[Fig. 221] is intended to represent another form of armature, but the principle upon which it operates, is the same, as the other shown. A A, represents the wire coils of the armature, B, is the shaft with its journals, C, is the commutator. All commutators both for generators and for motor armatures are insulated by mica between the bars.
Fig. 222.
[Fig. 222] shows a woven wire brush. The brushes on the dynamo, [page 247], are made of carbon.
Fig. 223.
[Fig. 223] shows an alternating induction motor. Induction is a property by virtue of which an electric current is transferred from one conducting line to another without any metallic connection; it is that influence by which a strong current flowing through a conductor controls or affects a weaker current flowing through another conductor in its immediate neighborhood,—the strong current remaining unaffected.
Fig. 224.