ALTERNA TING CURRENT WINDING 



241 



points, each connected to a collector ring. With a multiple circuit 

 winding there must be one tapping for each collector ring per pair 

 of poles, i.e. the total number of tappings is equal to the number 

 of poles. Taking, for example, the two-circuit single-winding shown 

 in Fig. 279, which has 6 poles, 64 conductors, arid pitch 11, the 

 winding is tapped at some point A to one collector ring, and then, 



FIG. 282. Winding for a Three-phase Rotary Converter, Two-circuit 

 Single-winding with Ninety Conductors, Eight Poles. Pitch 11. 



after tracing round one half of the conductors, a tap is taken out 

 at point B to the other collector ring. 



If the winding be doubly re-entrant there must be two taps at 

 neighbouring points to each ring; that is, one tap per ring for 

 each re-entrancy. Corresponding rules apply for other multiply 

 re-entrant windings. 



As an example of a multiple-circuit winding, Fig. 280 shows 

 a six-circuit single winding with 72 conductors and 6 poles. 



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