Abstract: A low loss composite spider arrangement for use in inductive electrical epment and an air core reactor incorporating the same in which a non-conductive or a conductive material having very low relative permeability and relatively high resistivity is used to fulfill the mechanical and structural requirements of the spider, and a relatively small amount of electrical conducting material, bonded to and preferably electrically isolated therefrom, is used to fulfill the electrical requirements of the spider.

Abstract: A circuit for correcting power factor and for reducing ac line current harmonic components in conjunction with bridge-connected capacitive-filtered loads and for providing a source of ac startup current for associated circuitry, for example a switch mode power supply which may form part of the load. The circuit comprises a rectifier bridge, a dual-tuned circuit having a tuned filter in series between an ac line input and the bridge, and a shunt capacitor across the input to the bridge. The tuned filter comprises a parallel connected inductor and capacitor, the shunt capacitor being tuned with the inductor to form a trap filter to reduce third-order and higher harmonic components in the ac line current. The circuit also includes a current source operatively connected to the shunt capacitor for providing a source of ac current immediately upon application of ac power to the ac line input.

Abstract: A ground fault interrupt circuit with an improved current window detector. The current window detector works by first rectifying the input current in a pair of current mirrors connected in back to back fashion in the feedback path of the input amplifier. The rectified current triggers an output when the rectified current exceeds a predetermined threshold.

Abstract: A miniature station protector module for communication systems includes a hollow housing into which is disposed a pair of line terminals with a ground terminal therebetween. The line terminals extend into the hollow housing and include thereon a back-up surge arrester in axial alignment with each of the terminals, either a three terminal surge arrester or a pair of two terminal arresters may be utilized having one electrode connected to the ground terminal with the other electrodes being connected to the line terminals.

Abstract: A protective relay system for generation apparatus connectable to a three-phase alternating current electrical utility system. The relay system includes a dual processing architecture wherein a digital signal processor executes all the signal-processing algorithms, and a separate microprocessor is used for input/output data processing. A dual-ported RAM is used to effect a fast communication link between the digital signal processor and the microprocessor to accomplish high-speed protective relaying functions to selectively trip and close a circuit breaker at a generator or cogenerator site, or that which connects it to an electric utility system.

Abstract: A miniature solid state surge protector apparatus for use in telephone central offices, or the like, that are provided with terminal blocks for communication lines which may include an in-line overcurrent coil arrangement that grounds each communication line if an overcurrent flows therethrough and is additionally provided with a solid state miniaturized surge protection device disposed across a pair of communication lines and a common ground terminal, thus providing overvoltage and overcurrent protection (fail short) to a pair of telephone communication lines.

Abstract: A railway track circuit surge suppression system for the protection of wayside equipment from transitory energy surges appearing in the rails. The system has a primary surge suppression stage typically near the rails and a secondary surge suppression stage typically near the equipment to be protected. The secondary stage comprises an apparatus having a pair of inductors arranged serially with the respective track line wires to oppose the flow of surging current. Thus, the much of the energy dissipates at the primary stage. Remaining energy is dissipated by a voltage clamp behind the inductors.

Abstract: An overload control circuit and method of operation for protecting a three-phase motor from damage due to overload includes monitors reading the load on each phase of the motor and circuitry for combining the three separate phase signals into a single combined load signal which triggers the overload circuit. The gain on the combined load signal and the overload trip delay time may be calibrated and monitored by an external meter to provide for accurate and inexpensive calibration to accommodate specific operating characteristics of the motor being monitored. The circuit provides visual readouts of the mode of operation, including: (1) operating mode; (2) overload onset; (3) shut down initiated; and (4) delay to restart.

Abstract: A contact for use in contacting a moving photoreceptor surface, is formed from a structure (preferably a pultrusion) including a plurality of continuous strand fibers of high electrical resistance, and a thermally stable insulating component between the resistive fibers. The resistive fibers are configured to form a brush extending from the insulating component for contact with the photoreceptor surface. The resistance of the fibers is sufficiently high to reduce leakage of surface charges away from the photoreceptor and to provide a high resistance between adjacent fibers. The insulating component, which serves to interface the carbon filaments from each other and from a host polymer may comprise an organic compound, such as a polyimide composition, or may comprise an inorganic compound such as Al.sub.2 O.sub.3 or water glass, and is thermally stable below about 1000.degree. C. The host polymer, on the other hand volatilizes rapidly and cleanly upon direct exposure to laser energy.

Abstract: A superconducting coil system includes an excitation power source, a superconducting coil, a DC circuit breaker connected in series between the excitation power source and the superconducting coil to disconnect them when quenching occurs, a protective resistor connected in a parallel manner to the superconducting coil for dissipating the energy accumulated in the superconducting coil when the quenching occurs, and a switch provided as a bypass of the DC circuit breaker, the switch being closed during the normal operation to pass the energy from the excitation power source to the superconducting coil through a resistor and being opened when the quenching occurs.

Abstract: The invention concerns a device for a.c. cut-in limitation of a power-sup unit with inductive reactance. The device has a series-connected first a.c. switch and a phase-angle control circuit by means of which a time lag can be introduced in the connection between the primary winding and the mains a.c. voltage at the point in time that cut-in takes place. The control electrode of the first a.c. switch of the floating phase-angle control circuit is connected to the output of a control circuit by means of which a trigger voltage, which is synchronized with the mains a.c. voltage, is generated, when the power-supply unit is switched in, at a selectable phase angle between 90 and 0 degrees before a zero passage of the main a.c. voltage. The trigger voltage can be suppressed before the zero passage of the mains a.c. voltage is reached in order to switch off the power-supply unit.

