EP0196994A2 - Unité de commutation à limitation de courant avec une disposition localement parallèle des bras de contact - Google Patents

Unité de commutation à limitation de courant avec une disposition localement parallèle des bras de contact Download PDF

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Publication number
EP0196994A2
EP0196994A2 EP86730059A EP86730059A EP0196994A2 EP 0196994 A2 EP0196994 A2 EP 0196994A2 EP 86730059 A EP86730059 A EP 86730059A EP 86730059 A EP86730059 A EP 86730059A EP 0196994 A2 EP0196994 A2 EP 0196994A2
Authority
EP
European Patent Office
Prior art keywords
contact
arrangement
current
switching unit
arm
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.)
Withdrawn
Application number
EP86730059A
Other languages
German (de)
English (en)
Inventor
David P. Mcclellan
John M. Brown
Robert E. Black
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.)
Siemens AG
Original Assignee
Siemens AG
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
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP0196994A2 publication Critical patent/EP0196994A2/fr
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H77/00—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting
    • H01H77/02—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism
    • H01H77/10—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism with electrodynamic opening
    • H01H77/102—Protective overload circuit-breaking switches operated by excess current and requiring separate action for resetting in which the excess current itself provides the energy for opening the contacts, and having a separate reset mechanism with electrodynamic opening characterised by special mounting of contact arm, allowing blow-off movement
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/12—Contacts characterised by the manner in which co-operating contacts engage
    • H01H1/14—Contacts characterised by the manner in which co-operating contacts engage by abutting
    • H01H1/20—Bridging contacts
    • H01H1/2083—Bridging contact surfaces directed at an oblique angle with respect to the movement of the bridge
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H73/00—Protective overload circuit-breaking switches in which excess current opens the contacts by automatic release of mechanical energy stored by previous operation of a hand reset mechanism
    • H01H73/02—Details
    • H01H73/04—Contacts
    • H01H73/045—Bridging contacts

