2 3 2 



ELEMENTS OF ELECTRICAL ENGINEERING. 



lines in the clock diagrams of Fig. 200 and Fig. 201. If the armature windings are 

 not interconnected, then any phase may be connected in any way to any receiving cir- 



A 



t 



Fig. 200. 



cuit, that is to say, the electromotive force A may be reversed with respect to any 

 receiving circuit by reversing its connections to that circuit. Therefore the two inde- 

 pendent phases, A and B, Fig. 200, constitute in a certain sense a four-phase system 



Fig. 201. 



having the available voltages A, , A f and B f \ and three independent phases, A 

 B and C, Fig. 201, constitute in a certain sense a six-phase system having the avail- 

 able voltages A, B, C, A f , B' and a. 



