Abstract: An enclosed high voltage circuit breaker with a sulphur hexafluoride insulating and arc-extinguishing medium includes breaking gaps arranged in a high-pressure chamber which, during breaking is put into communication with a low-pressure chamber through blast valves. A closing resistor is connected in series at each end with a contact device which, upon closing, connects the resistor in parallel with the main breaking gaps before they are closed. The resistor contact device is arranged in the high-pressure chamber while the closing resistor is arranged in a separate tank substantially entirely separated from the low-pressure chamber.

Abstract: An operating device for a high pressure circuit breaker enclosed in an elongated casing filled with compressed gas with a high-pressure chamber and a low-pressure chamber includes a driving arrangement operated by compressed gas. A compressed gas valve is provided for alternatively connecting the driving means to the high-pressure chamber and the low-pressure chamber. The device has openings into the high-pressure space and the low-pressure space respectively communicating with the driving arrangement. There is a valve seat around the first opening and a movable valve member engageable with the valve seat to close this opening. A space is provided on the opposite side of the valve member from the opening which is permanently connected with the high-pressure chamber. An impulse member outside the high-pressurechamber through an operating rod extending perpendicular to the longitudinal axis of the casing engages the valve member for moving the valve member away from the valve seat.