US2713623A - Thermally operated protective devices for polyphase currents - Google Patents

Thermally operated protective devices for polyphase currents Download PDF

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Publication number
US2713623A
US2713623A US367657A US36765753A US2713623A US 2713623 A US2713623 A US 2713623A US 367657 A US367657 A US 367657A US 36765753 A US36765753 A US 36765753A US 2713623 A US2713623 A US 2713623A
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United States
Prior art keywords
strip
strips
bimetal
current
levers
Prior art date
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Expired - Lifetime
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US367657A
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English (en)
Inventor
Bourdeau Eusebe
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Telemecanique SA
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La Telemecanique Electrique SA
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Publication date
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H83/00—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current
    • H01H83/20—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by excess current as well as by some other abnormal electrical condition
    • H01H83/22—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by excess current as well as by some other abnormal electrical condition the other condition being imbalance of two or more currents or voltages
    • H01H83/223—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by excess current as well as by some other abnormal electrical condition the other condition being imbalance of two or more currents or voltages with bimetal elements

Definitions

  • a known form of thermally operated device includes which is heated by some or all of the current flowing in The strips are heated directly or indirectly
  • existing devices of the kind just described have one disadvantage in that no protection is obtained on failure or underloading of one or more of the current phases.
  • a thermally operated protective device for polyphase currents includes thermally responsive means for each current phase and a common control member which controls the current supply, the arrangement being such that overloading of at least one of the current phases causes the thermally responsive means appropriate to that phase to operate the common control member to cut off the current supply and which also includes means operatively connected to each thermally responsive means which operate the common control means to cut off the current supply on failure or predetermined underloading of at least one of the current phases.
  • each strip carries a pivoted lever. Movement of the bimetal strip due to overloading causes a free end of the strip to operate the control member. Failure or underloading causes the free end of the bimetal strip to pivot the lever and so operate the control member.
  • the strips may be arranged close and parallel to one another and the levers may have projections which bear on supports attached to adjoining strips.
  • Fig. 1 is a view of part of a device suitable for a three phase supply.
  • Fig. 2 is a plan view of part of Fig. 1.
  • Fig. 3a is a section along the line III-III of Fig. 2.
  • Fig. 4a is a section along the line IVIV of Fig. 2.
  • Figs. 3b and 4b which correspond with Figs. 3a and 4a, show the operation of the apparatus in the case of a failure of the supply on one of the phases.
  • the apparatus shown in Fig. 1, which is intended for three phase current, comprises, in a casing 1, three par- E3, the upper faces of which, when viewed as in Fig. 1, are in the same plane When their temperatures are equal.
  • the bimetal strips are partially slotted and are supported on a ledge 8 which and to which they'are fixed by means of bolts (not shown) which traverse the apertures B1, S1, B2, S2, B3, S3, and which simultaneously form the connecting terminals of the device.
  • the current of each phase enters by one of the terminals E1, E2, E3, flows through each bi-metal strip, and emerges by way of the corresponding terminal S1, S2, S3.
  • Each bimetal strip is therefore directly heated by the whole of the current of the relevant phase.
  • the bimetal strips need not he slotted, and may be heated indirectly by means of resistance elements or may be heated directly or indirectly by a current which is only a part of the main phase current, the part being obtained, for example, by means of a current transformer.
  • a conducting strip 5 carrying at its end a contact-stud 6 which, when the plate 2 is not operated by the bimetal strips, is in contact with a contact-stud 7 carried at the end of a second conducting strip 9.
  • an auxiliary electric circuit connected to the strips 5 and 9 controls, for example, a contactor which controls the current supply of apparatus to be protected by the device and therefore the current for heating the bimetal strips B1, B2 and B3.
  • the plate 2 may in fact control any other contact arrangement, more particularly contacts of which the opening is rapid or which may be mechanically connected to the apparatus controlling the polyphase supply.
  • each of the bi-metal strips B1, B2 and B3 carries small uprights which form mountings 16 which support the pivot or pivots 17 of levers L1, L2, L'z and L3 cut from sheets of insulating material and'arranged edgewise in relation to the bimetal strips B1, B2 and B3.
