Insulated coil and coiled frame and method for making same

An insulated electrical coil comprising:

• a length of metal strip with electrical termination leads at the strip ends;
• the strip being helically wound on itself, with to form a plurality of turns of the strip being in a side-by-side relation with the turns adjacent thereto to define a central pole opening extending longitudinally along the coil between opposite sides of the coil;
• a coating of polymeric insulating material carried on the strip and applied as a powder to the strip while in a loosely wound configuration and heated to cure the coating on the strip material when pressed into a wound coil configuration to form a solid coil body;
• and
• a pair of preformed bobbins of electrical insulating material pressed on the coil, one of said bobbins being fitted on each of the opposite sides of the coil and covering the respective sides of the coils, with each of said bobbins having a base portion having an inner surface at respective sides of the coil, an outer peripheral flange that projects from the base portion of the bobbin and extending around the coil, and an inner flange that projects from the base portion and into the central pole opening of the coil along the inner surface thereof,
• the outer peripheral flanges of the bobbins extending parallel to a longitudinal axis of the coil toward each other, but stopping short of each other, whereby the sides of the coil are ground insulated by the bobbins and a substantial length of the coated strip coil intermediate the bobbins being uncovered by the bobbins.