Abstract: A method and apparatus for detecting an electrical fault in a printed circuit board includes a first conductive layer interconnecting a set of electrical components, a second conductive layer connected to an electrical ground, a set of fuses arranged about the printed circuit board, and a fault detection circuit electrically connected to the printed circuit board.

Abstract: A circuit device can be implemented, which includes a zener diode barrier composed of one or more zener diodes. The circuit device further includes one or more detection circuits electronically in series with the zener diode (or zener diodes) of the zener diode barrier. The zener diode barrier functions as an IS (Intrinsically Safe) barrier. The detection circuit (or circuits) facilitates the production of detailed information concerning different types of events detected by the detection circuit(s).

Abstract: A reactor according to an embodiment of the present disclosure includes a core body that includes an outer peripheral iron core composed of a plurality of outer peripheral iron core portions, at least three iron cores coupled to the outer peripheral iron core portions, and coils wound on the iron cores. A gap is formed between one of the iron cores and another of the iron cores adjacent to the one of the iron cores, so as to be magnetically connectable through the gap. The reactor includes a terminal base unit for electrically connecting the coils to an external device, and a temperature sensor attached to a surface of the terminal base unit, the surface being opposite the coils.

Abstract: An apparatus for monitoring at least one physical or chemical process variable, comprising at least one sensor unit and an electronics unit for signal registration, evaluation and/or feeding, wherein the sensor unit is operated with alternating electrical current and/or communication between the electronics unit and the sensor unit occurs with alternating electrical current and/or alternating voltage. An explosion protection circuit with intrinsic safety, which includes a safety barrier, which has at least one unit for electrical current- and/or voltage limiting, is provided within the explosion protection circuit a unit for impedance matching, which unit for impedance matching includes at least one transformer.

Abstract: Several embodiments of a novel technique for limiting transmission of fault current are disclosed. Current power distribution systems typically have an impedance, or reactor, on the output of the network equipment to limit current in the case of a fault condition. A low resistance switch, which changes its resistance in the presence of high current, is connected in parallel with this reactor. Thus, in normal operation, the current from the power generator bypasses the reactor, thereby minimizing power loss. However, in the presence of a fault, the resistance of the switch increases, forcing the current to pass through the reactor, thereby limiting the fault current.

Abstract: The present invention is directed to an electrical wiring device that includes a frameless shutter assembly disposed in the front cover portion or in a separator member between the receptacle openings and the receptacle terminals. The frameless shutter assembly comprises a first shutter member and a second shutter member configured to move from a closed position to an open position when the hot and neutral blades of a plug blade set are simultaneously inserted into the receptacle openings to engage a set of receptacle terminals and remain closed otherwise. The front cover member and/or the at least one separator includes a first stop member disposed proximate the first shutter member and a second stop member being disposed proximate the second shutter member.

Abstract: An externally replaceable primary fuse for a pole-mount electrical distribution transformer, thereby eliminating a need for a conventional internal fuse, and a method of use thereof is herein disclosed. The fuse is accessed using a bayonet-style fuse holder mounted to an outside surface of a transformer tank being internally wired thereto a primary transformer lead. The fuse holding apparatus permits fuse replacement while the transformer remains mounted to a pole, providing a reduction of down time and expense during said fuse replacement.

Abstract: A disconnector for distribution transformers with dielectric liquid intended for comprehensive protection of a power grid or for protecting distribution transformers. The disconnector provides at least two cylindrical current-limiting fuses located inside a transformer tank. Each fuse is electrically connected with an external phase power supply through fixed contacts and moving contacts of the disconnector with the active part of the transformer. The disconnector has an additional auxiliary contact which is electrically connected to a switch connected to the active part of the transformer on a low voltage side of the transformer.

Abstract: A circuit for balancing a sub-stack voltage in a stack of ultracapacitors includes a pair of electrical leads that are connectable across a first sub-stack of one or more ultracapacitors, wherein a stack includes N sub-stacks of ultracapacitors coupled to an electrical bus, a discharge device switchably connectable with the pair of electrical leads, the discharge device configured to discharge the sub-stack of ultracapacitors, a voltage sensing circuit coupled to the electrical bus and configured to sense and output a voltage of the stack of ultracapacitors after the first sub-stack of one or more ultracapacitors has been discharged to a given threshold, and a voltage amplifier coupled to the output of the voltage sensing circuit and coupled to the pair of electrical leads, the voltage amplifier configured to provide a re-charge voltage to the first sub-stack of one or more ultracapacitors.

