A dielectric material with heat transfer properties includes a first fluid and a second fluid different from the first fluid and miscible with the first fluid. The first fluid and the second fluid are mixed with each other so as to form a mixture and are kept at a temperature and a pressure so that the mixture is maintained in a supercritical phase. The mixture has at least one parameter that is preferably different from a corresponding parameter in both a supercritical phase of the first fluid and a supercritical phase of the second fluid. In a method of insulating electrical contacts and removing heat therefrom, the mixture is disposed about the electrical contacts and is maintained at a temperature and at a pressure that causes the mixture to be in a supercritical phase so that the mixture has favorable dielectric and heat transfer properties.

An electrical cable comprising a conductor and a foamed insulation surrounding the conductor is disclosed. The foamed insulation has a uniform void size and an improved adhesion to the conductor. Electrical cables having a conductor thickness less than 22 mil are also disclosed.

The present invention relates to compositions comprising at least one thermoplastic polyurethane TPU-1 based on an aliphatic diisocyanate, at least one metal hydroxide and at least one phosphorus-containing flame retardant, especially those compositions which further comprise at least one thermoplastic polyurethane TPU-2 based on an aromatic diisocyanate. The present invention further relates to the use of such compositions for production of cable sheaths.

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.

Disclosed herein are embodiments of high Q, temperature stable materials with low dielectric constants. In one aspect, a low loss dielectric material includes one or more transition metal oxides based on the (Zn, Ni, Co)OAl.sub.2O.sub.3TiO.sub.2 system comprising an aluminate comprising one of cobalt (Co) or nickel (Ni) crystallized in a spinel structure. The low loss dielectric material additionally comprises one or more of: a titanate comprising the one of Co or Ni crystallized in a spinel structure, an aluminum oxide and a titanium oxide crystallized in a rutile structure.

A cable includes an inner conductor and a dielectric layer extending around the inner conductor. The dielectric layer includes a linearly-stretched polypropylene film having a porous structure that includes a plurality of pores that extend through a thickness of the linearly-stretched polypropylene film. The dielectric layer includes air molecules trapped within the pores of the linearly-stretched polypropylene film such that the dielectric layer includes polypropylene and air. The cable includes an outer conductor extending around the dielectric layer.

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 m.