  • the bimetal strip B1 thus carries a lever L1 which extends towards and whose end B2 and which has a projecting portion A1 which rests on a strip T2 fixed to the lower face of the bimetal strip B2.
  • the bimetal strip B3 carries a lever L3 which extends toward and whose end rests on the bimetal strip B2 and has a projecting portion A3 which is supported on the opposite side of the strip T2.
  • the central bimetal strip B2 has two levers L2 and L'2 extending in opposite directions, the ends of which rest on the bimetal strips B1 and B3 respectively while the projecting portions A2 and A'2 of the levers bear on the strips T1 and T3 of the bimetal strips E1 and B3.
  • the free ends of the levers have projecting portions C1, C2, C2, C3 which are situated in the same plane when the bimetal strips are at the same temperature and which are in contact with the lower face of the plate 2 as seen in the drawings.
  • levers L1, L2, U2 and L3 enable every contingency to be guarded against, either of excess of current failure of the supply or underloading of one or more phases.
  • a thermally responsive element operatively connected to each of said circuits, said elements being located adjacent one to the other and having portions moving in the same direction in response to excessive current values
  • a movably mounted control member having a portion located within the limits of motion of said moving portions of said elements and moved in said direction by said portions in response to excessive current the movement of the free end l values, said control member thereupon being eifective to v interrupt all of said circuits
  • insulating levers pivotally mounted on each of said portions of said elements and between said elements and said control member, each of said levers further resting on means firmly connected to said portion of the adjacent element, whereby movement of any of said portions of said elements in said direction through a shorter distance than the movement of said portions of adjacent elements due to current falling below said second predetermined value raises theend of said
  • a thermally responsive strip element operatively connected to each circuit and having a free end portion moving in a given direction in response to excessive current and all of said free end portions extending in the same plane under similar conditions and moving in the same direction in response to excessive current
  • a pivotally mounted control member having an end portion extending in the path of movement of said free end portions in response to excessive current and displacement of said end portion of said control member in said direction operating an auxiliary circuit controlling all of said first-mentioned circuits
  • an insulating lever pivotally mounted adjacent said free end portion of each of said strips and between said strip and said control member, said lever further extending from the strip on which it is mounted to an adjacent strip and engaging means firmly connected to said adjacent strip and having a free end portion actuated toward said control member when said adjacent strip is nearer said control member than the strip on
  • a bimetal thermal responsive strip operatively connected to each circuit, said strips being mounted each by one of its ends and extending parallel one to the others and all in the same plane when the currents of their circuits are at predetermined values, said strips further having free end portions moving in the same direction in response to overloads of their respective circuits, a control plate pivotally mounted with its free end portion in the path of motion of said end portions of said strips and moved by any of said free end portions upon the overloading of the respective circuit, said control plate controlling all of said circuits, each of said strips further having pivotally mounted on said free outer end and between the latter and said plate an insulating lever extending from said strip toward an adjacent one of said other strips, each strip further having rigid means firmly connected thereto and engaging each lever extending theretoward from an adjacent strip, said strips, means and levers being so related as to move the free end of any lever toward said control plate when r the strip mounting said lever is more distant
  • a thermally operated protective device for use with three phase current, comprising the combination of three thermally responsive bimetal strips each strip being series connected in the circuit of its respective phase, said strips being slotted longitudinally for the major portion of their length from one end and being connected to said circuits at said end and the opposite ends of said strips extending freely therefrom, said strips further being parallel and extending in a common plane when at the same temperature and said free ends moving in the same direction in response to overloads of their respective circuits, a control plate pivotally mounted in overlying relation to said strips, the free end of said plate lying in the path of said strip ends when the latter move in response to overl0ad and.
  • levers each having a portion resting on said extension of said strip toward which said lever References Cited m the file of this patent extends, and an insulating lever pivotally mounted on UNITED STATES PATENTS said free ends of said outer strips and between said strips 10 1,652,527 Hodgkins Dec. 13, 1927 and said plate and extending toward said centrally 10- 2,177,775 Jackson O 31, 1939 cated strip, said centrally located strip further having an 2,547,604 Sharp Apr. 3, 1951

