794 



Dr. H. H. Poole on Vector Methods for 



higher harmonics. This is in some ways rather an advantage, 

 as after a little practice one recognizes by the sound which 

 side of the best balance has been reached. 



In what follows, one point of the system is taken as the 

 zero of potential. Points on the circuit diagram which are 

 at the same potential when a balance has been attained 

 are represented by the same letter, being distinguished 

 by suffixes. Currents are denoted by c's with suffixes. 

 Capital K's are used for the entire resistances of arms 

 possessing self-inductance (L). In some cases I is used for 

 the impedance of such an arm and 6 for its phase-angle, 

 p being used for the total impedance of two or more arms in 

 series or parallel. Small r's represent non-inductive re- 

 sistances, M's mutual inductances, and K's capacities. 



With each circuit diagram is shown the corresponding 

 vector diagram. The vectors in every case, except fig. 8, 

 represent falls in pressure in the corresponding arms. The 

 diagrams are lettered to correspond, points on the vector 

 diagrams not corresponding wdth any points on the circuit 

 diagrams being distinguished by the letters P, Q, S, etc. 

 V represents the P.D. generated by the source which is 

 assumed to be constant in some cases. Any phase-angles 

 employed are marked on the vector diagrams. 



Comparison of Two Self-Inductances [Maxwell's Method] . 



Fig. 1. 



Circuit Diagram 



c,r, a c,R, 



Vector Diagram 



Here A x is at the same potential as A 2 , both being repre- 

 sented by A on the vector diagram. The current c x in OAi 

 also flows through A : B, similarly the current c 2 in OA 2 flows 

 through A 2 B. It is evident that the vector diagram repre- 

 sents equally well the branch OA^ or the branch OA 2 B, 

 every point on the diagram for one branch coinciding with 

 the corresponding point for the other. 



