124 



ARMATURE CONSTRUCTION 



In Fig. 141 the lug consists of two strips, one on the 

 other, riveted together, which separate at their outer end and 

 embrace the ends of the armature coils in the manner shown. 



I 



FIG. 141. FIG. 142. FIG. 143. 



Methods of attaching Commutator Lugs and connecting to Armature Conductors. 



If the lug is only a single strip of copper, it is brought 

 round, as shown in Fig. 142. 



Another method of fixing the lug to the segment is to mill out a 



groove at the end, into which the 

 lug is sweated, as in Fig. 143. Fig. 

 144 shows a photograph of a com- 

 mutator having these grooves. If 

 the commutatordiameter is nearly 

 equal to the armature diameter, so 

 that no lugs are necessary, the con- 

 ductors, if of rectangular section, 

 are brought out straight into the 

 milled groove as shown in Fig. 145. 

 If the commutator is forged 

 with the lug in one piece with 

 the segment, the arrangement of 

 Fig. 145 is commonly used. 



Fig. 146 shows a common 



method for wire wound armatures. 

 FIG. 144. AliothCo. Finished 



Commutator. Fig. 147 shows a method in 



which the lug is attached to the 

 segment by screws; this method is not frequently employed. 



