Abstract: A load breaker arrangement includes first and second input terminals, respectively, and first and second output terminals. The arrangement also includes two relays connected in series with one another, wherein the two relays are coupled between the second input terminal and the second output terminal, a semiconductor switch connected in parallel with one of the two relays, and a third relay coupled between the first input terminal and the first output terminal. A control circuit, in a load breaker mode, turns on the semiconductor switch while the two relays and the third relay are closed, then opens the one of the two relays in parallel with the semiconductor switch, then opens the semiconductor switch to break a current between the second input and second output terminals, and then opens the other of the two relays not in parallel with the semiconductor switch and opens the third relay.

Abstract: A gas insulated circuit breaker system has: a container that encapsulates insulating gas; a main contact in the container that opens/closes the main circuit; a resistor contact in the container, connected in parallel to the main contact, to be opened after elapse of a predetermined time after the main contact is opened and to be closed at a predetermined time before the main contact is closed; a resistor in the container, serially connected to the resistor contact and connected in parallel to the main contact together with the resistor contact; a temperature sensor that measures temperature of surrounding of the resistor; and a temperature estimation section that estimates a temperature of the resistor based on a timing of opening/closing operation of the main contact, a current flowing through the main circuit and the measured temperature.

Abstract: A system and method for quickly discharging a DC relay is provided. In one embodiment, the invention relates to circuit for discharging a relay coil, the circuit including a first suppression circuit coupled across a control power source, a switch, a relay coil in series with the switch, wherein the relay coil and the switch are coupled across the control power source, and a second suppression circuit coupled across the relay coil, wherein the relay coil is configured to actuate at least one load switch when sufficiently energized by the control power source, wherein the first suppression circuit is configured to discharge energy stored in the relay coil, and wherein the second suppression circuit is configured to discharge energy stored in the relay coil.

Abstract: In order to provide a power semiconductor module for power distribution and transmission, having a power semiconductor circuit which is connected via connecting lines to an energy storage device, which limits the current amplitudes that occur in the electrical fault and effectively protects the power electronics, it is proposed that the connecting lines have a weak point which breaks when the current load is above a threshold value, with the connecting lines furthermore having a resistance which is connected in parallel with the weak point.

Abstract: An uninterruptible power supply (UPS) system includes an AC power input configured to receive AC power from a single-phase AC power source or a multi-phase AC power source, a DC power source, an output circuit including a power output, a controllable switch configured to selectively couple at least one of the AC power input and the DC power source to the output circuit, and a processor coupled and configured to affect operation of the output circuit depending upon which of single-phase and multi-phase operation of the UPS is indicated.

Abstract: Hybrid power relay for making and breaking an electrical circuit which includes electromagnetically operated contacts for making and breaking the circuit, a solid state switch connected across the contacts, a control circuit responsive to a control signal for actuating the solid state switch and the contacts such that the solid state switch closes before the contacts to make the circuit and the contacts open before the solid state switch to break the circuit, and a protective circuit for monitoring the temperature of the solid state switch and opening the switch in the event of a rise in temperature produced by abnormal current flow in the switch due to failure of the contacts to make and maintain the circuit.

Abstract: The present invention discloses an arc extinguishing hybrid transfer switch, including a mechanical switch and a first thyristor branch connected in parallel with the first contact branch of the mechanical switch, wherein the first thyristor branch includes a first thyristor, a second thyristor, a first polarized capacitor and a second polarized capacitor, the first thyristor and the first polarized capacitor are connected in series in the same direction, the second thyristor and the second polarized capacitor are connected in series in the same direction, and a branch consisted of the first thyristor and the first polarized capacitor and a branch consisted of the second thyristor and the second polarized capacitor are connected in parallel in reverse direction. The invention further discloses a switching method for the arc extinguishing hybrid transfer switch for implementing an arc extinguishing of a mechanical switch.

Abstract: An apparatus, such as a switch module, is provided. The apparatus can include an electromechanical switch structure configured to move between an open configuration and a fully-closed configuration (associated with a minimum characteristic resistance) over a characteristic time. A commutation circuit can be connected in parallel with the electromechanical switch structure, and can include a balanced diode bridge configured to suppress arc formation between contacts of the electromechanical switch structure and a pulse circuit including a pulse capacitor configured to form a pulse signal (in connection with a switching event of the electromechanical switch structure) for causing flow of a pulse current through the balanced diode bridge. The electromechanical switch structure and the balanced diode bridge can be disposed such that a total inductance associated with the commutation circuit is less than or equal to a product of the characteristic time and the minimum characteristic resistance.

