Abstract: An electrical resistance device which comprises a resistance element and a superconducting gate element electrically connected in series therewith. The normal state resistance of the superconducting gate element is substantially greater than the resistance of the resistance element. A plurality of such devices can be used with the windings of a superconducting magnet, for example, to protect the windings thereof if the temperature of a particular winding region rises rapidly (the winding region quenches) due to operational instabilities, for example. At a quench the voltage at the winding region being quenched is applied to all the other devices at the other windings to generate heat at such devices in response to a relatively small voltage increase at the initially quenched region. Each of the other winding regions is thereby quenched and the gate elements thereof are triggered into their normal resistive states so that the current in the devices is reduced to a safe level.

Abstract: In a switch gear, such as a high-voltage enclosed switchboard and a vacuum load-break switch, of the type wherein items of electrical equipment including disconnecting devices and circuit-breaking devices are installed within a case, masses of a silicone gel are filled in compartments accommodating the electrical equipment instead of the sulfur hexafluoride used heretofore. An air space is left above the silicone gel in each compartment. This construction enables the provision of a safer switch gear of smaller size than heretofore.

Abstract: A device to locate internal faults in a high-voltage capacitor battery that has a plurality of symmetrically parallel and series-coupled capacitor banks arranged in parallel branches coupled by shunt branches. The phase angles of the shunt currents flowing in the shunt branches relative to the total current flowing in the parallel branches are determined. A fault is located in one of the capacitor banks based upon these determined phase angles.

Abstract: A gate drive circuit for an insulated gate bipolar transistor initially drives the gate to a first voltage potential which causes the transistor to partially turn on. A sensor detects when the transistor saturates, at which point the gate drive voltage is increased to increase the conductivity of the transistor and reduce its saturation voltage drop. If, however, a load coupled to the transistor is short circuited, the transistor will never reach saturation and will remain partially turned on at a point where it has increased short circuit current handling capability. In addition, once the transistor has been fully turned on, should a short circuit load condition occur, the transistor will drop out of saturation causing the drive circuit to reduce the gate voltage to increase the short circuit current handling capability of the transistor.

Abstract: In an electrically powered apparatus, particularly a portable apparatus, having a flexible shielded main connection line (50) and an electronic protective device, said protective device is housed in the main connection plug (60) or in an adapter (61) to which the main connection line (50) can be coupled, wherewith said protective device serves as a safety device in the event of leakage of fluid into the apparatus or of current to ground or to protect the user.

Abstract: A protection system (80) for a first generator unit (12) connectible by a first switch (24) to a power generating system having at least one additional generator unit with the at least one additional generator unit being connectible in parallel to the first generator unit with the first switch being opened in response to a first control signal to enable the first generator unit to be disconnected from the parallel connection to the at least one additional generator unit in accordance with the invention includes a signal generator (12) for generating a reference signal having a frequency proportional to a frequency of a voltage generated by the first generator unit; a sensor (14) for sensing a common frequency at a point of reference of voltage generated by the generator units of the power generating system; and a controller (14) responsive to the signal generator and the sensor, for calculating a difference between the frequency of the reference signal and the common frequency and for generating the first con

Abstract: A circuit arrangement for protection against fault currents in power supplies, having an energy storage means, such as frequency converters for the operation of three-phase motors. The arrangement comprises two identical detector windings in the supply lines leading to the power supply so that a differential current detector winding connected with such detector windings causes a circuit breaker device to be actuated when a given value is exceeded. This circuit breaker device interrupts all the supply lines between the power supply and a load connected therewith by means of switching paths. This ensures that despite the energy stored in the power supply there is rapid and reliable switching off of the load should a fault current occur.

Abstract: A safety device adapted for use in a hand held tool for minimizing electrical shock from an AC power supply to a user includes a gound plane disposed inside the electrical tool, which, should the tool become immersed in water or become unreasonably wet, provides a path for electrical current, which energizes a solenoid which, in turn, disconnects the AC power supply. The safety device is encased in a cartridge or module. The safety device contains a power supply, such as a electret and/or a battery, that is independent of the AC power supply. Thus, the safety device can be tripped even if the tool is not plugged in or turned on.

Abstract: A computer system having a power supply monitoring arrangement employs a number of comparators for detecting whether or not various supply voltages produced by the power supply for use in the computer are above or below a reference level, or whether an overcurrent condition exists. These detected conditions are used to determine whether or not the power supply should be shut down, or during power-up to determine whether the initialization routine can be started by the CPU. Delays are included to prevent an undervoltage condition from indicating shut down of the power supply during power-up.

Abstract: An automatic override circuit is responsive to the magnitude of instantaneous current flow through a monitored conductor to produce an output signal which can actuate a solenoid or a ground fault interrupter to automatically trip a circuit breaker in repsonse to an excursion of current flow which exceeds a predetermined maximum current overhead level. The short circuit protector can automatically override a thermal trip delay and cause the circuit breaker to trip instantly or delay tripping for a prescribed period of short circuit events which exceed the maximum current overload level. In one embodiment, a control signal is generated which actuates a solenoid which is coupled to a thermal magnetic circuit breaker. In an alternative embodiment, the control signal is utilized for automatically triggering a ground fault interrupter.

