244 



ELECTRICAL ENGINEERING 



In Fig. 219 the semi-circumference represents the e.m.f. of the 

 concentrated winding and the diameter represents the e.m.f. of 

 the distributed winding. 



6 



FIG. 219. 



= 2.7336 



2.733 C 



3t: 



- 0.911 



FIG. 220. 



FIG. 221. 



The e.m.f .'s in the coils from b c add very little to the terminal 

 e.m.f. and this part of the winding is usually omitted and the 



terminal e.m.f. is decreased in the ratio = cos 30 = 0.866, or 



oc 



is decreased 13.4 per cent while the resistance and reactance of the 

 winding are decreased 33J per cent. 