Abstract: A control circuit for a washing machine that avoids contact bounce short circuit failures is provided. A washing machine that utilizes an induction motor including a starting winding used to start rotation of the motor at the beginning of a cycle. Such washing machines require that the motor be operated in both directions during different cycles. To enable such operation, a mechanical timer uses a pair of single pole, double throw switches in a switching assembly to reverse the L1 and neutral connections to the starter winding. To avoid the contact shorting problem, the control wiring runs either the L1 or neutral side of the voltage source, or both, through the centrifugal switch to open the input contact(s) once the motor has reached its operating speed. Then, if the switching assembly has L1 and N contacts touching at the same time, it will not result in a dead short.

Abstract: An electric circuit includes a load, a solid state device, and a control for opening the circuit such that current will not flow through the solid state device, and for facilitating flow of current to bypass said solid state device and provide a current path to an arc fault circuit interrupter. A bypass includes a normally opened switch which is closed to provide current to the arc fault circuit interrupter.

Abstract: An electronic switch structure capable of extinguishing arcs is provided. A device capable of extinguishing arcs generated when an electric switch is turned on or off is in a following structure. Two silicon controlled rectifiers are connected in inverse parallel. Trigger ports of the silicon controlled rectifiers are connected to triggering current limiting circuits each formed by a diode and a resistor connected in series, respectively. Positive poles and negative poles of the silicon controlled rectifiers are connected to a voltage dependent resistor and a resistance-capacitance absorption circuit for over voltage protection in parallel. A triggering end of the device is connected to a contact bridge of the switch. Two ends connected in inverse parallel of the silicon controlled rectifiers are connected to two ends of fixed contacts of the switch respectively. Thus, an electronic arc extinguishing device having a simple structure, a small volume, and high reliability is formed.

Abstract: A multiphase current interrupter is provided for interrupting a phase current between two contacts in an electrical phase. The current interrupter includes a first ablative chamber disposed around contacts for a first electrical phase. The first chamber has an ablative material thereon that causes a shock wave when an electrical arc is generated in an arc zone for the first electrical phase during a separation of the contacts therein. The current interrupter further includes at least a second ablative chamber disposed around contacts for at least a second electrical phase. The second chamber has an ablative material thereon that causes a shock wave when an electrical arc is generated in an arc zone for the second electrical phase during a separation of the contacts therein. An interconnecting structure provides fluid communication between the first ablative chamber and the second ablative chamber. The interconnecting structure is adapted to dissipate a shock wave generated in any of the ablative chambers.

Abstract: Pilot switch circuitry coupled across first and second terminals of a microelectromechanical system (MEMS) switch is provided to reduce or eliminate arcing between a cantilever contact and a terminal contact when the MEMS switch is opened or closed. The pilot switch circuitry establishes a common potential at the first and second terminals prior to, and preferably until, the cantilever contact and terminal contact come into contact with one another when the MEMS switch is closed. The pilot switch circuitry may also establish a common potential at the first and second terminals prior to, and preferably after, the cantilever contact and terminal contact separate from one another when the MEMS switch is opened.

Abstract: A contactor may operate to interrupt current in a circuit while the circuit is operating under load. A shunt is provided to by-pass surge power current around contacts to reduce arcing. The shunt includes a solid-state switch that may be operated in a series of pulses during movement of the contacts. The pulse control unit may detect a potential for arcing and then provide for periodic pulsing operation of the shunt. Because the solid-state switch may operate discontinuously, the contactor may be constructed with a switch that is selected on a basis of its pulse rating.

Abstract: A high voltage direct current (HVDC) power distribution system comprises at least one power bus; at least one load conductor; and a hybrid contactor for interconnecting the at least one power bus and the at least one load conductor and through which inductive energy passes upon disconnection of the at least one load conductor from the at least one power bus. A first portion of the inductive energy passes through the hybrid contactor as an arc. A second portion of the inductive energy passes through the hybrid contactor as resistively dissipated heat.

