A current ratio device for use in forming a current transformer
CA 2201968 C · Owner: So, Eddy · Inventors: So, Eddy; Bennett, David A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A current ratio device for use in forming a hand-held openable-core clamp-on type of current transformer. The device employs electronically-aided three-stage circuitry for forming a current transformer capable of accurate low current measurements over a wide range of operation. Such a current transformer is specifically adapted for use with highly accurate active/reactive power and energy meters and harmonic power analysers. For, example a preferred form of clamp-on transformer can be used to measure currents in the range from 1A to 200A with ratio errors of less than 50x10-6 for both the in-phase and quadrature components.
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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 March 26, 1997 and granted May 13, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 26, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 26, 2019.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.