CHAPTER IX. 

 REACTANCE OF WIRE, SINGLE-PHASE. 



Effect of Flux in Air. Let there be an alternating 

 current, /, in the transmission line wire, A, indicated in 



Fig. 12. 



The magnetic field set up 

 by the current at P, a dis- 

 tance x away from the wire, 

 will be at right angles to 



-d\ the wire. The intensity of 







the field will be equal to the 



rig. 12. 



force on a unit magnetic pole 



at P due to the current in the wire. The force due to the 

 current in a short length, dl, of the wire will be 



cos = - cos 



Y X 



since dl cos = r dd 



and 



COS0 



The total force at P due to the current in the wire A is 

 equal to 



IT 



/ 2 7 cos <# / , 

 - (where x is a constant) 

 , x 



/sing"! 2 

 x LE 



62 



