66 THE DESIGN OF STATIC TRANSFORMERS 



The results in Table 8 are plotted in Fig. 38, in which it 

 will be seen that while Transformer A has a decided com- 

 mercial advantage over Transformer B at low load factors, 

 this advantage decreases with higher load factors. 



In view of the considerable saving thus effected, the reader 



32. <4B 64- 30 



Load factor /n f&rcent 



f 



f 



ormer 



loss 360 tfMs 



B 



r Loss /30 



FIG. 38. Profit to electricity supply company in per cent, of cost of 

 power supplied to 20-kw transformers at various load factors. 



will be inclined to inquire whether the 20-kw transformer 

 should not be designed for a still lower core loss than 190 watts. 

 Any considerable reduction in the core loss below the value 

 of 190 watts already obtained in Transformer A would only be 

 obtained by a design with a regulation distinctly worse than 

 2 per cent. This is not desirable. The reader may be 



