US3249810A - Circuit interrupting apparatus - Google Patents

Circuit interrupting apparatus Download PDF

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Publication number
US3249810A
US3249810A US238872A US23887262A US3249810A US 3249810 A US3249810 A US 3249810A US 238872 A US238872 A US 238872A US 23887262 A US23887262 A US 23887262A US 3249810 A US3249810 A US 3249810A
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US
United States
Prior art keywords
thermistor
switch
circuit
voltage
current
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
US238872A
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English (en)
Inventor
Albert P Strom
Jr Thomas E Browne
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Westinghouse Electric Corp
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Westinghouse Electric Corp
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Publication date
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US238872A priority Critical patent/US3249810A/en
Priority to DEW35581A priority patent/DE1204302B/de
Priority to CH1386863A priority patent/CH413954A/de
Priority to JP6213563A priority patent/JPS407931B1/ja
Application granted granted Critical
Publication of US3249810A publication Critical patent/US3249810A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/04—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having negative temperature coefficient
    • 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
    • H01H33/02—Details
    • H01H33/04—Means for extinguishing or preventing arc between current-carrying parts
    • H01H33/16—Impedances connected with contacts
    • H01H33/161—Variable impedances
    • 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
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • 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
    • H01H33/02—Details
    • H01H33/04—Means for extinguishing or preventing arc between current-carrying parts
    • H01H33/16—Impedances connected with contacts
    • H01H33/161—Variable impedances
    • H01H2033/163—Variable impedances using PTC elements