Abstract: A stage-fused underground transformer loop system, which includes a series of transformers connected sequentially by a series of cables, and a series of fused elbow terminators connected to the inlets and outlets of the transformers. The fused elbow terminators are arranged in an order of decreasing the fuse capacity starting from the feed. The fused elbow terminator includes an elbow connector having a housing and a cable connector disposed within; and a fused pin connected to the cable connector. Further disclosed is a method of rapid diagnosis of a fault cable or a transformer failure using the stage-fused transformer loop system.

Abstract: A DC switchgear is provided with a commutation-type DC circuit breaker having a main circuit provided with a main switch for interconnecting a DC power supply and a load, and a commutating circuit provided with a commutating capacitor and a commutating switch, which is connected electrically parallel to the main switch. The switchgear further has a DC circuit breaker accommodating box that includes the main circuit provided with the main switch, and the commutation-type DC circuit breaker; a front accommodating box disposed on the front of the DC circuit breaker accommodating box, which accommodates devices having functions for controlling the switchgear and indicating a status, such as a failure status thereof; and a rear accommodating box disposed on the back of the DC circuit breaker accommodating box. The front and rear accommodating boxes are connected to the DC circuit breaker accommodating box to form an integrated DC switchgear.

Abstract: The electrical equipment comprises electrical elements corresponding to at least one phase of the distribution network and housed in a tank. The equipment is insulated with a dielectric liquid wherein the elements are immersed. The equipment comprises an input for each phase in the tank, and also a protection device, associated with at least one failure detector and configured so that, in the event of detecting such a failure, a short circuit will be established in the phases. The protection device is situated so as to establish the short circuit in a position before any protection, control or transformer element of the electrical equipment.

Abstract: A protection system for a transformer system that includes three single phase transformers with auxiliary secondary windings, respectively. The auxiliary secondary windings are connected to form an open delta configuration. The protection system is connected into the open delta configuration, between the auxiliary secondary windings of two of the transformers. The protection system includes a circuit having an element with a threshold voltage and current characteristic connected in series with a thermal protection device and a resistor.

Abstract: A transformer which includes a primary winding having a plurality of primary winding taps, and a secondary winding having a plurality of secondary winding taps. A core is included on which the primary winding and the secondary winding are mounted. The primary winding and the secondary winding are electromagnetically coupled through the core. At least one terminal block is provided where each terminal block is connected to the primary winding taps or the plurality of secondary winding taps. Each terminal block includes at least a first row of terminals and a second row of terminals, and at least some of the first row of terminals are each connected to a corresponding one of the winding taps.

Abstract: A DC—DC converter is composed of an overcurrent cut-off means connected in series to a direct power source, primary windings of a plurality of transformers connected in series to the overcurrent cut-off means, a switching element connected in series to the overcurrent cut-off means and secondary windings of a plurality of transformers connected in parallel with each other. According to the DC—DC converter, a voltage induced on the secondary windings are rectified and smoothed by a first rectifying and smoothing circuit to output the smooth direct voltage to a load. When a short-circuit test is carried out for one of the primary windings, the overcurrent cut-off means cuts off an overcurrent flow.

Abstract: A fused disconnect switch assembly includes a pull out fuse assembly and a switch housing assembly. The fuse assembly includes a line side conducting portion, a load side conducting portion, and a fuse element therebetween. The switch housing assembly includes a fuse receptacle for receiving the fuse, a first contact assembly coupled to the line side conducting portion of the fuse and a second contact assembly coupled to the load side conducting portion of the fuse when the fuse is inserted into the receptacle. An open fuse indication device is in communication with conducting portions of the fuse, and an alarm terminal output extends from the switch assembly housing and is in communication with the open fuse indication device. The open fuse indication device provides local fuse state indication and the alarm terminal output facilitates remote fuse state indication when coupled to external circuitry.

