Alternate Current Transformer. 

 Hence in this case 



^6910 . .766 





anda-=:51 . .000465=.0237, 



which, by means of the formula for R give the following approxi- 

 mate values for the regulation. 



These figures agree remarkably well with the following 

 (already discussed in Section I.), given by the Westinghouse Co. 

 as the regulation of their 10 K.W. 60 period O.D. transformers, 

 which are also wound in five sections — three primary and two 

 secondary. As regards regulation, the 12.5 K.W. 50 period 

 transformer considered above, and the 10 K.W. 60 period 

 Westinghouse one are nearly equivalent, as 7C>F is nearly the 

 same for both [27r . 625 as against 27r . 600]. 



Regulation of equivalent Westinghouse Transformer. 



Power P\ac'tor Drop per cent. 



1.0 ... 1.65 



.9 ... 2.45 



.8 ... 2.65 



.6 ... 2.80 



53. In order to obtain approximate values for the leakage 

 coefficients of transformers of the core type it will be sufficiently 

 accurate to consider the core as straight, and connecting two 

 large masses of iron. 



Let the core be circular in section of radius r having coil 2 

 lying betwen the cylinders whose radii are r and r-\-l/.^ and coil 1, 



