HARMONIC ELECTROMOTIVE FORCE AND CURRENT. 57 



line E in Fig. 48^, and the voltages across A and across B are 

 represented by the lines E a and E 6 respectively. The phase 

 difference may have any value between zero and 180. 



(d} Figure 49*2 shows two colls (or receiving units of any kind) 



main 



Fig. 47- 



Fig. 



A and B, connected in parallel between alternating-current 

 supply mains. The total current delivered to A and B is 

 represented by the line I in Fig. 49^, and the currents in A 

 and B are represented by the lines I a and I 6 respectively. 



w , 



14- 



Fig. 48. 



Fig. 48*. 



The phase difference 6 may have any value between zero and 

 1 80. 



24. Rate of change of harmonic current. When the current 

 in a circuit changes, a portion of the electromotive force which 



