GENERAL DIAGRAMS FOR SYNCHRONOUS MOTORS 191 



described around the center O, will define the load-conditions correspond- 

 ing to these currents. 



In order to obviate reactive currents it is sufficient, for each case, 

 that the reactance should be adjusted to a value exactly equal to that 



FIG. 13. 



which makes the reference line pass through G. This means that the 

 reactance X must be made successively equal to the following values: 



BK BK 



G'K' G"K'' 

 - R > -BK* R > 



These values of X can be calculated for each value of I w , by the Eq. 

 (a) given herein above. From this equation 



(a} 



on substituting for Z 2 its value (Z 2 R 2 + X 2 }, and solving for X 2 , we 

 have 



X 2 =-R 2 + F - 



IJ 



Practically, this regulation can be worked by hand or even auto- 

 matically, by making use of reactance-coils having movable cores, 

 which are pushed all the way in when the load is zero, and are gradually 



