Nikola Tesla - Free-Energy Devices

DIRECT CURRKNT ARC LIGHTING SYSTEM. 453small fraction of the total length of the armature core, and besidesthis the iron body is subdivided in the generating direction,and therefore the Foueault currents are greatly reduced. Anothercause of heatingis the shiftingof the poles of the armature core.In consequence of the subdivision of the iron in the armatureand the increased surface for radiation, the risk of heating islessened.The iron discs D D D are insulated or coated with some insulating-paint,a very careful insulation being unnecessary, as anelectrical contact between several discs can only occur at placeswhere the generated currents are comparatively weak. Anarmature core constructed in the manner described may be revolvedbetween the poles of the field magnets without showingthe slightestincrease of temperature.The end discs, d d, which are of sufficient thickness and, forthe sake of cheapness, of cast-iron, are curved inwardly, as indicatedin the drawings. The extent of the curve isdependenton the amount of wire to be wound upon the armatures. In thismachine the wire is wound upon the armature in two superimposedparts, and the curve of the end discs, dd,is so calculatedthat the first part that is, practically half of the wire just fillsFro. 273.up the hollow space to the line xx; or,any other manner, the curve is such that when the whole of thewire iswound, the outside mass of wires, M>,and the inside massof wires, w', are equalat each side of the plane x x. In this caseif the wire is wound inthe passive or electrically-inactive wires are of the smallestlength practicable.The arrangement has further the advantage