. Electric transmission of power : its present position and advantages. Between the arms of the magnets, and passing throughthe uprights supporting them, is the shaft, carrying at itscentre the rotating armature. This consists of a disc ofcast iron, near the periphery of which, and at right anglesto either face, are iron cores, wound with insulated wire,thus constituting a double series of coils. The armature c2 20 ELECTEIO TRANSMISSION OF POWER. coils (Pigs. 13 and 14) being connected end .to end, theloops so formed are connected in the same manner, andto a commutator of the same construction
. Electric transmission of power : its present position and advantages. Between the arms of the magnets, and passing throughthe uprights supporting them, is the shaft, carrying at itscentre the rotating armature. This consists of a disc ofcast iron, near the periphery of which, and at right anglesto either face, are iron cores, wound with insulated wire,thus constituting a double series of coils. The armature c2 20 ELECTEIO TRANSMISSION OF POWER. coils (Pigs. 13 and 14) being connected end .to end, theloops so formed are connected in the same manner, andto a commutator of the same construction as that of theGramme. As the armature rotates, the cores pass betweenthe opposed north and south poles of the field magnets,and the current generated depends on the change of Fig. 13. Tie. 14. - If i ?^• ^ 1 1 w :3. polarity of the It will be seen that this constitutesa double machine, each series of coils, with its commutator,being capable of use independently of the other; but inpractice the electrical connections are so made that thecurrents generated in the two series of armature coils passthrough the field magnet coils, and are joined in oneexternal circuit. This form of armature also presents considerable un-covered surface of iron to the cooling effect of the air, but,like that of the Brush, presents considerable resistance torotation. In the Wallace-Farmer machine there is considerableheating of the armature, the temperature being sometimessufficiently high to melt sealing-wax. In the Siemens machine, the conductor of insulatedcopper wire is coiled in several lengths and convolutions, THE WALLACE-FAEMER AND SIEMENS MACHINES. 21 upon a cylinder shown in transverse (Fig. 15), and in endview by Fig, 16. Each convolution is parallel to the Fig. 15.
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherlondon, bookyear187
