Resin potting of oil-impregnated electrical components - using cold-setting polyurethane resins without vacuum

摘要

The asembled electrical component is placed in a suitable casting mould, impregnated by filling the mould with liquid pref. insulating oil, a liquid resin compsn., pref. a cold-setting polyurethane fed into the mould to displace the liquid, the resin addition rate is adjusted to the extend of mould filling, and the mould removed after the resin has set. The mould is pref. diposable and made of polyethyelene. Good electrical props., esp. freedom from discharge are obtd. without use of vacuum.