Use of alumina paper for strain relief and electrical insulation in high-temperature coil windings

A coil comprising:

• a conductor formed in the shape of winding layers, the conductor comprising an insulating coating surrounding a conductive core;
• and
• a coil core having a shape defining corners;
• winding layers disposed around the coil core;
• and
• paper disposed between the winding layer adjacent the coil core and the coil core at the corners, and between winding layers, the paper comprising aluminum dioxide fibers or strands disposed between one or more of the winding layers to provide both strain relief against mechanical forces exerted on the coil and electrical insulation between winding layers at temperatures up to 550 degrees C.;
• and
• adhesive material, wherein the paper and the adhesive material are disposed between adjacent winding layers,
• wherein the adhesive material is disposed between an outer surface of the coil core and the paper.