H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
H02K—DYNAMO-ELECTRIC MACHINES
H02K23/00—DC commutator motors or generators having mechanical commutator; Universal AC/DC commutator motors
H02K23/02—DC commutator motors or generators having mechanical commutator; Universal AC/DC commutator motors characterised by arrangement for exciting
H02K23/20—DC commutator motors or generators having mechanical commutator; Universal AC/DC commutator motors characterised by arrangement for exciting having additional brushes spaced intermediately of the main brushes on the commutator, e.g. cross-field machines, metadynes, amplidynes or other armature-reaction excited machines