FORCED-COOLED TRANSFORMERS 



157 



coils dt' an air-blast transformer taken at a certain stage of their 

 inanut'artiuv, is givt-n in Fig. IK). l>y regulation of tin- amount 

 of openings in the cast- ly means of dampers provided for 

 tin- purpose, the relative amounts of air passing respectively 

 through the core-ducts and through the passages between the 

 coils, may be adjusted. Air-blast tran>fonuers are nowadays 



ED 



B 



'last 

 transform 



rarely employed for units of less than -500 kw capacity* The 



Mial appearance of t'lie typr to \\hicli PigB, W and 



i'ply is >h\vn in l-'i'j. !'l rl:itin-j to designs by the Genera] 

 \niciira. In Ki'j. '.'1, the overall dimensionfl 



A, I tmen for primary ]>n->suri'S of 



some 12 000 volts and secondary pn-sures of some 100<> t 

 2000 volts, and foi rated outputs of 500 kva and I<><H> 



lily s set forth in Tablr h'.. 



