ARMATURE WINDINGS. 447 



commutator segment is inserted, then another group of m ele- 

 ments are wound as another extended element, and so on. The 

 result will be a modified type of singly reentrant wave winding 

 having as many paths as the original /^-plex winding, namely 

 2m paths, but having only I /mth as many commutator segments, 

 each segment being made m times as broad as before. 



In the original ;/z-plex winding two brushes each broad enough 

 to touch at least m commutator segments are sufficient. In the 

 modified winding the brushes touch one segment (or at most two) 

 at a time, and two brushes are not sufficient. 



Fig. 62 shows one of these modified six-pole wave windings 

 with 1 6 commutator bars. This winding may be thought of as 

 derived from a singly reentrant triplex wave winding with a front 

 pitch of 17, and a back pitch of 17. In this case it is necessary 

 to use all six of the narrow brushes in order to utilize the six 

 paths in the armature. 



