Tap changer for transformer in pressure tight housing - has inside and outside cascaded sealed joints at housing

摘要

The tap changer with stepped action is used with a transformer which is contained in a pressure-tight housing. The internal volume of the stepping tap changer is hermetically separated from the external space. The entries in the housing for the electrical cables and mechanical actuators are sealed off by interchangeable units. Each seal consists of two cascaded joints. One of the joints provides the seal against the internal volume and the other joint provides the seal against external space. There is access to the internal or external space via a test channel which is sealed by a screw.