The invention relates to an excitation device for an electric machine having a superconducting load, in which a current control device is provided in the static part of the electric machine. A transmitter comprising a primary winding is provided in the static part of the electric machine and a secondary winding is provided in the rotating part of the electric machine. Said current control device comprises a controllable D.C voltage source. Said D.C voltage of the controllable D.C voltage source is transmitted on the secondary side by means of an inverter, the transmitter and a bridge rectifier, said D.C voltage defining the level of the magnetisation current. Using said magnetisation current level which is predefined by the controllable D.C voltage source, the magnetisation current is controlled by the primary side.