US2919329A - Air blast circuit breakers - Google Patents

Air blast circuit breakers Download PDF

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Publication number
US2919329A
US2919329A US668687A US66868757A US2919329A US 2919329 A US2919329 A US 2919329A US 668687 A US668687 A US 668687A US 66868757 A US66868757 A US 66868757A US 2919329 A US2919329 A US 2919329A
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US
United States
Prior art keywords
chamber
piston
contact
orifice
pressure
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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
Application number
US668687A
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English (en)
Inventor
Latour Andre
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Merlin Gerin SA
Original Assignee
Merlin Gerin SA
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Filing date
Publication date
Application filed by Merlin Gerin SA filed Critical Merlin Gerin SA
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Publication of US2919329A publication Critical patent/US2919329A/en
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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
    • H01H33/02—Details
    • H01H33/28—Power arrangements internal to the switch for operating the driving mechanism
    • H01H33/30—Power arrangements internal to the switch for operating the driving mechanism using fluid actuator
    • H01H33/32—Power arrangements internal to the switch for operating the driving mechanism using fluid actuator pneumatic

Definitions

  • This invention pertains to electrical circuit breakers, and especially to heavy current circuit breakers of the air blast type in which the compressed air used for the air blast to improve the extinguishing of the arc, is also employed to provide very positive and quick opening of the circuit breaker.
  • simply the chamber the admission of compressed air to the extinction chamber
  • Another'object of the invention is to provide a circuit breaker of the above type in which the motion of the movable contact is damped, near the end of its openingtravel, for smooth and efiicient operation and freedom from rebound.
  • the slowing down of the terminal phase of the opening movement also helps to ensure that the arc extinction air blast is allowed to act for a sufii cient time upon the arc andthe gases generated thereby, to purge the chamber completely.
  • a further object of the invention is to provide a circuit breaker of the above type in which means are provided to definea blast zone of invariable thickness; that is, one which does not change in size during the motion of the movable contact, and which hence can be designed to provide the optimum extinguishing eificiency.
  • Still another object of the invention is to provide a circuit breaker of the kind mentioned, and including a movable contact assembly provided with terminal motion damping means, such that the air pressure in the chamber during the opening movement is maintained more or less at the maximum level, for efiicient extinction, and until the moving contact has reached its maximum open position.
  • Fig. 1 is a vertical sectional view of the parts of an air blast circuit breaker essential to an understanding of the invention, the same having cylindrical symmetry.
  • Fig. 2 is a similar view of the lower portion of a modified circuit breaker, in which the moving contact is hollow so as to form a duct for the exhaust gases from the chamber.
  • Fig. 3 is also an axial vertical section of a circuit breaker wherein the moving contact withdraws through a blast orifice in the downward direction with respect to the orifice.
  • Fig. 4 is'again a similar view of the lower portion only of a modification related to the damping of the movement of the moving contact.
  • a form of circuit breaker in accordance with the invention employing a hollow tubular fixed contact 4 through which the gases of the arc are expelled to the atmosphere, and a movable solid contact 1 cooperating therewith.
  • Movable contact 1 is integral with a differential piston assembly comprising an upper piston 2 and a lower piston 3.
  • the movable contact 1 cooperates with the fixed hollow contact 4 having the duct 5 through which the arcgases, as well as the extinguishing gases, are discharged to the open atmosphere.
  • the two contacts may be of the pressure type, the pressure for holding them in contact being provided by a coil compression spring 6 urging the movable contact against the fixed contact.
  • the contacts may also be of the friction type, one penetrating into the other, in which case spring 6 could be omitted.
