Abstract: A dual armature single field DC motor/generator including at least some of a rotatable shaft maintained relative to a housing; an inner rotor armature secured to the rotatable shaft and including inner rotor armature electromagnets; field poles secured to the housing, each having a field pole electromagnet; interpoles secured to the housing, each having an interpole electromagnet; an inner rotor commutator assembly including an inner rotor commutator and inner rotor brush leads, wherein each inner rotor armature electromagnet is in electrical contact with a segment of the inner rotor commutator; an outer rotor armature secured to the rotatable shaft and including outer rotor armature electromagnets; and an outer rotor commutator assembly including an outer rotor commutator and outer rotor brush leads, wherein each of the outer rotor armature electromagnets in electrical contact with a segment of the outer rotor commutator.