Cooling system for rotors of electric machines, especially for turbo-generator rotors with a superconductive field winding

Cooling system for a rotor of an electric machine having a superconductive field winding and formed of a rotor drum with at least one outer, substantially hollow cylindrical rotor body with a co-rotating cold shield, an inner hollow rotor body fastened at given locations within the outer rotor body so as to be thermally insulated and serving as a coil-winding support, the fastening locations at the outer rotor body being cooled, and a co-rotating mixing chamber located at the inner periphery of the inner hollow rotor body and containing a phase mixture of a coolant fed thereto from the outside, the phase mixture forming, during rotation of the rotor, a radially outwardly flung liquidring and a radially inner vapor column coaxial thereto, including channels for conducting a first coolant flow with liquid coolant from the mixing chamber for cooling the field winding and a second coolant flow with at least partly vaporized coolant for cooling the fastening locations and for returning the first coolant flow, after it has traversed the field winding, back to the mixing chamber and for discharging the second coolant flow out of the electric machine.