  • the smaller piston 3 of the differential piston operates within a cylinder 7 which communicates with the open atmosphere through an orifice 8 at its bottom, and with the arc extinction chamber (the interior of housing 13) through an orifice 9 in the side wall of the cylinder 7.
  • the larger piston 2, which faces the movable contact 1, operates within a cylinder 10 communicating with the arc extinction chamber through orifices 11 in its side wall.
  • a sliding contact 12 ensures a good conductive path from the metallic cylinder 10 to the movable contact 2.
  • the cylinder 10 is connected through the metallic cylinder 7 to one terminal of the circuit breaker, the fixed contact being connected to the other terminal.
  • the chamber housing 13 will ordinarily constitute the insulating envelope of the breaker, herein shown as ribbed in the known way to provide a longer leakage path for currents.
  • This opening phase can be made very rapid by providing the supplementary orifices 14 in the side wall of cylinder 7, which are uncovered by the piston 2 early in its downward motion, thus allowing a large volume of compressed air to penetrate rapidly into cylinder to accelerate the remainder of the opening movement.
  • piston 3 closes orifice 9 and the air then within cylinder 7 is trapped and can only escape relatively slowly through exhaust orifice 8.
  • the dash-pot action thus damps the final phase of the circuit opening movement, up to the point at which piston 3 reaches the bottom of cylinder 7 and bears against the sealing gasket 15. From this instant on, the lower surface of piston 3 is only subject to atmospheric pressure, while the upper surface of piston 2 is exposed to the pressure in the extinction chamber and the assembly remains stationary.
  • this conduit can be maintained closed by a suitable delay mechanism with a view to maintaining at least a residual pressure within the chamber 13.
  • Closure of the circuit breaker requires only that the chamber be returned to atmospheric pressure, as by operation of valve V to shut off the air supply and to vent the chamber to open air.
  • the movable contact 2 will then return to the closed condition under the pressure of spring 6, and/or the action of the residual compressed air trapped between the pistons 2 and 3.
  • the outflow of air from cylinder 10 can be accelerated by providing the upper wall of cylinder 10 with orifices 16 normally covered by a flap valve in the shape of a resilient washer 17. Also, orifices can be provided in the piston 2.
  • the location of the orifice 9 in the side wall of cylinder 7 can be varied according to the amount of damping desired.
  • the invention can also be applied to circuit breakers in which the exhaust conduit is contained within the movable contact, rather than in the fixed contact, and such an arrangement is shown in Fig. 2 of the drawings, the contacts themselves being omitted in this showing.
  • numeral 1 designating the tubular member which would carry the movable contact.
  • the are gases can thus exhaust downward through this conduit and exit via orifices 18, flowing through the duct 19 and the exhaust orifice 20 into the outside atmosphere.
  • the movable tubular contact is here integral with the differential piston again formed by the two pistons 2 and 3 which function as already described.
  • the exhaust orifice 20 is arranged preferablyto be closed with a certain time delay by the valve 21, which is independent of the movable contact and is controlled by the pressure existing in chamber 13.
  • the valve 21 is maintained in open position by the spring 22 which acts upon a piston 23 sliding in cylinder 24 and integral with the valve 21.
  • the cylinder 24 communicates with the chamber 13, for example via the conduit 25.
  • This form of the invention operates as follows. Compressed air is again supplied through valve V to the chamber to initiate the opening movement.
  • the movable contact rapidly separates from the fixed contact, causing a heavy inrush of air into the hollow contact.
  • This air flows through the tubular conduit 1, orifices 18, conduit 19 and the exhaust orifice 20 into the free atmosphere.
  • the closing valve 21 does not move, either because it is located in a cavity not reached by the airflow which urges it into closed position, or because it is retained by the spring 22.
  • a sufficient pressure is built up in the cylinder, which pushes the piston 23, and with it the valve 21, towards the left.
  • valve 2-1 As soon as the valve 2-1 has left its cavity, it is sucked by the strong exhaust flow and suddenly closes orifice 20. The breaker is therefore maintained open without substantial additional loss of compressed air. It is readily reclosed merely by exhausting the air pressure in the chamber 13, as by the decompression valve V.
