FUNDAMENTAL PROBLEMS. 



rl, and xl as before. In the present case, however, the line re- 

 sistance produces a difference in phase between E Q and E v and the 

 line reactance produces a difference in value between^ and E r * 



(c) Voltage drop in a transmission line which delivers current 

 to a condenser or any receiving circuit having negative reactance, 

 but having small resistance. This case is shown in Fig. 79, and 

 E Q is the vector sum of E v rl, and 

 xl as before ; but, E^ and xl are 

 nearly opposite in'direction, inasmuch 

 as Ej_ is nearly 90 behind / under 

 the assumed conditions. Therefore 

 in this case the line resistance pro- 

 duces a difference in phase between 

 E Q and E l and the line reactance pro- 

 duces a difference in value between 

 Q and E v making E l greater than E Q .* 



(a) Voltage drop in a transmission 

 line which delivers current to a receiv- 

 ing circuit whose power factor, (cos 6\ 



has any given value. Let the line 01, Fig. 80, represent the cur- 

 rent flowing through the transmission line and the receiving cir-' 

 cuit. Let the line E l represent the voltage across the receiving 

 circuit, being the phase difference between / and E^ as shown. 



Fig. 79. 



Fig. 80. 



Let r be the resistance and x the reactance of the transmission 

 line, and let E Q be the voltage at the generator. Lay off rl par- 

 allel to 01, and xl at right angles to 01. Then the difference 



*This statement is made on the assumption that rl is small as compared with E r 



