Abstract: A turbo-generator with a rotor winding includes a plurality of slots in which the rotor windings are inserted and a plurality of slot wedges, at least two slot wedges lying in each slot on the outside of the winding and being electrically connected with each other. A plurality of relatively thin pressure tubes of a deformable material such as copper are positioned in the slots between the wedges and the windings. Thereafter, the pressure tubes are supplied with a thermosetting resin through feed tubes, the resin being supplied at a sufficient pressure and in a sufficient amount to produce an expansion of the space within the tube by at least 50 per cent. The feed tube is then subjected to heat in a localized area, thus accelerating the curing of the resin in this area of the tube and forming a plug, after which the supply of pressure to the pressure tube is disconnected. After the resin in the pressure tube has hardened, the feed tube is removed.

Abstract: An object of silicon steel, such as sheet and strip for motors, generators and transformers, which has an insulating coating of silicate, is provided with a solution of phosphate by applying to the silicate-coated object an aqueous solution containing phosphate ions and complex metal-ammonia ions and heating the coated object to a temperature of at least about 550.degree.C for a time sufficient to anchor the resulting phosphate layer to the silicate coating. The solution has a pH-value of at least 9, and consists essentially of monophosphate ions. The metal ions are cupric ions and/or chromic ions. An insoluble filler may be added to the aqueous solution.

Abstract: A semiconductor device is formed of a box having a bottom and a lid, formed of metallic material and each maintaining an electrical contact with one side of the semiconductor disc. The bottom and lid are each connected to a ring of insulating material. A metal ring is positioned between and secured to the rings of insulating material. A control electrode is secured at its ends to the metal ring and extends substantially diametrically thereacross. The control electrode has a projecting contact part which is in engagement with one side of the semiconductor disc and is of such height as to be held by the control electrode in pressure contact with such side.

Abstract: A steel object, such as sheet and strip for motors, is provided with a heat-resistant, electrically insulating coating in the form of a layer of calcium titanate. An intermediate layer of silicate may be provided between the steel surface of the object and the layer of titanate. The intermediate layer is preferably a silicate of one or more alkaline earth metals or of aluminum, and especially a silicate of magnesium.The coating of calcium titanate may also contain a vanadium compound. Likewise, a layer of phosphate may be provided on the outside of the layer of titanate.