href="@public@vhost@g@gutenberg@html@files@48846@[email protected]#FIG_262" class="pginternal" tag="{http://www.w3.org/1999/xhtml}a">fig. 262, the drum being shown in dotted lines so that all of each coil may be visible.

Fig. 263.—View of completed winding as indicated in the table fig. 259. Thus the path of the first coil, according to the table is A-1-6-B which means that the coil begins at segment A of the commutator, rises to slot 1, and proceeds through the slot to the back of the drum; thence across the back to slot 6, through the slot and ending at segment B. The other coils are wound in similar order as indicated in the table.

Ques. How are the remaining coils wound on the drum?

Ans. Each of the succeeding coils are wound as indicated in the table, the last connection being made to segment A, the one from which the winding started.

Ques. What is the general form of the completed winding?

Ans. It may be considered simply as a wire wound spirally around the drum, with loops brought down to the commutator segments, and ending at the segment from which the start was made.

The completed winding as indicated by the table is shown in fig. 263. Here the path of each coil is easily distinguished by means of the varied insulations although in part hidden by the drum. Fig. 264 shows a developed view of the winding.

Fig. 264.—Developed view of the winding shown in perspective in fig. 263.

Ques. What condition must obtain in winding an even number of coils?

Ans. The wire must not be wound around the drum to diametrically opposite positions, as for instance 1 to 7 in fig. 265.

Ques. Why is this?

Ans. The reason will be clearly seen by attempting the winding on the wooden core. A winding of this kind on the drum fig. 258, would proceed as follows:

In order now to continue winding in a regular way, the wire from segment d should pass to the rear of the armature along space 7, but this space is already occupied by the return of the first coil. Continuing the winding from this point, it would be necessary to carry the wire from segment d to 6 or 8, resulting in an unbalanced winding.