586 



ELECTRICAL MEASUREMENTS 



To find the condition of balance, the mesh equations are 



X(Zi + Z 8 ) -- YZ 2 + V, = 

 Y(Z a + Z,) - XZ 2 - F 2 = 0. 



The galvanometer current is 



z 2 ) - y,z 2 



Z,) + Z,Z,' 



In this, as in other similar cases involving networks, the equa- 

 tion for. Y might have been written at once from the solution for 

 the direct-current case, simply replacing the resistances by im- 

 pedances in the vector notation. 



Load 



Detector 



z a 



r * J G /h 



y^r-^.y 



OT'0'0 8 5 5 5 flWHAAA/VWVWWWWVi 

 Z2 | -Zi J 



FIG. 363. Connections for determining characteristics of potential trans- 

 formers. 



For balance, I G = Y = and 



Let Zi be without reactance, then, 



Z z must then be reactive, so 



r(^i + ^ 2 ) +j 

 == L" ft+jL, 



Vi 



The value of IV in terms of F 2 2 and the constants of the 

 circuit is 



r 2 _ 





-f- 



