ALTERNATORS. 



239 



greater increase in excitation would be obtained on an 

 inductive load circuit, since the armature drop in this case 

 would be greater. 



Since the curve of variation of excitation may be 

 approximately obtained from the results of the deter- 

 mination of the characteristic and magnetisation curves, 



2-6 



2-4 



2-2 



2-0 



V6 



1-4 



1-2 



30 



40 



10 20 



Amperes, Load. 

 FIG. 113. VARIATION OF EXCITATION TO MAINTAIN CONSTANT VOLTAGE. 



it will in most cases be better to make use of these rather 

 than to obtain a separate curve for inductive load by direct 

 experiment. 



The method of deriving the curve from those already 

 taken would be approximately as follows, the method of 

 procedure depending somewhat upon the information 

 required, and the curves already obtained. 



Suppose that the loss of voltage at a certain load, either 

 inductive or non-inductive has been obtained by experiment 



