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. 19, 1977
Filed:
Nov. 25, 1975
Henry D Smith, Bluefield, WV (US);
Pemco Corporation, Tazewell County, VA (US);
Abstract
An improved electrical power supply system is disclosed for preventing arcing between two or more electrical machines energized by a common power source with at least one of said machines receiving power through a lengthy power cable, said cable having a grounding conductor connecting the external conductive housing of said machine to earth ground. A unique multi-winding transformer is connected between the common power source and the cable, so that arcing attributable to voltage induced in the cable grounding conductor is limited to non-dangerous current levels by an inductive impedance from a first winding of the multi-winding transformers, which winding in series with the cable grounding conductor. However, under short circuit conditions, another winding of the multi-winding transformer overcomes the inductive impedance of the first winding so that the current carrying capacity of the cable grounding conductor is no longer limited by the impedance of the first winding.