DYNAMO-ELECTRIC MACHINES. 81 



800 revolutions per minute, costs 10,000 francs (400Z.), and can 

 precipitate 10 kilogrammes of copper with 7 horse-power. 



FIG. 16. 



Mather Machine. 



WILDE MACHINE. The machines previously described are 

 all continuous current machines, whereas those of Wilde, in use 

 for more than twenty years in England, are rectified alternating 

 current ones. 



This machine is composed of two superposed machines, the 

 top or small one exciting the electro-magnets of the bottom or 

 large one. Both machines are provided with a Siemens longi- 

 tudinal armature, that of the exciter revolving in front of 

 permanent magnets, and that of the other in front of electro- 

 magnets. The current of the small machine goes to excite 

 the electro-magnets of the other, and the current of the large 

 machine is used externally. 



By means of two driving bands and a suitable engine, the 

 two armatures are rotated, the small one at a speed of 2400, 

 and the large one at 1500 revolutions per minute. The 

 currents induced by the machine with permanent magnets 



G 