Definitions

  • circuit interrupting apparatus it is desirable that the switch gap be opened with a low interrupting effort. That is, it is desirable that the circuit may be interrupted from conduction to open circuit conditions with a minimum of physical effort and while limiting the amount of arcing in the gap of the circuit breaker. Moreovenit is desirable that the medium in the arc space between the contacts quickly lose its ionization after current zero and recovers its dielectric strength.- If such conditions are not present in circuit interrupters, excessive heat from the arcing will seriously damage the breaker structure and insulation, and greatly limit the life of the apparatus.
  • an object of the present invention to provide improved circuit interrupting apparatus in which the switching gap is shunted with a device to limit the rate of application of energy to the gap by the connected circuit.
  • the present invention provides circuit interrupting apparatus in which a thermistor having a large positive temperature coefiicient (PTC), that is, its resistance increases by many times for a small increase in temperature, is placed across the gap of a switch with the energy across the switch being dissipated quickly so that the switch is not damaged and the circuit may be opened with a minimum of interrupting effort.
  • PTC positive temperature coefiicient
  • FIGURE 1 is a schematic diagram of one embodiment of the present invention.
  • FIG. 2 is a plot of the resistivity versus temperature characteristic of a thermistor having a positive temperature coeflicient that may be utilized in the present invention
  • FIG. 3 is a plotof current as a function of time which will be used to explainthe operation of the present invention.
  • FIG. 4 is a plot of resistance and kilovolts as a function of microseconds which will be used to explain the operation of the present invention
  • FIG. 5 is a schematic diagram of another embodiment of the present invention.
  • FIG. 6 is a schematic diagram of another embodiment of the present invention for use in interrupting alternating and direct current.
  • the circuit interrupter is shown for use between a source of alternating potential V and a load circuit including a load Z.
  • the interrupter circuit includes the primary interrupting switch G1 which has connected thereacross a positive temperature coefiicient thermistor device RT. Connected in series with the parallel combination of the switch G1 and the thermistor RT is the isolating switch G2, which is, in turn, connected to the terminal T1. When the switch G2 is opened the potential source is completely isolated from the load.
  • Thermistor devices having positive temperature coeffiassignee as the present application.
  • a typical character-- -1st1c of one of the aforementioned devices is shown in FIG. 2. It may be seen from this plot of resistivity as a function of temperature that for -a smallincrease in temperature there is a substantial increase in the resistivity of the device.
  • the increase in resistivity is such that the conductivity of the device decreases to the order of 1% of the normal conductivity as the temperature rises from room temperature to approximately 200 C.
  • the switches G1 and G2 must be opened.
  • the switch G1 is opened at time t0.
  • the current then passing from T1 to T2 ordinarily passing through the closed switch G1 will tend to be transferred to the PTC shunt RT.
  • the voltage tending to transfer current to the thermistor RT will only be the arc voltage; thus negligible heating of the shunt RT will occur until the end of the half cycle.
  • a PTC thermistor as disclosed in the patent by Y. Ichikawa, supra, having a resistance of one ohm and a volume of 500 cubic centimeters that such a thermistor, having characteristics of those of FIGURE 2 will have a diameter of 13.5 centimeters and a thickness of 3.5 centimeters.
  • the specific heat of such a material is approximately 0.1 with a density of about 5 grams per 3 the first current zero and thus readily transfer the current to the shunt RT.
  • the resistance limited current may then be interrupted by the switching gap G2 at the next current zero, cycle after the current has been transferred to the shunt RT.
  • Calculations indicate that a 20,000 ampere current, 28,000 amperes peak, can be limited to a maximum of 5000 peak amperes before the current is brought to zero.
  • the thermistor will not overheat under these conditions since the energy input is reduced by the high resistance of the device with increasing temperature to a value that gives a temperature rise of about 4 C. per half cycle with full voltage impressed after the current has been limited.
  • two or more shunts may be provided. A new shunt may be inserted on reclosure, allowing the first thermistor shunt to cool.
  • thermistor shunts of this type could be utilized with higher voltages by placing them in series circuit relation.
  • FIGURE 5 Another embodiment is shown in FIGURE 5, in which a voltage sensitive resistor RV is connected across the thermistor device RT.
  • a voltage sensitive resistor RV is connected across the thermistor device RT.
  • a voltage sensitive resistor such as a lightning arrester valve element or voltage limiting non-linear resistor, which are both well known in the art, may be used in parallel with the thermistor RT.
  • Such a non-linear voltage sensitive resistor has a high resistance at low impressed voltages. However, when a predetermined voltage is reached, the resistance has decreased to a much lower value.
  • the switch G2 is in a series circuit relationship with the thermistor RT to permit the desired operation for the circuit interrupter circuit. Shunting the thermistor block with the arrester elements may also be used when several thermistor units are used in series as in a high voltage installation. So, if the resistance of one unit rises faster than others of the series, tending to take much more than its share of voltage, the current will bypass that unit by way of the arrester element until the other units rise to about the same resistance. Moreover, using such parallel combinations, the individual thermistor units need not be so carefully matched.
