US3725741A - Differential transformer mounting arrangement particulary for ground fault interrupter apparatus - Google Patents

Differential transformer mounting arrangement particulary for ground fault interrupter apparatus Download PDF

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Publication number
US3725741A
US3725741A US00158336A US3725741DA US3725741A US 3725741 A US3725741 A US 3725741A US 00158336 A US00158336 A US 00158336A US 3725741D A US3725741D A US 3725741DA US 3725741 A US3725741 A US 3725741A
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United States
Prior art keywords
core
conductor
tubular conductor
outer tubular
conductors
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Expired - Lifetime
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US00158336A
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English (en)
Inventor
J Misencik
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Westinghouse Electric Corp
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Westinghouse Electric Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/20—Instruments transformers
    • H01F38/22—Instruments transformers for single phase AC
    • H01F38/28—Current transformers
    • H01F38/30—Constructions
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/2823—Wires
    • H01F2027/2833—Wires using coaxial cable as wire
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/20—Instruments transformers
    • H01F38/22—Instruments transformers for single phase AC
    • H01F38/28—Current transformers
    • H01F38/30—Constructions
    • H01F2038/305—Constructions with toroidal magnetic core
    • 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
    • H01H83/14—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by imbalance of two or more currents or voltages, e.g. for differential protection
    • H01H83/144—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by imbalance of two or more currents or voltages, e.g. for differential protection with differential transformer
    • H01H2083/148—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by imbalance of two or more currents or voltages, e.g. for differential protection with differential transformer with primary windings formed of rigid copper conductors
    • 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
    • H01H83/14—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by imbalance of two or more currents or voltages, e.g. for differential protection
    • H01H83/144—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by imbalance of two or more currents or voltages, e.g. for differential protection with differential transformer

