[PT032AAI1], Technical Note, Thomas Alva Edison, August 24th, 1887



Dyer & Seely-- New patent-- System of Electrical distribution for Light heat & power. The object of this invention is to economically & efficiently distribute electric energy at a practically constant potential over extended areas without the use of large & expensive conductors & the employment of regulating apparatus consuming electrical energy-- The system being specially valuable in Towns & Cities when there is a minimum amount of lighting over a maximum area & where the ordinary 3 wire system of patentee is too expensive-- The invention consists in dividing the city or town in two or more areas each worked with the ordinary 3 wire system with feeders arranged in the ordinary manner-- but in this system all the feeders which I call sub feeders centering to a main feeder-- The areas being small the sub feeders are very short from the connection with the mains to the main feeder and are calculated for only 2 per cent drop of potential They have no lamp connected to them-- the main feeder being long is calculated for a drop of 10 or 15 percent. The 2nd area is arranged in a similar manner and the two areas are connected together in series, the two areas together forming as a whole a 5 wire system AA A'A' are the mains of the two areas BBB is a sub feeder BBB another connected to one side of the main feeder C' B'B'B' & B2B2B2 are two subfeeders connected to the mains & other side of the main feeder C' the portion of the main feeder C2 serves to connect the two areas together balancing wires d e q extend from the sub feeders back to the station. Thus each area is worked on the 3 wire system but the 2 areas together form a 5 wiresystem-- 4 Dynamos are employed each seperately regulatable, and have a surplus capacity for increased electrical pressure that if any section of either area is thrown greatly out of balance the pressure can be kept constant at all points notwithstanding a great drop in the 1/2 size blance wire d e & q in my patent ____ lately issued I shew what would seem at the 1st glance to be the same system but the distinction is the use of a greater number of subfeeders thus shorten them up so that even small wires will only give a drop of 2 percent in pressure & thereby do away with the necessity of feeder regulators & attendance at the point where the main feeders is connected to the sub feeders X X are pressure wires leading back to the central station. Fig 1 merely Illustrates the simple principle-- but fig 2 & 3 shews the plans I use in practice. The mains are not shewn in this diagram-- only the connected net work of sub-feeders; the extremeties c.c.e.f g . H in one area & c' d e' f' g' h' in the other area connect with the mains The main feeder & balance wires connect to the subfeeder net work at A. & B. This net work of subfeeders does away with individual feeders which owing to inequality of consumption of electric energy in different parts of the mains causes great variations in pressure and substitute one single net work of subfeeders through which the pressure can be equalized & if there is a great tendency to a drop at one point the pressure is equalized through the sub feeder net work & not through the mains as in the regular system fig 3 & 4 illustrate only subfeeder net work etc etc-- The main claim is for a connected subfeeder net work connected to the station by a main feeder 2 or more areas in series arranged with net work mains-- net work sub-feeders-- & main feeder-- etc








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[PT032AAI1], Technical Note, Thomas Alva Edison, August 24th, 1887

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Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University