Transformer iyi ndi epoxy resin yokhala ndi kapangidwe kotsekedwa kwathunthu komanso kutchinjiriza kwathunthu. Yapangidwa kuti igwiritsidwe ntchito poyesa magetsi, mphamvu zamagetsi ndi chitetezo cha relay mu dongosolo lamagetsi lomwe lili ndi ma frequency 50Hz - 60Hz komanso magetsi 3,6, 10 kV kapena pansi. Kukula kochepa, kulemera kopepuka kumatha kuyikidwa pamalo aliwonse.