Abstract: An electromagnetic coil assembly for an electromagnetic device comprises a bobbin, a multiple turn winding of electrical wire supported on a flange of the bobbin and a thermal protection device including a pair of lead wires extending from both sides thereof. The first lead wire is connected to one end of the multiple turn winding by a first joining member. The second lead wire is connected to an electric circuit by a second joining member. A connecting device, disposed on an outboard surface of one of the flanges of the bobbin, receives the thermal protection device, the first joining member and the second joining member.

Abstract: A portion of a solenoid coil melts after a predetermined time period has elapsed to interrupt the flow of current through the coil. The portion which melts can include a reduced cross sectional area which increases the resistance of the portion of the wire. Alternately, a portion of the coil wire can be formed from a material having a higher resistivity than the remainder of the wire.

Abstract: A voltage surge suppression system for the protection of electronic equipment from damage from voltage surges and voltage transients has at least one metal oxide varistor electrically connected to a primary power source; a transformer; at least one second metal oxide varistor electronically connected between said transmission interceptor and a power circuit board; and a circuit opener electronically connected between the a transformer and power circuit board; wherein the a transformer is connected between the primary power source and second metal oxide varistor. The circuit opener is a resettable breaker for protecting the transformer from surges greater than the rated value of the second metal oxide varistor by opening in order to close off current flow.

Abstract: A terminal bushing having integral overvoltage and fault current protection includes an insulator having an upper and a lower chamber. Nonlinear resistors are disposed in the upper chamber between a top terminal and an intermediate terminal which are mounted on the insulator. The top terminal, the nonlinear resistors and the intermediate terminal form a first current path through the bushing. The bushing also includes a pair of mounting arms which support a current limiting dropout fuseholder. The fuseholder is disposed in series between the top terminal and a bushing stud which is retained in the lower chamber of the bushing body. A second current path through the bushing is thus formed by the top terminal, the fuseholder and the bushing stud.

Abstract: A step down transformer power supply with short circuit protection which uses a minimal size transformer, as opposed to an energy limiting transformer. The transformer is mounted directly on a PC board without additional mounting hardware, and has a fuse in its secondary winding, which is required to pass a UL short circuit test, and is normally nonreplaceable. A low cost circuit limits the current output of the transformer such that the fuse is not blown, even under a shorted output condition, which would normally require replacement of the transformer. A rectifier circuit is coupled across the secondary winding of the step down transformer, and is coupled to a first terminal of a three terminal power regulator circuit which supplies a regulated stepped down voltage through a second terminal connected to a load. The third terminal thereof comprises a current/voltage limiting control terminal.

Abstract: A single three-terminal chip-type surge absorber combines two or three semiconductor surge-absorbing elements with three electrode plates and resin-molding the combination. When more lines must be connected to an electronic device subject to a voltage surge, instead of mounting a plurality of surge-absorbing elements, which requires a substantial space and many mounting steps, a single surge absorber with a plurality of surge absorbing elements absorbs the voltage surge.

Abstract: In the case of a method and a device for triggering an electromagnetic consumer (1), which is connected in series to a switching means (2), the voltage applied to the switching means (2) is fed to a voltage comparison means (12) and compared there to the voltage of a reference voltage source (13). Dependent upon this voltage comparison, an output signal is produced at the output terminal of the voltage comparison means (12), which serves to switch over a suppressor device (4).

Abstract: A transformer bobbin is provided comprising a frame of approximately a rectangular shape, a first wall arranged on one end of the frame, a second wall arranged on the other end of the frame, and a center wall arranged between the first wall and the second wall. The frame, the first wall, and the center wall constitute in combination a primary winding section. The frame, the center wall, and the second wall constitute in combination a secondary winding section. In particular, the primary winding section has a container case detachably mounted thereto for selective assignment for use. Also, the container is arranged for accommodating a current disconnecting means for deenergizing a transformer circuit when the coil temperature increases up to a limit level.

