US2717292A - Air circuit breaker - Google Patents

Air circuit breaker Download PDF

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Publication number
US2717292A
US2717292A US283038A US28303852A US2717292A US 2717292 A US2717292 A US 2717292A US 283038 A US283038 A US 283038A US 28303852 A US28303852 A US 28303852A US 2717292 A US2717292 A US 2717292A
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United States
Prior art keywords
contact
movable
contacts
stationary
plates
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US283038A
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English (en)
Inventor
Russell E Frink
Olsson Paul
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.)
Westinghouse Electric Corp
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Westinghouse Electric Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to BE519241D priority Critical patent/BE519241A/xx
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US283038A priority patent/US2717292A/en
Application granted granted Critical
Publication of US2717292A publication Critical patent/US2717292A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/50—Means for increasing contact pressure, preventing vibration of contacts, holding contacts together after engagement, or biasing contacts to the open position
    • H01H1/54—Means for increasing contact pressure, preventing vibration of contacts, holding contacts together after engagement, or biasing contacts to the open position by magnetic force

Definitions

  • a u ATTORNEQ WITNESSES 21x2 4 Sepia 1955 F2.
  • a BYl/ Z ATTORNE F lg 7 WITNESSES 94 I. W.
  • This invention relates to circuit breakers and, more particularly, to contact structures for air circuit breakers.
  • An object of the invention is to provide a circuit breaker with an improved contact structure which fits into a relatively small space and has high current-carrying capacity.
  • Another object of the invention is to provide a circuit breaker with an improved contact structure having high interrupting and current-carrying capacities Which is rugged and durable in construction.
  • Another object of the invention is to provide a circuit breaker with an improved contact arrangement according to the preceding paragraphs wherein the magnetic forces induced by the current flow are utilized to increase the contact pressure.
  • Figure l is a side elevational view, partly in section, of r a circuit breaker embodying the principles of the invention
  • Fig. 2 is a detail view of the latch mechanism
  • Fig. 3 is an enlarged side elevational view, partly in section, showing the improved contact structure in the closedcontact position
  • Fig. 4 is an enlarged elevational View of the stationary contact structure taken along line IV-IV of Fig. 3 and looking in the direction of the arrows;
  • Fig. 5 is a bottom view, partly in section, of the stationary contact structure shown in Fig. 4;
  • Fig. 6 is a vertical sectional view of the contact structure taken on line VI-VI of Fig. 4, showing the contacts in full lines in the closed position, and in dot-and-dash lines in the position at which the main contacts are about to separate;
  • Fig. 7 is a view similar to Fig. 6 but showing the contacts in full lines in the position at which the intermediate contacts are about to separate and in dot-and-dash lines in the position at which the arcing contacts are about to separate.
  • the circuit breaker is of the roll-out type and is mounted on a truck comprising a pair of side plates 11 (only one being shown) which are rigidly joined by cross members 13, 15, 17, and 19 to form a rigid frame for supporting the circuit breaker.
  • the truck is mounted on wheels 20 to facilitate rolling the breaker into and out of a cubicle in order to connect and disconnect the breaker in an electrical circuit.
  • the circuit breaker is of the multi-pole type (only one pole being shown) and comprises generally a plurality of sets of separable contact means 21, a common operating mechanism 23, a trip device 25, and a closing means 27.
  • the contact means consists generally of stationary contact blocks 29 and 31 mounted respectively on upper and lower terminal members 33 and 35 which, in turn, are
  • a switch arm 41 for operating the movable contacts (there being a switch arm 41 for each pole of the breaker) is pivotally mounted by a pivot pin 43 on the lower terminal member 35 and is operatively connected by means of an insulating operating rod 51 to the operating mechanism 23.
  • the upper ends of the operating rods 51 are pivotally connected by pivot pins 53 to the corresponding switch arms 41, and the lower ends of the operating rods are connected by suitable means to an angular crossbar 59 which is common to all of the poles of the breaker.
  • the crossbar 59 is pivotally connected at its ends by pivot pins 55 (only one being shown) to an operating lever 61 which is pivotally mounted on a shaft 67 supported in the side members of a generally U-shaped frame 69.
  • the frame 69 is supported on the cross members 13, 15, and 17 and is shown partly broken away more clearly to show the operating mechanism.
  • the operating mechanism consists of a closing lever also mounted on the shaft 67 and connected by means of a link 81 to the movable armature 85 of the closing solenoid 27
  • the operating lever 61 and the closing lever 75 are connected by means of an underset thrust-transmitting toggle comprising toggle links 87 and 89 pivotally connected together by a knee pivot pin 91.
  • the toggle link 87 is pivotally connected to the operating lever 61 and the toggle link 89 is pivotally connected to the closing lever 75.
  • the closing lever 75 is held in the closed position by a spring-biased latch which normally engages a roller 101 on the closing lever and holds the latter in the position shown.
  • the toggle 87-89 is releasably held in a slightly underset position by a latch member 103 mounted on the shaft 67 for movement relative thereto.
  • a link 105 connects the knee of the toggle 87-89 to the latch member 103 which is normally releasably held in latching position by the latching and tripping mechanism shown in Fig. 2.
  • This mechanism comprises a trip member 109 carrying a latch roller 119 which is biased by a spring 123 into latching engagement with a shoulder on the latch member 103 to releasably restrain the latter and the toggle 87-89 in thrust-transmitting position.
  • the latch 109 is of the slip-off type, and a trigger latch 127 is provided to releasably restrain the latch member 109 and the latch roller 119 in latching position.
