Abstract: Tubular electromagnetic components are mounted on the drive shaft of the ary anode of an X-ray tube and external magnet windings are provided both for maintaining the drive shaft in an axial position corresponding to a working position of the anode and for shifting the drive shaft to open a slip contact at one end thereof, thus providing a magnetic switch for the anode supply voltage. In addition, windings are provided through which a controlled current flows to provide a radially stabilized position for the shaft and thus constitute magnetic bearings that are free of friction. When one of the contacts of the magnetic switch is spring-mounted, the coil that does the switching can also be used to adjust the axial position of the anode so as to work with a different cathode.