CONVERTERS 373 



The voltage between the leads Zi and 1 2 or between the slip rings 

 RI and RI is alternating and reaches its maximum value when li 

 and ? 2 are under the brushes and it is then equal to the direct 

 voltage of the machine. Therefore, in a single-phase converter 

 the direct voltage is equal to the maximum value of the alternating 

 voltage and thus 



E=V2Ei ....... (339) 



or 



Neglecting losses and phase displacements the output of the con 

 verter is equal to the volt-amperes input or 7 



El = #!/! 



and the alternating current in the line is 



El El 



V2 



The alternating current in the winding is 



r-fi, 



P 



where p is the number of circuits in multiple through the winding. 

 In the bipolar machine in Fig. 353, p = 2 and, therefore, 



236. Two-phase or Quarter-phase Converter. When four 

 collector rings R\, R z , Rs and R 4 , Fig. 354, are connected to four 

 equidistant points ?i, Z 2 , Z 3 and Z 4 , the machine is a two-phase or 

 quarter-phase converter. The two voltages Ri to Rz and R-t to 

 RI are equal and are in quadrature, forming a two-phase system; 

 the four voltages RI to R S) Rs to #2, Rz to -R 4 and R^ to RI are 

 all C^ual and form a four-phase or quarter-phase system. 



The voltage between lines or the voltage per phase of the two- 

 phase supply is 



E> = .......... (343) 



