WINDING OF CONTINUOUS-CURRENT ARMATURES 283 



The slot portion of the coil is then insulated one section from 

 another by interlooping a strip of treated linen, as is shown in the 

 cross-section of the slot in Fig. 330. This strip is cut so long that 

 it may be wound around the complete bundle at least 2J times. 

 The parts of the coils outside of the slot portion are now covered 

 by one layer of tape. The coil is now ready to be spread to its 

 proper shape, and for this purpose a dummy wooden model of the 

 armature core is employed of the type already shown in Fig. 302, 



FIG. 335. Wedging Coil in Slot 



having one slot into which the bottom half of the coil is inserted. 

 The coil is then spread by placing a slotted wooden piece over 

 upper portion of coil, and sliding this piece with its part of the 

 coil over the core periphery until the desired shape is attained 

 and the coil has the correct pitch. 



The coils are now ready to be placed in the armature core slots 

 directly after the treated presspahn, fuller-board, or other similar 

 materials used for slot linings, are in position. The completed 

 armature should be placed in a baking oven and thoroughly dried, 

 after which it should be plunged while hot into a bath of in- 

 sulating varnish and afterwards oven-dried. 



TIT. A third way of winding these coils is to wind each com- 



