ftiagara falls power Bpplfances. 193 



of the steel ring that is carried by the hood, 

 so that there are no brushes connected with the 

 machine except the small ones used to carry 

 the current to the field-magnets. 



The current for power purposes is generated 

 in a large stationary armature about ten feet 

 in diameter and of the same depth as the re- 

 volving ring. The revolutions of the ring send 

 out currents of alternating polarity, and each 

 of the ten machines will furnish electrical 

 energy equal to 5000 horse-power, so that when 

 the work that is now under way is completed 

 50,000 horse-power can be furnished in the 

 form of electricity. About 35,000 horse-power 

 is now actually delivered to the various indus- 

 trial enterprises. The dynamos are set hori- 

 zontally, since the shaft which connects them 

 with the turbine wheel stands in a perpen- 

 dicular position. 



Not all <>f the energy that is developed by 

 the water-wheel is converted into electricity, 

 but some of it appears as heat. In order to 

 prevent the heat from becoming so great as to 

 be dangerous to the machine it must be con- 

 st nictrd in such a way as to admit of sufficient 

 ventilation for cooling purposes. The arma- 

 ture is so constructed that there are air-pas- 

 sages running all through it, and on top of 

 flic revolving hood are two bonnet-shaped air- 

 tubes set in such a way as to force the air 

 down through the armature, which carries off 