Abstract: The present invention is directed to a superconducting current limiting component, particularly to a ceramic high temperature superconducting current limiting component which is self triggering, comprising a coil (1) made of ceramic high temperature superconductor material, wherein around the outer surface of the coil (1) made of ceramic high temperature superconductor material a second coil (3) is applied as a shunt and, preferably, wherein the coil (1) made of ceramic high temperature superconductor material is applied onto a hollow cylindrical body (2) made of a ceramic high temperature superconductor material.

Abstract: An arc suppression circuit in a protection relay having trip contacts is used to turn off a battery-powered solenoid and trip an AC power circuit breaker. The arc suppression circuit uses a switch-control circuit to control the turning off of a semi-conductor switch so that the semi-conductor switch provides a current path around the trip contacts, and is carrying all, or substantially all, of the load current, before the trip contacts are opened. When the trip contacts begin to open, the switch-control circuit holds the semi-conductor switch on for a sufficient time to prevent an arc from becoming established before turning the semi-conductor switch off. In a second embodiment, the arc suppression circuit provides a second switch-control circuit. This second switch-control circuit is configured to accept control signals from a microprocessor within a protection relay.

Abstract: An improved switching apparatus and method are disclosed. In at least some embodiments, the apparatus includes first and second ports, a first switching device such as a contactor coupled between the ports, and a second switching device coupled in parallel with the contactor between the ports, where the second switching device can be or include a solid-state semiconductor device. The second switching device is operated to become conductive at a first time prior to a second time when the contactor switches between a conductive state and a non-conductive state, and remains conductive up to a third time subsequent to the second time. In at least some further embodiments, the apparatus also includes one or both of a voltage sensing capability and a current sensing capability and switches the second switching device to become conductive based upon voltage and/or current information.

Abstract: An electromechanical/solid-state AC relay has an electromechanical winding coil that moves an armature to force mechanical contacts to open or close. Electrical arcing across the mechanical contacts that occur as the contacts are opening or closing can damage and severely reduce the lifetime of the relay. Contact arcing is prevented by pulsing a triac on for a short period of time just before and after the mechanical contacts make or break contact. The triac limits the voltage difference across the mechanical contacts to less than one volt to prevent arcing. The triac is turned off after the mechanical contacts finish moving, reducing the heating and average power through the triac. A zero-sampling circuit that detects when the AC input voltage switches across 0 volts and activates a control integrated circuit to switch on the triac during zero-crossings to minimize power surges.

Abstract: A switching system is provided. The switching system includes electromechanical switching circuitry, such as a micro-electromechanical system switching circuitry. The system may further include solid state switching circuitry coupled in a parallel circuit with the electromechanical switching circuitry, and a controller coupled to the electromechanical switching circuitry and the solid state switching circuitry. The controller may be configured to perform selective switching of a load current between the electromechanical switching circuitry and the solid state switching circuitry in response to a load current condition appropriate to an operational capability of a respective one of the switching circuitries.

Abstract: A system is presented. The system includes detection circuitry configured to detect occurrence of a zero crossing of an alternating source voltage or an alternating load current. The system also includes switching circuitry coupled to the detection circuitry and comprising a micro-electromechanical system switch. Additionally, the system includes control circuitry coupled to the detection circuitry and the switching circuitry and configured to perform arc-less switching of the micro-electromechanical system switch responsive to a detected zero crossing of an alternating source voltage or alternating load current.

Abstract: The invention relates to a hybrid electrical switching device, comprising an electromechanical relay including a mechanical switching element to be operated by an electrical coil, and a main semiconductor switching element including a control input and a current conduction path which is connected in parallel with the mechanical switching element for energizing an electric load. The main semiconductor switching element is of the type that ceases to conduct when a current through the current conduction path thereof drops below a threshold value. The circuit furthermore comprises an auxiliary semiconductor switching element including a control input and a current conduction path which is connected for controlling the main semiconductor switching element.

Abstract: A switching circuit for connecting a power source to a load is described. The circuit comprises a first relay and at least one second relay in parallel arrangement with the first relay. The switching circuit is arranged such that in the event of a fault condition occurring that requires the disconnection of the power source from the load, the at least one second relay opens while the first relay remains closed. In this manner, a reliable disconnection of the load from the switching circuit is achieved.

Abstract: An electric circuit in which a combined resistance including a plurality of resistors of a small rating is disposed. The electric circuit includes a bypass section in order to allow a short-circuit current, when it occurs in the electric circuit, to intensively flow through one of the resistors in the combined resistance bypassing a remaining resistor in the combined resistance.

