FINISHING AND TESTING 329 



In addition to the bands on the armature core the end windings 

 are banded. This is necessary whether the bands on the core are 

 replaced by wedges in the slots or not. Fig. 408 illustrates the 

 method of applying the end bands. 



The tension may be put on the wire by clamping it 

 between two blocks, but the method shown in Fig. 408 is more 

 satisfactory, although a crude arrangement. 



Another way is to take one, two, or three turns of the banding 

 wire round a piece of brass or gun-metal barrel, fixed firmly at the 



FIG. 408. Banding Armature (Westinghouse Co.). 



bed of the banding lathe. The tension should be adjusted with 

 considerable care, and the wire should not be of too small gauge. 

 The bands must be tight enough to prevent them from being 

 displaced sideways. The bands are wound over a layer or two of 

 insulation, which should be of sufficient thickness to prevent the 

 coils sustaining any damage. 



As an example, the Westinghouse No. 12A Railway motor 

 armature has seven bands on it four on the core, f inch wide, 

 and one on each of the end windings and one on the commu- 

 tator leads. The bands on the core are insulated by one layer 

 of mica and fullerboard, and the end windings are protected 



