An apparatus includes a strength member including a core formed of a composite material, and an encapsulation layer disposed around the core. A conductor layer is disposed around the strength member. A coating is disposed on the conductor layer. The coating is formulated to have a solar absorptivity of less than 0.5 at a wavelength of less than 2.5 microns, and a radiative emissivity of greater than 0.5 at a wavelength in a range of 2.5 microns to 15 microns, at an operating temperature in a range of 60 degrees Celsius to 250 degrees Celsius. The coating may have an erosion resistance that is at least 5% greater than an erosion resistance of aluminum or aluminum alloys.

A flame retardant is included in a resin phase, and the flame retardant has a maximum number frequency in a range of 1 μm or less when a particle size distribution is evaluated by dividing a particle size into 1 μm increments. The resin phase includes inorganic particles, and the inorganic particles have a maximum number frequency in a range of 0.5 μm or less when the particle size distribution is evaluated by dividing the particle size into 0.5 μm increments. The flame retardant has an average particle size larger than the average particle size of inorganic particles. The number frequency of the flame retardant and the inorganic particles, respectively, decreases with increasing the particle size.

Thermally conductive electrically insulating compositions and structures and devices comprising such materials. In various embodiments, such materials comprise liquid crystal polymer and fillers, wherein the fillers comprise boron nitride and glass fiber. In various embodiments, the liquid crystal polymer is selected from the group consisting of semi-aromatic copolyesters, copolyamides, polyester-co-amides, and mixtures thereof.

Various applications of the teachings of the present disclosure include a powder coating formulation suitable for producing an insulation system of an electrical machine. The formulation may include: a curable resin mixture; and spherical SiO.sub.2 filler particles having a maximum particle diameter of 100 μm.

A dielectric high gradient insulator device comprises a stack of at least two dielectric layers which are in physical contact with each other and which have different dielectric constants. At least two dielectric layers are configured to form a shaped electric field, when the device is placed between electrodes having a voltage difference. The shaped electric field is in a region proximal to a surface of the at least two dielectric layers, and causes deflection of negatively charged particles away from the surface, thereby inhibiting voltage breakdown of the device. A method of manufacturing the device is also presented.

A flame resistant electrical insulating material comprises glass fibers, a particulate filler mixture, and an inorganic binder, wherein the electrical insulating material has a UL-94 flammability rating of V-0, 5VA and a thermal conductivity of less than 0.15 W/m-K. The particulate filler mixture comprises at least two particulate filler materials selected from the list of glass bubbles, kaolin clay, talc, mica, calcium carbonate, and alumina trihydrate. In an exemplary aspect, the insulating material is not punctured after direct exposure to 2054° C. (3730° F.) flame for at least 10 minutes.

A production method for a treatment solution for forming an insulating coating. The method includes mixing a solution A containing, on a PO.sub.4.sup.3− basis, 0.20 mol/L or more and 10 mol/L or less of at least one of (i) phosphoric acid and (ii) a phosphate salt, and containing, on a metal basis, less than 0.50 mol/L of one or more particulate metal compounds, and a solution B containing, on a metal basis, 0.50 mol/L or more and 20.0 mol/L or less of the one or more particulate metal compounds, and containing, on a PO.sub.4.sup.3− basis, less than 0.20 mol/L of at least one of (i) phosphoric acid and (ii) a phosphate salt, and stirring with a turbine stator-type high-speed stirrer such that a peripheral speed of a turbine reaches 10 m/s or more within 60 seconds after starting the mixing of the solution A and the solution B.

Disclosed is a polymer-ceramic composite, comprising: ceramic particles within a polymer matrix; wherein greater than or equal to about 70% of the ceramic particles by volume experience ceramic particle to ceramic particle contact; wherein a dielectric strength of the composite is greater than or equal to about 300 kilovolts per millimeter; and wherein a thermal conductivity of the composite is greater than or equal to about 10 watts per meter kelvin.

An electronic switch for a DC voltage system includes at least two turn-off semiconductor switches, a varistor and a capacitor, and at least two diodes connected in series with opposite polarity. The turn-off semiconductor switches are connected at a connection point in series with opposite polarity between a first connection of the electronic switch and a second connection of the electronic switch. In order to provide improved overvoltage protection, the varistor and the capacitor form a series connection, with one end of the series connection connected to the connection point. A DC voltage system employing the electronic switch and a method for limiting overvoltages in the electronic switch or in a corresponding DC voltage system are also disclosed. Inductive energy of an element connected to the electronic switch is transferred to the capacitor when a limit, defined by the varistor, has been exceeded.

A conductor assembly including an electrically conductive material defining a longitudinal axis, a microporous membrane surrounding the electrically conductive material defining a series of pores, and a ceramic material within at least a first portion of the series of pores.