A rotor form electric machine is provided including a rotor body that rotates about an axis of rotation, the rotor body having a superconducting rotor winding and cooling arrangement provided for cooling the rotor winding having at least one pair of cooling tube loops disposed substantially radially opposite each other on the rotor body, wherein a cryogenic coolant is transported in the axial direction in the coolant tube loops from a first axial rotor end to a second, opposite axial rotor end and back when the rotor rotates about the axis of rotation. One or more connecting tubes are provided in the cooling arrangement and connect one cooling tube loop to the other cooling tube loop of the at least one pair of cooling tube loops.