Method for regulating the motor current of a brushless d.c. motor
CA 2048018 C · Owner: Albrecht, Kai · Inventors: Albrecht, Kai; Meyer, Helmut
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The aim of the present invention is to propose a method for regulating a brushless d.c. motor which permits the current ripple of the motor to be reduced to a minimum. This is achieved by an arrangement in which a switchable semiconductor valve (Tr1 ... Tr4), of the energized bridge arms is switched off for a period of time ts dependent upon the speed of the motor, when the reference value of the motor current (IM) is reached. Furthermore, by this means the clocking frequency of, the switchable semiconductor valves is minimized; in addition to increasing the service life of the transistors, this helps to considerably reduce motor noise.
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 26, 1991 and granted September 16, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 26, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 26, 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.