46 Proceedioigs of tlie Royal Society of Victoria. 



and as, in a transformei' shaped as we have supposed 2/3 will be 

 very nearly 1.2 D, 



If we take/i.=2250, 



a:i=.00178, ^,=.00338 



Xi-\-x.i=z.005 

 which in a 10 K.W. 50 period transformer, t=6000, would give 

 a drop on non-inductive load of 4.3 per cent., and on an inductive 

 load of .8 power factor a drop of 18 per cent, approximately. 



[Take ti=t2=t, ji'= a/——*, SinS=.75, in formula in § 23 for 

 a rough estimate of the drop]. 



47. In order to determine x\ and x> for a shell transformer 

 with interleaved windings we have, as before, to determine x\ and 

 x'.j^ due to the lines that cross the windows, and x'\, x''^, due to the 

 remaining leakage lines, separately. We will first determine x'l 

 and a'j in the general case. Let the sections of the two coils be 

 arranged, as in Fig. 7, symmetrically, with regard to the median 

 plane across the window so that a section of one of the coils 

 occupies the central position in the window. Let the coil to 

 which the central section belongs be called the even coil and its 

 sections the even sections, and let the other coil be called the odd 

 coil and its sections the odd sections. The even coil will have 

 an odd number, / say, of sections, and the odd coil will have an 

 even number, J say, of sections where J may be equal to either 

 / — 1 as in Fig. 7, or to /+1, in which case the two outer sections 

 would be odd ones. Let d.^ be the thickness of each of the even 

 sections and l>j that of each of the odd ones ; and let L.^, x^, n.^ 

 C.2 refer to the even coil and Lj, x^, fi^, Cj, etc., to the odd one. 

 Let 2/3, 2j3', be the section of the iron tongue, 2/3' being measured 

 perpendicular to the laminae ; and let D be the breadth of the 

 window. 



In Fig. 7 is a diagram of the window in which the sections 

 are numbered in accordance with the above plan, the central 

 section being numbered O, and directly below is what we may 

 call the M.M.F. diagram for C, in which the zig-zag line 



