Abstract: An insulator for electrically insulating an electrical conductor. The insulator includes a roll defining a central longitudinal through hole along a longitudinal axis of the insulator. The through hole is arranged for allowing an electrical conductor to pass there through. The insulator also includes at least one shed arranged on an outer surface of the roll. The shed includes a shed tip having an outer non-flat curvature defined by a plurality of different radii of curvature and including a most distal point of the shed. An end radius of curvature at the most distal point of the curvature is larger than a first radius of curvature at one side of the most distal point and a second radius of curvature at the other side of the most distal point.

Abstract: A high-voltage column current transformer comprising a column insulating body and a head arranged thereon is disclosed, whereby the head defines a volume and comprises arranged therein a primary winding conductor, a secondary winding core assembly having secondary winding leads and a conical insulator spacer tapered from a base to an apex with a lateral face therebetween, the conical insulator spacer is arranged with its base on a bottom of the head facing the column insulating body and its apex holds the secondary winding core assembly distant from a wall of the head, the conical insulator spacer comprises at least one ring-shaped electrode embedded in and surrounding the base and another flat, circular shaped electrode embedded in and surrounded by the apex, and the conical insulator spacer comprises at least one opening in the lateral face.

Abstract: A composite insulator includes an insulating elongated core, a protective layer surrounding the elongated core, the protective layer including an outer surface with a shed profile and an adhesive primer layer disposed between the elongated core and the protective layer for adhering the protective layer to the elongated core, the adhesive primer layer including a coupling agent and particles of a low resistivity material. The method for producing a composite insulator includes preparing a first solution including a solvent, a coupling agent and particles of a low resistivity material, applying the first solution on at least a part of an envelope surface of an insulating elongated core and thus forming one or more first adhesive primer layers and applying a protective layer onto the first adhesive primer layer on the elongated core, wherein the protective layer includes an outer surface with a shed profile.

Abstract: A pressboard for high-voltage devices is disclosed. The pressboard has a density of 0.6-1.3 g/cm3 according to IEC60641-2, and includes 1-15% microfibrillated cellulose (MFC) based on the total dry weight of the pressboard. The pressboard also includes an insulation element. For example, the pressboard is impregnated with an electrically insulating compound. The insulation element may be used in a high-voltage device, such as a power transformer.

Abstract: The present disclosure relates to an electrical insulator, for an inductive device filled with an electrically insulating cooling fluid. The insulator defines a plurality of internal channels for allowing the fluid to flow there through to improve circulation of the fluid within the inductive device.

Abstract: The present disclosure relates to an electrical insulator, for an inductive device filled with an electrically insulating cooling fluid. The insulator defines a plurality of internal channels for allowing the fluid to flow there through to improve circulation of the fluid within the inductive device.

Abstract: There is provided a pressboard for high-voltage devices, the pressboard having a density of 0.6-1.3 g/cm3 according to IEC60641-2, and including 1-15% microfibrillated cellulose, MFC, based on the total dry weight of the pressboard. There is also provided an insulation element including such pressboard, wherein the pressboard is impregnated with an electrically insulating compound. There is also provided use of such insulation element in a high-voltage device as well as a high-voltage device comprising such insulation element, wherein the high-voltage device may be a power transformer.

Abstract: An insulator for electrically insulating an electrical conductor. The insulator includes a roll defining a central longitudinal through hole along a longitudinal axis of the insulator. The through hole is arranged for allowing an electrical conductor to pass there through. The insulator also includes at least one shed arranged on an outer surface of the roll. The shed includes a shed tip having an outer non-flat curvature defined by a plurality of different radii of curvature and including a most distal point of the shed. An end radius of curvature at the most distal point of the curvature is larger than a first radius of curvature at one side of the most distal point and a second radius of curvature at the other side of the most distal point.

Abstract: A composite insulator includes an insulating elongated core, a protective layer surrounding the elongated core, the protective layer including an outer surface with a shed profile and an adhesive primer layer disposed between the elongated core and the protective layer for adhering the protective layer to the elongated core, the adhesive primer layer including a coupling agent and particles of a low resistivity material. The method for producing a composite insulator includes preparing a first solution including a solvent, a coupling agent and particles of a low resistivity material, applying the first solution on at least a part of an envelope surface of an insulating elongated core and thus forming one or more first adhesive primer layers and applying a protective layer onto the first adhesive primer layer on the elongated core, wherein the protective layer includes an outer surface with a shed profile.

Abstract: The present disclosure relates to a filled silicone rubber material 2 including at least 20 wt % of alumina tri-hydrate as a filler 4 dispersed in SiR 5 to below the percolation threshold. The ATH is a mixture of a first ATH powder and a second ATH powder. The particle size distribution of the first and second ATH powders are such that the d90 value of the second ATH powder is less than the d10 value of the first ATH powder. The disclosure also relates to an insulator 1 made from the filled SiR material 2, and to a use of the insulator in a high-voltage direct current application.

