SYNCHRONOUS MOTORS. 



281 



current for a given load, and the two limbs of the curve 

 would coincide, giving a single line. 



The greater the self-induction of the armature the 

 more divergent will the two limbs of the curve be, and the 

 greater will be the difference between the two values of 

 the excitation at which it will operate with a given load and 

 current. This will be explained more fully in connection 

 with the graphic representation of the conditions (see 

 page 286). 



Fig. 132 shows the curves of power factor obtained 

 from the same readings as the curves of current and watts 



2-0 



2-5 



O -5 1-O 1-5 



Amperes, Excitation. 



PIG. 132. CURVES OF POWER FACTOR AND EXCITATION. 

 I. = No load. 

 II. = -38 h. p. 

 III. = -81 h. p. 



given in Figs. 130 and 131. The no-load curve shows how 

 rapidly the power factor changes with the excitation in 

 the case of an unloaded motor. This curve shows the 

 curious feature of a power factor rapidly falling and then 



