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:
Jan. 20, 1987
Filed:
Feb. 07, 1985
Michael A Damiano, Germantown, WI (US);
Richard F Schmerda, Oak Creek, WI (US);
Lawrence G Searing, Milwaukee, WI (US);
Eaton Corporation, Cleveland, OH (US);
Abstract
A motor (M) supplied by AC full-wave voltage is controlled by a triac (Q2) under the control of a double-time constant triggering circuit which has a speed setting branch (R3-C2) connected at the triac (Q2) side of the motor (M) and the other time constant branch (R1-C1) connected at the supply side of the motor (M) to provide a feedback function as well as a first time constant. A unidirectional diode (D1) is incorporated in the feedback sensing time constant branch for rendering feedback signals only on alternate half cycles to prevent oscillation and overcompensation of motor speed due to the feedback signal. A soft-start circuit, usable also in half-wave applications, is incorporated in the branch containing adjustable speed setting resistor and comprises a transistor (Q3) having its collector-emitter circuit connected in series with the adjustable resistor (R3). A resistor (R4)-capacitor(C3) time constant circuit is provided to supply time variable current to the base of the transistor (Q3) through a resistor (R5) for causing the transistor (Q3) to gradually conduct, thereby gradually decreasing its resistance and therefore gradually increasing the firing angle of the triac (Q2).