Vacuum Pressure Impregnation Plant

Vacuum Pressure Impregnation (VPI) is a process that uses vacuum and pressure to seal porous materials with varnish or resin. The process is used primarily for high-voltage motors and generators to fill gaps in materials to create a void free insulation in various devices.

The Vacuum Pressure Impregnation Process :

AR ENGINEERING specializes in vacuum pressure impregnation, which is more effective than traditional dip-and-bake methods and is better suited to high voltage motors and generators. Our basic vacuum pressure impregnation motor repair process comprises several steps.

Preheating : We place the equipment in an oven that heats the equipment and allows moisture to evaporate. This helps the resin better penetrate the material.

Vacuum Drying : We remove the equipment from the oven and place it into a vacuum chamber, which removes air and any remaining moisture.

Filling : We fill the chamber with resin, coating the part and filling in all the gaps and pores in the piece of equipment.

Wet Vacuuming : We reduce the vacuum levels and hold it for a set period of time.

Pressure/Soaking : We increase pressure within the chamber using dry air, nitrogen, or other gases. This allows for even deeper penetration of the resin.

Draining : We then vent the pressure, drain the chamber of excess resin, and remove the part.

Curing : Finally, the equipment is placed into an oven to cure the resin.

Impregnation Types :

• Varnish Impregnation
• Oil Impregnation
• Casting Impregnation

The Benefits of VPI :

In traditional impregnation, varnishes can lose up to 50% of their volume in the curing process. The reduced volume leads to air pockets and gaps, making it more susceptible to damage and wear. The vacuum used in a VPI creates a more solid structure that can withstand:

• Leaks
• Cracks
• Corrosion
• Moisture

VPI also accommodates longer insulation life and greater heat dissipation. Vacuum pressure impregnation is a more cost-effective solution as it extends the lifetime of products while saving energy.