US2937256A - Contact structure for electric switches of the gas blast type - Google Patents

Contact structure for electric switches of the gas blast type Download PDF

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Publication number
US2937256A
US2937256A US718342A US71834258A US2937256A US 2937256 A US2937256 A US 2937256A US 718342 A US718342 A US 718342A US 71834258 A US71834258 A US 71834258A US 2937256 A US2937256 A US 2937256A
Authority
US
United States
Prior art keywords
contact
nozzle
section
hollow
contacts
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
Application number
US718342A
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English (en)
Inventor
Baltensperger 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.)
BBC Brown Boveri AG Germany
BBC Brown Boveri France SA
Original Assignee
BBC Brown Boveri France SA
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
Application filed by BBC Brown Boveri France SA filed Critical BBC Brown Boveri France SA
Application granted granted Critical
Publication of US2937256A publication Critical patent/US2937256A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • H01H33/70—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid
    • H01H33/7015—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid characterised by flow directing elements associated with contacts
    • H01H33/7038—Switches with separate means for directing, obtaining, or increasing flow of arc-extinguishing fluid characterised by flow directing elements associated with contacts characterised by a conducting tubular gas flow enhancing nozzle

Definitions

  • the configuration of the passageway fits into "and closes off an opening in the s arour id the head o'flthe solid contact intothe open ⁇ o h e same as been e er y that noz 35 Un d Pam' O 2 as high as possible and to increase, at the same time, t eins l ns stren th to su h an e tcnt. h t e hi vo a e esist e d t *has fi iss a t ta s. 80 a e ks 'w th se two u remen t t to a s tisfactory degree in switch constructions now being supplied to the industry.
  • the object of the present invention to provide an improved configuration for the nozzle incorporated in the hollow contact which will serve to improve the dielectric strength of the contact zone during disconnectionof the contacts thereby lessening the chance form-ignition between the contacts and further to-decrease the splashing of metallic particles on the interior which has its most narrow cross-section in the w'cinity" of the contact plane with the rounded nose portion of the solid contact, the cross-section then progressively increasing in the direction away from the solid contact, i.e. in the direction of air flow through the hollow contact, thus to establish a nozzle effect intended to enhance the blasting action of the. compressed air.
  • the desired objective is attained byprofiling the interior passageway through the hollow contact to establish 'a nozzle in which the narrowest cross-section of the nozzle is so far away from the contact plane between the two contacts that the air pressure between the solid contact member and the place in the nozzle having the narrowest cross-section, at the instant of disengagement between the contacts, effects a sufficiently high dielectric strength with relation to, the recovery voltage.
  • the general configurationof the nozzle is thus, for example,- that of a Venturi comprising two truncated conical surfaces with theirsmaller ends in contact with each other.
  • the arrangement is such that the nose of the solid contact even though spaced from the area of minimum cross-section projects an appre extentintothe nozzle-like. passageway through the hollow contact that the latter formsa protective skirt prevents, at least at the wall of the insulator member surrounding and enclosing ,cl'es onto; walls of the surrounding insulating casing. This obtains when thetangent to the circular line of contact'hetween' the nose portion of the solid contact and the interior nozzle surface of the hollow contact extends through the lower skirt-like extension of the hollow contact which envelops the end portion of the solid contact.
  • the electric switch comprises a tubular insulator 1 through which compressed gas such as air is introduced in the direction ilb dicated by the arrows.
  • compressed gas such as air
  • the hollow contact 2 and the solid contact 3 are disengaged by effecting relative longitudinal movement therebetween.
  • This can be done in known manner by having the hollow contact stationary andthe solid contact movable, or vice versa.
  • the arrangement can also be such that both the hollow and solid contacts move together in the first moments of contact separation before being disengaged.
  • the interior of the hollow contact 2 which is formed as a surface of revolution, is shaped generally in the form a Ventun', there being an upper truncated conical surface section 2a joined at its narrow end along a line or plane 4 with a lower generally truncated conical surface section 2b.
  • the passage way through the nozzle consisting of sections 2a and 2b has a minimum cross-section at the plane 4.
  • the solid contact 3 has a nose portion 3a projecting into the lower nozzle section 2b and establishes a line of peripheral con tact with the surface of nozzle section 2b at the line or plane indicated at 5.
  • the contact plane 5 is disposed so far away from plane 4 designating 'ietsntssi M 7 960 3 v the point of minimum cross-section of the nozzle that an area of high pressure is formed in the nozzle section 2b between the planes 4 and 5 as well as between plane 4 and the end 8 of the nose portion 3a of the solid contact.
  • the interior surface of the hollow contact curves outwardly and then downwardly to establish a skirt or screen" portion 6 which envelops a part of the solid contact 3 below the contact plane 5.
  • the tangent to the contact plane 5 is indicated at 7 and it is seen that this tangent passes through the lower skirt portion 6 of the hollow contact 2.
  • the compressed gas such as air is present within the insulating casing 1 at the contacts.
  • this compressed air flows around the nose portion 3a into the lower nozzle section 2b pushing the are formed between the contacts upwardly through the nozzle thus elongating and cooling the same, the arc being ultimately broken.
  • the compressed air attains its full flow velocity through the nozzle, there is an interval during which metallic splashes can be formed. However, such splashes are now caught andretained by the depending skirt portion 6 and hence are prevented from reaching the wall of the insulating casing 1.
  • the improved switch is enabled to handle high disconnecting currents and with a high order of recovery voltage. Tests on the improved construction have indicated that the 4 disconnecting current can be increased by about 20% and the recovery voltage by about as compared with constructions which are now known.
  • the combination comprising a hollow contact having a longitudinal passageway therethrough forming a nozzle and a solid contact in alignment with said hollow contact, said contacts being movable relative to each other in a longitudinal direction to effect engagement and disengagement therebetween and an insulator casing surrounding said contacts, the end of said solid contact being rounded and adapted to enter said hollow contact and engage the wall of said nozzle formed therein along a peripheral contact line therebetween, said nozzle decreasing in cross-section from said peripheral contact line in the direction of gas flow therethrough and having its minimum cross-section disposed remotely from said contact line, said hollow contact including a peripherally extending depending skirt portion completely surrounding the end portion of said solid contact and through which passes the tangent to said peripheral contact line, said skirt portion serving to intercept splashings from said contacts upon separation thereof and thereby prevent the same from reaching the wall of said insulator casing.

