METHOD AND DEVICE FOR MEASURING AT NITROGEN TEMPERATURES THE AC LOSSES IN HIGH TEMPERATURE SUPERCONDUCTIVE BANDS

摘要

The method and the device find application in the power industry, transport, the electrical industry, in space research, in telecommunications and in medicine. The device comprises a cooling unit supported by a thin-walled stainless tube, which by a conical connection is aligned into a vacuum housing, and by means of a heat bridge is connected to a stationary unit, found in heat contact with two plates connected in series having ratio of the heat conductivity coefficient over three orders. On the plate having small heat conductivity, are mounted measuring thermometers, and on the high conductivity plate - an imitation heater and superconductive specimen-band. The two-part radiation screen surrounding the two plates with a division bushing at the level of the connection of the two plates is dismantably mounted on the stationary unit. Two proportional integral differential temperature regulators, connected to a reverse and differential connection, respectively to temperature sensors and heaters, mounted respectively on the stationary unit, and on the screen and the plate, carrying the superconductive specimen are used for stationing the desired temperature in the nitrogen temperature field, and for forming quasidiabatic conditions, respectively. The method is realized by the comparison of the temperature differences measured of a plate of low heat conduction, formed, respectively, by heat flows, generated by the dissipation energy in the superconductor in running of transportation current across it, and by heat flows, admitted across an imitation electric heater. The DC losses in the superconductive band are determined by the imitation heat flow, forming the same temperature difference under identical experimental conditions like the heat flow generated by the dissipation energy.