The invention relates to a short-circuiting device for use in low-voltage and medium-voltage systems for the protection of property and persons, comprising: a switching element, which can be operated by the tripping signal of a fault detection device; two mutually opposite contact electrodes having power supply means, which contact electrodes can be brought into contact with an electrical circuit having connection points at different potential; furthermore, in at least one of the contact electrodes, a movable contact part, which is under mechanical preload and executes a movement to the further contact electrode with the assistance of spring force in the event of a short circuit; and a sacrificial element as a spacer between the contact electrodes, with an electrical connection between the sacrificial element and the switching element on the one hand and one of the contact electrodes on the other hand, in order to deliberately cause current-flow-induced thermal deformation or destruction of the sacrificial element. According to the invention, the movable contact part is in the form of a hollow cylinder which is closed on one side, and a spring for generating preload is inserted in the hollow cylinder. The hollow cylinder is movably guided in a complementary cutout in the first contact electrode, a sliding contact thus being formed. In the region of the base of the closed hollow cylinder, the cylinder wall of said hollow cylinder transitions into a cone at the outer circumference. Furthermore, a first pin-like extension, opposite to which a second pin-like extension insulated from the contact electrodes is situated, extends within the hollow cylinder, proceeding from the base. The sacrificial element, in the form of a bolt or screw, is arranged between the first and the second pin-like extension. A cutout, which has an internal cone and is matched to the external cone of the movable contact, is provided in the second contact electrode. The external cone and the internal cone form a bounce-free short-circuit contact region having frictional locking and interlocking connection on account of plastic deformation which occurs. Furthermore, according to the invention the switching element is designed as an auxiliary short-circuiter on the basis of an electric match.

An overvoltage protection device includes: input terminals; output terminals; at least two overvoltage protection elements for forming staggered protection levels; and at least one longitudinal element electrically connecting an input terminal and an output terminal to conduct an operating current. In order to form a first protection level, a first overvoltage protection device is connected to two input terminals on an input side upstream of the at least one longitudinal element, and, in order to form a second protection level, a second overvoltage protection element is connected to two output terminals on an output side and downstream of the at least one longitudinal element, the at least one longitudinal element influencing a response of the at least two overvoltage protection elements in case of an overvoltage. The at least one longitudinal element is provided with a thermal overload protection device for reducing a possible current flow.

An overvoltage protection device includes: input terminals; output terminals; at least two overvoltage protection elements for forming staggered protection levels; and at least one longitudinal element electrically connecting an input terminal and an output terminal to conduct an operating current. In order to form a first protection level, a first overvoltage protection device is connected to two input terminals on an input side upstream of the at least one longitudinal element, and, in order to form a second protection level, a second overvoltage protection element is connected to two output terminals on an output side and downstream of the at least one longitudinal element, the at least one longitudinal element influencing a response of the at least two overvoltage protection elements in case of an overvoltage. The at least one longitudinal element is provided with a thermal overload protection device for reducing a possible current flow.

Various embodiments of the teachings herein include a grid influencing system for a power supply grid comprising: a current-conducting grid influencing component; and a vacuum circuit breaker including a vacuum circuit breaker tube containing an at least partly integrated pre-arcing device for actively generating an arc between two contacts.

A vacuum circuit breaker includes a vacuum circuit breaker tube having a vacuum housing in which a contact system is disposed. The contact system includes two contacts which are movable relative to one another. An electrical pre-arcing unit having an ignition electrode in the vacuum housing is provided for igniting an arc along an arc current path.

A temperature actuated switch (1) includes: first and second temperature sensing sections (10, 20) that each include a contact (12, 22) and a thermally deformable member (first bimetal 11, second bimetal 21) that is bent in accordance with a temperature rise from a normal temperature in a manner such that the contacts (12, 22) shift from an open state to a connected state, the contacts (12, 22) being provided on a free-end side and located on the individual surfaces of the first and second temperature sensing sections that face each other; first, second, and third terminals (31, 32, 33) connected to an external circuit; and an insulation section (40) that maintains the first, second, and third terminals (31, 32, 33) in an insulated state, wherein the first temperature sensing section (10) includes first and second regions (A1, A2) with a slit (13) that extends from a fixed-end side to the free-end side provided therebetween, the first terminal (31) is connected to the first region (A1), the second terminal (32) is connected to the second region (A2), and the third terminal (33) is connected to the second temperature sensing section (20).

