260 
The N.Z. Journal of Science and Technology. 
[Nov. 
with the current, and is represented by BD. DC represents the voltage- 
drop due to reactance, and is in quadrature with the current. The voltage 
at the sending end is represented by OC. In the diagram, for the sake 
of clearness, the quantities BD and DC are exaggerated. 
c < 
Jr PL 
\ 
o fl 
Vector Diagram. 
Correction: For ZI r PL read llyjph. 
The voltage-drop is given by 
V* — Vi¬ 
and is represented by the difference in length of OC and OB. 
By resolving along and perpendicular to OA we have 
V s (V r cos o -f~ ZI r R) 2 + (V r sin v + ll Y p L) a 
— V r yj ^ r (r cos 0 + pL sin ^ Rr + p 2 L 2 ^) 
Now, in all practical cases and —are small, and hence 
V r » r 
V, — V r 11 + (R cos 6 + pL sin 6) j ; 
V a — V r = H, (R cos 6 + pL sin 6). 
v t P x iooo T 
1,111 V, cos 6 ~ lr; 
. 1T P X 1000 Xl,. D , T x 
.. V s — V r =- if - (R + ph tan 6). 
V V 
If both ZI r R and ZI r pL are less than 10 per cent, of V r (as they will 
be in all practical cases), the error in the above approximation will be less 
