Abstract: To avoid arcing when the breaker is opened, load current is diverted from a circuit breaker, before it opens, to a pulse forming circuit containing a precharged capacitor and a switch. Load current normally flows from a source of electric power to a load through a network comprising the breaker and a series connected controlled impedance. The pulse forming circuit is connected across the network. When load current is to be interrupted, the switch is closed to discharge a current pulse through the network, and the impedance of the controlled impedance is increased. These actions divert load current from the network to the pulse forming circuit. The breaker is then opened. The voltage across the capacitor first linearly increases from the precharge voltage to zero and then tends to increase in magnitude with an opposite polarity, i.e. that of the source of electric power.

Abstract: Arrangement for arcless interruption of a-c load current in response to a current interruption command. Separable contact means serially connected with controlled impedance means, and parallel connected diversion means are intermediate the a-c source and the load. The controlled impedance comprises field effect transistors (FETs). Since FETs usually have only a single inherent junction, at least a pair of the FETs are oppositely poled so that load current can be cut off notwithstanding the direction of current flow when interruption is commanded. The pair of FETs may be connected back to back. An alternative embodiment has two branch circuits each comprising a FET and a separable contact means. Upon interruption load current is sequentially transferred from one to the other branch circuit and then to the diversion means.

Abstract: An insulated field effect semiconductor device having source and drain regions extending to opposed surfaces of its semiconductor body is bidirectional and capable of blocking voltages in either of two opposing polarities and comprises a four terminal device having source and drain electrodes disposed on the opposed surfaces and a base electrode all ohmically connected to corresponding portions of the semiconductor body. An insulated gate is provided in a trench which extends into the semiconductor body for controlling the conductivity of a channel region extending within the base region between the source and drain regions. The device is free of source-to-base and drain-to-base short circuits. Control circuits enable this device to conduct or block both polarities of a high current AC voltage applied across its source and drain terminals while preventing undesired avalanche breakdown within the device.

Abstract: A solid state switch connected across a pair of separable contacts for eliminating arcing across the contacts allows the contacts and the contact driver to be enclosed within an evacuated envelope. The vacuum environment allows the use of an inexpensive, highly conductive contact material, such as copper, without fear of chemical reaction.

Abstract: Load current is diverted from a circuit breaker, when it is opened, through a commutation circuit. The latter has a capacitor, inductance and solid state switch serially connected with the output of a bridge rectifier. The input of the bridge is connected across the breaker. The switch is turned on to discharge the precharged capacitor to form a current pulse, presenting an extremely low resistance across the bridge input and causing load current diversion.

Abstract: A solid state switch connected across a pair of separable contacts for eliminating arcing across the contacts allows the contacts and the contact driver to be enclosed within an evacuated envelope. The vacuum environment allows the use of an inexpensive, highly conductive contact material, such as copper, without fear of chemical reaction.

Abstract: A solid state switch connected across a pair of separable contacts for eliminating arcing across the contacts allows the contacts and the contact driver to be enclosed within an evacuated envelope. The vacuum environment allows the use of an inexpensive, highly conductive contact material, such as copper, without fear of chemical reaction.

Abstract: A solid state switch connected across a pair of separable contacts for eliminating arcing across the contacts allows the contacts and the contact driver to be enclosed within an evacuated envelope. The vacuum environment allows the use of an inexpensive, highly conductive contact material, such as copper, without fear of chemical reaction.

Abstract: A solid state switch connected across a pair of separable contacts for eliminating arcing across the contacts allows the contacts and the contact driver to be enclosed within an evacuated envelope. The vacuum environment allows the use of an inexpensive, highly conductive contact material, such as copper, without fear of chemical reaction.

Abstract: A solid state current limiting circuit interrupter for the arcless interruption of current through a protected circuit includes a pair of mechanically switched contacts electrically connected in series between the power source and the protected load. A solid state switch becomes electrically connected in parallel across the contacts when the contacts are opened to transfer the current to the solid state switch in a first state of voltage drop lower than arc voltage, and then in a second state of voltage drop higher than power source voltage in which stored energy is dissipated and current is forced to drop to zero to interrupt the circuit.

