Resin Rich High Voltage Coil Design Gram Density Optimization

One of the more challenging, and often misunderstood, design decisions in the manufacture of resin rich high voltage coils is selecting the proper ground wall build for the coil. How many layers of tape need to be applied to the coil for a given ground wall thickness? The selection of this proper build is critical to producing a coil that, after pressing, will have the proper ground wall density, and the proper ratio of glass, epoxy and mica, to assure maximum coil performance in the field as well as during the coil validation. This paper will explain how the proper gram density of a ground wall is determined, challenge some of the conventional wisdom, suggest target densities and acceptable ranges, and give examples for various resin rich mica tapes and design requirements. We will also explain how the volume of resin to mica and glass changes with these target densities.