Brushless dc motor
CA 2046149 C · Owner: Gotou, Makoto · Inventors: Gotou, Makoto; Inaji, Toshio
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention provides a brushless DC motor which does not have a position sensor for detecting a rotational point of a rotor. Instead of using a position sensor zero-crossing points of counter electromotive forces induced in the stator windings of the rotor are detected to obtain a pulse signal train. From the pulse signal train thus obtained and a slant waveform signal generated in response to the pulse signal train, a position signal with a trapezoidal waveform is formed. An electric current signal with a trapezoidal waveform is supplied to the stator windings of the rotor in response to the position signal thus formed for effecting an electric current switching of the stator windings …
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 July 3, 1991 and granted September 23, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 3, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 3, 2013.
- 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.