Abstract: The present disclosure relates to a filled silicone rubber material 2 including at least 20 wt % of alumina tri-hydrate as a filler 4 dispersed in SiR 5 to below the percolation threshold. The ATH is a mixture of a first ATH powder and a second ATH powder. The particle size distribution of the first and second ATH powders are such that the d90 value of the second ATH powder is less than the d10 value of the first ATH powder. The disclosure also relates to an insulator 1 made from the filled SiR material 2, and to a use of the insulator in a high-voltage direct current application.

Abstract: A method for melting steel in an electric arc furnace (EAF). A hot heel is provided in the EAF. Metal scrap is loaded into the EAF. The metal scrap is melted in the EAF. The mass of the hot heel in relation to the mass of the metal scrap that is initially beyond the surface of the hot heel is a certain minimum. This minimum is 0.75 times the relation between the heat required to melt the metal scrap beyond the surface of the hot heel and the heat that can be taken from the hot heel without it being solidified when a theoretical heat balance calculation is applied as defined in a formula.

Abstract: An apparatus for electromagnetic stirring of the steel melt in an electrical arc furnace includes two electromagnetic stirrer units, a current supply, and a control unit. The two stirrers are mounted on an outer bottom surface of the electrical arc furnace at opposites sides of a central position of the bottom surface, the current supply is operatively connected to the two electromagnetic stirrer units, and the control unit is operatively connected to the current supply to control the operation of the two electromagnetic stirrer units.

Abstract: A method for melting steel in an electric arc furnace (EAF). A hot heel is provided in the EAF. Metal scrap is loaded into the EAF. The metal scrap is melted in the EAF. The mass of the hot heel in relation to the mass of the metal scrap that is initially beyond the surface of the hot heel is a certain minimum. This minimum is 0.75 times the relation between the heat required to melt the metal scrap beyond the surface of the hot heel and the heat that can be taken from the hot heel without it being solidified when a theoretical heat balance calculation is applied as defined in a formula.

Abstract: An apparatus for crystallization of silicon includes a crucible for containing silicon, a heating and heat dissipating arrangement provided for melting the silicon contained in the crucible and for subsequently solidifying the molten silicon, and an electromagnetic stirring device provided for stirring the molten silicon in the crucible during the solidification of the molten silicon. A control arrangement is provided for controlling the heating and heat dissipating arrangement to solidify the molten silicon at a specified solidification rate and for controlling the electromagnetic stirring device to stir the molten silicon in response to the specified solidification rate of the molten silicon such that the ratio of a speed of the molten silicon and the specified solidification rate is above a first threshold value.

Abstract: An apparatus for crystallization of silicon includes a crucible for containing silicon, a heating and heat dissipating arrangement provided for melting the silicon contained in the crucible and for subsequently solidifying the molten silicon, and an electromagnetic stirring device provided for stirring the molten silicon in the crucible during the solidification of the molten silicon. A control arrangement is provided for controlling the heating and heat dissipating arrangement to solidify the molten silicon at a specified solidification rate and for controlling the electromagnetic stirring device to stir the molten silicon in response to the specified solidification rate of the molten silicon such that the ratio of a speed of the molten silicon and the specified solidification rate is above a first threshold value.

Abstract: An apparatus for electromagnetic stirring of the steel melt in an electrical arc furnace includes two electromagnetic stirrer units, a current supply, and a control unit. The two stirrers are mounted on an outer bottom surface of the electrical arc furnace at opposites sides of a central position of the bottom surface, the current supply is operatively connected to the two electromagnetic stirrer units, and the control unit is operatively connected to the current supply to control the operation of the two electromagnetic stirrer units.

Abstract: An apparatus for crystallization of silicon includes a crucible for containing silicon, a heating and heat dissipating arrangement provided for melting the silicon contained in the crucible and for subsequently solidifying the molten silicon, and an electromagnetic stirring device provided for stirring the molten silicon in the crucible during the solidification of the molten silicon. A control arrangement is provided for controlling the heating and heat dissipating arrangement to solidify the molten silicon at a specified solidification rate and for controlling the electromagnetic stirring device to stir the molten silicon in response to the specified solidification rate of the molten silicon such that the ratio of a speed of the molten silicon and the specified solidification rate is above a first threshold value.

Abstract: An apparatus for crystallization of silicon includes a crucible for containing silicon, a heating and heat dissipating arrangement provided for melting the silicon contained in the crucible and for subsequently solidifying the molten silicon, and an electromagnetic stirring device provided for stirring the molten silicon in the crucible during the solidification of the molten silicon. A control arrangement is provided for controlling the heating and heat dissipating arrangement to solidify the molten silicon at a specified solidification rate and for controlling the electromagnetic stirring device to stir the molten silicon in response to the specified solidification rate of the molten silicon such that the ratio of a speed of the molten silicon and the specified solidification rate is above a first threshold value.

Abstract: An electric insulation material for an electric device includes one or several electrical conductors and an electric insulation material arranged around the conductor or between the conductors, which insulation material is impregnated with a dielectric insulation liquid. The electric insulation material includes a main layer that is provided with a surface layer that has a dielectric constant that is lower than the dielectric constant of the main layer.