Vacuum – pressure – impregnation plants are used for the construction and repair of a large variety of electrical appliances.

To insulate electric motors and other electrical appliances correctly, VPI impregnation (Vacuum – Pressure – Impregnation) is used.

This technique is also used to fill any porosity present in aluminium and other metal cast parts (engine boxes and gear boxes, car rims, etc.).

The parts to be impregnated are put into an impregnation tank, which can have a diameter of up to 3 meters and a capacity of up to 50 cubic meters.

The vacuum is then applied so that no air ‘pockets' are present between windings, and the part is then immersed in varnish or resin, which enters the impregnation tank from below.

When the part is immersed in the resin, pressure can be applied, up to 8 bars, on the surface of the liquid, which forces the resin to completely fill the pores.