Abstract: A motor starter is provided. The motor starter includes micro-electromechanical system switching circuitry. The system may further include solid state switching circuitry coupled in a parallel circuit with the electromechanical switching circuitry, and a controller coupled to the electromechanical switching circuitry and the solid state switching circuitry. The controller may be configured to perform selective switching of a load current from a motor connected to the motor starter. The switching may be performed between the electromechanical switching circuitry and the solid state switching circuitry in response to a load current condition appropriate to an operational capability of a respective one of the switching circuitries.

Abstract: An apparatus, and a method of opening and closing electrical power feed lines using a hybrid contactor, which combines a traditional set of mechanical main contacts with a high voltage solid state switch. The solid state switch provides a parallel current path around the main contacts. When the main contacts are to be opened or closed, the solid state switch is first closed, diverting current away from the main contacts to prevent arc formation when the main contacts are being opened or closed. Once the main contacts are opened or closed, the solid state switch is opened, as the parallel current path is no longer needed. Optional auxiliary contacts are connected in series with the solid state switch to provide galvanic isolation between an input terminal and an output terminal.

Abstract: The subject matter of the present invention is a load breaker arrangement (1) for switching on and off a DC current of a DC current circuit in a photovoltaic plant with a semiconductor switching element (4) to avoid a switching arc, there being provided an electronic control unit (5) configured such that one or more signals are received by the control unit, and the load breaker arrangement (1) being configured such that in at least one current-carrying line of the DC current circuit there is galvanic separation by a switching contact that is automatically controllable by the control unit (5) in the switched-off condition and one or more control signals being transmitted to the load breaker arrangement (1) and a semiconductor switching element (4) interrupting the DC current so that the switching contact is de-energized, whereby the signals are flaw signals that are received in case of a flaw in the PV generator, inverter or on the AC side, the DC current circuit being automatically switched on or off by th

Abstract: This invention relates to a circuit breaker device comprising a main branch (1) comprising a mechanical switch element (2) and an auxiliary branch (3) containing a semiconductor breaking cell (4), this auxiliary branch (3) being mounted in parallel with the main branch (1). The main branch (1) comprises a serial switching assistance module (M2) in series with the mechanical switch element (2), comprising a semiconductor breaking cell (5) controllable in opening in parallel with an impedance (Z1). The auxiliary branch (3) comprises a parallel switching assistance module (M4) comprising an impedance (Z2), this impedance (Z2) including at least one capacitor type element (C).

Abstract: A modular and scaleable Matrix Fault Current Limiter (MFCL) that functions as a “variable impedance” device in an electric power network, using components made of superconducting and non-superconducting electrically conductive materials. The matrix fault current limiter comprises a fault current limiter module that includes a superconductor which is electrically coupled in parallel with a trigger coil, wherein the trigger coil is magnetically coupled to the superconductor. The current surge doing a fault within the electrical power network will cause the superconductor to transition to its resistive state and also generate a uniform magnetic field in the trigger coil and simultaneously limit the voltage developed across the superconductor. This results in fast and uniform quenching of the superconductors, significantly reduces the burnout risk associated with non-uniformity often existing within the volume of superconductor materials.

Abstract: A shunt activation signal is transmitted by an external control terminal through an external transmission interface to switch a flash memory controller in a shunt mode. The shunt activation signal of the external transmission interface can set up a switch as shunt. When the flash memory controller is defective due to errors or damage, the shunt mode enables the external control terminal to directly process data saving/retrieving to the flash memory chip or testing through the external transmission interface. Thus, the user need not purchase a new flash memory to replace the defective flash memory with the damaged flash memory controller.

Abstract: A universal hybrid solid-state switchgear for power transmission or distribution systems incorporates a fast mechanical switch and solid-state power electronics switching circuits to provide circuit breaker and fault current limiting applications.

Abstract: A voltage regulating circuit has a first switch, a transformer and a second switch. The first switch has an input node, a first node and a second node. The transformer is connected to the switches has a first coil and a second coil. The first coil and the second coil respectively have an end, and the second coil is connected to the first coil in series at a node. The node between the first and second coils is connected to the second node of the first switch. The second switch is connected to the transformer and has a first node, a second node and an output node. The first node is connected to the end of the first coil. The second node is connected to the first node of the first switch. The transformer will not heat up when the transformer needs not to be used.

