54 Proceediiu/s of the Royal Society of Victoria. 



P2=:12.5.K.W., T=6080, «'=1007r, and as the middle coil 

 is the primary one q.j;=Lq^^=z.f)^ ^1=^*- =.7. 

 From § 47, f, taking the lower signs, 



x\=^-^^ xi±] =.000490 

 3/.^ 2 



3/./? 2 

 From § 49, taking from the table the values of X.2 and Xj, 

 / = 1, b=:b{, and ^.,/^i = 3/4, which is sufficiently close to 5/7, we 



47rya^^ 



.",= _(M±-M2^±A).33= -.00015 

 47r/*;8^ 



From § 50, 



^"',=y' V = ^;( 1 + 21og2)=.000002, 



."-.'".= ^(l4-21og^) = 



000015, 



which in this case of few sections are relatively negligible. 



But Xp^=x'.2-\-x".2.-\-x"'.2, x^^=x\-\-x'\-\-x"\, 

 hence Xp =.00129, x., = -.00024, Xp +Xs =.00105. 



If this transformer had been wound so that the secondary as 

 a shigle coil occupied the central position, with half of the 

 primary ozi either side, its leakage coefficients x'p^ x'^, would be 



y^= -.00029, .r', =.0014. 

 and it is interesting to find what effect this change in the relative 

 positions of the two coils would have on the efficiency for 

 inductive loads. 



When we neglect all small terms but the one that depends on 

 the first power of the leakage, we find from §15 that the 

 maximum efficiency 



1 



1 + p — "7 A/TSin8 + 2a:s tan<^Sin8 



= 1 1 -Q^ VTSmS i(l - -Ixs tan^SinS) 

 := 7;o(l — 2aj,. tan^SinS) il-V-) 



