B. After one coil, or
side, is wound start at C in the same manner as at A, using the
same number of turns and the same length of wire. The two ends are
joined at B.

The armature ring is insulated by covering the inside and brass
spider with 1/16-in. sheet fiber. Two rings of 1/16-in sheet fiber
are cut and glued to the sides of the ring. When the glue is set,
cut out the part within the slot ends and make 12 channel pieces
from 1/64-in. sheet fiber, which are glued in the slots and to the
fiber washers. Be sure to have the ring and spider covered so the
wire will not touch the iron or brass.

Each slot of the armature is wound with about 12 ft. of No. 21
gauge double-cotton-covered magnet wire. The winding is started at
A, Fig. 5, by bending the end around one of the projections, then
wind the coil in one of the slots as shown, making 40 turns or
four layers of 10 turns each shellacking each layer as it is
wound. After the coil is completed in one slot allow about 2 in.
of the end to protrude, to

[Illustration: The Insulated Brush Holder and Its Studs for
Holding the Brushes on the Commutator]

fasten to the commutator segment. Wind the next slot with the same
number of turns in the same manner and so on, until the 12 slots
are filled. The protruding ends of the coils are connected to the
pins in the commutator segments after the starting end of one
coils is joined to the finishing end of the next adjacent. All
connections should be securely soldered.

The whole motor is fastened with screws to a wood base, 8 in.
long, 6 in. wide and 1 in. thick. Two terminals are fastened at
one side on the base and a switch at the other side.

To connect the wires, after the motor is on the stand, the two
ends of the wire, shown at B, Fig. 1, are soldered together. Run
one end of the field wire, shown at A, through a small hole in the
base and make a groove on the under side so that the wire end can
be connected to one of the terminals The other end of the field
wire C is connected to the brass screw in the brass brush stud.
Connect a wire from the other brush stud, run it through a small
hole in the base and cut a groove for it on the under side so that
it can be connected through the switch and the other terminal.
This winding is for a series motor. The source of current is
connected to the terminals. The motor can be run on a 110-volt
direct current, but a resistance must be placed in series with it.

** Protecti