  • the latch 127 has a projection 131 normally engaging a latching projection 133 on the trip member 109 and is biased to latching position by a spring 135.
  • a tripping electromagnet 137 is provided to operate the latch mechanism and effect release of the operating mechanism and opening of the circuit breaker.
  • the tripping electromagnet 137 When an overload current occurs, the tripping electromagnet 137 is energized and operates the latch mechanism to eifect release of the latch 109 which, in turn, releases the latch member 103. Upon release of the latch member 103, the toggle 87-89 immediately collapses, permitting clockwise rotation of the operating lever 61 and operating movement of the switch arms 41 for the several poles of the breaker.
  • the toggle 87-89 is reset to its thrust-transmitting position, and the latch member 103 is reset and relatched automatically during the opening operation. This is effected by a pair of springs 169 (only one being shown) connected under tension between the armature 85 and the closing lever 75 at a point near the shaft 67.
  • springs 169 (only one being shown) connected under tension between the armature 85 and the closing lever 75 at a point near the shaft 67.
  • the switch arm 41 is channel-shaped and has rigidly mounted thereon a pair of laterally spaced main movable contacts 177, an intermediate contact 179 and an arcing contact 181.
  • the main movable contacts 177 cooperate with spaced main stationary contacts 183.
  • the movable intermediate contacts 179 cooperate with a stationary intermediate contact 185, and the movable arcing contact 181 cooperates with a stationary arcing contact 187.
  • the stationary intermediate contact 185 and the stationary arcing contact 187 are mounted on a contact platform 205 (see also Figs. 4, 5, 6, and 7) mounted on the upper contact block 29 for limited movement relative thereto by means of a pair of spaced plates 207 disposed one on each side of the contact block 29.
  • the plates 207 are supported on bolts 209, extending through openings in the contact block 29 and threaded at both ends to receive nuts 210. Springs 212 are compressed between the nuts 210 and the plates 207 to provide good contact pressure between the plates 207 and the contact block 29.
  • the plates 207 are provided with elongated slots 214 surrounding the lower bolt 209 to permit limited pivotal movement of the plates about the upper bolt 209.
  • the platform 205 is provided with laterally extending studs 211 disposed adjacent the lower end theerof and extending into elongated slots 213 in the plates 207 for supporting the platform for limited movement relative to the plates 207.
  • Ears 215 extend laterally from the sides of the platform 205 into openings 217 in the plates to limit the movement of the platform.
  • the platform 205 is biased outwardly away from the contact block 29 by means of a coil spring 219 (Figs. 3, 6, and 7) disposed adjacent the upper end of the platform 205 and a pair of coil springs 221 (Figs. 3 to 7) located near the lower end of the platform.
  • the spring 219 is compressed between the contact block 29 and the contact platform 205 and is provided with a guide stud 223 secured to the contact block 29.
  • the springs 221 are compressed between the ends of a U-shaped flexible conductor 225 (Fig. 3) which serves to electrically connect the contact platform 205 to the contact block 29.
  • a flexible conductor 227 electrically connects the lower end of the switch arm 41 to the lower contact block 31.
  • the main stationary contacts 183 are formed on the lower corners of the plates 207 (Figs. 3, 4, and and extend inwardly toward each other.
  • a connecting bar 229 is supported on pins 231 mounted in the bar 229 and supported in openings in the main contacts 183.
  • Springs 233 compressed between the bar 229 and a bar 235 secured to the contact block 29 bias the plates 207 in a clockwise direction about the upper bolt 209 and provide contact pressure between the main stationary contacts 183 and the main movable contacts 177 in the closed position of the switch arm 41.
  • the purpose of the connecting bar 229 is to tie the plates 207 together laterally while permitting a slight independent pivotal movement of each of the plates.
  • the platform 205 pivots about the studs 211 and the upper end thereof follows the switch arm with the arcing contact 187 maintaining contact with the moving arcing contact 181 until the ears 215 are stopped by striking the walls of the openings 217 in the contact plates 207.
  • the main and intermediate movable contacts have opened to the positions shown, respectively, at 177b and 179k and the arcing contacts are about to separate.
  • the arc will usually be extinguished when the arcing contacts have separated approximately two inches.
  • a switching surge may be produced which will cause the arc to restrike across a gap of this dimension or larger.
  • Such restrikes may even occur outside the arc chute between live or grounded parts such, for instance, as between the main stationary contacts and the switch arm 41 at a point below the main movable contacts. The latter is prevented by providing the switch arm with an insulating sleeve 239.
  • the contact structure provides increased momentary and continuous current-carrying capacity in a small compact arrangement which permits placing the entire separating contact structure inside the arc chute; hence, any restriking of the arc will occur between the interrupting contact structure and will be confined within the arc extinguisher.
  • stationary contacts comprising a fixed contact member, a pair of spaced movable contact carrying plates disposed one on each side of said fixed contact member and mounted on said fixed contact member for limited movement relative thereto, springs providing pressure contact between said contact carrying plates and said fixed contact member, main stationary contacts on said movable contact carrying plates, a contact member disposed between said contact carrying plates and supported between said movable contact carrying plates for limited movement relative thereto, intermediate and arcing contacts on said contact member, and a movable switch member having movable main, intermediate and arcing contacts thereon for cooperating, respectively, with said stationary main, intermediate and arcing contacts to open and close the circuit.