Abstract: An electrical switching topology for a hybrid switch provides extremely low losses in both cryogenic and non-cryogenic electronic systems. In this switch having switch modules connected in parallel, switching losses in a first module are separated from conduction losses in the parallel-connected second module. The conduction losses are then further reduced by cryogenically cooling the second module. Since the switching losses of the first module can be absorbed outside a cryogenic container, the switching losses do not add to the cryogenic heat load. In other applications, the switching module operates at lower temperatures to provide higher switching speeds and reduces switching heat generation.

Abstract: An arc suppression circuit for a power switch or power supply with a relay having a coil and a set of contacts for providing a portion of an input power as load power to an output. The relay coil is configured for closing the relay contacts in response to receiving relay activating energy and for generating back EMF energy following termination of the receiving of the relay activating energy. A switch is connected in parallel to the relay contacts and is configured for providing a portion of the input power as supplemental load power to the output as a function of back EMF energy. Also, a method of suppressing damaging arcing across relay contacts in a power switch or power supply includes receiving back EMF energy generated by the relay coil following termination of the relay coil receiving activating energy and connecting supplemental load power to the output in parallel with the relay contacts in response to the receiving of the back EMF energy.

Abstract: A circuit for clamping current in a charge pump is disclosed. The charge pump includes switching circuitry having a number of switching circuitry transistors. Each of first and second pairs of transistors in the circuit can provide an additional path for current from its associated one of the switching circuitry transistors during off-switching of that transistor so that a spike in current from the switching circuitry transistor is only partially transmitted through a path extending between the switching circuitry transistor and a capacitor of the charge pump.

Abstract: An integrated circuit provides a load with back-flow and open-circuit protection and includes a load, a trigger circuit, and a shunt circuit. The integrated circuit provides large-size LED displays having series LED connection with back-flow and open-circuit protection. The shunt circuit of the integrated circuit shunts the back-flow current from the LED when an ESD is applied, and offers an alternative current path when an LED fails so that other functioning LEDs can still emit light.

Abstract: A control system for at least one vacuum interrupter gap in a high-voltage switching device includes at least one non-reactive control resistor disposed in parallel with the vacuum interrupter. The non-reactive control resistor merges concentrically onto the vacuum interrupter chamber and is mechanically and electrically coupled thereto.

Abstract: An electrical connector and methods for minimizing arcing when the connector is connected or disconnected under load are disclosed. The invention provides an arc reduction circuit with one or more regulators, such as transistors, integrated into the connector housing that sense movement of the connector and shunt the current to an impedance circuit when a potential arc condition is sensed.

Abstract: A shorting system, which eliminates persistent arcing faults in power distribution equipment, includes a first shorting switch having separable contacts, an actuation input and a fuse electrically connected in series with those contacts. A second shorting switch includes an actuation input and separable contacts, which are electrically connected in parallel with the series combination of the fuse and the first shorting switch contacts. A detection circuit includes one or more arcing light sensors and an actuation circuit. The light sensors detect arcing fault light and the actuation circuit responsively outputs a first trigger signal to the first shorting switch actuation input to close its contacts. For a persistent arcing fault, which is not eliminated by the first shorting switch, a predetermined time after the first trigger signal, the actuation circuit responsively outputs a second trigger signal to the second shorting switch actuation input to close its contacts.

Abstract: First and second switches and an arc-limiting switch are closed during a turn-on sequence in a switching circuit. The arc-limiting switch is left open during a turn-off sequence. Current flow through the switching circuit may be broken by opening the first or second switch during a turn-off sequence.

Abstract: The present invention provides a motor control circuit including a motor with a motor winding and a brush, a battery, a relay, and a ground return circuit. The battery is for energizing the motor. The relay selectively provides connection between the battery and the motor. A ground return circuit is in communication with the brush. The ground return circuit creates a path from the brush through the relay to an electrical ground.

Abstract: The forming of an integrated circuit including at least one element of electronic protection of the circuit formed of at least one switch for short-circuiting supply conductors arranged in a rail, the switch being integrated in the rail, under said conductors.

Abstract: The invention relates to a VSC-converter for converting direct voltage into auxiliary voltage and vice versa, which comprises a series connection of at least two current valves (5, 6) arranged between two poles (7, 8), a positive and a negative, of a direct voltage side of the converter, each current valve comprising several series connected circuits (12), each of which circuits comprising a semiconductor component (13) of turn-off type and a rectifying component (14) connected in anti-parallel therewith, an alternating voltage phase line (16) being connected to a midpoint (15), denominated phase output, of the series connection of current valves (5, 6) between two of said current valves while dividing the series connection into two equal parts.

