Water Power 



73 



Pelton wheels. The overshot wheel was extensively used in early 

 times to provide energy for operating mills. It was sometimes 

 of enormous size and was made with large pockets on the rim. 

 These pockets were placed so that the water released from a 

 dam above flowed on top of the wheel and into the pockets until 

 their weight was sufficient to turn the wheel. 



The breast wheel is quite similar in construction to the over- 

 shot wheel and is commonly used where there is a large supply 

 of water falling a short distance. This wheel also has pockets 

 on the rim. The water flows into the pockets at a point about 



The Breast Wheel 



The Pelton Wheel 



TYPES OF WATER WHEELS 



The Turbine Wheel 



level with the axis of the wheel. The weight of the water causes 

 the wheel to revolve, as in the case of the overshot wheel. 



The undershot wheel is used where the fall of water is slight. 

 It depends on the force imparted by water flowing against its 

 blades from underneath, as in a swiftly running stream. 



Turbine Wheels. The wheels described above have been 

 largely replaced by the turbine wheel. This type of wheel can 

 be well adapted to almost any condition of water supply. It 