  • stationary contacts comprising a fixed contact support member, a pair of movable c0ntact carrying plates disposed one on each side of said fixed contact support member and pivotally mounted on said fixed contact support member for limited pivotal movement relative thereto, a plurality of springs biasing said movable contact carrying plates into pressure contact with said fixed contact support member, main stationary contacts mounted on said movable contact carrying plates, a contact-carrying member supported between said movable contact carrying plates for limited movement relative to said contact carrying plates, intermediate and arcing contacts mounted on said contact-carrying member, and a movable switch member having movable main, intermediate and arcing contacts mounted thereon for cooperating, respectively, with said stationary main, intermediate and arcing contacts to open and close said circuit.
  • a stationary contact structure comprising a conducting member rigidly mounted on one of said terminals, a pair of movable contact plates pivotally mounted one on each side of said conducting member for limited sliding movement relative thereto, main stationary contacts rigid with said movable contact plates, springs biasing said movable contact plates for pivotally moving said main stationary contacts away from said conducting member, spring means biasing said movable contact plates into pressure engagement with said conducting member, a rigid contact member having stationary intermediate and arcing contacts thereon, said rigid contact member being mounted on said movable contact plates and biased for limited movement relative to said movable contact plates and said conducting member, and a movable switch member pivotally mounted on the other of said terminals and having movable main, intermediate and arcing contacts rigid therewith for cooperating with said stationary contact structure to open and close the circuit.
  • a pair of spaced terminals, a stationary contact structure supported on one of said terminals comprising a member of conducting material rigidly secured to one of said terminals, a pair of spaced movable contact-carrying members mounted on said conducting member, said contact-carrying members being pivotally mounted one on each side of said conducting member for limited movement relative thereto, main stationary contacts rigidly mounted on said spaced movable contact-carrying members, said contact-carrying members having openings therein, a rigid contact member having stationary intermediate and arcing contacts rigid therewith, said rigid contact member having projections thereon engaging in said openings in said spaced movable contact-carrying members to support said rigid contact member for limited movement relative to said spaced movable contact-carrying members, and a switch arm having main, intermediate and arcing contacts thereon and pivotally mounted on the other of said terminals for movement into and out of engagement with said stationary contact structure to open and close said circuit.
  • a pair of spaced terminals, a stationary contact assemblage mounted on one of said terminals comprising a pair of spaced contact-carrying members having openings therein and pivotally mounted one on each side of said terminal for limited movement relative to said terminal, each of said contact-carrying members being biased away from said terminal and having a main stationary contact thereon, spring means biasing said contact-carrying members against opposite sides of said terminal to provide pressure contact therebetween, a rigid contact member having stationary intermediate and arcing contacts rigid therewith and having projections thereon engaging in the openings in said spaced contact-carrying members to support said rigid contact member for limited movement relative to said spaced contact-carrying members, spring means biasing said rigid contact member away from said terminal, a movable switch arm having a movable contact assemblage rigid therewith comprising movable main, intermediate and arcing contacts, and said movable switch arm being pivotally mounted on the other one of said terminals and movable to an open position and to a closed position to
  • a pair of spaced terminals a member of conducting material mounted on one of said terminals, a pair of spaced contact-carrying members having a plurality of openings therein and disposed one on each side of said conducting member, each of said contact-carrying members having a main contact rigid therewith, pivot means pivotally mounting said contact-carrying members on said conducting member for movement relative thereto, stop members for limiting the movement of said contact-carrying members relative to said conducting member, springs biasing said contact-carrying members into close engagement with said conducting member, a rigid contact member disposed between said spaced contact-carrying members and having intermediate and arcing contacts rigid therewith, a plurality of projections on said rigid contact member engaging said openings to support said rigid contact member between said contact-carrying members for movement relative thereto and for limiting said movement, a pivoted switch arm pivotally supported on the other of said terminals and having movable main, intermediate and arcing contacts rigid therewith, said switch arm being mov
  • a circuit breaker a pair of spaced terminals, a stationary contact structure comprising main, intermediate and arcing contacts mounted on one of said terminals, a movable switch arm pivotally mounted on the other of said terminals and having a movable contact assemblage thereon comprising main, intermediate and arcing contacts for cooperating with the corresponding stationary contacts of the stationary contact structure for establishing an arc, an arc chute structure having arc-extinguishing means therein, said stationary contact structure and said co- 7 operating movable contact assemblage being compactly arranged and disposed entirely within said arc chute so that any are or restrike will occur within said are chute,-
  • a pair of terminals a stationary contact structure mounted on one of said terminals comprising stationary main, intermediate and arcing contacts, a movable switch member pivotally mounted on the other of said terminals, a flexible conductor electrically connecting said movable switch arm to said other terminal, a movable contact assemblage mounted on said movable switch member comprising movable main, intermediate and arcing contacts, said movable contact assemblage cooperating with said stationary contact structure to establish an arc, an arc chute structure having arc-extinguishing 8 means therein, said stationary contact structure and said cooperating movable contact assemblage being arranged compactly and disposed entirely Within said are chute so that any arc or restrike of the arc will occur within said are chute, and an insulating sleeve surrounding a portion of said movable switch member adjacent said arc chute.

