Abstract: A system for foreseeing deterioration in interrupting a performance of a vacuum interrupter, including a first measuring component for measuring potentials of electric lines connected to fixed and movable electrodes of the vacuum interrupter; a second measuring component for measuring a potential of an arc shield; a signal transmitting section for the transmission of potential signals resulting from the measurements in the first and second measuring component; a comparing section for making a comparison between the measured signal from the first measuring component and the measured signal from the second measuring component both transmitted through the signal transmitting section; and a judging section for judging that the fixed and movable electrodes have been deteriorated in their interrupting performance, on the basis of the result of the comparison made in the comparing section.

Abstract: A semiconductor integrated circuit includes an input terminal and a first circuit responsive to a signal supplied to the input terminal. An input voltage limiting circuit is further provided between the input terminal and the first circuit. The input voltage limiting circuit limits a voltage applied to the first circuit to a predetermined voltage.

Abstract: A sneak current protection device is disclosed including a series connected fuse, resistor and inductor for limiting the rate of current rise through the protective fuse whereby the fuse operates in compliance with all industry accepted standards for fire hazard and circuit protection.

Abstract: The DIN Standard VDE 160/01.86 involves specific requirements as far as the dielectric strength of electronic devices is concerned which are intended for operation at high-voltage networks. A guard circuit for the protection of capacitive loads is described. In this system, a current detector means is provided to detect the current flowing into the load and to emit a first blocking signal at least when the amount of the detected current exceeds a preset maximum value. A voltage detector means is provided to detect the voltage in the supply network and to emit a second blocking signal when the amount of the detected voltage exceeds a preset maximum value. A controllable switching means is provided which is so designed and in such controlled communication with the current and voltage detector means that the load will be isolated from the supply network as soon as at least one of the two blocking signals is applied.

Abstract: In a hair treatment device with a winding mandrel driven by a motor and used to wind up hair, the current used by the motor is led through a current limiter circuit in order to limit torque. The current limiter circuit comprises an operating stage and a safety stage. The safety stage is utilized to limit current if the operating stage fails.

Abstract: An apparatus is provided for controlling an electric motor that is doing some sort of work, whereby the apparatus automatically senses the presence of a work overload. Once the work overload is sensed, the apparatus automatically reverses the direction of rotation of the motor to eliminate the work overload. The reversed rotation is limited to either a predetermined period of time or to a predetermined number of reverse rotations. Once the predetermined limit of reverse rotation is reached, the apparatus automatically resumes normal rotation of the motor.

Abstract: A three phase loss protection circuit for a three phase rectifier. The rectifier includes a circuit which inhibits its operation when either of two of the three phases are lost. In response to the loss of the third phase, the loss protection circuit causes one of the other two phases to be lost at the input to the inhibiting circuit. The loss protection circuit does not interfere with the operation of the inhibiting circuit when either of the two phases are lost. In an alternative embodiment, the loss protection circuit includes circuitry to ensure that the rectifier is inhibited even though part of a lost phase may be recreated by the rectifier's input filter.

Abstract: A gas insulated switchgear system having two gas insulated switchgear equipments, each of which consists of first disconnecting switches, circuit breakers, and second disconnecting switches, three phase gas insulated buses which are respectively connected to the first disconnecting switches of the two gas insulated switchgear equipments in every three phases thereof, a single phase reserve buses which are commonly connected to all of the second disconnecting switches of the two gas insulated switchgear equipments, and an operating device for opening the circuit breakers and the first disconnecting switches in only one phase of the gas insulated switchgear equipments and closing the second disconnecting switch in only the one phase. A gas insulated switchgear system having single phase reserve bus is economical and switches one of the three phase main buses to the single reserve bus without forming short circuit.

Abstract: A highly efficient over current circuit breaker for an electric system is provided with a timer which is adjustable and can be set to produce a first control signal a predetermined time after the electric system is turned on, and a load detector in association with an over current control device which produces a second control signal when the load applied to the electric system exceeds a predetermined level. The first control signal and second control signal jointly activate an amplifier to produce a third control signal which activates relays to cause a magnetic switch to open, or "trip", whereby the electric system is turned off. The timer allows an electric surge to occur in the electric system without causing the magnetic switch to trip during the period of starting the electric system. The circuit breaker is particularly useful in systems having induction motors in which starting current surges are common.

Abstract: A ground fault current interrupter (GFCI) circuit is provided with the additional capacity of detecting and protecting against arcing between a power line and the metal sheath or cover of a power cable. An arc protection winding is located on the core of the GFCI differential transformer and is connected in series with a resistance between the metal sheath and a neutral or return line. By adjusting the number of turns of the arc protection winding and the size of the series resistance, the sensitivity of the arc portection arrangement to arcing current may be set at a desired level.

