Slip Rings and Brushes - Generators 

Examples of slip rings and brushes on generators/dynamos from the 1880s to today. The first brushes on commutators were made from copper brushes, copper strips were also used, and later graphite(carbon) blocks. Springs push the blocks against the moving surface of the armature.
This video is part of our webpage on the generator:
www.EdisonTechCenter.org/generators.html