Abstract: A DC arc-suppressor for network appliance power managers comprises an electromechanical relay that controls the flow of battery power to a network appliance by remote control. The relay includes electrical contacts that open to interrupt the flow of current in response to an off-command signal. A transistor is connected in shunt across the relay contacts to temporarily divert such flow of current. A timing circuit is connected to respond to the off-command signal by first turning on the shunt transistor, then open the relay contacts, then turn off the shunt transistor. Such shunt transistor is sized to carry the full rated power of the relay contacts, but only for the few milliseconds that are needed to allow the relay contacts to fully separate.

Abstract: The invention relates to a hybrid electrical switching device, comprising an electromechanical relay (1) including a mechanical switching element (2) to be operated by an electrical coil, and a main semiconductor switching element (10) including a control input (12) and a current conduction path (11) which is connected in parallel with the mechanical switching element (2) for energising an electric load (8). The main semiconductor switching element (10) is of the type that ceases to conduct when a current (iT) through the current conduction path (11) thereof drops below a threshold value. The circuit furthermore comprises an auxiliary semiconductor switching element (15) including a control input (17) and a current conduction path (16) which is connected for controlling the main semiconductor switching element (10).

Abstract: An electromechanical relay including a mechanical displacement electrical contact and a transistor parallel-connected with the electrical contact. The contact is closed for a voltage V corresponding to the forward direction of the transistor and a powering-on of the transistor that starts before the closure of the contact and ends after the closure. The contact is opened for a voltage V corresponding to the forward direction of the transistor and a powering-on of the transistor that starts before the closure of the contact and ends after the closure. Such an electromechanical relay may find particular application to electromechanical switches, hybrid relays.

Abstract: An arc fault causes the line voltage across the line terminals of an arc fault circuit interrupter (AFCI) to change its characteristic voltage pulse shape as the line voltage is momentarily removed from the AFCI terminals after the arc extinguishes and before it re-strikes by introducing a flat voltage portion to the pulse shape. This flat voltage portion changes the voltage pulse width. An arc detector/processor detects this change in pulse width to produce a signal indicative of upstream (line side) arcing. The flat voltage portion can also be detected using clamping diodes and charging capacitors.

Abstract: A technique is provided for forcing greater voltage investment in an arc developed during interruption of a current carrying path. A source element is provided in a secondary current carrying path parallel to a primary path through the device. Upon interruption of the primary current carrying path, an arc is forced to migrate towards a dissipating structure under the influence of an electromagnetic field. The source material then begins to carry current and undergoes surface ablation, releasing gas which is directed towards the migrating arc. The arc is thus caused to expand further, increasing voltage investment and resulting in more rapid extinction and reduction in let-through energy.

Abstract: A method and system are disclosed for protecting an electrical component from electrostatic discharge prior to its electrical connection to an additional component. Specifically, a flex on suspension circuit of a disc drive that is electrically connected to the read/write head is disclosed as having exposed leads for connection to a printed circuit cable assembly. The exposed leads are shunted with a solder conductor such as solder tape after testing of the circuit and head to prevent electrostatic build-up across the read and write elements. The flex on suspension circuit is then electrically connected to the printed circuit assembly cable by reflowing the solder conductor to bond the exposed leads of the flex on suspension circuit to the electrical contacts of the printed circuit assembly cable and also to remove the electrical short established between the exposed leads by the solder conductor.

Abstract: The current-limiting switch (S) has an arc-resistant contact arrangement (K1), which is intended to carry the rated current (IN), of a first switching point (S1), and two commutation paths (P1 and P2) connected in parallel with the first switching point (S1). The first commutation path (P1) contains, in series, a contact arrangement (KT) of a second switching point (ST) and an electronic power switching apparatus (T). The second commutation path (P2) contains, in series, a switching apparatus (SA) and a current-limiting element (RB). The contact arrangements (K1 and KT) are designed to be coaxially symmetrical and are arranged in a pressure-resistant housing (G). Both switching points have electrodynamic drives which open and close very quickly. Thanks to the extremely space-saving, coaxial arrangement of the contact arrangements, undesirable stray inductances can be avoided. This allows the current-limiting switch to be switched on and off very quickly.