Abstract: A fail-safe, non-fragmenting surge arrester includes a liner having outlets formed in the walls thereof for venting ionized gases generated within the liner by internal arcing. The vented ionized gas forms a lower impedance path for the current which is thereby shunted around the failed internal components, preventing the generation of internal pressure which could otherwise cause a fragmenting failure mode of the arrester. The internal components include stacked varistor elements and may include an internal fuse link electrically in series with the varistors.

Abstract: A capacitor protection circuit for protecting bulk storage capacitors in a storage capacitor circuit in an electronic power supply. The capacitor protection circuit is operatively coupled to the storage capacitor circuit and comprises a first and second thyristor. The first and second thyristors are selected so that when the voltage across one of the storage capacitors in the storage capacitor circuit exceeds a predetermined voltage, the second thyristor will trigger the first thyristor to cause an excessive amount of current to be drawn through a fuse in the electronic power supply, thereby causing the fuse to blow and uncoupling the electronic circuit from an AC input. Another embodiment is disclosed to show how the capacitor protection circuit can be used in a 110 or 220 volt environment by utilizing a switch.

Abstract: An electronic circuit is provided for protecting an electronic system and its power supply from damages caused by an over-current condition. The circuit automatically enters into a first state upon application of power from the power supply. In this first state, current is allowed to pass from the power supply through a channel to the electronic system. Upon detecting an over-current condition, a positive feedback will cause the circuit to enter into a second state, wherein the channel is cutoff.

Abstract: A method of and a circuit for temperature protecting a transistor (4) comprising:a controlled voltage supply (34) for applying to the transistor a first voltage substantially less than a predetermined voltage required to render the transistor conductive at normal temperature;a detector (8, 12, 18) for detecting whether the transistor conducts in response to the applied first voltage; anda controlled voltage supply (46), responsive to not detecting conduction of the transistor, for enabling the transistor by applying thereto a second voltage at least equal to the predetermined voltage, and, responsive to detecting conduction of the transistor, for disabling the transistor by removing the first voltage therefrom and inhibiting the application of the second voltage thereto so as to prevent damage thereto.

Abstract: An electric circuit breaker for protecting an electric circuit of an electrical installation of a building is of such a construction that a substantial proportion of its components are standard for the preferred current ratings of the breaker and that some components having a limited useful life can be readily replaced.

Abstract: A solid-state, four terminal optical relay has a current regulator with two input pins, and an output switch with two output pins. The relay includes an optical isolator assembly so that the current which causes switching of the relay is optically, rather than electrically, transmitted to an output switch driver. The relay includes an internal current overload detect and latch circuit which operates if the relay is switched on into a shorted load, or if a short is switched in across the load while the relay is on. The current overload detect and latch circuit is sufficiently fast to permit the relay to be continuously pulsed into a shorted load without damage to the relay.

Abstract: In a solid state relay circuit including a power semiconductor for switching power to a load circuit and having circuitry for disabling the power semiconductor to protect against current overload or short circuits, such disabling means including a silicon controlled rectifier for short circuiting the input to the power semiconductor, apparatus for sensing the presence of transient voltages in the load circuit, and apparatus for disabling any short circuit caused by the silicon controlled rectifier due to such voltage transients.

Abstract: A gas discharge device is provided for protecting a telephone line from certain voltage surges. The gas discharge device provides low voltage surge protection from tip to ring but still retains higher voltage surge protection from tip or ring to ground. The device is a three terminal device constructed with a rod extending from the tip or ring toward the other tip or ring to control the electrical distance between the tip or ring. The ground element may be positioned at the other end of the device or it may be positioned intermediate the tip and ring so that the rod extends through an opening in the ground conductor. In either position, the distance between tip or ring and ground is greater than the distance between tip and ring, and thus the breakdown voltage is higher.

Abstract: A transient protection circuit comprising using a circuit connected to operate as a diode while presenting lower forward voltage drop for the same area and current as in pn junction diodes to provide greater efficiency. The circuit is a standard merged SCR circuit wherein a resistive path is provide between the base and collector of the pnp transistor and between the base and emitter of the npn transistor. In addition, there is provided a trip circuit wherein current is shunted away from the lateral transistor after a predetermined threshold current is passed through said transistor to minimize current drawn through the later transistor.

Abstract: The device relates to a gas lightning arrester comprising a tight enclosure and at least two electrodes (2a, 2b). In the enclosure is placed a powdery mineral addition agent. This addition agent is a mixture of elementary or mixed metal oxides globally corresponding to the general formula Al X.sub.a Y.sub.b O.sub.c, in which formula X and Y respectively represent at least one alkaline or alkaline-earth metal, a is between 0.02 and 1.5, b is between 0 and 0.25 and c has the necessary value to comply with the valency rules. Can be used for the protection of the telephone lines.