The goal of vacuum pressure impregnation is complete saturation of a winding with insulating resin. As resin penetrates the insulating materials, it causes them to darken. If some insulation is a lighter shade, the coil or jumper is not fully saturated. The winding is not properly protected, and if the problem is not addressed, it is likely to cause premature failure of the unit. This could result in costly warranty work, or at a minimum, will be a failure to provide your customers with the quality they expect and deserve.

El objetivo de la impregnación por vacío y presión (VPI) es saturar completamente un devanado con resina aislante. A medida que la resina penetra en los materiales aislantes, los oscurece y al drenar la resina VPI del devanado, todo el aislamiento de las cabezas queda oscuro en un tono uniforme. El aislamiento de la conexión también debe quedar oscuro de forma pareja. Si algún aislamiento muestra un tono más claro, la bobina o el puente no han quedado completamente saturados y el devanado no está debidamente protegido. Si no se soluciona el problema, es probable que esto provoque un fallo prematuro en el equipo. Esto podría generar una garantía costosa o, como mínimo, la reparación no brindará a sus clientes la calidad que esperan y merecen.

One of the most briskly debated issues in our industry is the comparison – and procedures for – vacuum pressure impregnation (VPI) versus dip & bake. For this article, the discussion has been expanded to include trickle epoxy and B-stage coils.

Uno de los temas más debatidos en nuestra industria es la comparación y los procedimientos de impregnación a presión al vacío (VPI) versus inmersión y horneado. Para este artículo, la discusión se ha ampliado para incluir bobinas de etapa B y epoxi de goteo.

This paper, presented at the 2014 EASA Convention, describes research done by EASA service shops on the effectiveness and practicality of using offline partial discharge combined with a dielectrics characteristic test to evaluate the consolidation of stator windings in medium voltage machines manufactured by GVPI.

There seems to be a long and never ending list of equipment and facilities needed by most EASA service centers. But often we are constrained by cost, available space, and more urgent priorities that keep us from fulfilling some of these needs. One such (almost mandatory) need is a vacuum pressure impregnation (VPI) system. Normally there are two ways to provide this service. One way is to have another EASA service center do the VPI process for you. Another is to buy your own system at a considerable capital investment. There is also another option. We decided that the way to provide VPI processing was to build our own system. Most EASA service centers have a talented collection of people with numerous skills. Ours is no exception. We felt that we had the skills in house to do the job. All we needed was some hardware and to do a bit of research into how the process works