Fault indicator
CA 2024205 C · Owner: Schweitzer, Edmund O. Jr. · Inventors: Schweitzer, Edmund O. Jr.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A fault indicator for indicating the occurrence of a fault current in a monitored electrical conductor of an AC power distribution system utilizes a liquid crystal display having independent "F" and "N" display elements. A rectifier circuit capacitively coupled to the conductor charges a first capacitor in the presence of voltage on the conductor. A second capacitor is connected to the first capacitor by a first reed switch in magnetic communication with the conductor. Upon occurrence of a fault current the reed switch closes and a portion of the charge on the first capacitor is transferred to the second capacitor which is, connected to the "F" display segment electrodes of the liquid …
Read the whole patent
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 August 29, 1990 and granted December 29, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 29, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 29, 2012.
- 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.