AIR
TRANSFORMERS

Our VPI transformers are suitable for environmentally friendly installations with minimal flammable material content. Such special features are not new for GBE, which has been offering its own “Environmental Line” for several years.

The core is composed of grain oriented magnetic laminations with high magnetic permeability. They are cut at 45° and use step lap construction for standard production, or they are cut at 90° with butt joint construction for special versions that require low inrush currents and high magnetizing currents.

Various solutions are adopted to make medium-voltage windings. Subcoil, layered or disk windings are available, depending on the insulation class and application type. Class F and/or H insulating material is used to guarantee high temperatures with small sizes. Both windings are vacuum impregnated with high-cementation class H coatings.

All VPI production has a very small flammable material content compared to resin-encapsulated products, and especially compared to transformers with mineral oil insulation. The energy capacity in kWh or kCal of air transformers is 3–4 times lower than that of resin versions for the same power rating. Despite a greater initial purchase cost, this allows a significant saving when constructing the machine installation site because of the lower REI rating required in the event of a fault or fire.

This type of transformer can be supplied with protection boxes having the desired IP rating. The casings are painted with epoxy coatings of the required RAL (RAL 7032 is standard) with pickled or galvanized sheet metal for outdoor installation.