Thermosyphon cooled superconductor

A machine has a rotor, that can be rotated about an axis, with a superconductive winding that is coupled in a heat-conducting manner to a central coolant area of a fixed heat conducting body proturding into a hollow of the rotor via a winding carrier and a heat contact gas. The coolant area forms a line system with the line parts thereof, that are laterally connected thereto, and a condenser area of a cold unit, in which a coolant circulates in the line system as result of a thermosiphon effect. To maintain the supply of coolant to the central coolant area, even when the rotor encounters difficulties, the coolant area is provided with a lining of a porous material, preferably a sinter material, having high thermal conductivity.