Abstract: A procedure when joining the tail ends of sheet-wound coils stacked one on top of the other around an inductive apparatus core with a certain axial space between them, the joint being effected using a thin leader strip which is connected to adjacent parts of the coils and joined to the coils along almost one coil turn.

Abstract: A device for effecting mechanical prestressing in a pair of substantially concentric cylinders, in which the inner cylinder is prestressed in compression and the outer cylinder is prestressed in tension by means of the device in the form of a hose or hoses disposed in a gap between the cylinders and being subjected internally to a pressure medium, the hose or hoses being arranged helically in such a manner that the sum of the moments of the forces thereby caused by the pressure forces between the cylinders and occurring about the central axis of the cylinders in a plane containing such axis, is substantially zero.

Abstract: A direct-cooled layer winding for transformers is formed of a plurality of helically wound tapes, the tapes in successive layers being directed backwards and forwards in the axial direction so that the turns of successive layers form angles with each other. At least one cooling layer is arranged coaxial with the winding between two of the tape layers. The cooling layer is formed of a tubular cooling conductor which is helically wound into a complete layer with the inlet and outlet at the opposite ends of the winding.