Bbc Brown, Boveri & Company, Limited

Ekkehard Schade

Klaus Ragaller

Lutz Niemeyer

Gerhard Mauthe

Blaise Perrenoud

Roland Stelzer

Stanislas Ruffieux

Rolf Schaumann

Stanislaus Ruffieux

Walter Egli

Rudolf Moll

A gas blast switch, preferably for switching medium voltages, has two cylindrical contacts movable relative to one another along the cylinder axis in a casing filled with extinguishing gas. The contacts are coaxially surrounded by a hot space. The hot space serves to accept extinguishing gas which is heated by a switching arc. The heated extinguishing gas is led, via an annular gap, into the hot space where it is stored to be mixed with fresh extinguishing gas and to thereafter produce effective blasting of the switching arc. The extinguishing gas which is not cooled with a cooling device, still provides gas temperatures which are substantially below the temperature of the heated extinguishing gas. This is achieved in one embodiment by a radially extending annular duct having a width (B) which is small in comparison to the axial longitudinal extension (L) and the radial depth (D) of the hot space. Further, the axial longitudinal extension (L) and the radial depth (D) of the hot space, both measured from the entry or boundary of the annular duct into the hot space, are approximately equal to one another.

Gas blast switch

A gas-blast breaker with two contact members which are movable relative to one another. Each contact member is provided with a respective sparking contact. The contacts communicate with a cylindrical compression chamber whose volume varies as a function of the movement of the contact members and which is filled pressurized gas. A channel leading into a quenching zone between the sparking contacts extends into a first one of the two end faces of the compression chamber. A second one of the two end faces is bounded by a piston which is displaceable along the cylinder axis of the compression chamber and which is subjected to the action of a tensioned spring. The circuit breaker is suited for reliably interrupting both small and large currents, with a comparatively weak and simple drive mechanism for the movable contact member. The piston interacts with a fixed stop which is arranged such that the movement of the piston which is subjected to the action of the tensioned spring is blocked, below a predetermined first gas pressure in the compression chamber, against the movement of one of the contact members which is moved upon the occurrence of a breaking operation in the circuit breaker.

Gas-blast circuit breaker

In a high-voltage power switch having a movable contact and at least one other contact, wherein the contacts define a quenching path in which an arc burns, a piston/cylinder compression device in which fresh quenching gas is condensed, and a heating volume in which quenching gas is stored and compressed by the arc as a result of heating, quenching gas compressed during a switching process is blown into the quenching path and removed through a nozzle into an expansion space. So that the blowing of the arc is nearly independent of the intensity of the current to be interrupted and, in addition, an increase in the quenching capacity can be attained by means of a supply of fresh quenching gas, the movable contact is rigidly connected to the piston, which changes the volume of a compression space. The compression space and the heating volume open into a common annular duct. This annular duct is a part of a mixing device for hot and cold quenching gas and connects the compression space and the heating volume to the quenching path.

High-voltage power switch

A high voltage power switch for alternating current has a stationary, hollow contact, an axially displaceable contact, a nozzle through which compressed gas is directed into an expansion chamber, and a cylindrical coil. The coil is connected at one of its ends with a first part of the hollow contact, and at its other end with a second part of the stationary contact. In a switch of this type, the disconnect capacity is improved by an increased exchange of gas between the arc and the surrounding compressed gas, while the dimensions of the coil connected with the hollow contact and the magnitude of the flow of compressed gas are relatively small. These features are obtained by configuring the first part of the stationary contact as a nozzle, and providing a compression device, actuated by the contacts, to produce a flow of compressed gas of a magnitude so that the arc is commutated from the first part to the second part of the contact within a period of time that is short compared with the duration of the half-wave of the current, prior to the time the current changes polarity.

High voltage power switch

An electric gas-switch includes a switching chamber that is divided by a partition into an arc chamber and an additional chamber with a central pin being located within the arc chamber. The pin is embraced at least partially by a stationary switch part which is surrounded by a coil through which is flowing a cut-off current. One end of the coil is connected with an annular intermediate electrode which surrounds the central pin at a distance within the region of its free end. In an on position the central pin is embraced, at least at its free end, by the movable switch part that is designed in the form of a nozzle.

Electric gas-switch

A gas-pressurized electrical switch includes a casing provided with a transverse wall dividing the interior into two quenching chambers filled with a pressurized arc-quenching gas. A longitudinally movable contact member is supported within a first one of the chambers and includes a nozzle pipe projecting through the transverse wall into the other chamber for entry into an annular stationary contact member which is surrounded by a magnetic-field producing coil having one end connected to one terminal of the switch. The nozzle pipe is provided with apertures through the wall thereof in the first chamber which place the two chambers in communication with each other. A pin member is located centrally within the stationary contact member and is entered into the nozzle pipe in the contact-closed position, and this pin is surrounded by an annular electrode. When the contacts disengage, an arc is drawn and thereafter one portion of the arc burns between the annular electrode and the pin and is rotated by the magnetic field, and the other portion of the arc burns between the pin and the nozzle pipe of the movable contact member. Burning of the arc generates heat which causes an increase in gas pressure in the chamber containing the stationary contact member assembly which then acts to start flow of arc extinguishing gas through the nozzle pipe which results in arc extinction.

Gas-pressurized electrical switch with current-generated magnetic field

A structural component such as nozzle-forming member to be utilized in conjunction with the arc quenching chamber of an electrical circuit breaker operating with a pressurized gaseous fluid such as SF.sub.6 and made from a polytetrafluoroethylene composition that is gas-emissive under influence of heat generated by the arc in the vicinity of the nozzle is provided with a system of gas-conducting passageways to permit such gas to escape from sub-surface cavities formed by deterioration of the composition rather than accumulate therein which leads ultimately to undersirable chipping off of pieces of the surface. These passageways may be constituted by a system of blind holes or by a system of grooves.

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Wettingen, Switzerland

Ekkehard Schade