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US283038A 1952-04-18 1952-04-18 Air circuit breaker Expired - Lifetime US2717292A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
BE519241D BE519241A (en)) 1952-04-18
US283038A US2717292A (en) 1952-04-18 1952-04-18 Air circuit breaker

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Application Number Priority Date Filing Date Title
US283038A US2717292A (en) 1952-04-18 1952-04-18 Air circuit breaker

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US2717292A true US2717292A (en) 1955-09-06

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2993105A (en) * 1957-12-13 1961-07-18 Westinghouse Electric Corp Circuit breaker
US3177332A (en) * 1962-06-11 1965-04-06 Mc Graw Edison Co High voltage circuit breakers with contact pressure boosters and arcing contacts
US3210506A (en) * 1957-12-13 1965-10-05 Westinghouse Electric Corp Circuit breaker with improved contact structure

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1074431A (en) * 1910-10-29 1913-09-30 Gen Electric Circuit-controlling contact.
US2259971A (en) * 1938-11-02 1941-10-21 Westinghouse Electric & Mfg Co Circuit breaker
US2462283A (en) * 1945-07-20 1949-02-22 Kearney James R Corp Electrical switch
US2477189A (en) * 1946-12-05 1949-07-26 Allis Chalmers Mfg Co Electric arc extinguishing means
US2492762A (en) * 1944-08-23 1949-12-27 Gen Electric Electric switch
US2571933A (en) * 1948-07-30 1951-10-16 Westinghouse Electric Corp Air circuit breaker

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1074431A (en) * 1910-10-29 1913-09-30 Gen Electric Circuit-controlling contact.
US2259971A (en) * 1938-11-02 1941-10-21 Westinghouse Electric & Mfg Co Circuit breaker
US2492762A (en) * 1944-08-23 1949-12-27 Gen Electric Electric switch
US2462283A (en) * 1945-07-20 1949-02-22 Kearney James R Corp Electrical switch
US2477189A (en) * 1946-12-05 1949-07-26 Allis Chalmers Mfg Co Electric arc extinguishing means
US2571933A (en) * 1948-07-30 1951-10-16 Westinghouse Electric Corp Air circuit breaker

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2993105A (en) * 1957-12-13 1961-07-18 Westinghouse Electric Corp Circuit breaker
US3210506A (en) * 1957-12-13 1965-10-05 Westinghouse Electric Corp Circuit breaker with improved contact structure
US3177332A (en) * 1962-06-11 1965-04-06 Mc Graw Edison Co High voltage circuit breakers with contact pressure boosters and arcing contacts

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Publication number Publication date
BE519241A (en))

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