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. 16, 1996
Filed:
Apr. 20, 1992
John K Marsh, Rome City, IN (US);
Russell E Zemen, Jr, Fort Wayne, IN (US);
Group Dekko International, LaOtto, IN (US);
Abstract
A method and apparatus for providing a source of alternating current electrical power to a plurality of loads in an office environment, including a plurality of non-linear loads which draw power for only a portion of the alternating current cycle, includes an input source of electrical power to a primary side of a power transforming device which provides an output at its secondary side which comprises at least two phases and a shared neutral. The plurality of loads are evenly distributed between each phase of the output power source and the shared neutral so as to reduce by current cancellation the current which would otherwise flow in the shared neutral conductor due to the presence of the non-linear loads. In one embodiment, each of six output phase is separated from the other by 120 electrical degrees, and the fourth, fifth and sixth phases are separated from the first, second and third phases, respectively, by 180 electrical degrees. In another embodiment, two sets of six phases are provided, with each of the phases in the first set shifted, relative to respective phases of the second set, so as to reduce variations in the level of instantaneous power drawn from the input source which would otherwise occur due to the presence of the non-linear loads. Additional embodiments incorporate autotransformers which may be advantageous in smaller or preexisting installations. Benefits of the invention include lower ground to neutral noise, reduced transmission losses, more accurate power measurement by induction watt-hour meters, and fewer instances of neutral current overload.