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The Commutator

Author: E.E. Kimberly

In order that the alternating emf in each conductor on a rotating armature core may appear at the terminals as unidirectional voltage, the connections of every conductor to the external circuit must be reversed at every point in the revolution where its generated emf is zero, as at a in Fig. 10-1. To accomplish this reversal, connecting leads are brought out to the bars of a commutator. The commutator consists of a bundle of wedge-shaped copper segments assembled in cylindrical form and mounted on the armature shaft, as shown in Fig. 10-2, but insulated from one another. The details of construction of the commutator are indicated in Fig. 10-3.

Fig. 10-2. Direct-Current Motor or Generator Armature

Fig. 10-3. Details of Commutator

Last Update: 2010-10-06