RECTIFIERS: THE SYNCHRONOUS CONVERTER 351 



voltage is 550 volts. The alternating-current side is operated six-phase. 

 Find the direct current and all the A.C. line currents and voltages. 



V = 550 



,-fijp 



I = 550 X 0.354 

 From equation (83) 



195 volts between adjacent lines and to neutral. 



Str. Field 



Fio. 322. Currents and voltages in a 6-phase, 500 kw., synchronous converter 



and transformers. 



143. Conductor Currents in the Armature of a Converter. It 

 has already been pointed out that the synchronous converter has a 

 high efficiency because the net current in each armature conductor 

 i- the difference between the alternating current and the direct 

 current which would of themselves exist in that conductor. The 

 reason for this is obvious. The alternating current entering 

 through the slip-rings is a motor current, driving the machine as a 

 synchronous motor and is therefore in opposition to the induced 

 electromotive force. The armature current which is delivered 

 by the commutator to the brushes is a generator current and is 

 in conjunction with the induced electromotive force. 

 Both the alternating and the direct current utili/e the same con- 

 ductors, rotating in the same field, ruder these conditions 

 the two current- must flow in opposite directions. Therefore, 

 t current in each conductor must be the difference between 

 the motor current and the generator current. 



The \\ave-form for the resultant current in the various conduc- 

 tors is very irregular and <1; Of the different armature 

 conductors. The value of the resultant current also diff. 

 the different conductors. 



