THE ROTARY CONVERTER. 



329 



Fig. 164 shows the values of the direct current observed 

 during the same experiment, at the same values of the 

 alternating current. It is seen, as might have been 

 expected, that within the limits taken, the currents 

 decreased as the strength of field was increased and 

 as the speed of the converter became less. Less power 

 was consequently required to drive the converter with 



e -7 -s 



Amperes Excitation. 



Curve I. = 

 II. = 



III. = 



IV. = 4 



V. = 8 

 VI. = 14 



Amperes load. 



1 



2 



FIG. 164. ROTARY CONVERTER DRIVEN FROM D.C. SIDE. 

 BETWEEN CURRENT AND EXCITATION. 



RELATION 



higher excitations. Within the limits taken in the 

 experiment, the efficiency consequently increased with the 

 excitation. 



If the converter supplies an inductive circuit, the 

 effect upon its voltage will be similar to that in the case 

 of an alternating-current generator, ' A lagging current 

 will tend to lower the A.C. voltage, while a leading 

 current will tend to raise it. 



Rotary Converter Driven from Alternating-current Side. When 

 used to convert alternating into direct currents, the 

 converter is driven from the alternating side as a 

 synchronous motor, and generates direct currents which 

 are supplied to the load circuit from the commutator. 

 This is the most usual application of rotary converters. 



