S-B] 



100' 



70 



5 



^40 

 o 



1 



o 



3 



ui20 





 u 



(S) 



10 



30 



TEST BY LOSSES. 



Frequency; Cycles per Second 



40 



60 



80 



'57 



100 120 140 160 190 200 



30 



100 120 140 160 180 200 



VOLTS (Logarithmic Scale) 

 FIG. 5. Curves for core loss plotted with logarithmic scale. 



there are data for only two frequencies and hence only two 

 points on this curve, plot it as a straight line as it will be 

 practically a straight line through a considerable range. (When 

 the test is made at only one frequency, see 52.) 



The slope of this line gives the exponent (&), showing the 

 law of core-loss variation for different frequencies at constant 



V ltage: W.*n\ 



The exponent (b) should be determined; see 51. Plotted on 

 ordinary coordinate paper, this curve appears as in Fig. 4. 



