Medium voltage power circuit breaker - has plate on movable contact in extinguishing chamber generating intense gas flow when contact is opened

Medium voltage power switch has a gas filled, closed arc extinguishing chamber with an axially movable contact rod interacting with a fixed contact. The movable contact rod is sealed at the entry into the chamber by an elastic seal. A plate fitting the chamber (1) cross-section is placed on the movable contact (4) at its entry into the chamber. Its edge forms a gap with the extinguishing chamber wall which, when the contacts are opened, produces an intense gas flow (P) along the chamber walls. The extin gas is typically sulphur hexafluoride. The disc (7) is of metal, and typically of silvered copper.