US2882372A - Electrical switchgear for use in three-phase a.c. systems - Google Patents

Electrical switchgear for use in three-phase a.c. systems Download PDF

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Publication number
US2882372A
US2882372A US744405A US74440558A US2882372A US 2882372 A US2882372 A US 2882372A US 744405 A US744405 A US 744405A US 74440558 A US74440558 A US 74440558A US 2882372 A US2882372 A US 2882372A
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Prior art keywords
phase
breaks
switch
contacts
contact
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US744405A
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English (en)
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Preissler Karl
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Individual
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/54—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere
    • H01H9/56—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere for ensuring operation of the switch at a predetermined point in the ac cycle
    • H01H9/563—Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere for ensuring operation of the switch at a predetermined point in the ac cycle for multipolar switches, e.g. different timing for different phases, selecting phase with first zero-crossing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H19/00—Switches operated by an operating part which is rotatable about a longitudinal axis thereof and which is acted upon directly by a solid body external to the switch, e.g. by a hand
    • H01H19/54—Switches operated by an operating part which is rotatable about a longitudinal axis thereof and which is acted upon directly by a solid body external to the switch, e.g. by a hand the operating part having at least five or an unspecified number of operative positions
    • H01H19/60—Angularly-movable actuating part carrying no contacts
    • H01H19/62—Contacts actuated by radial cams
    • H01H19/626—Contacts actuated by radial cams actuating bridging contacts

