308 



ELECTRICAL ENGINEERING 



The power consumed by the induced current in section is 

 do> e = dE dl = 2 Tr^^yx 2 dx ergs per second 

 and thus the energy consumed per square centimeter of the plate is 



<o t = 2 



2 7 r 



~2 

 



[3-3-12 

 IT 

 *j t 



= 7r 2 / 2 Bo 2 77> ergs per second (297) 



dx 



FIG. 281. Eddy currents in sheet iron. 

 The power consumed per cubic centimeter of iron is 



01 = 7 



6 



ergs per second. . . (298) 



Thus the eddy current loss for a volume of V cubic centimeter is 



7r 2 / 2 $o 2 7* 2 V r 

 W e = - ergs per second 



= 7r2 ' f2 ^ T<27 10- 7 watts (299) 



7 has a value of about 10 5 for sheet iron. 