Definitions

  • the invention relates to a current-limiting switching unit with a locally parallel arrangement of contact arms.
  • a switching unit can be connected in series as a stand-alone device with an existing circuit breaker or can be an integral part of a circuit breaker which then contains two sets of contacts, namely a contact set which can be actuated by hand or in another manner and a current set which is electrically connected in series opening contact set.
  • such a switching unit is an economical means of increasing the rated short-circuit breaking current of a circuit breaker.
  • the current-limiting contacts limit the amount of current to be controlled by the circuit breaker to a fixed maximum value, so that the switch can be dimensioned according to the interruption of this maximum value instead of the dimensioning for the interruption of an undetermined value from a current source that can generate extremely high short-circuit currents .
  • Current-limiting circuit breakers usually operate on the principle of electromagnetic repulsion, with the extent to which the residual current rises to a predetermined value that builds up the magnetic forces which act on the movable contact in the sense of the distance from the fixed contact in order to interrupt the circuit.
  • US-A-3 991 391 and US-A-4 132 968 have disclosed a current-limiting circuit breaker which has a magnetic drive arrangement for the contacts (slot motor).
  • the threshold value of the overcurrent is indeed a current-limiting effect causes, increases, but the degree of current limitation at high overcurrents is by the
  • the plate maintain placement of a thin saturable magnetic steel plate over the open end of the magnetic drive assembly.
  • the plate dissipates most of the magnetic flux and prevents the generation of a magnetic dynamic force on the contact arm.
  • the overcurrent creates a magnetic flux sufficient to saturate the plate and drives additional magnetic flux into the air gap where the magnetic flux interacts with the contact arm in such a way that the contact arm is drawn into the gap and in the usual way has a current-limiting effect.
  • This arrangement changes the normal response to a low level fault current that the normal circuit breaker mechanism can handle and thereby limits the response range of the current limiting contacts.
  • Another known circuit breaker (US-A-4 001 738) has a device for electromagnetic rejection. This has a magnetic circuit excited by the current flowing through the switch and an induction plate which can be moved with the movable contact of the switch. The sudden increase in the fault current induces secondary currents in the induction plate, the induction plate being in the air gap of the magnetic circuit as long as the switch is in the closed position. The secondary currents endeavor to displace the induction plate from the air gap, whereby the movable contact is pushed away by the magnetic circuit with great force. This increases the repulsive forces for a given current and thus ensures rapid opening.
  • the contacts form a current path with a double loop.
  • the current enters one of the conductors, flows in a first direction, then flows in the opposite direction through the movable contact and then flows through the second fixed conductor in the first direction.
  • This double loop arrangement doubles the magnetic repulsive force.
  • a double loop arrangement of this type is also described in US-A-4118681 from 03.10.1978.
  • a delay element is also provided which is mechanically connected to the movable contact arrangement in order to delay the closing of the contact after the current-dependent opening and to prevent closing before the circuit breaker has tripped. While this switch ensures rapid contact opening due to high fault currents, there is a need for power switches that open quickly and reliably even due to low fault currents.
  • the object of the invention is to create a current-limiting switching unit which responds reliably to both low and high fault currents and develops the current-dependent opening forces in the smallest possible space. This is to be achieved in particular through the new design of the fixed part of the contact arrangement of such a switching unit.
  • the parallel arrangement of the contact arms in connection with the contact bridge arrangement results in a double current loop with a correspondingly large dynamic opening force. This is particularly effective at high false currents.
  • the magnetic part that can be excited by the contact arms is effective, which, in conjunction with the armature arrangement, reduces the opening force of the contact bridge arrangement and thus also ensures rapid response.
  • a good effectiveness of the contact arrangement can be achieved in that the fixed contact arrangement and the contact bridge arrangement form essentially parallel current paths.
  • the magnetic part can be arranged between the input arm and the output arm of the fixed contact arrangement and can have at least one pole face for the armature arrangement which protrudes from the encapsulation material.
  • a second magnet part can also be arranged at a distance from the first magnet part with an exposed pole face such that one of the two contact arms of the fixed contact arrangement is located between the first and the second magnet part. The force effect on the armature arrangement is thereby increased.
  • the locally parallel arrangement of the contact arms can advantageously be brought about in that one of the two contact arms of the fixed contact arrangement has a through-opening for the other arm and that both arms are embedded in the encapsulation material in a penetrating position.
  • a glass fiber-reinforced polyester resin should be used as the encapsulation material with good results.
  • FIG. 1 shows a current-limiting switching unit 10 which can be designed as an integral part of a low-voltage circuit breaker or as an addable unit for an existing circuit breaker in order to increase the nominal short-circuit breaking current of the circuit breaker.
  • the current-limiting switching unit 10 contains a fixed contact arrangement 12, a contact bridge arrangement 14 and a carrier arrangement 16.
  • An arc quenching chamber 18 is provided for arc quenching in the known manner.
  • the carrier arrangement 16 exerts a closing force on the contact bridge arrangement 14 for transferring movable and stationary contacts into the closed position.
  • armature arrangements 36 and 38 reduce the forces of the carrier arrangement 16 acting in the switch-on direction, with the result that the contacts are separated quickly and reliably due to a fault current of relatively low height. If a fault current with a relatively large height occurs, the magnetic repulsion is sufficient to drive the contacts apart. When the contacts open, the arc is transferred to the arc extinguishing chamber 18 and extinguished there.
  • the fixed contact arrangement 12 comprises two contact arms, namely an input arm 20 with an input contact 24 attached to its end and an outlet arm 22 with an output contact 26 attached to its end.
  • the contact arms 20 and 22 are enclosed in an encapsulation material 28 that isolates the contact arms from one another.
  • a first magnetic part 30 and a second magnetic part 32 are embedded in the encapsulation material 28, these magnetic parts being insulated from one another and from each of the contact arms 20 and 22 by the encapsulation material 28.
  • the first magnetic part 30 is preferably arranged centrally between the input arm 20 and the output arm 22 in such a way that it is located between the input contact 24 and the output contact 26, which are excluded from the embedding in the encapsulation material 28 for suitable contacting with the contact bridge arrangement 14. An edge or side of the magnetic part 30 protrudes from the encapsulation material 28. If the second (lower) magnetic part 32 is also used, this is preferably arranged below the input arm 20. In this case, the second magnetic part 32 is positioned on the bottom of the fixed contact arrangement 12.
  • the output arm 22 has an opening 34 of a size which is sufficient to accommodate a part of the input arm 20.
  • the output contact 26 is attached to one end of the output arm 22, while the other end of the output arm is designed so that it can be connected to a circuit breaker by means of flexible conductors or other means.
  • the end of the output arm 22 provided with the output contact 26 is angled. This arrangement means that the contact 26 remains freely accessible when the output arm 22 is inserted into the contact arrangement 12 and embedded in the insulating encapsulation material 28.
  • the input contact 2 4 is attached to one end of the input arm 20.
  • the other end of the input arm 20 is designed for connection to an input line.
  • the input arm 20 is formed from a flat piece of metal, which is provided with three bends. The first bend extends downwards from the horizontal, the second bend brings the metal back into the horizontal length and the third bend extends the metal upwards at an angle so that the contact 24 lies approximately in the same horizontal plane as the end piece of the input arm 20
  • the three bends divide the contact arm 20 into two sections, namely a horizontal end piece and a substantially U-shaped part, on one leg of which the input contact 24 is fastened.
  • the part of the input arm 20 provided with the input contact 24 is narrower than the remaining part of the input arm.
  • the narrower part of the input arm 20 can be introduced through the opening 34 in the output arm 22.
  • both contacts 24 and 26 can occupy the same horizontal plane.
  • This also forms a double current path, the inflowing current first crossing the input arm 20 to the input contact 24, then passing from the input contact 24 to the contact bridge arrangement 14 , flowing through it and passing through the output contact 26 to the output arm 22, from where it flows to a circuit breaker.
  • the current flow in the input arm 20 and also in the output arm 22 is to the right in Figure 6, while the current in the contact bridge flows in the opposite direction (to the left). Therefore, the current in each of the two arms generates a magnetic repulsive force. With a current of a given height, the combined repulsive force is therefore twice as large as the normal repulsive force.
  • the current flowing through the contact arms 20 and 22 creates a magnetic field around the magnetic parts 30 and 32.
  • the current coming from a line is received by the first or fixed input arm, from where it passes through the U-shaped arrangement of the input arm 20 to the input contact located thereon. From this, the current flows through the movable contact bridge arrangement 14 and the one at the fixed one Output arm 22 attached contact 26 and from there through the output arm 24 to a circuit breaker (not shown).
  • the contact arms 20 and 22 are embedded in an encapsulation material in a parallel arrangement so that the current flowing therein flows through substantially parallel paths. Now that the current loops back to the output contact 26, the current flow in the embedded contact arms 20 and 22 has the same direction. This double co-current flow creates a magnetic repulsive force that is twice the strength that would result from normal current flow.
  • This double magnetic field creates a strong repulsive force which tends to move the contact bridge assembly 14 to the open position.
  • a sufficiently strong fault current can cause an immediate separation of the contacts without additional help from the magnetic parts.
  • the magnetic field of the magnetic parts immediately attracts the armature assemblies 36 and 38, thereby reducing the biasing force of the carrier assembly 16 and the force required to separate the contacts.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Breakers (AREA)
  • Arc-Extinguishing Devices That Are Switches (AREA)
EP86730059A 1985-04-01 1986-04-01 Unité de commutation à limitation de courant avec une disposition localement parallèle des bras de contact Withdrawn EP0196994A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US06/718,693 US4630014A (en) 1985-04-01 1985-04-01 Current limiting circuit breaker stationary contact assembly with integral magnetic activating means
US718693 1985-04-01