Definitions

  • the rigid tubular 3 l 8 member is bent at two substantially right angles forming two parallel legs. At least an end of one leg is at- [56] References C'ted tached to a fixed support so that the coaxial conductor UNITED STATES PATENTS provides a way of fixing the electrical characteristics of the transformer as well as substantially mechani- 2,849,694 8/1958 Prince ..336/l74 ally ecuring the core of the transformer by a simple 3,614,694 10/1971 Koontz et al, ...336/l74 and ffective means.
  • ground fault interrupters show characteristics that vary in accordance with the load current on the primary conductors. That is, a device calibrated at zero load current would indicate at full load current a fault leadage current that might cause undesired tripping of the apparatus.
  • the outer conductor in the coaxial arrangement is a rigid tubular member of a conductor, such as copper, with means at its ends for input and output connections.
  • a conductor such as copper
  • One or more insulated wires is simply threaded through the tubing to create an inexpensive and readily formed coaxial member that eliminates the susceptability of the device to having the calibration level vary according to the amount of load current on the conductors. This way the calibration level is preserved from zero load current through the full range to full load current.
  • At least two inner conductors are required, it is preferred that they be provided in a twisted combination so that effectively they. are coaxial although individually they are simple insulated wires.
  • the rigid outer conductor serves as a mounting means for the transformer core. This may be achieved by having two legs of the tubular conductor, each at substantially right angles to that portion of the outer conductor that extends through the core, so that the core is effectively pinned therebetween. Alternatively, the core with a sensing coil wound on it may be fit snugly on the rigid outer conductor. The outer conductor ends, in either case, may be secured to a fixed support member thus accomplishing the securing of the core as well. The space between the legs of the bent tubular conductor that is not occupied by the core may be utilized for associated apparatus such as a trip circuit fabricated from solid state components.
  • FIG. 1 is an elevation view of one embodiment of the DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawing, there is illustrated in FIG. 1 a differential transformer 10 including a toroidal core 12 of magnetic material which has as single turn primary windings the conductors l3 and 14 of a coaxial cable 15 extending through the center aperture of the core 12.
  • a secondary winding 16 on the core 12 comprises a plurality of turns to sense differences in flux produced by the current in the primary conductors.
  • the signal on the sensing coil 16 is supplied to a trip circuit 17 which responds to a certain level of sensed leakage current to actuate the trip coil 18 of apparatus, not shown, such as a circuit breaker, for opening the circuit of the primary conductors.
  • a trip circuit 17 which responds to a certain level of sensed leakage current to actuate the trip coil 18 of apparatus, not shown, such as a circuit breaker, for opening the circuit of the primary conductors.
  • the coaxial cable 15 comprises an outer conductor 13 that is a rigid tubular member within which is disposed at least one inner conductor 14 of insulated wire. It can be seen that no special assembly techniques are required to form the coaxial cable but merely that the inner insulated wire 14 is threaded through the tubular conductor 13.
  • the tubular conductor 13 is bent at substantially right angles on each side of the transformer core 12. This means the core 12 is held in a relatively fixed position substantially only by the rigid tubular conductor 13.
  • the conductor 13 may be snugly fit within the toroid (FIG. 3) or, as shown in FIG. 1, the core may be substantially held by the bent legs of the conductor 13.
  • the coaxial conductor 15 is U-shaped with the bottom of the U being that portion 25 passing through the core 12 and the legs 26 and 27 extending substantially in parallel therefrom at substantially a right angle from portion 25.
  • the exact location of the coaxial cable 15 within the core is not critical. In general it is desirable to minimize the weight and volume of the core and the coaxial cable. Suitable insulation between the elements of the differential transformer must, of course, be provided.
  • the tubular outer conductor be provided with a flange-like element 19 at at least one of its ends for making the necessary connections to a sup porting surface 20.
  • the surface or wall 20 has output terminals 21 and 22 thereon for ultimate connection with one or more loads.
  • the flanged end 19 is welded or otherwise secured to one of the terminals 22 for electrical connection and also to provide substantial mechanical support for the conductor 15 and, in turn, the core 12.
  • FIG. 2 shows only a small part of coaxial conductor 15, without associated elements, as 'modified for systems requiring two or more inner conductors 14 and 34.
  • the inner conductors 14 and 34 are twisted together (at least in the portion passing through the core 12) so that they effectively comprise a coaxial pair without the expense of forming concentric conductors.
  • the apparatus of FIG. 1 may be modified for use in systems of pluralities of conductors greater than two.
  • Ground fault interrupter apparatus of the differential transformer type comprising:
  • said primary conductors comprising an outer tubular conductor and at least one inner wire conductor in a substantially coaxial arrangement, said outer tubular conductor being of relatively rigid conductive material and having a first portion within said core and two other portions extending at substantially right angles to said first portion, said outer tubular conductor having an extremity secured to a fixed support member, said core being supported substantially only by said tubular conductor; a secondary winding comprising a plurality of turns on said core; trip circuit responsive to sensed signals on said secondary winding, said trip circuit being at least partially disposed within the space between said two other portions of said outer tubular conductor.
  • said inner conductor in the form of a single insulated wire disposed in said outer tubular conductor.
  • said primary conductors number at least three and include an outer tubular conductor and at least two inner wire conductors with said inner conductors twisted together over at least the portion of their length within said core.
  • said core is substantially held in place by the portions of said tubular conductor extending at substantially right angles to the portion within said core.
  • said core is substantially held in place by the first portion of said tubular conductor snugly fitting within the aperture of said core.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transformers For Measuring Instruments (AREA)
US00158336A 1971-06-30 1971-06-30 Differential transformer mounting arrangement particulary for ground fault interrupter apparatus Expired - Lifetime US3725741A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US15833671A 1971-06-30 1971-06-30

Publications (1)

Publication Number Publication Date
US3725741A true US3725741A (en) 1973-04-03

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00158336A Expired - Lifetime US3725741A (en) 1971-06-30 1971-06-30 Differential transformer mounting arrangement particulary for ground fault interrupter apparatus

Country Status (5)

