178 



TREATISE ON ALTERNATING CURRENTS. 



Amperes per line = 



Amperes between adjacent lines = ^ ^- = 

 2nd. Quarter-phase converter 



3 

 2\/2 



= 0-943 

 = 0-545 



Volts between collector-ring and neutral point = -r= = 0'354 



2 v '2i 



Volts between adjacent collector-rings = ^ sin 45 = J = 0'5 



v 2 



2\/2 

 Amperes per line = ~ = 0707 



Amperes between adjacent lines = 



\/2 



4 sin 45 C 



= 0-5 



We can, for reference, tabulate the results thus obtained as 

 follows, R.M.S. values being given throughout : 



The ratios found above between the E.M.F.s on the direct and 

 alternating-current sides of a rotary converter are calculated on the 

 assumption that the induced alternating E.M.F. follows the sine 

 law. This is approximately the case, since the armature of a 

 converter contains a distributed winding. 



The ratio between the P.D.s between the commutator-brushes 

 and the collector-rings respectively will, as a rule, not quite agree 

 with the values given above, since there is a drop of volts in the 

 converter armature ; and also from the result of armature reaction 

 when the alternating current is not in phase with the P.D. between 

 the collector-rings. 



