APPENDIX 



115 



61 ...... L = 741.13 logio ' 



X 



i (Single wire) L = 741.13 logio -^ X icT 6 



In the above, d is the outside diameter of the cable, 

 measured in the same units as s, the spacing between 

 centres of the cables. 



The significance of the above equations is best ap- 

 preciated by consideration of the following examples of 

 calculated reactance. The values tabulated are in ohms 

 per mile at 60 cycles, where 



Reactance in ohms = 2 x X 60 L 



Reactance per mile at 60 cycles of No. oooo wire and 

 cable, 211,600 circular mils. 



The reactance of the cables is less than that of the 

 wire, because the diameter is larger, though the sectional 

 area is the same. The formulas, therefore, show that 

 stranding reduces the reactance of a conductor of a cer- 

 tain cross-section by i or 2 per cent. As is well known, 

 an increase of about the same percentage takes place in 

 the resistance, due to stranding. 



PROPERTY OF ELECTRICAL LABORATORY, 



FACULTY OF APPLIED SCIENCE. 



