US2798919A - Electric circuit breaker - Google Patents

Electric circuit breaker Download PDF

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Publication number
US2798919A
US2798919A US486378A US48637855A US2798919A US 2798919 A US2798919 A US 2798919A US 486378 A US486378 A US 486378A US 48637855 A US48637855 A US 48637855A US 2798919 A US2798919 A US 2798919A
Authority
US
United States
Prior art keywords
contact
contacts
metal
strip
circuit breaker
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
US486378A
Other languages
English (en)
Inventor
Richard C Ingwersen
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.)
Mechanical Products Inc
Original Assignee
Mechanical Products Inc
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 to NL204311D priority Critical patent/NL204311A/xx
Application filed by Mechanical Products Inc filed Critical Mechanical Products Inc
Priority to US486378A priority patent/US2798919A/en
Priority to GB2943/56A priority patent/GB805447A/en
Priority to FR1141168D priority patent/FR1141168A/fr
Priority to DEM29554A priority patent/DE1048991B/de
Priority to CH350355D priority patent/CH350355A/de
Application granted granted Critical
Publication of US2798919A publication Critical patent/US2798919A/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
    • H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/74—Means for adjusting the conditions under which the device will function to provide protection
    • H01H71/7427—Adjusting only the electrothermal mechanism
    • H01H71/7436—Adjusting the position (or prestrain) of the bimetal
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/10—Operating or release mechanisms
    • H01H71/12—Automatic release mechanisms with or without manual release
    • H01H71/14—Electrothermal mechanisms
    • H01H71/16—Electrothermal mechanisms with bimetal element
    • H01H71/162—Electrothermal mechanisms with bimetal element with compensation for ambient temperature

