Abstract: In order to achieve improved mechanical properties for a coil (1), it is proposed to structure a first electroconductive winding (3) of the coil (1) as a coil former. This coil has a first connecting element (15), to which a second connecting element (17) is attached via an insulating part (25). The two connecting elements (15, 17) form the connections for the coil (1). In this way, a self-supporting coil structure is achieved. The coil (1) is particularly intended as an undervoltage winding with a low number of windings for cast resin transformers.

Abstract: For the production of a cast resin coil consisting of a plurality of axially superimposed flat coils, it is proposed that the corresponding flat coils be first of all produced by winding a first inner partial winding and a second outer partial winding with the interposition of individual spacer members by which sector-shaped intervening spaces are formed. The individual flat coils are then placed together axially and oriented so that their intervening spaces coincide, thus forming axial cooling channels. Moldings are inserted into each of said channels. This is followed by the encapsulation of the assembled flat coils. After the curing of the casting resin, the moldings are removed from the cooling channels. A cast resin coil produced in this manner has an impregnable layer of material, preferably in the region of the cooling channels by which the wall thickness of the cooling channels is predetermined in relation to the corresponding strip conductors.

Abstract: A clamping frame for a transformer core has a clamping frame part and a tensioner. The surfaces of the tensioner and of the clamping frame part abutting the transformer core lie in a common plane. The tensioner features an engagement part, which engages in a recess of the clamping frame part.

Abstract: The invention relates to a method for impregnating and embedding electrical windings, especially coils of transformers, by means of an impregnating or casting resin based upon polyepoxide-polyisocyanate mixtures in the presence of a reaction accelerator latent at the processing conditions, which employs conditions that prevent the formation of gas and shrinkage voids in the cast in winding. To this end, the resin including, if applicable, additives, is dried at reduced pressure and while stirring at temperatures of up to 110.degree. C. and the winding is cast-in with the dried resin at reduced pressure and at temperature of up to 110.degree. C.; then the reduced pressure is removed and the winding is exposed to overpressure. Subsequently, generating by an elevated temperature in the electrical winding by Joule heat in the conductor, the cross-linking reaction of the resin is started and is controlled as a function of the reaction heat, until the winding is removed from the mold and post-hardened.

Abstract: A dry-type transformer cast into casting resin, includes windings, a main leakage canal, at least one of the windings being subdivided into coaxial winding parts spaced apart from each other defining an additional axial cooling canal therebetween, separate inner and outer casting resin bodies each having end faces and being cast around a respective one of the winding parts, reinforcements formed on diametrically opposite outer surface regions of the outer casting resin body for receiving axially extended connecting conductors for electrically wiring the winding parts, line terminals and tap terminals disposed on respective reinforcements, and elastic blocks common to all of the windings and winding parts between which the winding parts of a respective winding are clamped and metallically interconnected in front of the end faces of the casting resin bodies.

Abstract: Multiphase transformer for power distribution in a supply network includes a single block of cast resin having high voltage and low voltage conductor windings embedded therein, and an iron core with a plurality of legs and an upper and lower yoke formed of closely-stacked transformer laminations centrally embedded in the block, the block having axially-extending ribs integral therewith defining troughs between the ribs and defining spaces between the ribs and the core, legs and yokes, watertight caps disposed between the ribs closing off the troughs and holding the core, legs and yokes, and mechanically compacted dry quartz sand filled in the space.