klternate Current Transformer. 



43 



Hence, as the other window contributes an equal amount of 



energy 



Q of \ 



M'i,Ci C,= -g^«i«,OiGA 



M ^.y= —rr'fiifi-Ai- 



Similarly, 



D 



87ry8' 



y (IV.) 



M'3i= ~jy~n,;i.,/>i. 



Substituting from (II.) and (IV.) in tlie equations for A-'^^and 

 ., in ^43, we get ^ ^^QAI 



and 



IGtt/?' 

 crD 



r 5 1 



/ 



(V.) 



;<«8,/-* -^•^ •\^i 



XiH-.r.,=: 



287r^' 



3o-D 



{/^i + /^. 



45. The determination of the coefficients x'\ and a:'., due to 

 leakage lines other than those that cross the windows can only 

 be approximate. 



A fair approximation can, however, be obtained by assuming 

 that these lines form circuits like aa'cb'ba, Fig. 6, of which ba is 

 in the iron, as the inner surfaces of the coils bear against the 

 iron tongue, aa and bb' are parallel to the plane of separation of 

 the coils and acb^ is a semicircle in the air joining a and //. 



Let us consider the lines due to C^. 



If aa and bb' are a distance z on either side of the median 

 plane of the primary coil, then the M.M.F. round the circuit 

 aacb'ba is 



which will send through the magnetic circuit at 5, whose breadth 

 is dz the flux 

 47r«iCi B^3 



if B be the mean width perpendicular to dz of this elementaiy 

 circuit. Now where the coil bears against the iron the width is 



