Edison patentIn 1870, Thomas A. Edison was issued a U.S. patent for an “Improvement in Magneto Electric Machines” (No. 222,881). The object of his improvement was to increase the effectiveness and cheapen the construction of the revolving armature. He designed the armature of a cylinder of wood with two iron heads between which fine iron wire was wound on the cylinder. At the ends of the cylinder, outside the iron heads there were disks of hard rubber or other insulating material, and the wires forming the induction helix are wound lengthwise of the cyclindres into notches in the edges of the disk. |
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