SYNCHRONOUS CONVERTERS 



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phase; what is its capacity as a three-phase converter; also as a 

 4-phase and a 6-phase converter; also as a direct-current generator? 

 (10 raw.) 



18. A certain converter is wound for a 3-phase system, with 

 50 pounds of copper; with the same heating, what would be the 

 saving in copper, if this machine were to be connected and used 

 for the same output on a 4-phase system; also for a 6-phase? 

 (7 min.) 



19. Plot as ordinates the currents for one period, in a conductor 

 T*J of the pole-pitch distant from the collector-ring connection in 

 a 3-phase converter, giving 130 amperes direct current. (5 min.} 



20. For an 8-phase converter, determine the e.m.f. and current 

 relations and the ratio of its power capacity to the same machine 

 used as a direct-current generator. (10 min.} 



21. A 3-phase, 2-pole converter gives 250 amperes, direct 

 current ; when the ring connection has passed the brush 30 degrees, 

 plot the curve of current in each conductor. (15 min.} 



