Superior Electric 9T92A1Product Attribute Attribute Value Series POWERSTAT Volt Pac Series Type Variable Transformer Overview The Volt Pac variable transformer provides continuously adjustable voltage over a range of zero to either 100% or 117% of the line voltage. Its operation is simple and efficient, and is based on autotransformer action. The Volt Pac coils are precision wound on a toroidally shaped core. One face of the winding is properly smoothed and gold plated to