THE CONTINUOUS CURRENT GENERATOR 113 



Fig. 68 shows the developed winding and commutator 

 and also indicates the position of the field poles. Three 

 positions of the brush are shown corresponding to three 

 positions of the armature; the brush is shown as moving 

 backward, having position No. 1 at an earlier time than 

 position 2, etc. In position 1 the current from the right- 

 hand part of the winding gets to the outside circuit through 

 lead d and segment g. In position 2 this current has two 

 paths of about the same resistance through d and g as 

 before or through coil B lead b and segment /. Whatever 



ABC 



N 



Armature coils 

 Connecting leads 



\ Commutator 



FIG. 68. Showing Possible Paths for Currents from Coils to Brush. 



current does take this latter path will evidently oppose 

 the current which has previously been flowing in B. So 

 that the actual current through B may be considered as 

 the difference between the current coming from A and that 

 coming from C. 



With the brush in position 3 it is seen that the resist- 

 ance of the path through segment g is very high, as the 

 area of brush contact on this segment is very small. 

 Hence in this position most of the current from the right 

 side of the armature winding comes through leads d and c, 

 through coil B, and then through b and / to the brush. 

 Hence we see that at the same time that the variation of 



