DTHMOr CURRENT ARC LIGHTING SYSTEM.

455

active wire is reduced to a minimum, and the coils at eachside of the plates that are in contact with the brushes are prac-tically equal. In this way the electrical efficiency of the ma-chine is increased.

The commutator plates t are shown as outside the hearing b of

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Fig. 276.

Fig. 275.

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the armature shaft. The shaft 11 is tubular and split at the endportion, and the wires are carried through the same in the usualmanner and connected to the respective commutator plates. Thecommutator plates are upon a cylinder, and insulated, and thiscylinder’ is properly placed and then secured by expanding thesplit end of the shaft by a tapering screw plug, v.

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Fig. 277.

The arc lamps invented by Mr. Tesla for use on the circuitsfrom the above described dynamo are those in which the separa-tion and feed of the carbon electrodes or their equivalents is ac-complished by means of electro-magnets or solenoids in connectionwith suitable clutch mechanism, and were designed for the purpose