320 SYNCHRONOUS MACHINES. [Exp. 



6. Data. With the synchronous motor driven as a generator, 

 determine the synchronous impedance ( 10-15, Exp. 3~B) and 

 the no-load saturation curve (5, Exp. 3~A). 



7. Predetermination of Circular Loci. Predetermine the loci 

 of Fig. 2 for the case when E' = E, for over-excitation (E' > E) 

 and for under-excitation ('<). 



8. Current Loci by Test. With constant excitation and vary- 

 ing load determine the current loci for several excitations and 

 compare with the predetermined loci. 



9. Further Investigations. The investigation may be ex- 

 tended to include a predetermination of O-curves and F-curves 

 (as by McAllister), measurement of angular armature position 

 (as by Bedell and Ryan), study of the frequency of hunting, 

 limits of stability, etc. See la; also 24, Exp. lo-A. 



