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Expired Canadian patentCanada

Plasma cutting or arc welding power supply with phase staggered secondary switchers

CA 2192891 C · Owner: Schneider, Joseph C. · Inventors: Schneider, Joseph C.; Reynolds, Jon O.; Li, Stephen H.

CIPO record

Overview

Drawings and full text

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

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Abstract From the Canadian patent

A power supply, such as a plasma cutting power supply or a welding power supply, that provides an output to a pair of output terminals is disclosed. The power supply includes a source of voltage and a plurality of choppers. The choppers are connected in parallel between the voltage source output terminals. A controller controls the choppers so that they are out-of-phase with respect to each of the other of the plurality of choppers. The choppers preferably include a freewheeling diode, an inductor and a switch. The number of choppers is approximately equal to the ratio of the open circuit voltage to the output load voltage.

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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

  • Filed December 13, 1996 and granted February 22, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 13, 2016.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 13, 2018.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledDecember 13, 1996
GrantedFebruary 22, 2000
Term endedDecember 13, 2016
Patent numberCA 2192891 C
Classification (IPC)H02M7/12 +2 more

Timeline

Timeline From CIPO dates

1997199920012003200520072009201120132015Application filedDec 13, 1996Patent grantedFeb 22, 2000Term endedDec 13, 2016

Sources & verification

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