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: Method of manufacturing a transformer winding embedded in casting resin by winding coils respectively by themselves and independently of one another for disposition thereof in tandem in axial direction of the winding includes placing the wound coils in a substantially annular casting mold having an inner and an outer jacket, with respective impregnated corrugated mats of insulating material as spacers disposed between the inner jacket and the coils as well as between the coils and the outer jacket, the inner and the outer jackets being fixed between mold end walls at respective ends of the casting mold; and disposing the casting mold containing the wound coils in an evacuated chamber and pouring casting resin into the casting mold through an axially parallel slot formed in the outer jacket thereof.

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.