244 ELEMENTS OF ELECTRICAL ENGINEERING. 



The flux 3> f/r which passes between the coils is produced by 

 the full magnetomotive force A^N'i' (or ^rrN"i" which is the 

 same thing), and the air part of the magnetic circuit through 



Fig. 210. 



which <'" passes has a length / and a sectional area 

 (counting both legs of the coils). Therefore 



(V) 



The total leakage flux, counted as if it all passed between the 

 coils, is <>' -f <l>" + 4>'" which is equal to p -f s in equation 



