Kinsley — Discussion of Series Dynamo-Electric Machines. 119 



It is occasionally desirable in actual practice to operate one 

 series motor as the only load of a series dynamo. Usually 

 then it is essential that the motor regulate for constant speed 

 with widely varying loads. 



If it was desirable to run a motor whose characteristic was 

 as given by DU of fig. 8, — data, p. 121 the necessary con- 

 ditions could be gotten as follows: — 



The motor characteristic is drawn on the Ei plane of fig. 

 8, without reference to the speed axis. 



In this case the motor constants are 



a'=0.0067 

 6=0.0066 



determined when the motor speed (n') was 1000 rev. pr. min. 



The motor characteristic equation is therefore 



(17) 



(18) 



ais cai 

 (18) 



If the desired conditions that n', n, and R be constant, for 

 varying loads and consequently varying current, are possible 

 with the above dynamo and motor a plot of 



v and 



l + -6i 



a' 



l + b\ y 



will give a straight line. 

 Through what range of current the above conditions are 