  • Fig. 3 of the drawings illustrates a modified form of the invention in which the movable contact, again connected with the gas discharge conduit, cooperates with means defining a radial blast zone of fixed axial length, and hence operable efficiently regardless of the position to which the movable contact has moved during the opening movements.
  • This form of the invention also provides a valve, integral with a moving contact assembly, for closing off the chamber from atmosphere after complete opening of the contacts (to maintain full or partial pressure in the chamber), and includes the motion damping and delaying features of the previously described embodiments.
  • the movable contact 1 is formed at its contact end as a solid rod, fixed to one extremity of the tubular conduit 36 for the exhaust blast. This permits the use of very small arc blast orifice, but obviously the contact could be made hollow clear to its end if this size feature were not desired.
  • the movable contact passes through at least one cylindrical cap 37 of insulating material having a rounded profile, and defining with fixed hollow contact 4 a radial blast zone of invariable thickness.
  • the movable contact may also pass through a second cylindrical cap made of metal and operating as an arcing tip and electrostatic shield.
  • the compressed air on admission, flows through the blast orifice in the cap 38 and thence through orifices 39, 40 and 41.
  • the tube 36 carries the pistons 2 and 3 which again form a difierential piston.
  • the exhaust valve 21 is fixed to the lower extremity of tube 36.
  • the operation is similar to the species Figs. 1 and 2. However, when the extremity of the movable contact 1 has cleared the blast orifice of cap 37, the compressed air can flow freely through orifices 39, 40, 41 and 20 to the outside. After a very short interval, following parting of the contacts, the orifice 9 is closed by the piston 3 whereby the air beneath the piston is trapped, to damp the further motion of the contact tube.
  • the orifice 9 may be placed, as shown in the modification of Fig 4, near the bottom of the cylinder within which the piston 3 moves, and provided with a check valve 42, arranged to prevent the return of the trapped air into the arc extinction chamber 13.
  • an orifice 43 (Fig. 3) may be provided to secure communication between the space enclosed between the pistons and the free atmosphere, until the movable contact has reached its fully open position.
  • a circuit-breaker having a pair of normally closed contacts, one at least of which is axially movable and the movement of which is controlled by the pressure of an arc extinguishing gas admitted in to the arc extinction chamber and comprising pneumatic means responsive'to the initial admission of gas into said chamber, for pressing the contacts together to prevent premature separation thereof
  • the improvement which comprises a diiferential piston mounted on a movable one of said contacts, a dual chamber cylinder receiving said piston, and in which said opposite faces of said piston defines two chambers, the first chamber being so disposed that a rise of pressure in said first chamber upon admission of gas tends to cause said piston to move in the contact-opening direction, the second chamber being so disposed that a rise of pressure in said second chamber tends to cause said piston to move in the contact-closing direction, each of said first and second chambers having orifice means connecting respectively said first and second chambers with said are extinction chamber, said orifice means being so rated relatively one to the other that the pressure upon admission of pressure gas in
  • said second chamber comprises supplementary orifice means connecting said second chamber to the atmosphere, said orifice means connecting respectively said first and second chambers to the are extinction chamber and said orifice means connecting said second chamber to the atmosphere being so rated relatively one to the other that the pressure upon admission of pressure gas in said are extinction chamber rises more rapidly in said second chamber than in said first chamber, whereby said piston presses the contacts together to prevent premature separation thereof.
  • a circuit-breaker in accordance with claim 2 in which at least one of said orifice means connecting said first chamber to said are extinction chamber is provided with exhaust flap, whereby the movement of said piston is accelerated in contact-closing direction.
US668687A 1956-07-10 1957-06-28 Air blast circuit breakers Expired - Lifetime US2919329A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR1059533X 1956-07-10

