Siemens Vacuum Pressure Impregnated (VPI) Medium Voltage Transformers

VPI transformer coils are vacuum pressure impregnated in high temperature polyester varnish. The process includes complete submersion in varnish under vacuum and pressure and regulated curing using statistically process controlled equipment to ensure consistency. The finished coils are effectively protected against moisture, dirt, and most industrial contaminants. VPI transformers are generally suitable for use indoors or outdoors where people work and breathe. A 220˚C Class UL Listed insulation system is used on all VPI transformers regardless of specified temperature rating.

Features and Benefits

The standard temperature rise is 150˚C. Optional temperature rises of 80˚C and 115˚C and fan cooling allow for unsurpassed overload capacity. VPI transformers offer design flexibility and are constantly used for power upgrades and retrofit designs. Special design options:

  • Seismic Qualifications

  • Special Sound Requirements

  • Low X/R Ratios

  • Higher Overload Capacity

  • Special Altitude Requirements

  • Retrofit Designs

  • High Efficiency Requirements

  • Special Ambient Conditions

  • Rectifier Transformer Design


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