The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 19, 1979
Filed:
May. 24, 1978
Wolfgang Kosak, Moglingen, DE;
Peter Werner, Stuttgart, DE;
Hans Gerber, Luterbach, CH;
Ivan Hidveghy, Zuchwil, CH;
Robert Bosch GmbH, Stuttgart, DE;
Abstract
A universal motor is energized by a speed setting circuit during one half wave and a speed control circuit during the next half wave of each cycle of an AC supply. The speed setting and speed control circuits each have a separate timing circuit including a capacitor. There is thus no residual charge on the capacitor of the speed setting circuit remaining from the operation of the speed control circuit during the preceding half wave. The residual charge prevented the setting of low motor speeds in the known systems. The speed control circuit includes a storage capacitor transformer coupled to the motor so that its initial charge corresponds to the current through the motor during the preceding half wave. The charge is transferred to a second capacitor. When the voltage across the second capacitor reaches a predetermined threshold valve, a switch in the speed control circuit becomes conductive and current flows through the motor.