ELECTRICAL METHODS 



[Chap. 10 



represented by lines of equal potential, by equiphase lines, or by in-phase 

 and quadrature equipotential lines. 



The compensator shown in Fig. 10-39 permits of determining the real 

 and imaginary components directly. The generator side is connected, as 

 before, to the reference lead ; the reference voltage is split up into its com- 



Primorif tiectrodts 



Search Electrodts 



Fig. 10-38. Arrangement for determining amplitude and phase of ground poten- 

 tials (adapted from Ludwiger). PH, phase transformer; G, ground transformer; 

 A, amplifier; T , air-core transformer; P, potentiometer; F1-4 variometer coils. 



■e- 



Ph 



■oaaojMfl- 



iiU 



a 



irawwnr 



//AWWAVVAW^VAW/ 



WAWAV^ 



Primarij Eltcfrodes 



W*A\VAVmV''AW''A'WA\V!«* 



Starch £ltctrod»s 



Fig. 10-39. Bridge arrangement for determining in-phase and quadrature potentials 



(adapted from D. C. Gall). 



ponents which are applied to the in-phase potentiometer P and quadrature 

 potentiometer Q. These are connected to the search electrodes through 

 two switches, *S»S, which permit of changing the sign of the reference 

 components. Current null is determined by a differential transformer, D, 

 connected to an amplifier, A. 