Country Link
US (1) US3725741A (de)
AT (1) AT311467B (de)
CA (1) CA949659A (de)
CH (1) CH535482A (de)
DE (1) DE2231431A1 (de)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4034266A (en) * 1975-08-29 1977-07-05 Westinghouse Electric Corporation Electric wall receptacle with ground fault protection
US4287545A (en) * 1978-06-08 1981-09-01 Ferdy Mayer Differential transformer
US4591942A (en) * 1984-12-07 1986-05-27 General Electric Company Current sensing transformer assembly
US4808910A (en) * 1985-03-14 1989-02-28 Sprecher & Schuh Ag High voltage measurement transformer for suspension from a high voltage switching apparatus
WO1989010621A1 (en) * 1988-04-28 1989-11-02 Fmtt, Inc. Matrix transformer having high dielectric isolation
US5602519A (en) * 1994-12-30 1997-02-11 Samsung Electro-Mechanics Co., Ltd. Synchronous cable coupling device of fly back transformer
US5684683A (en) * 1996-02-09 1997-11-04 Wisconsin Alumni Research Foundation DC-to-DC power conversion with high current output
US6087916A (en) * 1996-07-30 2000-07-11 Soft Switching Technologies, Inc. Cooling of coaxial winding transformers in high power applications
US6760206B2 (en) 2001-03-16 2004-07-06 Cooper Industries, Inc. Current sensor supporting structure
GB2473014A (en) * 2009-08-27 2011-03-02 Sean Christopher Ganley Single and multi-phase current sensor and current transformer
US8269592B1 (en) * 2010-05-05 2012-09-18 Lockheed Martin Corporation Pulse transformer
WO2017021248A1 (en) * 2015-07-31 2017-02-09 Siemens Aktiengesellschaft Current transformer having multi-turn conductive rod
EP3442000A1 (de) 2017-08-09 2019-02-13 Schneider Electric USA, Inc. Bussing-verfahren mit differentieller strommessung
EP3441999A1 (de) 2017-08-09 2019-02-13 Schneider Electric USA Inc. Integrierte lichtbogen- und erdschlussstrommesspaket
RU2772982C2 (ru) * 2017-08-09 2022-05-30 ШНЕЙДЕР ЭЛЕКТРИК ЮЭсЭй, ИНК. Интегрированный блок определения тока дугового замыкания и замыкания на землю

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2581264B1 (fr) * 1985-04-26 1993-04-30 Etude Realisa Disjoncteurs Transformateur de sommation et processus de sa fabrication
DE4410076A1 (de) * 1994-03-23 1995-09-28 Valentron Ag Fehlerstromschutzschalter

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1866345A (en) * 1929-12-19 1932-07-05 Westinghouse Electric & Mfg Co Current transformer with primary parallel resistance and flux leakage path
US2531820A (en) * 1943-02-03 1950-11-28 Rca Corp Voltage transformer
US2679025A (en) * 1952-05-28 1954-05-18 Rca Corp Magnetic testing system
US2849694A (en) * 1954-07-12 1958-08-26 Gen Electric Current transformer
GB833364A (en) * 1955-07-18 1960-04-21 Gen Electric Improvements in and relating to high voltage current transformers
FR1288166A (fr) * 1961-02-08 1962-03-24 Comp Generale Electricite Perfectionnements aux transformateurs de mesure pour haute tension
US3031736A (en) * 1957-07-24 1962-05-01 Bell Telephone Labor Inc Fabrication of magnetic core structures
US3154757A (en) * 1961-08-02 1964-10-27 F R Hannon & Sons Inc Transformer with secondary winding suspended within primary core
US3614694A (en) * 1969-09-17 1971-10-19 Atomic Energy Commission Coaxial cable high-voltage pulse isolation transformer

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1866345A (en) * 1929-12-19 1932-07-05 Westinghouse Electric & Mfg Co Current transformer with primary parallel resistance and flux leakage path
US2531820A (en) * 1943-02-03 1950-11-28 Rca Corp Voltage transformer
US2679025A (en) * 1952-05-28 1954-05-18 Rca Corp Magnetic testing system
US2849694A (en) * 1954-07-12 1958-08-26 Gen Electric Current transformer
GB833364A (en) * 1955-07-18 1960-04-21 Gen Electric Improvements in and relating to high voltage current transformers
US3031736A (en) * 1957-07-24 1962-05-01 Bell Telephone Labor Inc Fabrication of magnetic core structures
FR1288166A (fr) * 1961-02-08 1962-03-24 Comp Generale Electricite Perfectionnements aux transformateurs de mesure pour haute tension
US3154757A (en) * 1961-08-02 1964-10-27 F R Hannon & Sons Inc Transformer with secondary winding suspended within primary core
US3614694A (en) * 1969-09-17 1971-10-19 Atomic Energy Commission Coaxial cable high-voltage pulse isolation transformer

