US1996304A - Electric switch - Google Patents

Electric switch Download PDF

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Publication number
US1996304A
US1996304A US199580A US19958027A US1996304A US 1996304 A US1996304 A US 1996304A US 199580 A US199580 A US 199580A US 19958027 A US19958027 A US 19958027A US 1996304 A US1996304 A US 1996304A
Authority
US
United States
Prior art keywords
electrodes
switch
vacuum
vessel
electric
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
US199580A
Other languages
English (en)
Inventor
Robert A Millikan
Royal W Sorensen
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.)
CALIFORNIA INST
CALIFORNIA INSTITUTE
Original Assignee
CALIFORNIA INST
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 claimed from US148418A external-priority patent/US1784302A/en
Priority claimed from GB3159426A external-priority patent/GB291815A/en
Priority to DEM97403D priority Critical patent/DE539812C/de
Priority to FR626633D priority patent/FR626633A/fr
Application filed by CALIFORNIA INST filed Critical CALIFORNIA INST
Priority to US199580A priority patent/US1996304A/en
Application granted granted Critical
Publication of US1996304A publication Critical patent/US1996304A/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
    • H01H33/60—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

Definitions

  • This invention relates to a method and means for eliminating arcing and refers particularly to electric apparatus, such as electric switches for use upon, electric power lines for the transmission 5 of electrical energy.
  • electric apparatus such as electric switches for use upon, electric power lines for the transmission 5 of electrical energy.
  • An object of the present invention is to provide an apparatus which will be small in size, inexpensive to manufacture, and which can be I used for high voltage or high power transmission lines without the dangers encountered in the present apparatuses employed for like purposes.
  • an object of the present invention is to provide an apparatus and methodand means for conditioning same which includes an extraordinary insulation surrounding the elec trodes, which insulation is suitable for use on lines carrying high power.
  • an object of the present invention is to provide a switch of improved type for interrupting currents on high power transmission lines.
  • the vapor liberated would fill the vacuum chamber and change any insulating vacuum to a conducting vacuum by providing a conducting atmosphere between the electrodes, a condition conducive to the maintenance of an are. It was also believed that the presence of a high potential gradient will detach the electrons from cold electrodes and that high vacua could not be relied upon for the required insulation.
  • arcing can be controlled by the control of the amount of readily freed electrons or ions which can be obtained from the electrodes or the absorbed gases in the electrodes.
  • electrodes of an apparatus such as a switch whichis to be employed upon high power lines are freed of all material on the surface of the metal, absorbed by the metal, occluded by the metal, or
  • the electrodes are freed of this electron-liberating material by high voltage. high current electric arc, appliedbetween the electrodes. It appears that the material which forms or liberates the electrons from the electrodes of the switch may by the energy of the are be freed from the electrodes.
  • the device is to be put in practice. If the device is to be operated at low power and low voltages, a small amount of treatment will be found suiiicient to remove from the electrodes all materials which will form electrons in operation of the apparatus at such conditions of low electric energy, or potential. In cases where the apparatus is to be employed under conditions of high electrical energy and potential, the treatment must be considerably more thorough. In certain cases, this conditioning of the electrodes is carried on by forming an arc with several hundred amperes at potential of 15,000 volts, or higher.
  • the apparatus is attached to a vacuum pump, or other means adapted to remove all vapors, gases, metallic particles, ionized or neutral,
  • the switch comprises a vessel 2 of insulating material, such as glass.
  • 3 indicates a fixed contact or electrode sealed at one end 4 to the housing 2 and extending into the center of the housing with the inner end cored out, as indicated at 5, to assist in centering the fixed and moving contacts of the switch and secure adequate contact.
  • 6 indicates a moving contact or electrode for the switch adapted to make contact with the fixed contact 3 when the switch is closed, as illustrated; Said moving contact 6 has an annular recess 1 at its end for engaging the annular end of the stationary contact, thus centering the two contacts in the contacting position and securing a firm, intimate contact.
  • the moving contact 6 is indicated as connected with a rod 8 which extends without the housing 2, so that the upper end of the rod may be connected with mechanical means (not shown) by which the switch may be operated.
  • a rod 8 which extends without the housing 2
  • the rod 8 of the moving contact is likewise sealed to the housing of the switch.
  • the housing 2 has a portion of its wall flexible or movable-relative to the remainder of the housing. This is shown as preferably accomplished by having part of the housing or vessel wall 2 in form of an accordion or bellows 9, including the rod 8.
  • the switch is indi- .electricity. High degree of vacuum
  • a shield 2i indicated as surrounding the contacts and spaced between the contacts and chamber walls. Said shield 2
  • the chamber formed by the vessel 2 must be evacuated to such a low pressure as prevents the existence of a gas medium of sufiicient density to carry an arc.
  • the electrodes 6 and 3 of the switch must also be in condition to free the same from any material which will emit electrons sufficient to carry an are under the conditions of operation.
  • the extent to which the vessel must be evacuated to operate satisfactorily depends upon the thoroughness in which the electron-liberating material is removed from the electrodes; preferably, however, the evacuation is as thorough as possible.