Abstract: In a common drive output circuit for driving dissimilar switching semiconductor devices having different drive input characteristics by turning on and off dc power supplies to apply a voltage between the drive input terminals of either one of the switching semiconductor devices through two transistors connected in a Darlington pair, the collector circuit of one of the two transistors which is not at the output stage has a diode inserted in series which has such a polarity as to permit passage of the collector current.

Abstract: A thyristor valve circuit protected having an arrester to protect it from an overvoltage. The circuit includes a voltage detector for detecting a forward voltage level applied to the thyristor valve and generating a signal sVp when the detected voltage level exceeds a predetermined voltage which is set lower than the protection level of the arrester, and a circuit for generating a gate pulse applied to the thyristor valve in response to the signal sVp* from the voltage detector. The gate pulse generating circuit permits the gate pulse to be applied to the thyristor only when the condition of the presence of conduction command signal PHS and forward voltage signal FV, and the absence of output signal sVp* of the voltage detector, is satisfied.

Abstract: A remote control power disconnect circuit for providing a ground fault across an electrical outlet when an unsafe condition such as a lost neutral or shorting of the AC power switch is detected. The remote control power disconnect circuit is placed at each electrical outlet within a dwelling and applies AC power to the outlet only when an appliance (load) is plugged into the outlet and no fault condition is detected. However, when a fault condition is detected, the circuit also functions to apply a ground fault across the outlet and to shut-off the supply of AC power to the outlet. Then, once the fault condition has been remedied, the circuit may be remotely reset so that AC power may again be applied to the electrical outlet.

Abstract: An electronic circuit interrupter digital display and keypad device includes a display to view circuit breaker settings combined with a keypad to select settings and values to be displayed. The display and keypad device connects to an electronic trip unit within the circuit interrupter by means of a tamper-free seal to prevent the circuit interrupter set points from being changed without authorization. Alternatively, a password-operated control switch provides a similar function.

Abstract: An integratable circuit configuration includes a first transistor of one conduction type having an emitter being acted upon by a first potential, a collector being acted upon by a second potential, a base, a base-to-collector path and a base-to-emitter path. A resistor is connected in parallel with the base-to-emitter path of the first transistor. A second transistor of the other conduction type is connected to the base of the first transistor for triggering. A diode may be connected in parallel with the base-to-collector path of the first transistor. The diode conducts in inverse operation for reverse current reduction during inverse operation of the first transistor. A third transistor may be connected to the first transistor instead of the diode and fourth and further transistors may also be connected to the first transistor.

Abstract: A power source device including a lower voltage inverter transformer having plural secondary windings and a higher voltage inverter transformer having a primary winding connected directly to one of the secondary windings of the lower voltage inverter transformer without any rectifying circuit or inverter circuit interposed therebetween. The lower voltage and higher voltage transformers are contained in the same casing, the internal space of which is filled with an electrically insulative material to provide a unit device.

Abstract: Instantaneous trip capability is provided to an electronic circuit breaker, which is of the type that generates trip signals by accumulating squares of power line current samples and thresholds the accumulation results. Samples of power line current are taken directly from the current transformer and analog-to-digital converter cascade generating them. The analog-to-digital converter is of an oversampling type, using a delta-sigma modulator. The samples are threshold detected against a prescribed threshold value without previous squaring, integration and detection. The threshold detector result is checked for two consecutive overcurrent indications before an instantaneous trip signal is generated.

Abstract: Generating systems are operable in a starting mode to provide motive power to a prime mover to bring it up to a self-sustaining condition. However, a malfunction in a component connected between the generating system and the prime mover or in the prime mover itself may cause a potentially damaging condition to arise. In order to overcome this problem, a system for detecting, for example, the failure of a prime mover to achieve a self-sustaining condition continuously senses speed and acceleration of the prime mover, determines a minimum acceleration during a particular speed range, compares the minimum acceleration to prime mover acceleration at a point outside of the speed range and develops a signal to indicate no ignition if the minimum acceleration is greater than the acceleration at the point outside of the speed range.

Abstract: In a half-controlled three-phase bridge for feeding an inductive load, a further, externally charged capacitor and a further thyristor are additionally connected to the conventional protective capacitor which is already in existence. The further capacitor, which is charged from an external high-impedance voltage source, has the effect of causing an increased load current to be taken over by the further thyristor so that one of the conducting thyristors of the bridge is extinguished. The capacitor recharges and its voltage is used as a blocking voltage for the thyristor of the bridge which has just been extinguished so that the energy supply from the power system is stopped. The current in the load circuit can then be removed through a free-wheeling diode.

Abstract: A solid-state surge protection device comprises a semiconductor chip sandwiched between two electrodes. A resilient sealing member or layer comprised of a thermoplastic or thermosetting resin extends around the periphery of the device, adhering to both electrodes, so as to seal the interface region between the chip and each electrode. The resin is a flexible, dielectric material which is not disrupted by heat generated under surge conditions in the device, is environmentally inert, and preferably remains compliant under exteremely cold conditions. The electrodes of the device can move together into electric-conductive contact in the event of chip destruction, or can move back into contact with the chip if separated therefrom by an arc.