The article gives general aspects of superconducting alternator, which is noticed as an application of superconductivity on electrical machine recently. A careful consideration is required to design the machine composed of some unique parts. Electrical characteristics of superconducting machine have been found considerably different from conventional machines owing to lack of iron core. Mainly, superconducting alternator has been considered to be useful as large turbo-generator for central power station, but it is expected to be useful as electrical ship propulsion system and as synchronous condensor also. Finally, present status of development is reviewed.
This paper is a review tracing the development of superconductive communication cables. A 1.6mm superconductive coaxial line constructed of Pb conductors and FEP dielectric has been developed, which has the characteristic impedance of 50±0.3 ohms and the attenuation of about 0.6dB/Km at 1GHz and 4.2K. The attenuation up to 4GHz is mainly due to dielectric losses. Superconductive coaxial lines are arranged in a helium conducting tube and refrigerated by liquid helium. The helium tube is insulated thermally from room temperature environment by multilayer insulators, shield conductors and vacuum space. At present, the total heat inflow into cryogen in the refrigerant conductor is about 100W/Km.