  • FIGURE 6 shows a circuit interrupter for interrupting alternating current or high magnitudes of direct current.
  • the parallel combination including the thermistor RTl having a positive temperature coefficient and the voltage sensitive arrester element RV1, is connected in series circuit relation with the parallel combination including the thermistor element RT2 and the arrester element RV2.
  • the switch G1 is connected across the elements RTl-RVI and RT2RV2. Connected in series with the parallel circuit of switch G1 and these shunting elements is the switch G2 to completely isolate a voltage source from the rest of the circuit.
  • the arc voltage rapidly shunts current into the positive temperature coefficient thermistor elements RTl and RT2.
  • the are at G1 becomes unstable and is extinguished.
  • the current will be limited to a low value which then may be easily interrupted by the isolating switch G2. If, for example, a 50,000 ampere, 600 volt circuit is to be interrupted, an .arc voltage of 500 volts will shunt the current into a 0.01 ohm thermistor element thereby increasing the resistance of the thermistor elements to about 1 ohm, leaving only 600 arnperes to be interrupted by the switch G2.
  • the arrester elements RVl and RVZ serve to protect the thermistor devices against overvoltages, as explained in reference to FIG. 5.
  • a circuit interrupter comprising, first switching means, thermistor means comprising material having a positive temperature coefiicient whose resistivity increases rapidly with temperature connected across said first switch means, voltage sensitive means having a resistance which decreases with voltage connected across said thermistor means, second switching means operatively connected in series with said thermistor means and switch actuating means for sequentially actuating the opening of the first switching means first and then actuating the opening of the second switching means in a predetermined time relation after the opening of the first switching means.
  • Circuit breaking apparatus for interrupting a circuit between a source of potential and a load circuit the combination of, interrupting switch means operative to disconnect a conducting path therethrough, a thermistor device comprising material having a positive temperature coeflicient wherein its resistance increases rapidly with the temperature, said thermistor device being connected across said interrupting switch to provide a conducting path when said interrupting switch means is opened, voltage sensitive means having a resistance which decreases with increasing voltage connected across said thermistor device, isolating switch means operatively interrupting switch to isolate said source of potential from said load circuit and switch actuating means for sequentially actuating the opening of the interrupting switch first and then actuating the opening of the isolating switch means a predetermined time after the opening of the interrupting switch means.
  • Circuit breaking apparatus for interrupting a circuit between a source of alternating potential and a load circuit the combination of, interrupting switch means operative to disconect a conducting path therethrough, a thermistor device comprising material having a positive temperature coefiicient so that its resistance increases rapidly with the temperature, said thermistor device being connected across said interrupting switch means to provide a conducting path when said interrupting switch means is opened, voltage sensitive means having a resistance which decreases with increasing voltage connected across said thermistor device, isolating switching means operatively connected in series with said thermistor device, said isolating switch means being opened a predetermined time after said interrupting switch means is opened and operative to isolate said source of potential from said load circuit and switch actuating means for sequentially actuating the opening of the interrupting switch means first and then actuating the opening of the is-olating switch means a predetermined time after the interrupting switch means is opened.
  • Circuit breaking apparatus for interrupting a circuitbetween a source of potential and a load circuit the combination of, interrupting switch means operative to disconnect a conducting path therethrough, a plurality of thermistor devices each comprising material having a positive temperature coefficient so that its resistance in v creases rapidly with the temperature, said thermistor devices being connected across said interrupting switch means to provide a conducting path when said interrupting switch means is open, a plurality of voltage, sen sitive devices each having a resistance which decreases with increasing voltage, one of said voltage sensitive devices being connected across each of said thermistor devices, isolating switch means operatively connected in series withsaid thermistor devices, said isolating switch means being opened in a predetermined time relation with respect to said interrupting switch means to isolate said source of potential from said load circuit and switch actuating means for sequentially actuating the opening of the interrupting switch means first and then actuating the opening of the isolating switch means a predetermined time after the interrupting switch means is opened.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Emergency Protection Circuit Devices (AREA)
  • Thermistors And Varistors (AREA)
  • Circuit Breakers (AREA)
  • Keying Circuit Devices (AREA)
US238872A 1962-11-20 1962-11-20 Circuit interrupting apparatus Expired - Lifetime US3249810A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US238872A US3249810A (en) 1962-11-20 1962-11-20 Circuit interrupting apparatus
DEW35581A DE1204302B (de) 1962-11-20 1963-11-07 Schalteinrichtung
CH1386863A CH413954A (de) 1962-11-20 1963-11-12 Schalteinrichtung zum Unterbrechen von elektrischen Stromkreisen
JP6213563A JPS407931B1 (mo) 1962-11-20 1963-11-20

