Abstract: A method and a device for detecting faults and for protection of electrical networks, the electrical networks being fed from a transformer station through a first three-phase switching device with circuit breaker, a distribution network and feeders. A second three-phase switching device with circuit breaker is connected before the feeders. The circuit breaker of the second switching device, has parallel-coupled damping impedances and is connected in series between the first three-phase switching device and the feeders when a short circuit current is detected. At least one of the damping impedances has deviating properties compared to the others, so as to create a negative sequence current detectable in the electrical networks. The damping impedances are bypassed by the circuit breaker of the second switching device after a predetermined period of time.

Abstract: An inter-pole drive bar in accordance with the disclosed and claimed concept is usable to extend among a plurality of poles of an improved switch apparatus and to cause the plurality of poles to be together moved between a CLOSED position and an OPEN position. The inter-pole drive bar is elongated and has a plurality of connection points that are connectable with the poles and further includes a number of features that avoid engagement or other interference between the inter-pole drive bar and the various structures of the switch apparatus. The inter-pole drive bar includes an elongated linkage element whose movement between the CLOSED and OPEN positions of the switch apparatus are primarily translation of the linkage element in a direction generally parallel with its longitudinal extent and translation of the linkage element in a direction generally perpendicular to its longitudinal extent.

Abstract: Provided herein is a power transmission mechanism of a four poles circuit breaker in which the contact points of a neutral pole thereof are brought into contact earlier at the time of closing and separated later at the time of opening than those of the other poles thereof, and according to the present invention, there is disclosed a power transmission mechanism of a four poles circuit breaker comprising: a switching shaft configured to provide a driving force for switching to the movable contactors of the poles; an arm provided to correspond to the four poles to transfer the rotational torque of the switching shaft; and a link configured to transfer the rotational torque of the arm to the movable contactor as a switching force, and provided to correspond to the four poles, wherein the sum of the length of the arm and the link in a neutral pole is longer than the sum of the length of the arm and the link in the poles excluding the neutral pole.

Abstract: A medium voltage switch unit comprising an interruption unit and a disconnection unit, wherein the interruption unit comprises a first and a second interruption contact and a first drive unit which moves one of said interruption contacts between a first position in which they are in electrical connection and a second position in which they are spaced apart. The disconnection unit comprises a first and a second fixed disconnection contacts couplable and uncouplable with respective first and second movable disconnection contacts mounted on the interruption unit and electrically connected to the first interruption contact. The interruption unit is mechanically supported by a first fixed conductor and the second interruption contact is electrically connected to said first fixed conductor.

Abstract: An alternator disconnector circuit-breaker of the invention presents a compact structure. The axes of opening/closure of the change-over first switch (12, 14), of the circuit-breaker second switch (22, 24), and of the disconnector switch (32, 34) are such that an angle of 90° is present between two of them. Actuator means (40) associated with synchronization means (52, 54, 56, 58) make it possible to ensure that each switch is operated in a time-shifted manner by common control means.

Abstract: An alternator disconnector circuit-breaker of the invention includes a cylindrical cam (40) for optimizing the sequence for opening/closing the switch-over first switch (10), the circuit-breaker second switch (20), and the disconnector third switch (30). The cam (40) has a cylindrical wall in which three slots (42), and preferably three pairs of slots, of different shapes, are defined; an end element of an element driving a respective one of the switch contacts is mounted to slide in each slot.

Abstract: The circuit breaker according to the present invention has first and second terminals having favorable electric conductivity and joined to each other with solder; and a heater whose circumference is insulated installed for melting the solder and supplied with electric power from the current path separate from current paths passing through the first and second terminals; wherein the first and second terminals are separated by a spring force and insulated when the solder is melted.

Abstract: A multipoint switch, especially for high voltage, having identically configured interrupter units (2, 3, 4), the pivoting contacts (10) of which are connected to a common drive (44) by a linkage mechanism (50, 60, 71) associated with the interrupter unit (2, 3, 4) and by a drive linkage (47), whereby the linkage mechanisms (50, 60, 71) of all interrupter units (2, 3, 4) are identically configured and are moved back and forth between the on- and off-position by the drive. Each linkage mechanism (50, 60, 71) includes a rocker arm (21, 65) attached to a pivoting shaft (20, 64) and a connecting rod (22, 63) articulated to it and to the pivoting contact. A rocker link (27, 66) is arranged on the pivoting shaft (20, 64), which under combined action is connected to the drive linkage (47) with at least another linkage mechanism (32, 33, 36, 62, 70). Two operatively combined links of the linkage mechanism (50, 60, 71) take a position at least close to a stable position in the on- and off-position.

Abstract: A circuit breaker having a movable load contact arm (14'), which pivots between an open position and a closed position, and a stationary line contact arm (16'). The circuit breaker includes an arcing contact structure (210) which is pivotally mounted on the stationary line contact arm. The arcing contact structure is generally "J" shaped, having a straight portion and a curved portion. The straight portion includes a bearing surface (211) which engages a bearing surface (221) on the bottom side of the line contact arm. The curved portion of the arcing contact extends beyond the end of the line contact arm and includes an electrical contact (212) which extends above the line contact arm when the load contact arm is in the open position.

Abstract: A device for switching electric current includes a compressed gas switch, at least one vacuum switch, and two terminals. A first consumable contact of the compressed gas switch is electrically connected to a first of the two terminals and a movable electrode of the vacuum switch is connected to a second of the two terminals to form a quenching circuit. The two electrodes of the vacuum switch can be separated without the use of the drive and a contact pressure is applied to them which prevents the electrodes from breaking below a threshold value of the current to be switched off. On switch-off, the current to be interrupted is switched over from a rated current circuit containing two rated current contacts of the compressed gas switch to the parallel quenching circuit. The vacuum switch now in the quenching circuit breaks only if the current to be switched off exceeds the aforementioned threshold.

Abstract: A contact arrangement is provided for engaging first and second stationary contacts in a predetermined sequential manner, for example so as to appropriately provide a pre-insertion function via the first contact and prior to engagement of the second contact that provides a circuit-closing function in a main current path. In a preferred arrangement, the moving contact of the contact arrangement includes first and second contact surfaces that are spaced apart and parallel to each other, the first and second contact surfaces of the moving contact sequentially engaging the first and second stationary contact surfaces respectively during closing movement. In a specific embodiment, the first and second contact surfaces are provided by a unitary contact member having a circular cross-section, this arrangement being especially suited for a switch where the contact member is rotated as it moves to the closed position.

Abstract: Each interrupter unit (10, 12, 14) of the switch for medium voltage and high voltage has a drive shaft (30), a moving switch contact piece (18) and a transmission linkage (38) which connects the switch contact piece (18) to the drive shaft (30). All the interrupter units (10, 12, 14) are of identical construction. A drive lever (40) is seated in a rotationally fixed manner on each drive shaft (30), which drive levers (40) are connected to one another via connecting rods (44, 46). In order to bring about staggered switching, the drive levers (40) of at least two interrupter units (10, 12, 14) are arranged in a different rotation position with respect to their drive shafts (30).