shield 36 and coat the internal surface of the insulating envelope 12 a pair of end shields 38 and 40 are provided at opposite ends of the central shield 36.
The contacts 20 and 22 comprise two portions, a first portion of a non-welding material 52 such as chrome, copper tungsten, or the like, and the second portion 54 comprises a material having low resistance and nonchopping properties such as copper or the like. When the contacts 20 and 22 are closed, initial engagement occurs on the non-welding material 52. After initial engagement of the contacts 20 and 22 the operating means (not shown) moves operating rod 28 transverse to the longitudinal axis of the interrupter so that the contact points shift from non-welding material 52 to the low resistance non-chopping material 54. As shown in FIG. 2, in the final closed position, contact is made on the second material 54 which has good opening characteristics. During opening of the interrupter 10, final contact parting occurs on the second material 54.
In another embodiment of the invention shown in FIGS. 3 and 4, the movable contact 22 is pivotally attached to the operating rod 28. The operating rod 28 is supported for movement along the longitudinal axis of the interrupter 10. The contacts are comprises of a first material 52 having non-welding characteristics and a second material 54 having low resistance, nonchopping characteristics. As shown in FIG. 3, when the vacuum interrupter is in the open position, the movable contact 22 is held in position by a magnet 56 attached to contact 22 and a magnet 58 attached to the movable operating rod 28. The movable contact 22 is attached to the operating rod 28 through a ceramic bearing 60. Current flows from the movable contact 22 to the operating rod 28 through a flexible connection 62. During the closing operation of the vacuum interrupter 10 initial contact between the contacts 20 and 22 is made on the non-welding material 52. As the operating rod 28 continues to move toward the closed position, along the longitudinal axis of the interrupter 10, the movable contact 22 moves about the pivot 60 so that final contact is made on a second material 54, as shown in FIG. 4. During circuit opening, final contact parting takes place on the second material 54 which has good opening characteristics. The operating rod 28 moves the contact 22 to the fully open position very rapidly so that the circuit is interrupted before the movable contact 22 returns to the position as shown in FIG. 3.
Referring now to FIGS. 5 and 6 there are shown a pair of vacuum interrupter contacts illustrating another embodiment of the present invention. The first contact 64 is pivotally attached to the stationary conducting rod 26. A second contact 66 is pivotally attached to the movable operating rod 28. Each contact 64 and 66 is made from a first material 52 having good non-welding characteristics and a second material 54 having good circuit opening characteristics. The contact arrangement is such that when the contacts 64 and 66 are brought together under pressure, engagement is first made between the first material 52 which is weld free and then the two contacts revolve around their respective pivots 68 and continuously making a good electrical contact until when the contacts are fully closed, contact is made between the second material 54 having good opening characteristics. Opening of the contacts will occur between the materials 54 having good opening characteristics with minimum current chopping.
Contacts 64 and 66 are identical and semicircular in construction. The contacts 64 and 66 pivot on ceramic bearings 68 and 70, respectively. The contacts 64 and 66 are held in the open position by flat spiral springs 72 and 74, respectively, when the contacts are disengaged, as shown in FIG. 5. When the contacts 64 and 66 are brought together under pressure, they revolve around the respective pivot bearings 68 and 70 continuously making electrical contact until in the final closed position, as shown in FIG. 6, contact is made between the second material 54 having good opening characteristics. On circuit interruption the movable operating rod 28 moves rapidly to the open position, before the flat spiral springs 72 and 74 can rotate the contacts 64 and 66, so that opening occurs on the second material 54. A flexible connection 76 electrically connects contact 64 to conducting rod 26. A flexible connection 78 connects contacts 66 with the movable operating rod 28. Thus when the contacts are in the closed position as shown in FIG. 6 a continuous current path extends from the conducting rod 26, through the flexible connection 76, through the second material 54 of contact 64, through the second material 54 of contact 66, through the flexible connection 78, to the movable operating rod 28. This design is such that on closing any metallic vapor formed due to arcing between the closing contacts 64 and 66, will be directed away from the final closing surfaces. Likewise, during an opening operation, any metallic vapor expelled from the contacts will be directed away from the point where initial contact engagement is made.
