36 THE DESIGN OF STATIC TRANSFORMERS 



.. the " alloyed steel ") the eddy loss is very nearly absent ; 

 whereas in the formerly- em ployed material, the eddy loss con- 

 stituted a decidedly substantial component of the total core loss. 

 In fact, it is principally in virtue of the very considerable 



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FIG. 13. Eddy [current loss curves for various periodicities for old low 

 resistance sheet iron. 



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FIG. H. Eddy current loss curves for various periodicities for modern 

 high resistance alloy steel. 



increase in the specific resistance of the material and of the 

 consequent great reduction in the eddy loss that the marked 

 decrease in the total core loss has been brought about. The 

 older material sometimes had a specific resistance as low as 

 10 microhms per centimeter cube, whereas in the new 



