Kinsley — Discussion of Series Dynamo-Electric Machines. 127 



Throughout the range of current covered by a straight line 

 the constants of the characteristic equation are absolutely 

 correct. When the current varies outside of that range 

 then the constants change. 



E« 



ynamo 



Current 



Fig. 13 



Series Dynamo and Motor Tests. Determination of Constants 

 when the Speed does not Change. 



The departure of the points from the straight lines show 

 with what degree of accuracy the equation assumed fulfills 

 the conditions found in the actual machine. 



It will therefore be possible in all machines to show by a 

 surface the relations between E, i and n throughout the com- 

 plete range of operation. Sometimes one and never more 

 than three equations of the same form but with slightly 

 different constants will give the algebraic relation between 

 the variables under all conditions.* 



It has already been pointed out that the brushes must not be moved. 



