THE TRANSFORMER 281 



core is made) are built up around two legs of the assembled 

 coils. 



Lamination of Coils. In order that the primary and 

 secondary coils may be placed closely together, they are 

 built up in thin sections (called " pancake " coils) and the 

 sections of the two coils are sandwiched together, first a 

 thin section of the primary, then one of the secondary, etc. 



FlG 172. A Small Shell-type Transformer, Completely Assembled. 



T? /->.+ YX/"m7-na Triar>f vin "WVivlra 



Fort Wayne Electric Works. 



One of these thin sections is shown in Fig. 174. In Fig. 

 177 is shown a cross-section of the assembled coils showing 

 how the sections are interspersed; there may be a dozen 

 or more of these sections in a large transformer. Fig 175 

 shows another method of winding shell type transformers; 

 here pan-cake coils were not used but the two coils are 

 placed intimately together by having the low tension coil 



