Laminate structure suitable for use as electrical insulation comprising: a) a corona-resistant layer comprising 90 to 99 weight percent uniformly distributed calcined mica and 1 to 10 weight percent aramid material, the aramid material being in the form of floc, fibrid, or mixtures thereof; b) a support layer comprising unidirectional or woven filament yarns, the support layer having a first and second face; and c) a resin-compatible layer comprising 60 to 80 weight percent uniformly distributed uncalcined mica and 20 to 40 weight percent aramid material, the aramid material being in the form of floc, fibrid, or mixtures thereof;

wherein the first face of the support layer is directly bound to the corona-resistant layer and the second face of the support layer is directly bound to the resin-compatible layer; the laminate structure having a total mica content of 60 weight percent or greater.

Laminate structure suitable for use as electrical insulation comprising: a) a corona-resistant layer comprising 90 to 99 weight percent uniformly distributed calcined mica and 1 to 10 weight percent aramid material, the aramid material being in the form of floc, fibrid, or mixtures thereof; b) a support layer comprising unidirectional or woven filament yarns, the support layer having a first and second face; and c) a resin-compatible layer comprising 60 to 80 weight percent uniformly distributed uncalcined mica and 20 to 40 weight percent aramid material, the aramid material being in the form of floc, fibrid, or mixtures thereof;

wherein the first face of the support layer is directly bound to the corona-resistant layer and the second face of the support layer is directly bound to the resin-compatible layer; the laminate structure having a total mica content of 60 weight percent or greater.

Various embodiments of the teachings herein include a corona shielding tape for further processing to give an insulation system comprising an impregnated winding with potential control via outer corona shielding AGS and/or internal potential controller IPS and/or terminal corona shielding EGS, the insulation system being producible by impregnating the winding with an anhydride-free and resin-based impregnating agent at 45-85 C. and under reduced pressure. The corona shielding tape may include: a carrier tape; an electrically conductive and/or partly conductive filler in a polymer matrix; and a tape accelerator suitable for curing and/or gelation of the impregnating agent. The polymer matrix contains at least one polyvinylalcohol and/or a polyvinylalcohol copolymer. The accelerator is selected from the group consisting of: superacids and superacid salts suitable for acceleration of a cationic homopolymerization of the resin-based anhydride-free impregnating agent.

An electric wire is disclosed having a metal conductor, a first synthetic heat stable tape layer in direct contact with the metal conductor, wherein the first synthetic heat stable tape layer has a first edge and a second edge, wherein the first edge and the second edge are substantially parallel to one another, wherein the second edge overlaps the first edge by at least 180 degrees on a cross-sectional view, a second synthetic heat stable tape layer, wherein the second synthetic heat stable tape layer is helically wrapped around the first synthetic heat stable layer, a third synthetic heat stable tape layer, wherein the third synthetic heat stable tape layer is helically wrapped around the second synthetic heat stable layer, wherein electric wire contains no silicone, and an extruded layer, wherein the extruded layer is extruded over the second synthetic heat stable tape layer.

An electric wire is disclosed having a metal conductor, a first synthetic heat stable tape layer in direct contact with the metal conductor, wherein the first synthetic heat stable tape layer has a first edge and a second edge, wherein the first edge and the second edge are substantially parallel to one another, wherein the second edge overlaps the first edge by at least 180 degrees on a cross-sectional view, a second synthetic heat stable tape layer, wherein the second synthetic heat stable tape layer is helically wrapped around the first synthetic heat stable layer, a third synthetic heat stable tape layer, wherein the third synthetic heat stable tape layer is helically wrapped around the second synthetic heat stable layer, wherein electric wire contains no silicone, and an extruded layer, wherein the extruded layer is extruded over the second synthetic heat stable tape layer.