Overtemperature speed control for a variable speed device
CA 1202673 A · Owner: Hughes Tool Company · Inventors: Leuthen, John M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A variable speed drive for an AC motor has features to reduce the speed of the motor if excess temperature is encountered in the variable speed drive system. The system has a rectifier that converts AC supply voltage into DC voltage on the positive and negative rails. Frequency switches switch the DC voltage to power conductors in a sequence and at a rate to determine the selected frequency. The frequency switches are controlled by a DC demand voltage. A temperature sensor provides an electrical response corresponding to the temperature in the system. The temperature response is compared to a reference voltage and, if it exceeds the reference voltage the comparator provides, an output that …
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
- Granted April 1, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 1, 2003.
- 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.