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US238872A US3249810A (en) 1962-11-20 1962-11-20 Circuit interrupting apparatus

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US3249810A true US3249810A (en) 1966-05-03

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US238872A Expired - Lifetime US3249810A (en) 1962-11-20 1962-11-20 Circuit interrupting apparatus

Country Status (4)

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US (1) US3249810A (mo)
JP (1) JPS407931B1 (mo)
CH (1) CH413954A (mo)
DE (1) DE1204302B (mo)

Cited By (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3544843A (en) * 1967-12-19 1970-12-01 Westinghouse Electric Corp High-voltage direct current circuit interrupter
US3611031A (en) * 1970-06-11 1971-10-05 Hughes Aircraft Co Series sequential circuit breaker
US3614464A (en) * 1969-04-22 1971-10-19 Ite Imperial Corp Arcless tap- or source-switching apparatus using series-connected semiconductors
US3641358A (en) * 1970-06-10 1972-02-08 Hughes Aircraft Co Consecutive crowbar circuit breaker
US3651374A (en) * 1970-02-20 1972-03-21 Bbc Brown Boveri & Cie Switching arrangement for disconnecting high-voltage direct-current lines
US3737724A (en) * 1970-08-06 1973-06-05 Kind D Current limiting interruption of currents at high voltages
US3864604A (en) * 1972-05-08 1975-02-04 Josef Pfanzelt Electrical switching device
US3925707A (en) * 1973-10-17 1975-12-09 Westinghouse Electric Corp High voltage current limiting circuit breaker utilizing a super conductive resistance element
US4001643A (en) * 1975-05-29 1977-01-04 The United States Of America As Represented By The Secretary Of The Interior Method and apparatus for a power circuit breaker controller
US4005340A (en) * 1974-05-07 1977-01-25 Dieter Kind Apparatus for the current limiting interruption of currents at high voltages
US4296449A (en) * 1979-08-27 1981-10-20 General Electric Company Relay switching apparatus
US4583146A (en) * 1984-10-29 1986-04-15 General Electric Company Fault current interrupter
FR2592208A1 (fr) * 1984-11-26 1987-06-26 Gen Electric Ensemble de contacts pour interrupteur de circuit limiteur de courant
FR2592521A1 (fr) * 1985-12-27 1987-07-03 Gen Electric Interrupteur de courant de defaut
FR2606929A1 (fr) * 1986-11-14 1988-05-20 Telemecanique Electrique Dispositif interrupteur pour appareil de protection
US4937696A (en) * 1985-12-23 1990-06-26 Kabushiki Kaisha Toshiba Protection circuit for a semiconductor device
USRE33314E (en) * 1984-10-10 1990-08-28 Mars Incorporated Vending machine power switching apparatus
FR2733353A1 (fr) * 1995-04-18 1996-10-25 Gec Alsthom T & D Sa Limiteur de courant de court-circuit pour reseau a haute tension
FR2738681A1 (fr) * 1995-09-12 1997-03-14 Gec Alsthom T & D Sa Limiteur de courant a polymere
WO1997010609A1 (en) * 1995-09-14 1997-03-20 Raychem Corporation Electrical switch
US5633540A (en) * 1996-06-25 1997-05-27 Lutron Electronics Co., Inc. Surge-resistant relay switching circuit
US5637964A (en) * 1995-03-21 1997-06-10 Lutron Electronics Co., Inc. Remote control system for individual control of spaced lighting fixtures
WO1997010636A3 (en) * 1995-09-14 1997-07-17 Raychem Corp Overcurrent protection circuit
US5666254A (en) * 1995-09-14 1997-09-09 Raychem Corporation Voltage sensing overcurrent protection circuit
US5689395A (en) * 1995-09-14 1997-11-18 Raychem Corporation Overcurrent protection circuit
WO1999010903A1 (en) * 1997-08-25 1999-03-04 Square D Company Current limiting circuit breakers with ptc (positive temperature coefficient resistivity) elements and arc extinguishing capabilities
US5886860A (en) * 1997-08-25 1999-03-23 Square D Company Circuit breakers with PTC (Positive Temperature Coefficient resistivity
US5977862A (en) * 1996-04-26 1999-11-02 Gec Alsthom T & D Sa Polymer high voltage current limiters packaged in series
US5987205A (en) * 1996-09-13 1999-11-16 Lutron Electronics Co., Inc. Infrared energy transmissive member and radiation receiver
US6037721A (en) * 1996-01-11 2000-03-14 Lutron Electronics, Co., Inc. System for individual and remote control of spaced lighting fixtures
US6490141B2 (en) 1999-05-28 2002-12-03 Ellenberger & Poensgen Gmbh Power distribution system
US20060002046A1 (en) * 2004-06-25 2006-01-05 Francis Roderick M Overcurrent protection circuit including auto-reset breaker and PTC resistor
US20090274051A1 (en) * 2008-04-30 2009-11-05 Agilent Technologies, Inc. Dynamic Switch Contact Protection
US20120243129A1 (en) * 2011-03-24 2012-09-27 General Electric Company Shorting protection for systems having electric machines
DE102012016696A1 (de) * 2012-06-06 2013-12-12 Diehl Ako Stiftung & Co. Kg Schaltungsanordnung und Verfahren zur Gleichstromunterbrechung

