TABLE IV 107 



When this quantity is positive, the reactive Kva. and 

 the line P. F. are leading, and when it is negative, they 

 are lagging. 



(n) Efficiency of the Transmission Line. 



FM + HN 

 100 =-p per cent. 



As * * 



(12) Reactive Kva. of Synchronous Motors Required 

 when Load Power-Factor is cos 6. 



The reactive Kva. of the load are equal to the Kw. at 



receiver end, from (7), multiplied by -. To this re- 

 sult, treated as a positive quantity, add the reactive Kva. 

 in the line at the receiver end, from (10), with d,ue regard 

 to the sign. This is a positive quantity when the line 

 P. F. is leading. The sum is the reactive Kva. of synchro- 

 nous motors required. 



(13) Amperes per Wire. 



As all the expressions for current are in total am- 

 peres, it may be noted that 



total amperes 

 amperes per wire, 3-phase, = 5=*- 



^3 



total amperes 

 amperes per wire, 2 -phase, = - 



and amperes per wire, single-phase, = total amperes. 

 For single-phase lines use a 2 R and 2 X in place of R 

 and X and use > Y in place of Y. 



(14) Allowance for Extra Impedance. 



Only a very slight error is introduced by adding the 

 resistance and reactance of the transformers and react- 

 ance coils, referred to high tension, to the line resistance 

 and reactance. See (14), Table III. 



