The commutator part of the motor should be enclosed so that there may be no possibility of a spark igniting the film.
A commutator, B, permits of establishing or interrupting the current at will.
As in the other cases, the commutator revolves while the collector remains stationary.
To these arms the brushes are attached, so that their spring ends engage with the commutator .
As armature, commutator, and shaft rotate, the brushes connect first with one segment of the commutator and then with the other.
The commutator is in two parts, which must be insulated from each other.
The armature winding is not to be put on the core until the commutator has been constructed and mounted on the shaft.
The slots in the commutator must be under the center of the yoke, 14.
The armature is marked A, the shaft B, and the commutator C.
In a direct current motor this reversal is brought about by the commutator.