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. 31, 1984
Filed:
Feb. 12, 1982
Karmen D Cox, Lafayette, IN (US);
Roper Corporation, Kankakee, IL (US);
Abstract
An induction heating apparatus which includes an induction coil with an associated load and a resonant inverter circuit coupled to a DC power supply for energizing the heating coil. The inverter circuit includes a gate controlled thyristor which is cyclically gated to produce a conductive first period followed by an nonconductive second period in order to energize the heating coil. A diode of opposite polarity to the gate controlled thyristor is coupled in parallel therewith and has an impedance connected in series. The voltage across this series impedance is coupled to the gate of the gate controlled thyristor. The inverter circuit additionally includes an improper load check circuit for disabling the gating of the thyristor in the event of an improper load coupled to the heating coil, and a gate triggered timing generator for adjusting the timing of production of thyristor gate pulses to maintain substantially constant power to proper heating coil loads.