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  • Thermally Actuated Switches (AREA)
  • Breakers (AREA)
US367657A 1952-07-18 1953-07-13 Thermally operated protective devices for polyphase currents Expired - Lifetime US2713623A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR1003331X 1952-07-18

Publications (1)

Publication Number Publication Date
US2713623A true US2713623A (en) 1955-07-19

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Application Number Title Priority Date Filing Date
US367657A Expired - Lifetime US2713623A (en) 1952-07-18 1953-07-13 Thermally operated protective devices for polyphase currents

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US (1) US2713623A (en(2012))
BE (1) BE521499A (en(2012))
DE (1) DE1003331B (en(2012))
FR (1) FR1060403A (en(2012))
GB (1) GB740282A (en(2012))

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1012360B (de) * 1955-07-21 1957-07-18 Voigt & Haeffner Ag Anordnung fuer Schalter und Relais in Mehrphasen-Wechselstromkreisen mit Bimetallstreifen zur Betaetigung einer Ausloesevorrichtung
DE1014636B (de) * 1955-11-26 1957-08-29 Voigt & Haeffner Ag Anordnung fuer Schalter und Relais in Mehrphasen-Wechselstromkreisen zur Betaetigung einer Ausloesevorrichtung
US2864915A (en) * 1957-05-03 1958-12-16 Telemecanique Electrique Monitoring device for polyphase power supply systems
US2866035A (en) * 1955-02-17 1958-12-23 C T Electrical Controls Ltd Thermally operated electric switching mechanisms
US2964602A (en) * 1956-04-02 1960-12-13 Joe Davidson Snap acting mechanism
US3743992A (en) * 1972-08-04 1973-07-03 Westinghouse Electric Corp Thermally responsive electrical control device for polyphase currents

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1051952B (de) * 1957-08-06 1959-03-05 Siemens Ag Getriebe fuer Bimetallueberstromausloeser
US3265831A (en) * 1962-06-21 1966-08-09 Westinghouse Electric Corp Thermally responsive electrical control device

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1652527A (en) * 1924-11-08 1927-12-13 Westinghouse Electric & Mfg Co Protective device
US2177775A (en) * 1936-07-25 1939-10-31 Square D Co Circuit breaker
US2547604A (en) * 1948-05-04 1951-04-03 Sharp William Electric switch

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB624957A (en) * 1947-07-17 1949-06-20 British Thomson Houston Co Ltd Improvements in and relating to current sensitive devices for the protection of polyphase circuits

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1652527A (en) * 1924-11-08 1927-12-13 Westinghouse Electric & Mfg Co Protective device
US2177775A (en) * 1936-07-25 1939-10-31 Square D Co Circuit breaker
US2547604A (en) * 1948-05-04 1951-04-03 Sharp William Electric switch

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2866035A (en) * 1955-02-17 1958-12-23 C T Electrical Controls Ltd Thermally operated electric switching mechanisms
DE1012360B (de) * 1955-07-21 1957-07-18 Voigt & Haeffner Ag Anordnung fuer Schalter und Relais in Mehrphasen-Wechselstromkreisen mit Bimetallstreifen zur Betaetigung einer Ausloesevorrichtung
DE1014636B (de) * 1955-11-26 1957-08-29 Voigt & Haeffner Ag Anordnung fuer Schalter und Relais in Mehrphasen-Wechselstromkreisen zur Betaetigung einer Ausloesevorrichtung
US2964602A (en) * 1956-04-02 1960-12-13 Joe Davidson Snap acting mechanism
US2864915A (en) * 1957-05-03 1958-12-16 Telemecanique Electrique Monitoring device for polyphase power supply systems
US3743992A (en) * 1972-08-04 1973-07-03 Westinghouse Electric Corp Thermally responsive electrical control device for polyphase currents

Also Published As

Publication number Publication date
BE521499A (en(2012))
DE1003331B (de) 1957-02-28
FR1060403A (fr) 1954-04-01
GB740282A (en) 1955-11-09

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