The VPE (Vacuum Pressure Encapsulated) transformer was developed to meet stringent shipboard applications for the U.S. Navy. ABB uses a multiple sealant process on VPE transformers, which provides enhanced protection against moisture, salt air, dust, and industrial contaminants. The sealing process uses resin, which provides excellent dielectric strength and extended life expectancy. VPE transformers provide excellent mechanical and short circuit strength, no danger of fire or explosion, less weight than comparable cast coil units.
VPI (Vacuum Pressure Impregnated) transformers are vacuum pressure impregnated with a high temperature polyester varnish. VPI ventilated dry type transformers are designed to meet most commercial and industrial applications. VPI transformers provide excellent mechanical and short circuit strength, no danger of fire or explosion, and no liquids to leak.