Wound capacitor in plastic encapsulation - with peripheral parts filled by closed-cell plastic foam

摘要

A wound capacitor in a metal or plastic casing is located inside by a casting compound. This compound fills only a part of the casing, e.g. the bottom, a centre stalk, and a cover. The peripheral space is filled by a plastic foam, pref. closed-cell polyurethane or polyethylene foam. This creates a space in which gases or fused parts of the capacitor element can penetrate. Excessive internal pressure does not destroy the capacitor casing.