Publications (1)

Publication Number Publication Date
EP0196994A2 true EP0196994A2 (fr) 1986-10-08

Family

ID=24887115

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86730059A Withdrawn EP0196994A2 (fr) 1985-04-01 1986-04-01 Unité de commutation à limitation de courant avec une disposition localement parallèle des bras de contact

Country Status (6)

Country Link
US (1) US4630014A (fr)
EP (1) EP0196994A2 (fr)
JP (1) JPS61227339A (fr)
AU (1) AU5531586A (fr)
BR (1) BR8601437A (fr)
ZA (1) ZA862315B (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4633207A (en) * 1985-04-01 1986-12-30 Siemens Energy & Automation, Inc. Cam following bridge contact carrier for a current limiting circuit breaker
US4991050A (en) * 1989-09-18 1991-02-05 Allen-Bradley Company, Inc. Method and device for protecting starters from fault currents
US5072203A (en) * 1989-09-18 1991-12-10 Allen-Bradley Company, Inc. Method and device for protecting starters from fault currents
SE9203234L (sv) * 1992-11-02 1994-01-10 Seldim I Vaesteraas Ak Anordning för skydd mot överström i elektriska kretsar

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3575680A (en) * 1969-08-08 1971-04-20 Gen Electric Current-limiting circuit breaker
US3575676A (en) * 1969-11-04 1971-04-20 Gen Electric High-speed, high-current solenoid
US3588762A (en) * 1970-02-25 1971-06-28 Gen Electric Circuit breaker with short circuit magnetic tripping means
US3588761A (en) * 1970-02-26 1971-06-28 Gen Electric Electric circuit interrupter with magnetic trip level adjusting means
FR2185853B1 (fr) * 1972-05-26 1977-12-30 Merlin Gerin
US3991391A (en) * 1974-01-29 1976-11-09 Westinghouse Electric Corporation Circuit interrupter with electromagnetic opening means
US4118681A (en) * 1976-05-12 1978-10-03 Merlin Gerin High-speed current-limiting device having a contact reclosing retarding member
US4132968A (en) * 1977-09-06 1979-01-02 Westinghouse Electric Corp. Current limiting circuit breaker with improved magnetic drive device
US4409573A (en) * 1981-04-23 1983-10-11 Siemens-Allis, Inc. Electromagnetically actuated anti-rebound latch
US4458224A (en) * 1982-04-20 1984-07-03 Siemens-Allis, Inc. Current-limiting circuit breaker adapter

Also Published As

Publication number Publication date
AU5531586A (en) 1986-10-09
BR8601437A (pt) 1986-12-09
JPS61227339A (ja) 1986-10-09
ZA862315B (en) 1987-01-28
US4630014A (en) 1986-12-16

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Inventor name: BLACK, ROBERT E.

Inventor name: MCCLELLAN, DAVID P.

Inventor name: BROWN, JOHN M.