Vacuum Pressure Impregnation

Inman Electric Motors has a capability that provides the ultimate in rewind quality and electrical performance. That capability is Vacuum Pressure Impregnation or VPI.

Motors, generators, and coils up to seven feet in diameter are processed under vacuum and pressure with solventless epoxy resin to provide void-free electrical windings. The VPI process provides maximum penetration of resin throughout the turns of individual coils.

VPI is greatly superior to solvent varnishes and the conventional “dip and bake” method. Solvent varnishes lose 50% to 70% of volume during baking, leaving voids and air pockets in the windings. A weak sponge-like structure results. VPI provides a 100% solid mass structure that gives you the greatest mechanical strength, a cooler running motor due to superior heat dissipation, and the highest level of environmental protection. A motor winding that undergoes VPI is virtually impervious to oil, moisture, and chemical contaminants. VPI may be used for both A.C. and D.C. stators, armatures, field coils, and applications such as lifting magnets. Large frame motors from 460 volts through 13,800 volts should receive VPI to ensure the longest attainable service life. IEEE and NEMA ME-1 submergence testing is available for all motors that are rewound and VPI processed by Inman Electric Motors.