A temperature actuated switch (1) includes: first and second temperature sensing sections (10, 20) that each include a contact (12, 22) and a thermally deformable member (first bimetal 11, second bimetal 21) that is bent in accordance with a temperature rise from a normal temperature in a manner such that the contacts (12, 22) shift from an open state to a connected state, the contacts (12, 22) being provided on a free-end side and located on the individual surfaces of the first and second temperature sensing sections that face each other; first, second, and third terminals (31, 32, 33) connected to an external circuit; and an insulation section (40) that maintains the first, second, and third terminals (31, 32, 33) in an insulated state, wherein the first temperature sensing section (10) includes first and second regions (A1, A2) with a slit (13) that extends from a fixed-end side to the free-end side provided therebetween, the first terminal (31) is connected to the first region (A1), the second terminal (32) is connected to the second region (A2), and the third terminal (33) is connected to the second temperature sensing section (20).

A protection device for protecting an electrical load, from a short-circuit current, comprising a line arrangement having a first electrical line and a second electrical line for supplying the electrical load with electrical energy, the first electrical line having a first line constriction having a reduced line cross-section and the second electrical line having a second line constriction having a reduced line cross-section, the first line constriction and the second line constriction being arranged adjacent to each other, and comprising at least one insulation layer which electrically insulates the first line constriction from the second constriction the at least one insulation layer being thermally destructible in dependence on temperature.

The invention relates to a short-circuiting device for use in low-voltage and medium-voltage systems for the protection of property and persons, comprising: a switching element, which can be operated by the tripping signal of a fault detection device; two mutually opposite contact electrodes having power supply means, which contact electrodes can be brought into contact with an electrical circuit having connection points at different potential; furthermore, in at least one of the contact electrodes, a movable contact part, which is under mechanical preload and executes a movement to the further contact electrode with the assistance of spring force in the event of a short circuit; and a sacrificial element as a spacer between the contact electrodes, with an electrical connection between the sacrificial element and the switching element on the one hand and one of the contact electrodes on the other hand, in order to deliberately cause current-flow-induced thermal deformation or destruction of the sacrificial element. According to the invention, the movable contact part is in the form of a hollow cylinder which is closed on one side, and a spring for generating preload is inserted in the hollow cylinder. The hollow cylinder is movably guided in a complementary cutout in the first contact electrode, a sliding contact thus being formed. In the region of the base of the closed hollow cylinder, the cylinder wall of said hollow cylinder transitions into a cone at the outer circumference. Furthermore, a first pin-like extension, opposite to which a second pin-like extension insulated from the contact electrodes is situated, extends within the hollow cylinder, proceeding from the base. The sacrificial element, in the form of a bolt or screw, is arranged between the first and the second pin-like extension. A cutout, which has an internal cone and is matched to the external cone of the movable contact, is provided in the second contact electrode. The external cone and the internal cone form a bounce-free short-circuit contact region having frictional locking and interlocking connection on account of plastic deformation which occurs. Furthermore, according to the invention the switching element is designed as an auxiliary short-circuiter on the basis of an electric match.

A switching device including a frame, a first fixed contact member having a first contact area, and a first movable contact member having a first contact arm provided with a contact area. The first movable contact member is adapted to pivot relative to the frame around a first pivoting axis between a first position and a second position. The switching device includes a spreader member that is adapted to provide a first intermediate position for the first movable contact member in which a projection of the contact area of the first contact arm overlaps at least partially with a projection of the first contact area on a switch plane perpendicular to the first pivoting axis while the contact area of the first contact arm is spaced apart from the first contact area.