Page:Incandescent electric lighting- A practical description of the Edison system.djvu/23

 according to the number of coils of wire wound about the drum, and when arranged in place and secured to a drum or core of insulating material,—that is material which will not conduct electricity,—are

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called the "commutator;" their office being to conduct the impulses of current from each coil as it comes into proper position with relation to the ends of the magnet, into the brushes, from which it passes out through the line wires to the lamps or other electrical devices.