Abstract: A bridging contact is arranged across two fixed contacts with a pair of parallel, closely spaced conductors serving as the bridging contact carrier. The conductors each form a pair of upper and lower links joined by means of a toggle pivot pin and are refrained from movement by means of a pair of tension springs. A high current pulse in opposite direction within the parallel conductors generates electromagnetic forces which propels the conductors apart. The bridging contact carried by the parallel conductors is thereby rapidly driven out of contact relation with the fixed contacts to interrupt the circuit.

Abstract: A commutating circuit in combination with a snubber circuit are employed to switch a thyristor from a conducting state to a non-conducting state. The snubber circuit is connected across the cathode and anode of the thyristor to absorb system energy when the thyristor is switched. The commutating circuit is coupled in series with the cathode of the thyristor by means of a current transformer for increasing the cathode resistance, causing the cathode current to immediately transfer to the gate.

Abstract: A control circuit combined with a magnetically bistable solenoid armature provides a bistable undervoltage release function to a circuit breaker. The solenoid is fabricated from a material having high magnetic remnance and low coercivity. A first signal to the solenoid coil develops a high remnance flux to hold the armature against a spring force. A second signal, of opposite polarity and predetermined voltage, produces an opposing magnetic flux to cancel that retained by the solenoid. The armature then becomes extended under the influence of a charged spring to trip the breaker.

Abstract: A solid state switch connected across a pair of separable contacts for eliminating arcing across the contacts allows the contacts and the contact driver to be enclosed within an evacuated envelope. The vacuum environment allows the use of an inexpensive, highly conductive contact material, such as copper, without fear of chemical reaction.

Abstract: A magnetic contact driver is arranged to drive a bridging contact out of electrical connection with a pair of fixed contacts to interrupt the current therethrough. The magnetic driver comprises a conductor winding embedded within notches in a plurality of metal laminations and an armature arranged transverse to the metal laminations. An auxiliary contact driver arrangement consisting of a pair of spaced electrical conductors arranged on the opposite side of the bridging contact is simultaneously energized for electrodynamic repulsion at the instant the magnetic driver winding becomes energized.

Abstract: A high speed contact driver for use in an electrical circuit interrupter includes a pair of series-connected, elongate and generally opposing electrical conductors bowed in predetermined, generally opposing contours. These conductors are connected to a bridging electrical contact which is normally biased into a bridging position between a pair of stationary contacts. Pulse generating means are provided for applying a current pulse of predetermined magnitude to the electrical conductors. In response to this current pulse, these electrical conductors electromagnetically repulse each other and drive the bridging contact out of bridging position between the stationary contacts.

Abstract: A pair of main contacts and a pair of arcing contacts are electrically and mechanically interconnected within a current limiting circuit interrupter. A common operator biases the main contacts in a closed contact condition, while simultaneously biasing the arcing contacts to an open condition. A contact driver operating to open the main contacts simultaneously closes the arcing contacts causing circuit current to pass through both the main and arcing contacts. Further displacement of the moving contacts completely directs the circuit current through the arcing contacts for electromagnetic repulsion and arcing within a magnetic structure.

Abstract: Synchronous circuit interruption is provided by operation of a diversion circuit for diverting most of the circuit current away from a pair of series-connected electrical contacts over to a solid state current interrupter prior to energizing a contact operator to separate the contacts to interrupt the remaining circuit current. To ensure arcless contact separation, the contact operator is arranged electrically in series with the solid state current interrupter which ultimately dissipates the system energy within a voltage dependent element. The arrangement of the contact operator circuit in series with the solid state current interrupter synchronizes the operation of the contact operator to ensure that the contacts are separated immediately after the circuit current has become diverted.

Abstract: A bridging contact is arranged across two fixed contacts with a pair of parallel, closely spaced conductors serving as the bridging contact carrier. A high current pulse in opposite direction within the parallel conductors generates electrodynamic forces rapidly propelling the conductors further apart. The bridging contact carried by the parallel conductors is rapidly driven out of contact relation with the fixed contacts to interrupt the circuit.

Abstract: A varistor quenched arc chute for current limiting circuit interrupters utilizes the combination of a plurality of stacked metal plates for attracting the arc that forms upon separation of the current limiting contacts with interspersed varistor elements for dissipating the system stored energy. The number of metal plates and the clamping voltage of the varistors is adjusted for optimum arc de-ionization. After arc extinction, the metal plates serve as cooling fins for the varistors.