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS464679A (mo) * 1970-04-10 1971-11-18
CH581377A5 (mo) * 1975-02-11 1976-10-29 Bbc Brown Boveri & Cie
DE4330607A1 (de) * 1993-09-09 1995-03-16 Siemens Ag Limiter zur Strombegrenzung
DE4441280C2 (de) * 1994-11-19 1998-08-27 Asea Brown Boveri Kaltleiter und Vorrichtung zur Strombegrenzung mit mindestens einem Kaltleiter

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1327777A (en) * 1917-11-19 1920-01-13 Westinghouse Electric & Mfg Co Circuit-interrupter
US1717260A (en) * 1921-09-14 1929-06-11 Gen Electric Circuit interrupter
US2261686A (en) * 1937-12-31 1941-11-04 Westinghouse Electric & Mfg Co Circuit interrupter

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE170074C (mo) *
DE236344C (mo) *
DE969067C (de) * 1943-02-18 1958-04-30 Aeg Elektrischer Stromunterbrecher
NL252649A (mo) * 1959-06-30

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1327777A (en) * 1917-11-19 1920-01-13 Westinghouse Electric & Mfg Co Circuit-interrupter
US1717260A (en) * 1921-09-14 1929-06-11 Gen Electric Circuit interrupter
US2261686A (en) * 1937-12-31 1941-11-04 Westinghouse Electric & Mfg Co Circuit interrupter

