Kinsley — Discussion of Series Dynamo-Electric Machines. 115 

 (4) E rtni 



1 + b\ 



Impose the condition that n = a constant = 1400 

 It has already been found that 



a = 0.007 and 

 b = 0.004 



(8) E= 9 ' 8i 



1 + 0.004 i 



This is the equation of an hyperbolic curve having the 

 asymptotes 



and 



E = -r- = 2450 when i = CO 



o 



i = _ = — 250 when E = co 



o 



See fig;. 4. 



laracteristic at a constant speed of n = 10 

 equation 



(9) E= 7 ' 0i 



1 + 0.004 i 



and can be plotted without difficulty. 



See fig. 6 JJ'. 



If we impose the condition that i = a constant = 120 



E(l+bi) = ani from (4) 



(10) E= 0.567 n 



See fig. 5 BC 



when the constants are substituted. 



Equations (9) and (10) are the equations of the lines of 

 intersection of planes, parallel to the co-ordinate planes, with 

 the characteristic surface. 



These planes will limit the solid and bound the surface 

 within the limits used in this particular case. 



