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:
Mar. 07, 1989
Filed:
Mar. 10, 1988
George Havas, Youngstown, OH (US);
Ajax Magnethermic Corporation, Warren, OH (US);
Abstract
A control circuit particularly useful for controlling the application of power to a single phase induction furnace from a normal line frequency power supply is provided. The load has a large inductance and a resistance. A switch, preferably formed from thyristors, is provided in series connection with the furnace load. A first capacitor is provided in parallel connection with the series connected switch and load. A second capacitor is provided in series connection with the series connected switch and load and the first capacitor whereby selective operation of conduction of the switch results in the smooth and continuous control of furnace power. In an alternative embodiment small inductors are placed in series with the capacitors to provide a filter preferably tuned to the fourth harmonic of the power supply.