Spiral windings

Abstract

Several embodiments of coil assemblies suitable for a variety of uses are disclosed herein all of which employ spiral windings which minimizes coil layer-to-layer voltage gradients to levels which conventional enamel wire insulation is able to withstand. In one embodiment a spiral winding is fabricated in strip form using a continuous strand of wire secured to a continuous ribbon-like substrate by an adhesive composition which may be provided on the wire so as to form a plurality of spiral windings on segments or portions of the substrate, each winding having one turn in each radial layer. The substrate will include other segments located between each winding portion to provide insulating means for the spiral windings and for the transition of the wire as it passes to the next successive winding containing segment. These spiral windings may be fabricated in elongated strips and coiled for storage upon a cylindrical spool or the like, so as to allow any desired number of winding and insulating segments to be subsequently selected and folded in such a manner as to place an insulation segment between each winding portion which may then be impregnated with an epoxy composition. These spiral windings are particularly suitable for use with such improved core structures as the highly efficient ferrite 'pot' core types wherein several hundred volts per turn may be developed.