Abstract: A rotor assembly, including at least one driven member, e.g., a compressor rotor, and at least one driving member, e.g., a turbine. At least one rotating thermal insulator rigidly attached to either the driven member or the driving member. A coupling feature that includes mating geometric surfaces on the driven member and the driving member, wherein the geometric surfaces are configured to allow radial sliding, relative centering, torque transmission, and axial constraint between the driven member and the driving member.

Abstract: A rotor assembly, including at least one driven member, e.g., a compressor rotor, and at least one driving member, e.g., a turbine. At least one rotating thermal insulator rigidly attached to either the driven member or the driving member. A coupling feature that includes mating geometric surfaces on the driven member and the driving member, wherein the geometric surfaces are configured to allow radial sliding, relative centering, torque transmission, and axial constraint between the driven member and the driving member.

Abstract: Potentially very high power ratings can be achieved from rotary electrical generators in which permanent magnet rotor stages using modern high intensity magnetic materials, for example cobalt samarium or neodymium boron iron. The machine described comprises a plurality of axial field rotor stages each comprising a plurality of magnet segments arranged around a driven hub in a pre-stressed assembly in which encompassing hoop means exerts sufficient compressive stress on the magnets and hub assembly to counter centripetal forces generated by speeds of up to 100,000 rpm. Alternative methods of stressing the hoop means is described.