Symmetrical fault current detector
CA 1287110 C · Owner: Ea Technology Limited · Inventors: Aubrey, David Richard; Jameson, Ian
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Excess currents due to faults in an electrical power system are generally larger than excess currents due to the magnetisation of distribution transformers: discrimination has hitherto relied on a threshold detector. Magnetising currents are however, asymmetrical whereas fault currents are symmetrical. This specification discloses a detector which can detect symmetrical current waveforms on a conductor 1 and thus discriminate between a fault and a magnetising excess current. A resistor 4 placed across, the output terminals of a bridge rectifier 3 has a resistance selected so that the voltage across it exceeds the breakdown voltage of trigger diodes 7 and 8 when the current in conductor 1, …
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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 30, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 30, 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.
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.