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:
Aug. 12, 1986
Filed:
Feb. 05, 1982
James B Cockroft, Wauwautosa, WI (US);
Sunbeam Corporation, Oak Brook, IL (US);
Abstract
A motor speed control circuit for closed loop control of an electric motor of a household electric appliance is disclosed herein. The motor speed control circuit includes a coil adapted to be placed in proximity with a fan connected to an electric motor and producing a time varying signal in response to rotation thereof. A comparator connected to the coil generates a rectangular wave having a frequency proportional to the frequency of the coil signal. Additional means are provided for converting the rectangular wave signal, a D.C. signal having an amplitude which corresponds to the frequency of the rectangular wave. The D.C. signal is compared to a reference signal at an amplifier to produce an error signal which is fed through an opto-isolator to a conduction angle controlled thyrister. The thyrister is connected to the electric motor and a source of electric power to control the speed of the electric motor.