28 THE DESIGN OF STATIC TRANSFORMERS 



does, to a very considerable extent, limit the choice of 

 dimensions and arrangement of the primary coils. In general, 

 the value of the " volts per layer " does not affect the dimen- 

 sions and arrangements of the secondary conductors, especially 



7.0 



(5.0 



30 



J 



20 



/.o 



y 



/oo 



/fated Oufyout /n 



FIG. 9.^Curves showing " volts per turn " of 



transformers of different rated outputs and periodicities. 

 Curve A, 50 cycles ; curve B, 25 cycles. 



where the secondary pressure is low. This is for reasons 

 which will be more apparent at a later stage in the working- 

 out of the design. In transformers of low and of moderate 

 capacity, the range of suitable values for the " volts per turn " 

 is limited by other reasons, the chief of which is the necessity 



