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:
Jul. 25, 1989
Filed:
Jul. 14, 1988
John F Farrow, Plymouth, MI (US);
Medar, Inc., Farmington Hills, MI (US);
Abstract
Structure for and method of controlling the firing point of thyristors in a phase controlled contactor in a resistance welding circuit in accordance with variations in current line voltage and/or one of resistance and inductive impedance in the welding circuit including structure for and the method of determining the firing point in a cycle of alternating electrical energy fed to the welder in terms of its distance from zero voltage cross over point and determining the current lag after a subsequent zero voltage cross over point of the voltage signal, determining the power factor of the welding circuit from these angular measurements and selecting a new firing delay for the contactor in accordance with the circuit power factor and the percent heat selected in the welding circuit, and subsequently correcting the firing delay in accordance with the percent heat selected in view of changes in the line voltage and circuit current.