Among the elements applied for impregnation is the silicone resin, which is generally only used in the case of specific machines designed for very high temperatures. The varnishes and resins improve the thermal and electrical characteristics of the materials used, being attributed to them, a thermal class superior to the impregnated materials, compared to the same materials without impregnation.
Two types of varnishes and two types of impregnating resins, all of which are based on polyester, are normally used to fill all possible constructive and application needs of the engines. The impregnation varnishes and resins have as main objective to conserve together all the enamelled wires that are in the coil with all the components of the stator and filling the voids within the groove.
It is important to remember that the connection of the wires has the capacity to prevent them from vibrating and striking each other. Friction can cause wire enamel to fail, resulting in a short circuit. Removal of the voids helps in the thermal dissipation of the heat caused by the driver and, especially in applications of motors fed by frequency inverters, can avoid or even reduce the partial discharges, known as corona effect, that occurs in the engine.