The embodiment of the invention illustrated in FIGS. 5 and 6 will prevent contact welding even if the contacts 64 and 66 are made of one material such as copper, since the contact rolling motion on closing prevents welding. When contact motion has ceased the current then flowing is insufficient for welding of the contacts 64 and 66. Many variations and improvements are possible with this construction of contact. For example, by suitably grading the resistivity of the contact area used for closing and opening, and by controlling the motions of contacts 64 and 66 the are initially formed between the low contacts resistance material 54 would experience an increasing resistive path as it continued between the high resistance material while finally extinguished as the contacts separate further. This would be a type of resistive opening.
Referring now to FIGS. 7, 8 and 9, there is shown a movable contact structure 80 and a stationary contact structure 82 disposed within a vacuum interrupter 10. In this embodiment of this invention, two sets of contacts are used in a vacuum interrupter. One set made out of a non-welding material 52 for closing, and the other set made out of material with non-chopping characteristics 54 for opening. The lower contact structure 82 which is relatively stationary comprises a central contact made of non-welding material 52, an outer contact 92 made of a non-chopping material 54, an outer housing 94, a compression spring 96 to resilv iently support contacts 90 and 92, and flexible connections 98 to electrically connect the contacts 90 and 92 to end'cap 14. The outer contact 92 is joined to the central contact 90 by suitable means such as welding or brazing. Conducting studs 100 are mounted on the end cap 14 for making electrical contact and for mounting the vacuum interrupter 10. Movable contact structure 80 comprises, a central contact 81 made of a nonwelding material 52, an annular surrounding contact 83 made of a non-chopping material 54, a compression spring 84 for moving contact 81 relative to contact 83, and an operating means (not shown) for moving contact structure 80 into and out of engagement with contact structure 82. A cup-shaped shield 85 surrounds the flexible metallic bellows 32 to prevent the bellows 32 from being bombarded by particles expelled during contact arcing. A metal bellows 33 is attached to reset rod 86 to permit movement of the reset rod 86 to return contact 81 to its normal open position upon opening of vacuum interrupter 10.
Referring now to FIG. 7, vacuum interrupter is shown in its normal open position. The first step in the closing operation of vacuum interrupter 10 is shown by dashed lines 87 in FIG. 7. As the vacuum interrupter 10 is closed, the contact structure 80 moves toward the contact structure 82 and the central contacts 81 and 90 engage as shown by the dashed lines 87 in FIG. 7. As the contact structure 80 continues to close, the outer contacts 83 of contact structure 80 begins to move relative to the stationary contact 81. In the open position contact 81 is held stationary with respect to contact 83 by spring loaded ball bearings 102 engaging a circular depression 104 in supporting rod 106. As the contact structure 80 continues to move toward the closed position after contacts 81 and 90 touch, the rod 106 is disengaged from the position shown in FIG. 7 where it is held stationary by the spring loaded bearings 102, and moves toward the position shown in FIG. 9 where it is held stationary by the spring loaded bearings 108 engaging the circular depression 104. As the rod 106 is disengaged from the spring loaded bearings 102, and starts to move relative to the outer portion 88 of contact structure 80 the outer portion 88 is moving faster than the rod 106 tends to be moved by spring 84, so that before contacts 81 and 90 separate contacts 83 and 92 engage, as shown in FIG. 8. As shown in FIG. 8, contacts 81 and 90 remain engaged until after contacts 83 and 92 are engaged. After contacts 83 and 92 are engaged, and fully closed so that contact 83 is no longer moving, rod 106 continues to move from the position where it was held stationary by bearings 102 to the position as shown in FIG. 9 where it is held stationary by the spring loaded bearings 102, and moves toward the position shown in FIG. 9 where it is held stationary by the spring loaded bearings 108 engaging the circular depression 104. As the rod 106 is disengaged from the spring loaded bearings 102, and starts to move relative to the outer portion 88 of contact structure 80 the outer portion 88 is moving faster than the rod 106 tends to be moved by spring 84, so that before contacts 81 and 90 separate contacts 83 and 92 engage, as shown in FIG. 8. As shown in FIG. 8, contacts 81 and 90 remain engaged until after contacts 83 and 92 are engaged. After contacts 83 and 92 are engaged, and fully closed so that contact 83 is no longer moving, rod 106 continues to move from the position where it was held stationary by bearings 102 to the position as shown in FIG. 9 where it is held stationary by spring loaded bearings 108. As the rod 106 continues to move towards position where bearings 108 engage the depression 104, the centrally located contacts 81 and 90 separate so that the final closed position is as shown in FIG. 9. The vacuum interrupter 10 is now closed on contacts 83 and 92 which are made from a material 54 having good opening characteristics. When the vacuum interrupter 10 opens contacts 83 and 92 separate with little current chopping. As contact structure moves towards the open position a reset means (not shown) operates the reset rod 86 to move the rod 106 from the position where it is held stationary by spring loaded bearings 108 to the position where it is held stationary by spring loaded bearings 102. The interrupter 10 is then in fully opened position as shown in FIG. 7 and ready for another closing operation.
