RESISTANCE DEVICES 



149 



The current which will flow between two parallel cylindrical 

 electrodes when they are immersed in a great body of liquid is 



IMp'lE 



7 1 \ l ) 



in id the power absorbed is 

 P = 



I.I | WATER RHEOSTAT WITH PARALLEL CYLINDRICAL ELECTRODES 

 Length in Cm. 



Conductivity, P, in Mho, Cm. 

 Three Phase Single Phase 



Fi<;. 7'. -Showing constants of water rheostat with different spacings of 

 cylindrical electrodes. 



In the case of a three-phase rheostat the line current will be 

 //. = -/-I' = 1.15/' 



vi 



and the power absorbed will be given by 



2.72 P 'IE* 



P = EI L \/3 - 



The conductivity, p', which is greatly influenced by local 

 conditions and by temperature, must be found for the water which 

 is to be used. To determine it two conducting cylinders of a 

 known diameter may be fixed at a known distance apart and the 

 arrangement immersed in the running water. A measured 