  • the vessel 2 is connected with a suitable vacuum pump. In certain forms of the invention, such vacuum pump may be left attached to the switch for operation continuously or intermittently.
  • the degree of evacuation must be beyond the vacuum at which rarefied gas is a conductor for however, is not of itself sufiicient to produce a non-conductive condition around the electrodes of the apparatus. Moreover, if the electrodes have been thoroughly conditioned as hereinafter described, or seasoned, and used for a period, the switch will operate satisfactorily with vacuums very much re-' Jerusalem as compared to the vacuums necessary when the switch is being conditioned or during the early stages of its operation.
  • the electrodes can be eliminated therefrom.
  • the electrodes are much more readily and generally only can be freed-of electron-liberating material by developing between the electrodes a high potential, high current arc, so that the energy of the arc itself repels all material, such as occluded gases, etc., which otherwise would emit electrons from the electrodes.
  • the switch after being baked for the removal of occluded gases may be placed upon a high power line and an arc struck between the electrodes carrying about 400 amperes at 15,000 volts, the are being maintained for approximately fifteen seconds while the emitted material driven off by the energy of the arc is expelled from the vessel. In this manner the contact surfaces of the electrodes and adjoining area of the switch terminals are definitely relieved of substantially all material which might be detached from'the terminals during operation.
  • a switch so treated has been operated successfully to interrupt 900 amperes at approximately 50,000 volts.
  • the heating In case attempt is made to remove such material from the electrodes merely by heating the same, the heating must be carried out to extremely high temperatures, preferably to Such heat can be obtained by inducing the electric currents into the' electrodes. For apparatus to be employed upon high power lines, it is generally necessary to develop some arcing between the electrodes, even if such heating method would properly condition the-electrodes. It is also possible to condition the electrodes of the switch entirely by arcing, in which case the potential and current employed in, the early stages of the arcing is much reduced until considerable of the occluded gases and other material is driven from the electrodesand expelled from the vessel.
  • the required vacuum may be thereafter maintained on the switch by tightly sealing the vacuum chamber, or the switch may be left connected to a vacuum pump which is operated as required to maintain, such vacuum or there may be sealed to the vacuum chamber a pocket containing charcoal made absorbent for gases.
  • charcoal When charcoal is used, its absorbent power is increased 'bycooling with some refrigeration, such as cooled brine, or liquid air.
  • the use of charcoal cooled by a refrigerating agent, such as liquid air, may be employed as an aid in the conditioning of the electrodes to facilitate expelling the materials driven from the electrodes from the vessel.
  • the switch construction as herein described operates by properly conditioning with the emission of so few metallic particles from the electrodes during switching that no evidence of pitting can be found on the switch terminals. It is also found that the limited number of metallic particles which are emitted do not come off as a gas which willv reduce the vacuum to a conducting one, nor as active ions in sufiicient quantity to reduce the insulating vacuum to a conducting vacuum. Moreover, the vacuum chamber does not fill with accumulated ions because the small bits of material shot off from the electrodes travel with practically no interference to the walls of the vacuum chamber, or shield, where they become attached and are no longer free to float about in the chamber.
  • the electrodes of the invention may be formed of various materials, such as copper, tungsten, or aluminum.
  • the present invention includes the generic discovery that arcing in apparatus of this kind is due to materials liberating electrons from the electrodes and that such electrodes can be conditioned to be sufliciently freed of such electron emitting material that under vacuum arcing can not be maintained between reduced neck of substantial length extended from said body portion at the other end, and a contact member disposed within said container and in the neck thereof and having its exposed terminal at the upper end of said neck, said neck being long to insulate the terminals against flash over externally of the container and being remote from any external conducting object, said neck including a flexible vacuum tight metal member sealed in a vacuum tight manner to said contact member, and operating mechanism for the interrupter locatedat the end of and mainly beyond said neck and said terminal.
  • a circuit interrupter comprising an evacuated container having a wall composed of insulating material and a flexible gas-imperforate metal wall which is sealed to said insulating wall in a vacuum-tight manner, stationary and movable contact members disposed within said container, said stationary contact members being extended through and having a vacuum-tight connection with said insulating wall, said movable contact member having an operative connection with said flexible'metal wall in the interior of said casing, and externally disposed operating mechanism having an operative connection with said flexible metal wall on the exterior of said casing.
  • An electric switch circuit interrupter comprising a vessel evacuated beyond the conducting point, contact members having their contacts disposed within said vessel, one of said contact members extending without the vessel sealed to said contact member in vacuum tight relation and operative to permit the contact member to open the contacts suificiently to prevent discharge between the contacts, and an insulating neck forming part of said housing, said neck being long to insulate thecontacts against fiashover externally o the vessel, the neck being formed of glass and having vacuum tight glass to metal seal with the flexible metallic member.
  • An electric 'circuit interrupter comprising a vessel evacuated beyond the conducting point
  • the vessel including an insulating portion formed the vessel and being reconducting object.