This invention has advantages over prior art contacts in that there is no contact welding on closing and there is little current chopping on opening. Another advantage is that there is reduced contact wear because of closing on a non-welding material. Other advantages are that when the contacts are in the fully closed position, they are closed on contact material having low contact resistance, also no expensive release mechanism to break welded contact is required.
Since numerous changes may be made in the above described apparatus, and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all the matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
What is claimed is:
l. A vacuumtype circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first portion constructed from a material having good nonwelding characteristics and a second portion constructed from a material having low resistivity and good opening characteristics, said second contact structure comprising a first portion having good non-weld characteristics and a second portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure, when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion of said first contact are disengaged, when said vacuum type circuit interrupter is operated from a closed position to an open position separation of said first contact from said second contact occurs between said second portion of said first contact and said second portion of said second contact.
2. A vacuum type circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first portion constructed from a material having good nonwelding characteristics and a second portion constructed from a material having low resistivity and good opening characteristics, said second contact structure comprising a first portion having good non-weld characteristics and asecond portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure, when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion of said first contact are disengaged, when said vacuum type circuit interrupter is operated from a closed position to an open position separation of said first contact from said second contact occurs between said second portion of said first contact and said second portion of said second contact, and including a stationary conducting means to which said first contact is rigidly attached, operating means to which said second contact is rigidly attached, said operating means being supported for movement along a longitudinal axis defined by said conducting means and for movement transverse to the longitudinal axis defined by said conducting means, and in which when said vacuum interrupter is closed said first portion of said second contact initially engages said first portion of said first contact and then said second portion of said second contact engages said second portion of said first contact and said first portion of said first contact is disengaged from said first portion of said second contact.
3. A vacuum type circuit interrupter as claimed in claim 2, wherein said first portion of said first contact and said second portion of said first contact are rigidly joined, and said first portion of said second contact and said second portion of said second contact are rigidly joined.
4. A vacuum type circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first portion constructed from a material having good nonwelding characteristics and a second portion constructed from a material having low resistivity and good opening characteristics, said second contact structure comprising a first portion having good non-weld characteristics and a second portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion of said first contact are disengaged, when said vacuum type circuit interrupter is operated from a closed position to an open position separation of said first contact from said second contact occurs between said second portion of said first contact and said second portion of said second contact, said first portion of said first contact and said second portion of said first contact are rigidly joined, and said first portion of said second contact and said second portion of said second contact are rigidly joined, and a conducting rod rigidly supports said first contact structure, a movable operating rod, said movable operating rod being supported for movement along its longitudinal axis, said second contact structure being pivotally supported by said movable operating rod.
5. A vacuum interrupter as claimed in claim 4 including a first magnetic means attached to said second contact structure, a second magnetic means attached to said movable operating rod, said first magnetic means and said second magnetic means cooperating to retain said second contact structure in predetermined position when said vacuum type circuit interrupter is open.
6. A vacuum type circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first portion constructed from a material having good nonwelding characteristics and a second portion constructed from a material having low resistivity and good opening characteristics, said second contact structure comprising a first portion having good non-weld characteristics and a second portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure, when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion of said first contact are disengaged, when said vacuum type circuit interrupter is operated from a closed position to an open position separation of said first contact from said second contact occurs between said second portion of said first contact and said second portion of said second contact, said first portion of said first contact and said second portion of said first contact are rigidly joined, and said first portion of said second contact and said second portion of said second contact are rigidly joined, and including a stationary conducting rod said first contact being pivotally attached to said stationary conducting rod, a movable operating rod, said second contact being pivotally attached to said movable operating rod, said first contact and said second contact being semicircular in configuration so that when said second contact moves into engagement with said first contact a rolling contact point is maintained and said first and said second contact structures revolve around their respective pivot points.
7. The combination as claimed in claim 6 wherein a first spiral spring is provided around the pivot point of said first contact to maintain said first contact in a predetermined position when said vacuum interrupter is opened, and a second flat spiral spring provided around the pivot point of said second contact structure to maintain said second contact structure in a predetermined position when said vacuum interrupter is opened.
