Plate Transformers and VPI (Vacuum Pressure Impregnation) In Detail

Dr. Transformer:  Welcome back to the Power Magnetics Institute, my friends!  Our customers have been asking for a clarification of the VPI and plate transformers post we discussed earlier. Vacuum Pressure Impregnation (VPI) is the process of treating the finished coils with varnish by placing it a vacuum chamber.  First, the transformer is placed in an oven and heated to approximately 275 ˚F. This heat treatment drives out moisture from the[…]

Temperature Rise and Insulation System Ratings

Dr. Transformer:   Welcome back to Power Magnetics Inc. Institute!  Temperature rise and insulation for transformers, reactors and inductors is today’s hot topic.  Your burning questions as a design engineer and these answers can hopefully increase the reliability of your products in the field.  And some of those are deployed in pretty extreme environments, like our Trap Reactors and Current Limiting Reactors and Furnace Transformers.  You can find them in steel mills, deserts of the Middle[…]