[NM020ABJ], Technical Note, Thomas Alva Edison, October 25th, 1886


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[NM020ABJ], Technical Note, Thomas Alva Edison, October 25th, 1886

Editor's Notes

THIS IS SELF-EXCITING AC DYNAMO US. PAT. 379,944 "Dyer take out patent for this Use regular dynamo with regular brushed but they only serve to energize the field which is regulatable by the resistance no lamp current is taken off these. On the end of the shaft next commutator are two continuous contact disks secured to shaft & rotated together, on the surface which is continuous a contact brush rests, both disks are insulated from each other. I permanently connect one commutator bar to one disk & the commutator bar directly opposite on the other side of the commutator I connect to the other disk then at every revolution the current is reversed in the wires leading from the disks while the regular commutator brushes take off a continuous current The two wires connected to the two disk contact brushes bass to a distant point say a mile etc There the two primary wires of converters are connected across multiple arc preferably they can be in series. The scondaries are connected in series to give say 200 volts. The center wire being connected between thus I have a three wire system, if 2 wire the secondaries are put in Multiple arc the High tension Machine is say 2000 volts-- The Converters have large masses of iron in the form of fine iron wire or sheet, hence the slow reversals will not show in lamp, but perhaps if not necessary you needent say anything about ths way of getting reversals-- I don’t want to confine myself to using this machine in connection with converters as the lamps may be put on direct the tension being reduced of course to the regular required volts. Also I can in addition to putting on lamps on the reverse circuit or when using the converter put lamps on the regular brush circuit" [drawing]




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