8. A vacuum type circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first I portion constructed from a material having good nonacteristics and a second portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure, when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion of said first contact are disengaged, when said vacuum type circuit interrupter is operated from a closed position to an open position separation of said first contact from said second contact occurs between said second portion of said first contact and said second portion of said second contact, said first portion of said first contact structure and said second portion of said first contact structure are rigidly joined, and said first portion of said second contact structure is movable with respect to said second portion of said second contact structure, and said second contact structure comprises a first portion which is centrally located and a second portion which forms an annular contact area around said first portion, said first portion being supported so that when the vacuum interrupter is closed, said first portion moves with respect to said second portion.
9. The vacuum interrupter as claimed in claim 8 wherein said first portion of said second contact structure is movable between a first and second position with respect to said second portion of said second contact structure and a spring loaded ball bearing means are provided to hold said first portion of said second contact structure in said first and said second positions.

Claims (9)

1. A vacuum type circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first portion constructed from a material having good non-welding characteristics and a second portion constructed from a material having low resistivity and good opening characteristics, said second contact structure comprising a first portion having good non-weld characteristics and a second portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure, when said vacuum type circuit interrupter is fulLy closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion of said first contact are disengaged, when said vacuum type circuit interrupter is operated from a closed position to an open position separation of said first contact from said second contact occurs between said second portion of said first contact and said second portion of said second contact.
2. A vacuum type circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first portion constructed from a material having good non-welding characteristics and a second portion constructed from a material having low resistivity and good opening characteristics, said second contact structure comprising a first portion having good non-weld characteristics and a second portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure, when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion of said first contact are disengaged, when said vacuum type circuit interrupter is operated from a closed position to an open position separation of said first contact from said second contact occurs between said second portion of said first contact and said second portion of said second contact, and including a stationary conducting means to which said first contact is rigidly attached, operating means to which said second contact is rigidly attached, said operating means being supported for movement along a longitudinal axis defined by said conducting means and for movement transverse to the longitudinal axis defined by said conducting means, and in which when said vacuum interrupter is closed said first portion of said second contact initially engages said first portion of said first contact and then said second portion of said second contact engages said second portion of said first contact and said first portion of said first contact is disengaged from said first portion of said second contact.
3. A vacuum type circuit interrupter as claimed in claim 2, wherein said first portion of said first contact and said second portion of said first contact are rigidly joined, and said first portion of said second contact and said second portion of said second contact are rigidly joined.
4. A vacuum type circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first portion constructed from a material having good non-welding characteristics and a second portion constructed from a material having low resistivity and good opening characteristics, said second contact structure comprising a first portion having good non-weld characteristics and a second portion haVing low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion of said first contact are disengaged, when said vacuum type circuit interrupter is operated from a closed position to an open position separation of said first contact from said second contact occurs between said second portion of said first contact and said second portion of said second contact, said first portion of said first contact and said second portion of said first contact are rigidly joined, and said first portion of said second contact and said second portion of said second contact are rigidly joined, and a conducting rod rigidly supports said first contact structure, a movable operating rod, said movable operating rod being supported for movement along its longitudinal axis, said second contact structure being pivotally supported by said movable operating rod.
5. A vacuum interrupter as claimed in claim 4 including a first magnetic means attached to said second contact structure, a second magnetic means attached to said movable operating rod, said first magnetic means and said second magnetic means cooperating to retain said second contact structure in predetermined position when said vacuum type circuit interrupter is open.
6. A vacuum type circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first portion constructed from a material having good non-welding characteristics and a second portion constructed from a material having low resistivity and good opening characteristics, said second contact structure comprising a first portion having good non-weld characteristics and a second portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure, when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion of said first contact are disengaged, when said vacuum type circuit interrupter is operated from a closed position to an open position separation of said first contact from said second contact occurs between said second portion of said first contact and said second portion of said second contact, said first portion of said first contact and said second portion of said first contact are rigidly joined, and said first portion of said second contact and said second portion of said second contact are rigidly joined, and including a stationary conducting rod said first contact being pivotally attached to said stationary conducting rod, a movable operating rod, said second contact being pivotally attached to said movable operating rod, said first contact and said second contact being semicircular in configuration so that when said second contact moves into enGagement with said first contact a rolling contact point is maintained and said first and said second contact structures revolve around their respective pivot points.
