Pigmented polyester magnet wire for high-temperature operation

This work was done to develop a conductor insulation with good space factor and winding properties, capable of operating at 1,000 degrees Fahrenheit (538 degrees centigrade). A flexible, clean-burning polyester resin was used as a binder for a glass frit and a refractory in a wire enamel composition. The polyester resin contributes sufficient flexibility to the enamel to wind it into equipment. After completion of the winding operation, the organic portion of the magnet wires is burned out and the glass frit is fused to bind the refractory. The resulting insulation is not a continuous film, and air breakdown values are obtained.