Abstract: A DC dynamoelectric machine with interpoles between field poles operable in sparkles even under heavy operating conditions comprising a solid soft iron magnetic flux bypassing members, each disposed between respective field poles and interpoles at their ends near its armature with an air gap between the field pole for controlling interpole magnetic flux, the solid soft iron magnetic flux bypassing member suppresses sudden change of magnetic flux flowing therethough by permitting flow of eddy current therethrough and maintains the interpole magnetic flux at a desired amount even during a sudden change of load current.

Abstract: A commutator apparatus for rotary electric machines comprises a plurality of commutator segments mounted side by side on a rotary shaft through an insulating ring along the periphery thereof, an armature winding wound on a rotor core and including a plurality of coil ends projected axially from the rotor core, and a plurality of risers made of a conductor, one end of each thereof being connected to one axial end of the corresponding commutator segments, the other end of the riser being securely connected to one end of the corresponding armature coil. Each pair of adjacent risers are bound by an insulating binder to reduce the space therebetween, thus forming a substantially delta-shaped space defined by the adjacent risers on each side of said binder. The vibrations of the risers are thus absorbed and the vibratory stress of the risers is reduced, thus improving the mechanical strength and reliability of the commutator apparatus.