374 



ELECTRICAL ENGINEERING 



The voltage between adjacent rings or the- quarter-phase volt- 

 age is 



(344) 



Assuming the volt-amperes input two-phase to be equal to the 

 direct-current output, that is, 



2 Ei/i = El, 

 the alternating current per line is 



7 - EI - EI 7 



*1 ST? -- B -- ~75 ..... 



FIG. 354. Two-phase or quarter-phase converter. 

 The alternating current hi the winding is the resultant of two 



currents -^ = j=- in quadrature and its value is therefore 

 2 2V2 



I I 



2V2 



(346) 



237. Three-phase Converter. With three collector rings Ri, 

 R 2 and Rs, Fig. 355, connected to three equidistant points li, lz 

 and k the machine- is a three-phase converter. 



The e.m.f. between each of the rings and the neutral point or 

 the " star " e.m.f. is equal to half of the single-phase voltage. 

 It is shown as E$ in Fig. 356. 



*'- ' ' (347) 



