ffalls power Bppllancca. 195 



rotating part of the dynamo will move with 

 great ease and little power, as compared with 

 what is required when the circuit is closed, 

 and the current is going out and doing work. 

 The increased amount of energy that will be 

 required to keep the dynamo moving at a cer- 

 tain rate of speed when the load is on in 

 other words, when the circuit is closed will 

 depend upon the amount of current that is go- 

 ing out from the dynamo to perform work at 

 other points. As the amount of current used 

 outside for the various purposes is constantly 

 changing, it follows that the load on the 

 dynamo is constantly changing also. As the 

 load changes, the speed will change, unless the 

 amount of water that is flowing into the tur- 

 bine is changed in a like proportion; hence 

 the necessity for a governor that will perform 

 this work. You can easily imagine that it will 

 require a great amount of power to move the 

 gate up or down with such a pressure of water 

 behind it. It is not possible here to explain 

 the operation df ilic governor in detail, as that 

 o.uM ii. t be done without elaborate drawings; 

 it to say that the whole thing is con- 

 trolled by a small ball governor such as we see 

 used in ordinary steam-engines for regulating 



-ure. 



The rising or falling of the balls of this 

 governor to only a very slight extent will 

 bring into action a power that i< driven by 



