Abstract: A superconducting field winding for the rotor of an electric machine having several winding sections, the conductors of which each have a predetermined permissible bending radius which is larger than the bending radius provided at the coil heads of the winding section, wherein two associated conductor sections of a winding section are always electrically connected at at least one coil head by means of a prefabricated yoke-like conductor element whereby conductors with relatively large conductor cross section need not be subjected to excessive tensile stresses at the coil heads thereby avoiding damage to their superconducting material.

Abstract: In an electric machine with a superconducting exciter winding and a cylindrical shaft end piece in its rotor around which end piece a nonrotating connector head part is arranged, with at least one bearing and at least one sealing device provided between these components, the radial bearing clearance is made so small that the connector head part follows the radial deflections of the shaft end piece from its ideal position relative to the axis of rotation permitting the use of seals with good sealing properties, in particular ferrofluidic seals.

Abstract: A coolant connecting head for an electric machine which contains a rotor with a superconducting winding, the head including a device for feeding a coolant from a non-rotating coolant line part into a rotating coolant line part, with at least one sealing device for sealing a space forned between these line parts with a pre-determined pressure dependent leakage rate in which, for sealing off the interspace, a further sealing device with an adjustable seal gap formed between the sealing surfaces thereof is provided so that, during the cooling down phase of the winding, the coolant leakage rate can be kept low with this further sealing device.

Abstract: A cooling arrangement for the rotor of an electric machine having a superconducting field winding includes a co-rotating mixing chamber, a coolant distribution system arranged at the outer circumference of the winding, and radial cooling canals passing through the winding as well as coolant connecting lines outside the winding, in which the coolant flows through the cooling canals due to self-pumping. The coolant connecting lines have thermally insulating end sections which protrude further into the coolant distribution system from the rotor axis than the inlet openings of the cooling canals, so that a coolant flow direction from the outside-in, through the cooling canals, is fixed in an advantageous manner.

Abstract: A cooling arrangement for the rotor of an electric machine having a superconducting field winding and a co-rotating mixing chamber containing a phase mixture of a coolant has a coolant distribution system arranged at the outer circumference of the field winding which feeds coolant into cooling canals through the field winding into the mixing chamber. There are also corresponding coolant connecting lines outside the winding, at least one coolant feed line connected to the coolant distribution system for supplying coolant from the outside, and a discharge for the gaseous coolant at a pressure below 10.sup.5 Pa. In this cooling arrangement, cooling of the field winding is advantageously brought about by self-pumping. Simple and effective cooling-down is achieved.

Abstract: An arrangement for cooling an electric machine such as a turbo generator having a rotor with an excitation winding which must be cooled to a low temperature, the excitation winding concentrically surrounded by a cooled damper winding in which separate cooling loops are provided for cooling the excitation winding, the damper winding and the current supply and/or discharge lines to permit the refrigeration power necessary to remove losses to be adapted to the actual losses in the machine and to be kept relatively small.

Abstract: An improved rotor for an electric machine, particularly for a synchronous machine, comprising a field winding cooled to a low temperature in which the rotor includes a concentric, hollow, cylindrical support body having internal slots on its inside for accommodating the field winding so that the winding can be placed in the slots in a simple manner and the windings retained more securely therein.

Abstract: In a current feeding device for conductors which are cooled to a low temperature, the conductors being connected to a cooled normal conductor which consists of metal netting, metal net with constant conductor cross section over its entire axial length is employed and has connected thereto in an electrically conducting manner a predetermined number of conductor elements of predetermined conductor cross section permitting simple metal netting with a large heat exchange area to be used for the normal conductors while allowing the conductor cross section of the normal conductor to be optimized with respect to minimum heat loss.

Abstract: A cooling arrangement for the rotor of an electric machine with longitudinal slots having disposed therein exciter winding sections which must be cooled to a low temperature, the arrangement having a feed and discharge line, in which a multiplicity of individual cooling canals running in the circumferential direction and a multiplicity of individual radial coolant feed lines and/or discharge lines are provided for each winding section over its axial length so that the cooling arrangement can be optimized with regard to the thermodynamic pressure losses of the coolant, its temperature rise and the heat transfer conditions while at the same time achieving a favorable space factor of the conductor material within the slots.

Abstract: This invention concerns an improvement in a fluid contact arrangement employed in a DC machine. The invention provides a contact fluid which is interposed between the rotor and the stator of the machine. The fluid is ferromagnetic. Further, the invention provides a magnetic field which is directed perpendicular to the air gap. The effect of the magnetic field on the ferromagnetic contact fluid is such that the fluid is retained within the gap both when the rotor is at a standstill and when it operates at its normal speed.