CHAPTER XIII 



FINISHING AND TESTING 



Banding. Rotating armatures having open slots are generally 

 banded round with a number of turns of steel wire at several 

 points along the armature core to secure the coils in the slots 

 against centrifugal force. The alternative to this is to close the 

 mouth of the slots with a thin wedge of fibre or hard wood, engaging 

 in recesses in the sides of the slots. 



FIG. 407. Armature with Eluding Bands. 



Up to a few years ago, the binding bands were commonly put 

 on outside the surface of the armature core and standing up above 

 it. If the clearance between the armature and field is small, this 

 becomes dangerous with increasing wear of the bearings. The 

 bands are now customarily recessed into the core so that they 

 appear flush with, or slightly below, the surface, as in Fig. 407. 

 Finished armatures banded up will be seen in Figs. 349 and 360 

 of Chat>. XT. 