Publications (1)

Publication Number Publication Date
US2919329A true US2919329A (en) 1959-12-29

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ID=9599139

Family Applications (1)

Application Number Title Priority Date Filing Date
US668687A Expired - Lifetime US2919329A (en) 1956-07-10 1957-06-28 Air blast circuit breakers

Country Status (6)

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US (1) US2919329A (de)
BE (1) BE557909A (de)
CH (2) CH338884A (de)
DE (1) DE1059533B (de)
FR (1) FR1155626A (de)
GB (2) GB837825A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3017482A (en) * 1957-07-01 1962-01-16 British Thomson Houston Co Ltd Air or gas blast electric circuit breakers
US3118996A (en) * 1960-12-15 1964-01-21 Forwald Haakon Contact operating means for air blast circuit breaker
US3134875A (en) * 1960-02-27 1964-05-26 Asea Ab Rebound preventing means in air blast circuit breaker
US6100778A (en) * 1996-09-16 2000-08-08 Siemens Ag Movably disposed circuit breaker having a blow-out attenuator

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1072679B (de) * 1958-03-26 1960-01-07
DE1212189B (de) * 1962-11-09 1966-03-10 Bbc Brown Boveri & Cie Impulsartig arbeitende Schalteinrichtung fuer Druckgasschalter
CH410112A (de) * 1964-08-21 1966-03-31 Bbc Brown Boveri & Cie Druckgasschalter

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US798082A (en) * 1903-02-07 1905-08-29 Otis Elevator Co Automatic controller for electric circuits.
GB319277A (en) * 1928-09-19 1930-09-18 Gen Electric Improvements in and relating to pneumatically operated electric switches
GB335380A (de) * 1928-10-03 1930-09-25 Sigwart Ruppel
GB432453A (en) * 1934-03-28 1935-07-26 Gen Electric Co Ltd Improvements in electric switches or circuit breakers of the kind provided with separable electrodes, the arc gap between which is adapted to be swept by a stream of fluid
FR811341A (fr) * 1935-10-10 1937-04-12 Brown Interrupteur de puissance à soufflage par gaz comprimé pour très hautes tensions
GB542601A (en) * 1939-11-01 1942-01-19 Oerlikon Maschf Improvements in or relating to gas blast circuit breakers
US2574334A (en) * 1940-04-06 1951-11-06 Merlin Gerin Air-blast circuit breaker
US2592079A (en) * 1948-07-31 1952-04-08 Bbc Brown Boveri & Cie Compressed gas operated circuit breaker
US2747055A (en) * 1952-05-31 1956-05-22 Asea Ab High tension circuit breakers

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US798082A (en) * 1903-02-07 1905-08-29 Otis Elevator Co Automatic controller for electric circuits.
GB319277A (en) * 1928-09-19 1930-09-18 Gen Electric Improvements in and relating to pneumatically operated electric switches
GB335380A (de) * 1928-10-03 1930-09-25 Sigwart Ruppel
GB432453A (en) * 1934-03-28 1935-07-26 Gen Electric Co Ltd Improvements in electric switches or circuit breakers of the kind provided with separable electrodes, the arc gap between which is adapted to be swept by a stream of fluid
FR811341A (fr) * 1935-10-10 1937-04-12 Brown Interrupteur de puissance à soufflage par gaz comprimé pour très hautes tensions
GB542601A (en) * 1939-11-01 1942-01-19 Oerlikon Maschf Improvements in or relating to gas blast circuit breakers
US2574334A (en) * 1940-04-06 1951-11-06 Merlin Gerin Air-blast circuit breaker
US2592079A (en) * 1948-07-31 1952-04-08 Bbc Brown Boveri & Cie Compressed gas operated circuit breaker
US2747055A (en) * 1952-05-31 1956-05-22 Asea Ab High tension circuit breakers

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3017482A (en) * 1957-07-01 1962-01-16 British Thomson Houston Co Ltd Air or gas blast electric circuit breakers
US3134875A (en) * 1960-02-27 1964-05-26 Asea Ab Rebound preventing means in air blast circuit breaker
US3118996A (en) * 1960-12-15 1964-01-21 Forwald Haakon Contact operating means for air blast circuit breaker
US6100778A (en) * 1996-09-16 2000-08-08 Siemens Ag Movably disposed circuit breaker having a blow-out attenuator

Also Published As

Publication number Publication date
FR1155626A (fr) 1958-05-06
CH341549A (fr) 1959-10-15
GB837825A (en) 1960-06-15
BE557909A (de)
CH338884A (fr) 1959-06-15
GB837824A (en) 1960-06-15
DE1059533B (de) 1959-06-18

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