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Expired Canadian patentCanada

D-c motor flashover protection

CA 1099376 A · Owner: General Electric Company · Inventors: Stitt, Thomas D.; Williamson, Dennis F.

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

A method and apparatus for detecting and correcting the occurrence of flashover in a direct current electric motor. The polarity and magnitude of voltage on the field winding of the motor is continuously monitored. Detection of a sudden reversal of the polarity of the field voltage accompanied by a rapid increase in magnitude results in the generation of a flashover signal. The flashover signal is coupled to power controlling elements regulating power supplied to the motor and is effective to force removal of power from the motor. In a preferred embodiment the appartus is disclosed in a two-motor system with two field windings serially connected such that the field voltage monitoring is …

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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 April 14, 1981. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 14, 1998.
  • 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 15, 1977
GrantedApril 14, 1981
Term endedApril 14, 1998
Patent numberCA 1099376 A
Classification (IPC)G05D1/00 +1 more

Timeline

Timeline From CIPO dates

1978198119841987199019931996Application filedDec 15, 1977Patent grantedApril 14, 1981Term endedApril 14, 1998

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