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4034266A (en) * 1975-08-29 1977-07-05 Westinghouse Electric Corporation Electric wall receptacle with ground fault protection
US4287545A (en) * 1978-06-08 1981-09-01 Ferdy Mayer Differential transformer
US4591942A (en) * 1984-12-07 1986-05-27 General Electric Company Current sensing transformer assembly
US4808910A (en) * 1985-03-14 1989-02-28 Sprecher & Schuh Ag High voltage measurement transformer for suspension from a high voltage switching apparatus
WO1989010621A1 (en) * 1988-04-28 1989-11-02 Fmtt, Inc. Matrix transformer having high dielectric isolation
US5602519A (en) * 1994-12-30 1997-02-11 Samsung Electro-Mechanics Co., Ltd. Synchronous cable coupling device of fly back transformer
US5684683A (en) * 1996-02-09 1997-11-04 Wisconsin Alumni Research Foundation DC-to-DC power conversion with high current output
US6087916A (en) * 1996-07-30 2000-07-11 Soft Switching Technologies, Inc. Cooling of coaxial winding transformers in high power applications
US6760206B2 (en) 2001-03-16 2004-07-06 Cooper Industries, Inc. Current sensor supporting structure
US6858172B2 (en) 2001-03-16 2005-02-22 Cooper Industries, Inc. Current sensor supporting structure
GB2473014B (en) * 2009-08-27 2014-07-16 Sean Christopher Ganley Single and Multi Phase Current Sensor Combined with a Current Transformer
GB2473014A (en) * 2009-08-27 2011-03-02 Sean Christopher Ganley Single and multi-phase current sensor and current transformer
US8269592B1 (en) * 2010-05-05 2012-09-18 Lockheed Martin Corporation Pulse transformer
WO2017021248A1 (en) * 2015-07-31 2017-02-09 Siemens Aktiengesellschaft Current transformer having multi-turn conductive rod
CN106710857A (zh) * 2015-07-31 2017-05-24 西门子公司 具有多匝导电杆的电流互感器
CN106710857B (zh) * 2015-07-31 2018-12-11 西门子公司 具有多匝导电杆的电流互感器
EP3441999A1 (de) 2017-08-09 2019-02-13 Schneider Electric USA Inc. Integrierte lichtbogen- und erdschlussstrommesspaket
EP3442000A1 (de) 2017-08-09 2019-02-13 Schneider Electric USA, Inc. Bussing-verfahren mit differentieller strommessung
US20190049489A1 (en) * 2017-08-09 2019-02-14 Schneider Electric USA, Inc. Differential current sensing bussing method
US20190052072A1 (en) * 2017-08-09 2019-02-14 Schneider Electric USA, Inc. Integrated arc fault and ground fault current sensing package
CN109390902A (zh) * 2017-08-09 2019-02-26 施耐德电气美国股份有限公司 集成的电弧故障和接地故障电流感测封装件
US10622800B2 (en) * 2017-08-09 2020-04-14 Schneider Electric USA, Inc. Integrated arc fault and ground fault current sensing package
US10852326B2 (en) * 2017-08-09 2020-12-01 Schneider Electric USA, Inc. Differential current sensing bussing method
RU2772982C2 (ru) * 2017-08-09 2022-05-30 ШНЕЙДЕР ЭЛЕКТРИК ЮЭсЭй, ИНК. Интегрированный блок определения тока дугового замыкания и замыкания на землю
AU2018208761B2 (en) * 2017-08-09 2022-06-30 Schneider Electric USA, Inc. Integrated Arc Fault And Ground Fault Current Sensing Package
US11385300B2 (en) * 2017-08-09 2022-07-12 Schneider Electric USA, Inc. Differential current sensing bussing method

Also Published As

Publication number Publication date
DE2231431A1 (de) 1973-01-11
CH535482A (de) 1973-03-31
AT311467B (de) 1973-11-26
CA949659A (en) 1974-06-18

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