Definitions

  • This invention relates to electric circuit breakers which have overload protection provided by a bi-metal latch part connected in circuit with a movable Contact assembly and adapted for automatic release from a relatively xed abutment, upon the occurrence of a predetermined current overload, so as to permit the movable contact assembly to move immediately to open position with respect to a companion xed contact assembly.
  • Circuit breakers constructed to operate as thus indicated are disclosed in several prior patents in my name, including Patent No. 2,485,736, dated October 25, 1949, and Patents 2,514,545, dated July 1l, 1950.
  • circuit breakers are capable of being iinely calibrated so that they will possess a quick break action on overload, but the sensitivity of the latch parts becomes increasingly less as the currents ratings are increased so that the break action becomes slower, or sluggish, in the case of the high rated circuit breakers.
  • bi-metal strip In connection with these electric circuit breakers, employing a bi-metal latch part, it should be taken into accountV that bi-metal strip possesses the inherent characteristic that at a certain given temperature (in the order of 70 .F.) the bi-metal strip will be in a neutral flat state but, upon heating, the strip will bend to the arc of a. circle, with the high expansion side of the bi-metal strip assuming a convex shape. If the bi-metal strip is cooled below the given temperature it will bend in the opposite direction so that the high expansion side will assume a concave shape. All this assumes that there is nothing to restrain such bending motion.
  • a certain given temperature in the order of 70 .F.
  • Fig. l is an elevational view of the interior of a prior art circuit breaker modified in accordance with the present invention.
  • Fig. 2 is a similar view to Fig. l but of another form of the invention.
  • Fig. l the circuit breaker is shown as comprising a casing 10 upon which there is mounted the re-set actuator plunger 12 for a U-shaped bi-metal latch part 14 carrying the movable contacts 16, 16' and held engaged against the fixed abutment ledge 18 by the action of the tensioned coil springs 20.
  • the companion fixed contacts are indicated at 22, 22 and the improvement provided by the present invention involves connecting an electrical shunt between one of the xed contact terminals and the movable contact and bi-metal latch assembly.
  • This shunt is formed by a bi-metal strip 24 connected at one end to one of the fixed contact terminals 26 and carrying at its opposite end a contact 28 shown in contact with a contact 30 on the conductor arm 32 of the said movable contact and bi-metal latch assembly.
  • the bi-metal strip 24 is of relatively low resistance and has its low expansion side 34 disposed remote from the Contact 30.
  • the pressure of the contact 28 against the contact 30 is capable of adjustment by actuation of the grub screw 35.
  • the circuit breaker casing 36 has the re-set actuator plunger 38 mounted thereon for setting the brimetal U-shaped latch part 40 against the fixed abutment ledge 42 so that the movable contacts 44, 44 are held closed with respect to their companion lixed contacts 46, 46' and the coil springs 48 are ytensioned. All this is known from my said prior patents.
  • the present improvement involves rendering this circuit breaker so as to be operable properly under conditions of extreme ambient temperature variation by connecting the movable contacts 44, 44' in a separate and shunt circuit formed by the electrical leads 50, 50' and a bi-metal strip and contact assembly indicated by the general reference 52.
  • This assembly comprises two bi-metal strips l54, 54 connected at one end to anchor blocks S6, 56 and carrying contacts S, 58' at their opposite and free ends. These bi-metal strips are arranged with their high expansion sides facing an adjustment screw 60 which can be positioned immediately opposite the contact 58', as shown in full lines in Fig. 2, or at a remote position, as shown in the dotted position of this screw.
  • an adjustment screw 60 which can be positioned immediately opposite the contact 58', as shown in full lines in Fig. 2, or at a remote position, as shown in the dotted position of this screw.
  • the screw 60 When in the full line position the screw serves to restrain movement of the bi-metal strip 54 outwards with respect to contact 58 upon exposure to reduced temperature, it being noted that strip 54' is not included in the electrical conductive part of the circuit.
  • the screw 60 in said full line position also serves to maintain the desired contact pressure between contacts 58, 58' by adjustment of the screw.
  • the screw 60 loses its ability to restrain outward movement
  • the strips 54 and 54' will bend together in the same direction and thereby maintain the contacts 58, 58' closed until the one bi-metal strip 54, due to it being heated to a higher temperature by the conducted current will move ahead of the other strip 54 and thereby produce relative movement between contacts 58, 58 and cause the circuit to be opened at these contacts.
  • the current flow will take place along the one path only, which includes the bi-metal latch part 40.
  • the adjustment screw 60 may be situated, as shown in the full line position, to impose a restraint against movement of the bi-metal strips 54, 54 in the direction corresponding to ambient temperatures on the downgrade, including zero and sub-zero temperatures.
  • This restraint causes the pressure at the contacts 58, 58 to be correspondingly increased, with the result that with current flowing, and the one strip 54 subjected to the heat thereof, there will be a time lag before the circuit will be opened at the contacts 58, 58', this time lag corresponding tothe increased contact pressure resulting from the presence of the restraining screw 60.
  • the occurence of such time lag may be advantageous under conditions of zero and sub-zero ambient temperatures in the case where motors, actuators and other equiment with which the circuit breakers are connected have become frozen, or stiff, and require time in which to attain running speed.
  • An electric circuit breaker having overload current protection including a bi-metal latch assembly operatively associated wth fixed and movable contacts, an electrical shunt connecting said contacts for conduction of current along two separate paths, only one of which includes said bi-metal latch, said shunt including bi-metal strips carrying separate contacts, one said strip being connected as a conductor in said shunt and the other strip being non-conductive and subject to actuation only by ambient temperature conditions, said bi-metal strips having their different expansion sides facing in the direction in which the circuit will be opened at said separate contacts due to increased heating of the conductive strip relatively to the non-conductive strip.
  • An electric circuit breaker as claimed in claim 1 including means for restraining the opening of the circuit at said separate contacts under conditions of low ambient temperature.
  • An electric circuit breaker having overload current protection including iixed contact means and companion Contact means movable into and out of engagement with said xed contact means, latch means operatively and electrically connected with said movable contact means and actuatable upon the occurrence of a predetermined current overloadl to permit said movable contact means to move out of engagement with said fixed contact means,
  • one of said thermostat elements being disposed in the conductive path of said shunt means and the other of said thermostat elements being out of said conductive path and being subject to actuation only by ambient temperature conditions, whereby upon variations in ambient temperature said shuntcontact elements will remain in engagement with each other and whereby upon predetermined current overload said one thermostat element will be actuated so that said shunt contact elements will move out of engagement with each other.
  • An electric circuit breaker as claimed in claim 3 including means for restraining the disengagement of said shunt contact elements under conditions of low ambient temperature.

