Study of Transformers. 183 



and even when B/ is not small, for frequencies and sizes of 



R' 



iron usual in transformers, the term ^7, is insignificant. 



R'C 

 In fact, the term M ^ even when R/ = co is merely the 



small value of when the secondarv is open, being then 



— V 



• p ,t A • We may say then that it is true for all practical 



purposes that Effective G = m-\-nX Effective C, where n 



r f o 



is nearly -^= or p, m being a small constant which depends 



upon frequency, &c. 



If R' is small, or the loads are the usual loads on trans- 

 formers, 



_ y 

 C/== RL' + R'LT LI/-M» 0> ' • (16) 



V 



R + R'^r-f ^ M 6 



Generally, then, unless when there is a very small load on 

 the transformer : — 



The secondary current is the same as if the primary voltage 

 acted in one circuit of resistance 



BL' + R'L n S P 



and self-induction — ^ , there being no other circuit ; 



and the primary current is as if the primary voltage acted in 

 one circuit of resistance, 



L P 2 



R + Rj, orR + R-^2, 



LL' — M 2 



and self-induction j-, — . When R' is go , of course C 



is as before, the current in a circuit of resistance R and self- 

 induction L, Y being the voltage and C' = 0. 



Writing M= s/\AJ{l—y), y being small, we may write 

 (16) as 



r ,_ Y 



Rp +R'g+2L^ 



