ends, and that in consequence the eight wires passing on each side of the shaft can be placed side by side in one layer, instead of being built up in two layers as in the first coils. These wires should be kept in as small space as possible, that there may be plenty of room for the commutator on one end of the shaft; and on the pulley end of the shaft the winding must not extend as far as the

shoulder on the shaft or it will be injured against the bearing when the armature is running.

The eighth and last coil begins in slot 8 and returns through slot 4. When this coil is completed there will be sixteen ends projecting from the slots, eight of them marked as "Outside" wires and the remaining eight marked as "Inside" wires. These are clearly shown in Fig. 57.

When the winding is completed to this stage a careful

test should be made not only for grounds on the armature, but also for short circuits between each of the coils.

If grounds or short circuits are found they should, of course, be remedied.

Be sure that none of the wires of the upper coils project from the slots along the circumference of the armature. Give the wires a good coat of shellac and allow it to dry thoroughly, after which they should be given a second

coat. See that plenty is allowed to soak in along the slots. This will cement the wires together and prevent their being lifted out of the slots by centrifugal force when the armature is revolving at high speed.

Should the coils be tested for grounds, or short circuits, when first shellacked, the galvanometer will, in all probability, be deflected, but this need not cause any uneasiness, as the moisture of the shellac penetrates the insulation

of the wire and forms a conductor for the current, but as soon as the shellac is thoroughly dried out no current will pass through it.

As soon as the shellac is thoroughly dry the commutator can be placed in position on the shaft and the ends of the coils connected thereto by clamping the bare wires under the heads of the commutator screws.

The proper position for the commutator is shown in

Fig. 58. In this cut the armature slots are numbered from 1 to 8 and the commutator segments are numbered to correspond.

It will be noticed that the mica insulation between segments 8 and 1 is directly on a line with the center of slot 1, and the mica between segments 1 and 2 is opposite

slot 2, etc.

It will also be seen that the two ends of the coils of

wire on leaving any one of the slots do not pass to the same segment of the commutator, but attach to adjoining segments.

'Let us begin with slot 1. From this slot protrudes the inside end of coil 1, marked "I," and the outside end of coil 8, marked "O." The inside wire, marked "I" for

identification, connects to segment 1, and the outside wire, marked "O," goes to segment 2.

The inside wire from slot 2 goes to segment 2, and the outside wire from this slot goes to segment 3, etc.

This is continued around the armature until all the coils are connected to their proper segments.

Before being clamped under the heads of the commutator screws, the ends of the wires must be scraped clean to remove the insulation and insure a good electrical contact. After the wires are bent around under the