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. 17, 1984
Filed:
May. 01, 1981
Bela G Nagy, Acton, MA (US);
Alfredo H Saab, Malden, MA (US);
Sprague Electric Company, North Adams, MA (US);
Abstract
A power factor controller for a motor is of the type having a bidirectional triode thyristor and a circuit for sensing the voltage across the thyristor to determine the time by which the current lags the line voltage and for generating a signal voltage across an integrating capacitor that is inversely proportional to the current lag time. In addition, a voltage ramp generator produces a ramp voltage having a slope that increases as the lag time decreases. A sum of the signal voltage and ramp voltage is applied to the input of a threshold detector that triggers firing of the thyristor when a predetermined threshold is reached. The entire controller employs only five integrated switches or gates and two individual transistors, and power dissipation, size and cost are thereby minimized.