Landscapes

  • High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
US199580A 1926-11-15 1927-06-17 Electric switch Expired - Lifetime US1996304A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DEM97403D DE539812C (de) 1926-11-15 1926-12-14 Verfahren zum Entgasen der Kontakte von Hochspannungsvakuumschaltern
FR626633D FR626633A (fr) 1926-11-15 1926-12-22 Interrupteurs électriques
US199580A US1996304A (en) 1926-11-15 1927-06-17 Electric switch

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US148418A US1784302A (en) 1926-11-15 1926-11-15 Process for conditioning electric switches
GB3159426A GB291815A (en) 1926-12-13 1926-12-13 Electrical switches
US199580A US1996304A (en) 1926-11-15 1927-06-17 Electric switch

Publications (1)

Publication Number Publication Date
US1996304A true US1996304A (en) 1935-04-02

Family

ID=27258984

Family Applications (1)

Application Number Title Priority Date Filing Date
US199580A Expired - Lifetime US1996304A (en) 1926-11-15 1927-06-17 Electric switch

Country Status (3)

Country Link
US (1) US1996304A (fr)
DE (1) DE539812C (fr)
FR (1) FR626633A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2794087A (en) * 1955-06-10 1957-05-28 Jennings Radio Mfg Corp Coaxial switch
US2832872A (en) * 1955-05-13 1958-04-29 Jennings Radio Mfg Corp Vacuum switch
US2897322A (en) * 1956-04-24 1959-07-28 Era Patents Ltd Electrical switching apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE975483C (de) * 1943-02-21 1961-12-07 Aeg Hochspannungsvakuumschalter

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2832872A (en) * 1955-05-13 1958-04-29 Jennings Radio Mfg Corp Vacuum switch
US2794087A (en) * 1955-06-10 1957-05-28 Jennings Radio Mfg Corp Coaxial switch
US2897322A (en) * 1956-04-24 1959-07-28 Era Patents Ltd Electrical switching apparatus

Also Published As

Publication number Publication date
DE539812C (de) 1931-12-02
FR626633A (fr) 1927-09-15

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