Definitions

  • This invention is concerned with the problem of increasing the breaking power of a switch for three-phase A.C. either in order to reduce the dimensions of the switch or, for equal dimensions, to increase the life of the switch.
  • the breaking power applied to each contact or, in the case of double breaks, to the pair of contacts which has opened first is equal to the total breaking power applied to both subsequent contacts or pairs of contacts.
  • the breaking power applied to the contact switching first is twice the breaking power applied to each of the following contacts. In other words: The half of the total breaking power is applied to the contact switching first Whereas only one fourth of the breaking power is applied to each of the two other contacts load. This applies to staras well as delta-connected con- 'sumers.
  • the switch rating of a three-phase A.C. switch is expressed by the rated current, the rated voltage and the smallest phase angle (,0 at which the switching is still properly performed.
  • the present invention resides in that the actuation of the breaks in the phase which has twice or approximately twice the number of breaks is positively effected before the interruption of the breaks in the other phases.
  • Fig. 1 of the accompanying drawings show a three-phase high-voltage switch in elevation and plan, respectively.
  • Fig. 4 shows a detail of a cam-operated switch according to the invention and
  • Fig. 5 shows the application of the invention to electrical switchgear constructed as a contactor.
  • Fig. 1 the three phases R, S, T of a three-phase A.C. system are apparent, which has a consumer Z connected thereto, which represents inductive (wL) and ohmic (W) loads on the system.
  • an additional double break contact bridge 4 is inserted in any desired phase, e.g., R.
  • the bridges 1 and 4 are intentionally and positively opened before the bridges 2 and 3.
  • the bridges 1 and 4 will be positively and not only incidentally those that switch first and to which, therefore, half the total breaking power with respect to the consumer Z to be disconnected is applied. In this case one fourth of the breaking power is applied to each of the bridges 2 and 3.
  • the second half of the breaking power is applied to the two bridges 2, 3, which switch after 1, 4, and this second half is divided so that one fourth thereof is applied to each break.
  • the time between the beginning of the opening of the bridges 1 and 4 in phase R and the beginning of the opening of the bridges 2, 3 in phases S and T must be such, as is known per se, that the bridges of phase R breaking first have completely interrupted the current in that phase before the other contact bridges 2, 3 begin their switching movement. This time will have to be about 23 periods. This mode of switching will hereinafter be referred to as preferential multibreak arrangement.
  • each contact or contact pair of the switch need not be designed for a reserve rupturing capacity which would be utilized only in one contact during the switching.
  • each contact is utilized to the same degree as all other switching points and the reserves which remained previously unutilized can be used entirely for increasing the switch rating of the equipment.
  • the switch rating in the phase opening first can be increased to 2N or doubled, which represents an important advance, which is achieved with relatively small structural expenditure, as will be shown hereinafter.
  • the principle of construction according to the inven tion is of general application if the number of breaks in the preferred phase switching first equals the total number of breaks in the two other phases. Thus, if a switch had normally four breaks in each phase, the invention would require eight breaks in one phase and a positive opening of these contacts first in order to double the switch rating.
  • the principle of the preferred multi-break arrangement can be applied to high and low voltages, in three-pole circuit breakers, change-over switches, star-delta switches, reversing switches and the like and enables an increase of the switch rating also in electrical contactors (switching relays).
  • Figs. 2, 3 show the application of the invention to a high-voltage switch for a three-phase conductor system in elevation and plan, respectively.
  • a base plate carries to switch columns 11, 12, 13, which may contain known switchgear, such as gas-blast switches.
  • the column 14 represents the additional break (e.g., also a switch of known type), which is preferentially operated and lies, e.g., in phase R.
  • the actuating line 15 which releases or causes the switch operation includes a retarding device 16 in order to actuate the two switches in the switch columns 11, 14 before those in the switch columns 12, 13.
  • This line 15 may consist of a linkage or a pressure fluid line.
  • Fig. 4 illustrates the application of the invention to a three-phase cam-operated switch, which may have a double-break contact bridge per pair although only the stage which effects the fourfold break (corresponding to contact bridges I, 4) is shown.
  • the switch as a whole may be of a construction known per se.
  • An angularsection shaft 20 carries in addition to the cams associated with the contact bridges 2 and 3 of Fig. 1 a cam 21 with two edges 25, which control the lifting movement of the plungers 22 and of the contact bridges 24 connected thereto.
  • the cams act by means of rollers 26 on the plungers sliding in guides 27, which are lifted against the action of compression springs 28 supported in the switch casing (not shown) to open the contacts 30.
  • the two bridges 24 are connected in series by a conductor 31. Because it is assumed that the switch is opened by a rotation of the angular section shaft 20 in the sense of the arrow, the control edges 33 of the cams associated with the bridges other than 24 must lag behind the control edges in order to ensure that the bridges 24 open before the other bridges.
  • the invention can be embodied simply by providing one of the guides 27 which has previously been left free in three-phase switches with a fourth bridge 24 and the control cam for this pair of bridges is slightly staggered relative to the other cams. This refers to the construction shown in said Austrian patent specification in which the contact bridges are symmetrical with respect to a central plane which includes the switch axis.
  • the four double-break contact bridges required are arranged in pairs on opposite sides of the central plane.
  • the contactor shown in Fig. 5 has a movable contact bridge 40 with resilient contacts 41, 42, 43 and 44.
  • the countercontacts are shown at 41, 42', 43 and 44'.
  • the contacts 43' and 44 are connected in series by a series connector 45 (corresponding to 31 in Fig. 4).
  • the two contact sets contact each other when the circuit is closed.
  • the contacts 43 and 44 will open first because they are intentionally set back by an appropriate distance a relative to the contacts 41 and 42.
  • the dimensioning of the distance a or of the angle of lead of cam-operated switches is-not critical.
  • the breaking power applied to a preferentially opened contact is 5' 1 wherein n is the number of contacts points in the preferentially opened phase.
  • n is the number of contact points in each of these phases.
  • the advantage is still retained that such differences in the utilization of the contacts will always occur in one and. the same phase, which in the present case is preferentially opened.
  • the present invention is applicable to any elec- .trical switchgear which controls a three-conductor A.C.
  • the invention can be embodied in numerous forms.
  • the basic construction of the switchgear will not be changed and an additional switch unit of an existing or contemplated type is added to the device and provision is made for this additional switch unit to break reliably before the other switch units in the device.
  • Electrical switchgear for a three-phase A.C. system which comprises three sets of contacts, each of which sets is associated with one phase and forms a number of breaks in said phase, one of said sets forming a number of breaks which is at least approximately twice the number of breaks formed by each of the others of said sets, and means for operating said contacts in such a manner that the breaks of said one set are opened positively in advance of the breaks of said other sets.
  • said one set comprises at least four breaks and each of said other sets comprises at least two breaks and in which said means for operating said contacts comprise a plurality of contact bridges each of which carries one of said contacts of two breaks of one of said sets, said contact bridges being operable to open said breaks associated therewith, and a plurality of cams, at least one of which is associated with the contact bridges associated with each of said sets, each of said cams having a working portion adapted to operate each of said contact bridges with which said cam is associated upon a predetermined movement of said cam, said cams being coupled for joint movement and said working portions of said cams associated with said contact bridges of said one set leading the working portion of the others of said cams in the direction of said predetermined movement to cause said breaks of said one set to be opened in advance of said breaks of said other sets.
  • said means for operating said contacts comprise a contact bridge carrying one of said contacts of each of said breaks and electrically operable means for moving said contact bridge to open said breaks, said contacts of said one set being resilient and arranged so that the breaks formed thereby open after a smaller movement of said contact bridge that the breaks formed by the contacts of said other sets.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
  • Breakers (AREA)
  • Circuit Breakers (AREA)
US744405A 1957-06-28 1958-06-25 Electrical switchgear for use in three-phase a.c. systems Expired - Lifetime US2882372A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT858385X 1957-06-28