Abstract: A tubular fuseholder housing carries two sets of generally-stationary contacts located at points spaced apart along the length of the housing. Within the housing is a fuse comprising a cartridge and, at opposite ends of the cartridge, terminal contacts for respectively engaging the stationary contacts when the cartridge is fully inserted into the housing. An insulating operating rod within the fuseholder housing is coupled to the fuse cartridge and extends toward the outer end of the housing.Actuation of the operating rod separates the terminal contacts from the generally-stationary contacts and draws electric arcs between these contact. Closely adjacent the individual contacts of each set of stationary contacts and angularly aligned with the individual contacts, supplemental exhaust ports are provided in the fuseholder housing. The fuseholder housing normally contains dielectric liquid covering the fuse which is vaporizable by the arcs to generate gases that are exhausted through the supplemental ports.

Abstract: A fuse housing for an oil-cooled transformer that uses a stopper to prevent oil from escaping the transformer tank as the fuse and fuse holder are removed. During normal operation, the stopper is held in an open position by the fuse holder. When the fuse and fuse holder are removed, the stopper closes and seals the upper end of the holder, preventing oil from draining through the upper portion of the fuse housing and escaping from the transformer tank.

Abstract: A double-insulated transformer of the coaxial type comprises a core assembly having a center core, a primary winding assembly assembled to surround coaxially the center core which has a primary bobbin case, a primary coil winding wound around the bobbin case and a primary terminal portion provided at an axial end of the bobbin case for connecting the primary coil winding and input lead lines, a secondary winding assembly to surround coaxially the primary winding assembly which has a secondary bobbin case, a secondary coil winding wound around the secondary bobbin case and a secondary terminal portion provided at an axial end of the secondary bobbin case opposite to the primary terminal portion for connecting the secondary coil winding with external lead lines, and an insulating case assembled to surround coaxially the secondary winding assembly.

Abstract: In a ground circuit apparatus for electronic equipment according to this invention, a motor driving circuit group constituted of a drum motor, a loading motor and a capstan motor is connected with a DC power source through a power source line and a ground line to have power supplied therefrom. A signal processing circuit group constituted of a camera circuit, a logic circuit, servo circuit, video circuit and an audio circuit as well as an electronic view finder is connected with the DC power source through the power line and a ground line. A video circuit of the signal processing circuit group is connected through a ground line to a chassis which serves as a reference potential point. In addition, two diodes connected in parallel and directed in mutually opposite directions to have opposite polarities and a ground line are connected between the electronic view finder and the chassis.

Abstract: An assembly which includes a transformer having a primary winding, a secondary winding, wires extending from the windings, a core at least partially disposed within the windings, a mounting flange, a housing surrounding at least a part of the windings and apparatus for mounting a fuse block on the transformer. The apparatus for mounting includes a tongue extending within the housing and a potting compound disposed in the housing.

Abstract: An improved, lowcost double-fused vacuum switchgear apparatus designed for underground electrical distribution systems is provided which makes use of a specially configured oil tank-defining wall and insulative protective fuse well sleeves to give enhanced protection to workmen performing unauthorized energized servicing of the unit, while also using a minimum of dielectric oil and separate wall components. The preferred tank includes an oblique sidewall eliminating unnecessary oil space in the tank, while each fuse well is equipped with an insulative sleeve which guides fuse removal and installation and largely prevents short-circuiting even during energized servicing. The fuse assembly preferably includes a current-limiting fuse and a series-coupled expulsion fuse, the latter being oriented in the wells for directing conductive arcing gases downwardly and away from the switchgear components.

Abstract: A fault sensing system for protecting a transformer, the system including a partial range current limiting fuse connected in series in the primary circuit for the network transformer, a normally open vacuum switch connected to the primary circuit and shunted to ground between the current limiting fuse and the transformer, a solenoid actuated assembly for closing the vacuum switch and a fault sensing circuit assembly operatively connected to energize the solenoid assembly, the fault sensing circuit being normally de-energized and including a current transformer mounted on the primary circuit and a low voltage fuse element connected across the current transformer, the fault sensing circuit assembly being energized on operation of the low voltage fuse element to momentarily energize the solenoid.

Abstract: A spool for a power supply transformer with one flange having attachments for providing the necessary connections to and from the transformer windings and holding fuses in place and another flange having slots for snap-in attachment to a baseplate.

