Abstract: Several embodiments of an uninterruptible power supply (UPS) system, which system provides highly reliable output power to a load using a slip-ring induction machine and a flywheel combination, are disclosed as well as methods relating thereto. In a preferred embodiment, the UPS system comprises a back-up power source, e.g., an engine and generator, and a slip-ring, or wound-rotor, induction motor and flywheel combination, which are in parallel to a primary power source, e.g., a utility grid. During normal operation of the UPS, the primary power source supplies alternating current and voltage to the load and the UPS compensates for voltage drop across the isolating inductor. Moreover, the primary power source keeps the slip-ring induction machine and flywheel in an excited state, i.e., the rotor of the slip-ring induction machine, the shaft of which is shared by the flywheel, is excited above normal synchronous speed.

Abstract: A homopolar radial magnetic bearing includes a single bias coil common to a plurality of pole pieces equi-angular spaced from each other, a plurality of control coils, one control coil being disposed at each pole piece and a rotor being secured to the rotating member. The bias coil and each of the control coils cooperate with each pole piece so as to establish a homopolar magnetic field for rotatably supporting a rotating member. The bias coil is circumferentially disposed about the rotating member and passes through an inside area at one end of each pole piece. A control coil is wrapped around the other end of each pole. In operation, the bias coil establishes a steady state electromagnetic field to suspend the rotating member when it is energized. Each of the control coils are configured so as to be selectively and individually energized to establish another magnetic field that is superimposed on the steady state magnetic field to yield a net magnetic field that suspends and centers the rotating member.

Abstract: An a.c. electrical machine includes a plurality of first elements spaced from each other; a plurality of second elements spaced from each other and interstitially disposed with the first elements; a plurality of electrical windings on each of the first elements providing a current flow in a first direction; and a return for completing a magnetic flux path in a second direction perpendicular to the first direction on successive first elements and through the second elements for generating a force in a third mutually perpendicular direction between the first and second elements.