Siemens Vacuum Pressure Encapsulated (VPE) Medium Transformers

VPE transformer coils are vacuum pressure encapsulated in high temperature Silicone varnish to provide the ultimate protection against moisture. The silicone VPE process utilizes a special four cycle procedure that employs the fundamental principles of vacuum pressure encapsulation and curing.

Features and Benefits

Because of the inherent bonding strength of silicone varnish, the finished coating remains smooth and gives superior environmental protection. Coils receive a minimum of 4 cycles of silicone varnish, and the core and clamping structure are coated with a corrosion resistant sealant that guards against moisture and industrial contaminants. Silicone varnish provides excellent dielectric strength that remains pliable even after thermal aging. The silicone varnish is a true 220˚C insulating material tested to above 250˚C. The silicone VPE process utilizes conventional dry type designs and offers optional conductors, BIL levels, and temperature rises with a 220˚C Class insulation system. This advanced process provides the ultimate in overload capacity. The nominal coating of silicone varnish received through the silicone VPE process provides excellent dielectric strength. The varnish has been tested, after immersion in water for 24 hours, and still maintained a dielectric strength of 1500 volts per mil. When cured, the silicone varnish meets, or exceeds, UL 94 VO flammability tests. VPE transformers are available with all the same special design options as VPI units.

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