Landscapes

  • Breakers (AREA)
  • Thermally Actuated Switches (AREA)
US486378A 1955-02-07 1955-02-07 Electric circuit breaker Expired - Lifetime US2798919A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
NL204311D NL204311A (zh) 1955-02-07
US486378A US2798919A (en) 1955-02-07 1955-02-07 Electric circuit breaker
GB2943/56A GB805447A (en) 1955-02-07 1956-01-30 Improvements in and relating to electric circuit breakers
FR1141168D FR1141168A (fr) 1955-02-07 1956-01-31 Disjoncteur à maximum de courant
DEM29554A DE1048991B (de) 1955-02-07 1956-02-04 UEberlast-Selbstschalter
CH350355D CH350355A (de) 1955-02-07 1956-02-07 Elektrischer Ausschalter

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US486378A US2798919A (en) 1955-02-07 1955-02-07 Electric circuit breaker

Publications (1)

Publication Number Publication Date
US2798919A true US2798919A (en) 1957-07-09

Family

ID=23931652

Family Applications (1)

Application Number Title Priority Date Filing Date
US486378A Expired - Lifetime US2798919A (en) 1955-02-07 1955-02-07 Electric circuit breaker

Country Status (6)

Country Link
US (1) US2798919A (zh)
CH (1) CH350355A (zh)
DE (1) DE1048991B (zh)
FR (1) FR1141168A (zh)
GB (1) GB805447A (zh)
NL (1) NL204311A (zh)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2930937A (en) * 1958-01-16 1960-03-29 Rowan Controller Company Circuit protector
US3158715A (en) * 1961-01-18 1964-11-24 Mechanical Products Inc Electric switch incorporating an automatic circuit breaker
US3683140A (en) * 1971-05-21 1972-08-08 Square D Co Canada Ltd Electric circuit breaker with arc current shunting blade stacked on contact blade
WO2008092923A1 (de) * 2007-02-01 2008-08-07 Siemens Aktiengesellschaft Elektromechanisches schaltgerät zum schutz von elektrischen leitungen bzw. verbrauchern und verwendung einer thermischen ankopplung in einem elektromechanischen schaltgerät
CN106356258A (zh) * 2016-11-24 2017-01-25 天津航空机电有限公司 一种并联控制断路器的导电结构
CN106356262A (zh) * 2016-11-24 2017-01-25 天津航空机电有限公司 一种用于多相并联控制的断路器的传动杆
CN106531571B (zh) * 2016-11-24 2018-06-15 天津航空机电有限公司 一种具有自清洁功能的辅助触点断路器

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2625624A (en) * 1949-12-22 1953-01-13 Mechanical Products Inc Circuit breaker with shunt for changing current rating
US2679565A (en) * 1953-02-02 1954-05-25 Gen Electric Self-protecting bimetal member

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2629034A (en) * 1951-06-02 1953-02-17 Gen Motors Corp Electrical apparatus

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2625624A (en) * 1949-12-22 1953-01-13 Mechanical Products Inc Circuit breaker with shunt for changing current rating
US2679565A (en) * 1953-02-02 1954-05-25 Gen Electric Self-protecting bimetal member

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2930937A (en) * 1958-01-16 1960-03-29 Rowan Controller Company Circuit protector
US3158715A (en) * 1961-01-18 1964-11-24 Mechanical Products Inc Electric switch incorporating an automatic circuit breaker
US3683140A (en) * 1971-05-21 1972-08-08 Square D Co Canada Ltd Electric circuit breaker with arc current shunting blade stacked on contact blade
WO2008092923A1 (de) * 2007-02-01 2008-08-07 Siemens Aktiengesellschaft Elektromechanisches schaltgerät zum schutz von elektrischen leitungen bzw. verbrauchern und verwendung einer thermischen ankopplung in einem elektromechanischen schaltgerät
US20100102918A1 (en) * 2007-02-01 2010-04-29 Siemens Aktiengesellschaft Electromechanical swithcing device for protecting electrical wires and/or consumers and use of a thermal coupling in an electromechanical switching device
CN106356258A (zh) * 2016-11-24 2017-01-25 天津航空机电有限公司 一种并联控制断路器的导电结构
CN106356262A (zh) * 2016-11-24 2017-01-25 天津航空机电有限公司 一种用于多相并联控制的断路器的传动杆
CN106356262B (zh) * 2016-11-24 2018-04-10 天津航空机电有限公司 一种用于多相并联控制的断路器的传动杆
CN106531571B (zh) * 2016-11-24 2018-06-15 天津航空机电有限公司 一种具有自清洁功能的辅助触点断路器

Also Published As

Publication number Publication date
GB805447A (en) 1958-12-03
FR1141168A (fr) 1957-08-27
NL204311A (zh)
CH350355A (de) 1960-11-30
DE1048991B (de) 1959-01-22

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