Trickle impregnating with polyester resin to maximize the quality of wound components in high volume production lines

The satisfactory results obtained so far with polyester resins indicate that they will gradually replace epoxies, a trend that can be traced to improvements in their formulation and manufacture. The trickle or drip method ofimpregnating wound electrical components with resin has made rapid progress over the conventional "dip and bake" process. The resin is applied only where its presence is desired, namely on the windings, and it impregnates these evenly and thoroughly due to capillary action. The absence of solvent both ensures excellent filling of the cavities and improves thermal conductivity. The method lends itself readily to a continuous and high rate of in-line production, and the floor area required by the system is relatively small compared with dip tanks and ovens.<>