Abstract: An electromagnetic coil construction consisting of a bobbin having a primary winding and a secondary winding, the bobbin having an end flange at either end of the hub and a central separator flange intermediately spaced between the first and second flanges, the separator flange having a through opening into which a thermal sensing device electrically, interconnected in series with the primary winding or a secondary winding is adapted to be interposed whereby the device is in physical contact with both the primary and the secondary winding to interrupt the circuit upon overheating of either or both windings.

Abstract: A protective fuse comprising a fusible element disposed within an enclosure formed by a gas generating fiber tube connected at one end to a conductor rod and at the other end to an arc intercepting member. The arc intercepting member is connected to an elongated tubular resistor element which in turn is connected at its opposite end to a cap comprising a conductor connected to the fusible element. Upon parting of the fusible element an arc established by the fault current comes into contact with the arc intercepting member so that a circuit is established through the resistor element thereby momentarily reducing the fault current to a level which can be extinguished by the deionizing gases generated within the interior of the fuse. The conductor rod is formed of a magnetic material which is capable of generating a substantial magnetic flux which functions to bias the arc against the interior wall of the fiber tube to enhance the generation of deionizing gases.

Abstract: A high voltage transformer bushing having an inner conductor extending from a lower end to a point spaced from an upper end and having a side terminal at that point connected to a fuse link which is in turn connected to a high voltage line connector supported on the upper end of the bushing. A lightning arrester supported by and grounded to the transformer casing has an upper end spaced from the high voltage line connector to provide a spark gap.

Abstract: Protected liquid-filled electrical inductive apparatus having a dry well fuse assembly which includes a dry well fuse holder sealingly disposed through an opening in the associated metallic casing, separate from the electrical bushings, and a removable fuse portion. The dry well fuse holder includes first and second spaced terminals each having portions immersed in the liquid dielectric and portions accessible within the dry well for cooperative engagement with contacts on the removable fuse portion. The first terminal is closer to the metallic casing than the second terminal. Ionization of the air within the dry well fuse holder adjacent to the first terminal is prevented by a tubular shield member mounted on the outside of the dry well fuse holder. One of the axial end portions of the tubular shield member makes electrical contact with the immersed portion of the first terminal.

Abstract: Protected liquid-filled electrical inductive apparatus having a dry well fuse assembly which includes a dry well fuse holder sealingly disposed through an opening in the associated metallic casing, separate from the electrical bushings, and a removable fuse portion. Ionization of the air within the fuse holder is prevented by a resilient plug mounted on the removable fuse portion which, when the fuse portion is assembled within the dry well fuse holder, is immediately adjacent to the electrical terminal which is closest to the grounded casing. The resilient plug member provides an air seal adjacent to the terminal without providing a pressure seal within the receptacle.

Abstract: A protective device for electrical power distribution equipment includes a removable fuse holder and an integral load switch. The protective device may be affixed to a grounded metal enclosure, such as an oil-filled transformer, into which the protective device extends. The fuse holder may be removed from the protective device for checking or replacement with a minimal opening into the enclosure into which the protective device extends. A suitable load switch actuator is provided for controlling current flow through a fuse in the fuse holder. This load switch actuator also provides an interlock arrangement to prevent removal of the fuse holder from, as well as insertion of the fuse holder into, the protective device unless the load switch is open, thus ensuring that interruption and initation of current flow through the fuse in the removable fuse holder is controlled by the load switch.

Abstract: Overpressure protection for a vaporization cooled electrical inductive apparatus. A pressure responsive device is actuated by a predetermined pressure within a sealed housing and de-energizes a pump, thereby stopping the flow of dielectric fluid to the heat producing members which prevents further pressure increases within a tank due to continued vaporization of the dielectric fluid. In one embodiment, a discharge valve is actuated by the pressure responsive device to drain the dielectric fluid from the windings to prevent further pressure increases caused by continued vaporization of the dielectric fluid. A fusible link is provided to disconnect the windings of the electrical inductive apparatus from a source of electrical potential subsequent to the de-energization of the pump. In another embodiment, the pressure responsive device actuates the circuit breaker which disconnects the windings of the electrical inductive apparatus from the source of electrical potential.