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Expired Canadian patentCanada

Current limiting circuit breaker

CA 1082270 A · Owner: Square D. Company · Inventors: Oster, Clark L.; Khalid, Joseph M.; Cook, James W.

CIPO record

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

Abstract of the Disclosure A current limiting circuit breaker having for each pole a, pair of main contacts separable upon operation of a thermally and electromagnetically operable tripping device and a pair of auxiliary contacts for current limiting in series with the main contacts and in parallel with a transformable resistor having a positive temperature coefficient of resistance. The auxiliary contacts are separable when an electromagnet is energized by a fault current which simultaneously energizes a field magnet to produce a transverse magnetic field across the auxiliary contacts and the arc formed between them when separating. This simultaneous action of electromagnet and field …

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Granted July 22, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 22, 1997.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledAugust 31, 1977
GrantedJuly 22, 1980
Term endedJuly 22, 1997
Patent numberCA 1082270 A
Classification (IPC)H01H71/24 +2 more

Timeline

Timeline From CIPO dates

1978198019821984198619881990199219941996Application filedAug 31, 1977Patent grantedJuly 22, 1980Term endedJuly 22, 1997

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.