195 



through its own center in the position 

 indicated. In dealing with the heating 

 of armature conductors by eddy-currents, 

 the author had drawn a distinction be- 

 tween coils with and without iron cores, 

 showing the need of an explanation of 

 the differences noted. His own view of 

 the matter had for some time been this : 

 It is well known that, in a transformer 

 with a well-closed iron circuit, very large 

 sections of conductors might be employed 



Fig. 40 



Fig. 41 



in the coils without introducing trouble 

 from eddy-currents. The extreme case 

 occurred in transformers for electric 

 welding, in which the section of the 

 single secondary turn might be many 

 square inches without showing the effects 

 of eddy-currents. The reason, as it 

 appeared to him, for such a condition 



