Abstract: A homopolar machine for use as a motor or a generator. The machine includes an elongated shaft rotatable about a longitudinal axis, a barrier disposed about the shaft, and first and second electrically conductive, magnetic field inducing disks connected to and disposed about the shaft such that the barrier is sandwiched therebetween. The barrier is conductive of a magnetic field and electrically insulated from the disks. The disks are electrically interconnected and generate a magnetic field perpendicular to the barrier with the magnetic field of the first disk in opposition to the magnetic field of the second disk. The machine also includes first and second electrical contacts electrically connected to the centers of the disks. The conductive path defined by the disks includes first and second ends at the centers of the disks and substantially travels the radius of each of the disks such that when used as a generator i.e.