Kinsley — Discussion of Series Dynamo-Electric Machines. 135 



Another and much more extensive test was made, but the 

 speed of the dynamo was too erratic to allow a smooth curve 

 to be drawn; the average difference between the computed 

 and observed values of the motor speed was only 0.05%. 



The resistance of the circuit that will cause the motor to 

 operate at constant speed when the dynamo runs at 1300 

 r. p. m. can be determined by the method given on p. 119. 



From the lines of fig. 13 we can get the constants for par- 

 ticular parts of the dynamo and motor surface and then can 



n' R 



solve for the ratios — and — for that range of current : 



Dynamo 



n n 



1 .6 i 

 - + l - = =r n 

 a a & 



Speed constant = 1300 



L + 10 - = 0.093 n 

 a a 



- + 13 -- = 0.111 n 

 a a 



Motor 



a = 0.0233 

 6 = 0.1815 



I ,.b' i , 



— + 1 — = ^r 11 



a a E„ 



Speed constant = 1500 



i + 9-, = 0.170n' 

 a a 



1 7 ' 



+ 13 °- = 0.203 n' 

 a a 



a' = 0.00702 

 b' = 0.0878 



We have then within the same range of current 



a' n' a R 



1 + b'i n 1 + bi n 