Cited By (43)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3544843A (en) * 1967-12-19 1970-12-01 Westinghouse Electric Corp High-voltage direct current circuit interrupter
US3614464A (en) * 1969-04-22 1971-10-19 Ite Imperial Corp Arcless tap- or source-switching apparatus using series-connected semiconductors
US3651374A (en) * 1970-02-20 1972-03-21 Bbc Brown Boveri & Cie Switching arrangement for disconnecting high-voltage direct-current lines
US3641358A (en) * 1970-06-10 1972-02-08 Hughes Aircraft Co Consecutive crowbar circuit breaker
US3611031A (en) * 1970-06-11 1971-10-05 Hughes Aircraft Co Series sequential circuit breaker
US3737724A (en) * 1970-08-06 1973-06-05 Kind D Current limiting interruption of currents at high voltages
US3864604A (en) * 1972-05-08 1975-02-04 Josef Pfanzelt Electrical switching device
US3925707A (en) * 1973-10-17 1975-12-09 Westinghouse Electric Corp High voltage current limiting circuit breaker utilizing a super conductive resistance element
US4005340A (en) * 1974-05-07 1977-01-25 Dieter Kind Apparatus for the current limiting interruption of currents at high voltages
US4001643A (en) * 1975-05-29 1977-01-04 The United States Of America As Represented By The Secretary Of The Interior Method and apparatus for a power circuit breaker controller
US4296449A (en) * 1979-08-27 1981-10-20 General Electric Company Relay switching apparatus
USRE33314E (en) * 1984-10-10 1990-08-28 Mars Incorporated Vending machine power switching apparatus
US4583146A (en) * 1984-10-29 1986-04-15 General Electric Company Fault current interrupter
FR2592208A1 (fr) * 1984-11-26 1987-06-26 Gen Electric Ensemble de contacts pour interrupteur de circuit limiteur de courant
US4937696A (en) * 1985-12-23 1990-06-26 Kabushiki Kaisha Toshiba Protection circuit for a semiconductor device
FR2592521A1 (fr) * 1985-12-27 1987-07-03 Gen Electric Interrupteur de courant de defaut
FR2606929A1 (fr) * 1986-11-14 1988-05-20 Telemecanique Electrique Dispositif interrupteur pour appareil de protection
US4816958A (en) * 1986-11-14 1989-03-28 La Telemecanique Electrique Fault current interrupter including a metal oxide varistor
US5637964A (en) * 1995-03-21 1997-06-10 Lutron Electronics Co., Inc. Remote control system for individual control of spaced lighting fixtures
FR2733353A1 (fr) * 1995-04-18 1996-10-25 Gec Alsthom T & D Sa Limiteur de courant de court-circuit pour reseau a haute tension
FR2738681A1 (fr) * 1995-09-12 1997-03-14 Gec Alsthom T & D Sa Limiteur de courant a polymere
WO1997010609A1 (en) * 1995-09-14 1997-03-20 Raychem Corporation Electrical switch
CN1084944C (zh) * 1995-09-14 2002-05-15 雷伊化学公司 过电流保护电路
WO1997010636A3 (en) * 1995-09-14 1997-07-17 Raychem Corp Overcurrent protection circuit
US5666254A (en) * 1995-09-14 1997-09-09 Raychem Corporation Voltage sensing overcurrent protection circuit
US5689395A (en) * 1995-09-14 1997-11-18 Raychem Corporation Overcurrent protection circuit
US5737160A (en) * 1995-09-14 1998-04-07 Raychem Corporation Electrical switches comprising arrangement of mechanical switches and PCT device
US5864458A (en) * 1995-09-14 1999-01-26 Raychem Corporation Overcurrent protection circuits comprising combinations of PTC devices and switches
KR100459357B1 (ko) * 1995-09-14 2005-01-15 레이켐 코포레이션 전기스위치장치및구동방법
US6037721A (en) * 1996-01-11 2000-03-14 Lutron Electronics, Co., Inc. System for individual and remote control of spaced lighting fixtures
US6310440B1 (en) 1996-01-11 2001-10-30 Lutron Electronics Company, Inc. System for individual and remote control of spaced lighting fixtures
US5977862A (en) * 1996-04-26 1999-11-02 Gec Alsthom T & D Sa Polymer high voltage current limiters packaged in series
US5633540A (en) * 1996-06-25 1997-05-27 Lutron Electronics Co., Inc. Surge-resistant relay switching circuit
US5987205A (en) * 1996-09-13 1999-11-16 Lutron Electronics Co., Inc. Infrared energy transmissive member and radiation receiver
WO1999010903A1 (en) * 1997-08-25 1999-03-04 Square D Company Current limiting circuit breakers with ptc (positive temperature coefficient resistivity) elements and arc extinguishing capabilities
US5886860A (en) * 1997-08-25 1999-03-23 Square D Company Circuit breakers with PTC (Positive Temperature Coefficient resistivity
US6490141B2 (en) 1999-05-28 2002-12-03 Ellenberger & Poensgen Gmbh Power distribution system
US20060002046A1 (en) * 2004-06-25 2006-01-05 Francis Roderick M Overcurrent protection circuit including auto-reset breaker and PTC resistor
US7145759B2 (en) * 2004-06-25 2006-12-05 Shallco, Inc. Overcurrent protection circuit including auto-reset breaker and PTC resistor
US20090274051A1 (en) * 2008-04-30 2009-11-05 Agilent Technologies, Inc. Dynamic Switch Contact Protection
US8922957B2 (en) * 2008-04-30 2014-12-30 Keysight Technologies, Inc. Dynamic switch contact protection
US20120243129A1 (en) * 2011-03-24 2012-09-27 General Electric Company Shorting protection for systems having electric machines
DE102012016696A1 (de) * 2012-06-06 2013-12-12 Diehl Ako Stiftung & Co. Kg Schaltungsanordnung und Verfahren zur Gleichstromunterbrechung

Also Published As

Publication number Publication date
DE1204302B (de) 1965-11-04
JPS407931B1 (mo) 1965-04-22
CH413954A (de) 1966-05-31

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