7. The combination as claimed in claim 6 wherein a first spiral spring is provided around the pivot point of said first contact to maintain said first contact in a predetermined position when said vacuum interrupter is opened, and a second flat spiral spring provided around the pivot point of said second contact structure to maintain said second contact structure in a predetermined position when said vacuum interrupter is opened.
8. A vacuum type circuit interrupter comprising a highly evacuated insulating envelope, a first contact structure disposed within said insulating envelope, a second contact structure disposed within said insulating envelope, said second contact structure being movable between a first position in contact with said first contact structure and a second position in which said second contact structure is spaced from said first contact structure to establish an arcing gap therebetween, said first contact structure comprising a first portion constructed from a material having good non-welding characteristics and a second portion constructed from a material having low resistivity and good opening characteristics, said second contact structure comprising a first portion having good non-weld characteristics and a second portion having low resistivity and good opening characteristics, said first contact structure and said second contact structure being constructed so that when said second contact structure moves into engagement with said first contact structure said first portion of said second contact structure makes initial engagement with said first portion of said first contact structure, when said vacuum type circuit interrupter is fully closed said second portion of said second contact is in engagement with said second portion of said first contact and said first portion of said second contact and said first portion of said first contact are disengaged, when said vacuum type circuit interrupter is operated from a closed position to an open position separation of said first contact from said second contact occurs between said second portion of said first contact and said second portion of said second contact, said first portion of said first contact structure and said second portion of said first contact structure are rigidly joined, and said first portion of said second contact structure is movable with respect to said second portion of said second contact structure, and said second contact structure comprises a first portion which is centrally located and a second portion which forms an annular contact area around said first portion, said first portion being supported so that when the vacuum interrupter is closed, said first portion moves with respect to said second portion.
9. The vacuum interrupter as claimed in claim 8 wherein said first portion of said second contact structure is movable between a first and second position with respect to said second portion of said second contact structure and a spring loaded ball bearing means are provided to hold said first portion of said second contact structure in said first and said second positions.
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080302765A1 (en) * 2005-11-02 2008-12-11 Siemens Aktiengesellschaft Vacuum-Insulated Switching Device
US20100220417A1 (en) * 2006-01-17 2010-09-02 Areva T & D Sa Compact disconnector circuit-breaker for an alternator
US20120241413A1 (en) * 2011-03-22 2012-09-27 Wangpei Li Contact member including purposely introduced undulations and vacuum interrupter including the same
US9269514B2 (en) 2011-12-21 2016-02-23 Alstom Technology Ltd. Device for protection against particles generated by an electric switching arc
US9443666B2 (en) 2012-10-02 2016-09-13 Alstom Technology Ltd. Electrical contact device of the contact finger type with a strong nominal current

Citations (3)

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Publication number Priority date Publication date Assignee Title
US2324891A (en) * 1941-05-01 1943-07-20 Gen Electric Electric circuit interrupter
US2897322A (en) * 1956-04-24 1959-07-28 Era Patents Ltd Electrical switching apparatus
US3017480A (en) * 1958-08-27 1962-01-16 Hazemeijer Co High-voltage circuit-breaker

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2324891A (en) * 1941-05-01 1943-07-20 Gen Electric Electric circuit interrupter
US2897322A (en) * 1956-04-24 1959-07-28 Era Patents Ltd Electrical switching apparatus
US3017480A (en) * 1958-08-27 1962-01-16 Hazemeijer Co High-voltage circuit-breaker

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080302765A1 (en) * 2005-11-02 2008-12-11 Siemens Aktiengesellschaft Vacuum-Insulated Switching Device
US20100220417A1 (en) * 2006-01-17 2010-09-02 Areva T & D Sa Compact disconnector circuit-breaker for an alternator
US8081407B2 (en) * 2006-01-17 2011-12-20 Areva T&D Sa Compact disconnector circuit-breaker for an alternator
US20120241413A1 (en) * 2011-03-22 2012-09-27 Wangpei Li Contact member including purposely introduced undulations and vacuum interrupter including the same
US8507822B2 (en) * 2011-03-22 2013-08-13 Eaton Corporation Contact member including purposely introduced undulations and vacuum interrupter including the same
US9269514B2 (en) 2011-12-21 2016-02-23 Alstom Technology Ltd. Device for protection against particles generated by an electric switching arc
US9443666B2 (en) 2012-10-02 2016-09-13 Alstom Technology Ltd. Electrical contact device of the contact finger type with a strong nominal current

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