[Illustration: Fig. 69. Generator Armature]

Another form of armature largely employed in recent magneto
generators is illustrated in Fig. 70. In this the shaft on which the
armature revolves does not form an integral part of the armature core
but consists of two cylindrical studs _2_ and _3_ projecting from the
centers of disks _4_ and _5_, which are screwed to the ends of the
core _1_. This =H= type of armature core, as it is called, while
containing somewhat more parts than the simpler type shown in Fig. 69,
possesses distinct advantages in the matter of winding. By virtue of
its simpler form of winding space, it is easier to insulate and easier
to wind, and furthermore, since the shaft does not run through the
winding space, it is capable of holding a considerably greater number
of turns of wire. The ends of the armature winding are connected, one
directly to the frame and the other to an insulated pin, as is shown
in the illustration.

[Illustration: Fig. 70. Generator Armature]

[Illustration: Fig. 71. Generator Field and Armature]

The method commonly employed of associating the pole pieces with each
other and with the permanent magnets is shown in Fig. 71. It is very
important that the space in which the armature revolves shall be truly
cylindrical, and that the bearings for the armature shall be so
aligned as to make the axis of rotation of the armature coincide with
the axis of the cylindrical surface of the pole pieces. A rigid
structure is, therefore, required and this is frequently secured, as
shown in Fig. 71, by joining the two pole pieces _1_ and _2_ together
by means of heavy brass rods _3_ and _4_, the rods being shouldered