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  • Circuit Breakers (AREA)
  • Contacts (AREA)
US718342A 1957-03-04 1958-02-28 Contact structure for electric switches of the gas blast type Expired - Lifetime US2937256A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH2937256X 1957-03-04

Publications (1)

Publication Number Publication Date
US2937256A true US2937256A (en) 1960-05-17

Family

ID=4572887

Family Applications (1)

Application Number Title Priority Date Filing Date
US718342A Expired - Lifetime US2937256A (en) 1957-03-04 1958-02-28 Contact structure for electric switches of the gas blast type

Country Status (5)

Country Link
US (1) US2937256A (fr)
CH (1) CH352726A (fr)
DE (2) DE1149774B (fr)
FR (1) FR1205064A (fr)
NL (1) NL224968A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3264439A (en) * 1962-07-26 1966-08-02 Bbc Brown Boveri & Cie Pressure gas operated electrical switch with two stationary main contacts and a movable bridging contact basket

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH531246A (de) * 1971-05-12 1972-11-30 Bbc Brown Boveri & Cie Druckgasschalter mit einer Düsenkontaktanordnung
DE2828773C2 (de) * 1978-06-30 1982-09-30 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Autopneumatischer Druckgasschalter

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE639566C (de) * 1933-05-28 1936-12-08 Siemens Schuckertwerke Akt Ges OElloser Leistungsschalter
US2067673A (en) * 1933-11-17 1937-01-12 Westinghouse Electric & Mfg Co Circuit interrupter

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE639566C (de) * 1933-05-28 1936-12-08 Siemens Schuckertwerke Akt Ges OElloser Leistungsschalter
US2067673A (en) * 1933-11-17 1937-01-12 Westinghouse Electric & Mfg Co Circuit interrupter

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3264439A (en) * 1962-07-26 1966-08-02 Bbc Brown Boveri & Cie Pressure gas operated electrical switch with two stationary main contacts and a movable bridging contact basket

Also Published As

Publication number Publication date
CH352726A (de) 1961-03-15
DE1070265B (de) 1968-09-12
NL224968A (fr)
FR1205064A (fr) 1960-01-29
DE1149774B (de) 1963-06-06

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