Abstract: An arresting insulator is provided which includes an insulator body made of an insulative material and a non-linear resistor. The insulator body includes a head for linking the insulator to an adjacent insulator, and a shed formed integrally with the head. The resistor is secured in the insulator body and has a non-linear relation between residual voltage and current. More specifically, the resistor has a characteristic that satisfies the equation:V.sub.NmA /H.gtoreq.300 V/mmwherein V.sub.NmA is a threshold reference voltage that causes a current of at least N milliamps to start flowing across the resistor to cause the resistor to perform a surge absorbing function. N is an arbitrary value in the range of 1 to 10, and H is the axial length of the resistor along a direction of electric field in millimeters.

Abstract: A superconducting magnet device which is capable of protecting at the time of quenching a superconducting magnet divided into a plurality of sections comprises a superconducting magnet circuit which is formed by sequentially connecting in series coil pairs 1a, 1b, and 2a, 2b which are positioned symmetrically with respect to a ferromagnetic shield 6, and by connecting in parallel to the superconducting coils 1a, 1b and 2a, 2b superconducting coil protecting elements 3a and 3b which protect the superconducting coils 1a, 1b and 2a, 2b when the voltage at the ends of the coils has exceeded a predetermined value. If quenching occurs at the superconducting coils 1a, 1b and 2a, 2b, generation of an unbalanced electromagnetic force, a local electromagnetic force, etc., against the ferromagnetic shield 6 is prevented, so that the support structure for the superconducting coils and the ferromagnetic shield can be simplified.

Abstract: A microprocessor watch-dog monitor for electronic trip units includes an input transistor (Q1), a timing circuit (16), and a comparator circuit (18). The comparator circuit is formed of a first bipolar transistor (Q3) of the PNP-type conductivity and a second bipolar transistor (Q4) of the NPN-type conductivity.

Abstract: A vacuum circuit breaker particularly suitable for use in an electric motor vehicle. The circuit breaker includes a vacuum interrupter to which a voltage is applied, the series combination of a capacitor and a switch which are connected in parallel with the vacuum interrupter, a provision for charging the capacitor with a voltage opposite the voltage applied to the vacuum interrupter, and a resistance connected in parallel with the vacuum interrupter. The vacuum interrupter, the resistance, and the series combination of the capacitor and switch form oscillation circuit having an oscillation frequency at least 2 KHz and an inductance of at least 1 .mu.H, with a commutating current of at least 5000 A for consuming energy stored in the circuit.

Abstract: A miniature solid state surge protection device having an unsealed solid state device having first and second electrodes with the first electrode in contact with a fusible pellet is provided. When a surge occurs the pellet melts to thereby short the first and second electrodes together.

Abstract: A superconducting coil protective system comprises a quenching detector (QD) for detecting occurrence of a quenching in a superconducting coil (L) and generating a quenching signal indicative of the occurrence of the quenching. In response to the quenching signal, a voltage controller (VC) reduces an output voltage from a power source (PS) to zero or to a negative polarity. A current interrupter (CI) including a circuit breaker (CB) or a fuse (F) is connected in parallel to the superconducting coil (L) for allowing a first commutation of a current from the superconducting coil (L) to the current interrupter (CI) upon the reduction of the output voltage from the power source (PS). The system also comprises a protective resistor (RD) connected in parallel to the current interrupter (CI) for allowing a second commutation of the first-commutated current thereto upon the opening of the current interrupter (CI), whereby energy of the second-commutated current is dissipated in the protective resistor.

Abstract: Being operable as a presentation layer defined by the International Standard ISO 7498, each data communication system comprises (A) a syntax transforming unit and (B) an abstract syntax storing unit besides (a) an application program unit for producing and receiving abstract syntaxes descriptive of data according to the International Standard ISO 8824 and (b) a sending and receiving unit for sending and receiving trasfer syntaxes to and from at least one counterpart system. Before carrying out data transfer, negotiation is had in the known manner to decide a set of abstract syntaxes, which can be used in the data transfer and are herein called negotiated syntaxes and encoded by the transforming unit into primary transfer syntaxes as herein called with these transfer syntaxes accompanied by first information. The application program unit may produce different syntaxes which are the abstract syntaxes other than the negotiated syntaxes.

Abstract: A circuit protects the series coupled PMOS-NMOS transistor output stage, input stage or input/output stage commonly found in a CMOS device from output pad ESD, whether or not the CMOS device is mounted in a circuit board or coupled to a power source. The circuit includes a second PMOS transistor whose output leads are coupled between the output pad and the gate of the output NMOS transistor, and also includes a resistor coupled between the gate of this second PMOS transistor and a voltage source node. A positive potential ESD at the output pad will turn on the second PMOS transistor, thereby coupling positive ESD potential to the gate of the output NMOS transistor. This causes the output NMOS transistor to turn on, avoiding the "snapback" mode destruction that would occur if the second PMOS transistor were not present.

Abstract: A protection circuit for protecting circuit elements (TX) connected to line via terminal means (L1 and L2) from the effects of a transient abnormal high voltage surge, comprising a semiconductor switch (TR1 and TR2), a first circuit comprising a resistor (R1 ) in series with the conductor path of the semiconductor switch and a voltage reference means (D1, and D2)in parallel with the resistor and a junction of the semiconductor, and a second circuit comprising the first voltage reference means in series with a second voltage reference means (D3), the second circuit being connected in parallel with the resistor. The second circuit further includes a voltage dependent resistance (VC1). When the current through the resistor exceeds normal line current the voltage reference means (D1, D2, D3) clamp the voltage drop across the resistor and turn off the semiconductor switch.