Publications (1)

Publication Number Publication Date
US2882372A true US2882372A (en) 1959-04-14

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ID=3682307

Family Applications (1)

Application Number Title Priority Date Filing Date
US744405A Expired - Lifetime US2882372A (en) 1957-06-28 1958-06-25 Electrical switchgear for use in three-phase a.c. systems

Country Status (4)

Country Link
US (1) US2882372A (de)
BE (1) BE568871A (de)
DE (1) DE1051357B (de)
GB (1) GB858385A (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3124669A (en) * 1959-09-23 1964-03-10 peroun
US3243558A (en) * 1963-05-29 1966-03-29 Cutler Hammer Inc High voltage three-phase circuit breaker module
US4015186A (en) * 1974-10-11 1977-03-29 Kraftwerk Union Aktiengesellschaft System for limiting torque in a turbine-generator shaft
DE2854092A1 (de) * 1977-12-14 1979-06-28 Hazemeijer Bv Schaltverfahren fuer eine dreiphasige hochspannungsschaltung
US4471183A (en) * 1981-11-02 1984-09-11 Siemens Aktiengesellschaft Three-phase switchgear
US4628393A (en) * 1977-12-14 1986-12-09 Hazemeijer B.V. Method for switching in a three-phase high voltage circuit
DE3833166A1 (de) * 1988-09-27 1990-03-29 Siemens Ag Verfahren zum betrieb eines leistungsschalters

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1176231B (de) * 1960-03-25 1964-08-20 Licentia Gmbh Schalteinrichtung fuer p-phasigen Wechselstrom
DE3306926A1 (de) * 1983-02-26 1984-08-30 Fritz Driescher KG Spezialfabrik für Elektrizitätswerksbedarf GmbH & Co, 5144 Wegberg Mittelspannungs-lasttrennschalter
DE3332684A1 (de) * 1983-09-10 1985-03-28 Fritz Driescher KG Spezialfabrik für Elektrizitätswerksbedarf GmbH & Co, 5144 Wegberg Mittelspannungs-lasttrennschalter
DE4105698C2 (de) * 1991-02-21 1997-06-19 Eaw Relaistechnik Gmbh Verfahren zum Betrieb eines dreipoligen Vakuumschützes mit Gruppenantrieb
DE19638753C2 (de) * 1996-09-13 2002-04-18 Eckehard Gebauer Schütz, vorzugsweise Vakuumschütz
DE19639064C2 (de) * 1996-09-16 2001-05-31 Eaw Relaistechnik Gmbh Elektromagnetisch betätigtes, dreipolig symmetrisch aufgebautes Schütz

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3124669A (en) * 1959-09-23 1964-03-10 peroun
US3243558A (en) * 1963-05-29 1966-03-29 Cutler Hammer Inc High voltage three-phase circuit breaker module
US4015186A (en) * 1974-10-11 1977-03-29 Kraftwerk Union Aktiengesellschaft System for limiting torque in a turbine-generator shaft
DE2854092A1 (de) * 1977-12-14 1979-06-28 Hazemeijer Bv Schaltverfahren fuer eine dreiphasige hochspannungsschaltung
US4628393A (en) * 1977-12-14 1986-12-09 Hazemeijer B.V. Method for switching in a three-phase high voltage circuit
US4471183A (en) * 1981-11-02 1984-09-11 Siemens Aktiengesellschaft Three-phase switchgear
DE3833166A1 (de) * 1988-09-27 1990-03-29 Siemens Ag Verfahren zum betrieb eines leistungsschalters

Also Published As

Publication number Publication date
GB858385A (en) 1961-01-11
DE1051357B (de) 1959-02-26
BE568871A (de) 1900-01-01

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