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Expired Canadian patentCanada

Current measuring and magnetic core compensating apparatus and method

CA 1286366 C · Owner: Schlumbergersema Inc. · Inventors: Goodwin, R. Wendell

CIPO record

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Abstract From the Canadian patent

Current Measuring and Magnetic Core, Compensating Apparatus and Method Abstract, DC magnetic flux bias imposed on a magnetic core of a current transformer is compensated in response to an indication of the amplitude and duration of opposite polarity secondary winding current components. In a second embodiment, the magnetic bias is compensated by responding to the integral of the secondary current. The integral of the secondary current is a measure of the magnetic core flux variations. The durations of the positive and negative flux variations are compared.

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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 16, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 16, 2008.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMarch 3, 1988
GrantedJuly 16, 1991
Term endedJuly 16, 2008
Patent numberCA 1286366 C
Classification (IPC)G01R21/00 +2 more

Timeline

Timeline From CIPO dates

1989199119931995199719992001200320052007Application filedMarch 3, 1988Patent grantedJuly 16, 1991Term endedJuly 16, 2008

Sources & verification

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