Abstract: A method in which ionization associated with fine wire or solid electrode systems causes mist droplets to charge and collect on electrode surfaces or at a region of highest electrical stress. The method includes manipulating droplet clouds to reach high stress regions. This process achieves improved electrical strength by depositing a mist in optimum locations before voltage applications.

Abstract: In a measuring device including a magnetic-optic current transformer (2) defining an optical path having an input (4) and an output (6) and having an optical transmission characteristics such that the relation between optical energy supplied to the input (4) and optical energy arriving at the output (6) is a function of an electrical parameter being monitored, an electrically driven photoemitter (8) disposed for supplying optical energy to the optical path input (4), a photodetector circuit (10, 12) optically coupled to the optical path output (6) for producing an electrical signal representative of the optical power arriving at the output (6), and a control circuit (14,16) connected between the photodetector circuit (10,12) and the photoemitter (8) for controlling the light energy supplied by the photoemitter (8) and forming with the transformer (2) a high pass filter having a corner frequency, the control circuit (14,16) is composed of an amplifier (20) and a first compensation unit (24,26) connected to for

Abstract: The voltage between two objects is measured utilizing an electro-optic crystal exhibiting birefringence in two axes (slow and fast) mutually orthogonal to an optic axis extending between the two objects. Two collimated light beams polarized at an angle to the slow and fast axes is passed through the crystal parallel to the optic axis with one of the collimated light beams retarded relative to the other by about 1/4 wave. The two beams emerging from the crystal are passed through a polarizer and converted to phase shifted electrical signals by photo diodes in electric circuits which regulate the sources of the light beams to maintain the peak magnitudes of the two electric signals constant and equal.

Abstract: A device for monitoring a magnetic field intensity having a given direction, the device including: a light conducting member (11) defining a first optical port (23), a second optical port (24), an optical path extending between the ports, and elements (31,34) for causing light to travel along the path between the ports (23,24); a first polarizer (31) disposed in the optical path for polarizing the light beam in a first plane of polarizaiton transverse to the path; a second polarizer (33) disposed in the optical path for polarizing the light beam in a second plane of polarization transverse to the path, the second polarizer (33) being spaced along the path from the first polarizer (31); and a focusing surface (18) disposed to intersect the beam at a point along the path between the polarizers (31,33) to focus the light beam from the first optical port (23) onto the second optical port (24).

Abstract: A microcomputer based reclosing relay performs a number of sequences to generate a succession of reclosure signals for a circuit breaker at timed intervals. The digital processing unit of the relay maintains flags, counts and running times for generating the succession of timed reclosures in a volatile memory. Periodically, these flags, counts and running times are copied to a non-volatile memory such as an EEPROM. Upon restoration of power following an interruption of power which results in loss of the contents of the volatile memory, the digital processing unit recopies the flags, counts and running times saved in the non-volatile memory back into the volatile memory, so that the relay can resume generating the succession of reclosures from the point at which power was lost. The flags and counts are copied to the EEPROM only when they change state, while the running times are only saved once a second to prolong the service life of the EEPROM.

Abstract: Monitoring and control of analog electromechanical protective relays and digital mcroprocessor based relays is integrated through a system including slave stations which record and time tag contact activity at each of the analog relays. The slave stations continuously retain digital samples of a predetermined number of the most recent cycles of the currents and voltages at the analog relays and when a trip occurs store the retained samples as pre-fault values together with a preset number of post-fault samples. A master station communicates with the slave stations monitoring the analog relays and with the digital relays through a two way communications network. The master station repetitively polls the slave stations and digital relays for contact activity. Detailed data such as the time tags and pre-fault and post-fault currents and voltages are then requested from those stations reporting contact activity.

Abstract: A transformer having a core having a butt-lap-step joint. The laminations of the core are the turns of a spiral into which a web of very thin amorphous magnetic material is wound. At the joint, the core is cut producing opposite folds whose ends are aligned. The purpose of the joint is to enable the core to be opened by pealing off the folds defining the cuts and converted into a U-shaped structure; coils are telescoped on the arms. The core is closed by refolding the folds and aligning the ends of the opposite folds. At the joint the laminations, subdivided into successive groups, are cut at an angle of the order of 87.degree. to the center line of the laminations; alternate groups being cut inclined in one direction and the intervening groups being cut inclined oppositely. The oppositely inclined cuts preclude mismatching and mislocating the groups when the core structure is closed after the coils are telescoped on the arms.

Abstract: A circuit breaker utilizes a plurality of vacuum interrupters immersed in oil. A cross-bar with electrically conductive sections completes a series electrical circuit through the circuit breaker and actuates operating mechanisms, to close the contacts of the vacuum interrupters when in the raised position as the cross-bar is lowered, the contacts of the vacuum interrupters are opened by impact forces before isolation gaps which fill with oil are created in the series electrical circuit. Various arrangements of the vacuum interrupters are disclosed for uprating existing oil circuit breakers.

Abstract: A rotating disc electromagnetic relay has an operating element which applies a torque to the disc tending to close the main contacts and a restraint element generating a torque which together with a spring tends to open the relay contacts. The operating and restraint elements each have an E-shaped core defining two magnetic circuits with a common center leg. Two voltages to be compared are applied to two input coils on the center leg of each element in the same sense to generate a flux representative of the sum of the voltages in the operating element and in the opposite sense to produce a flux representative of the difference between the two voltages in the restraint element. The flux in the common leg of each element divides between the two magnetic circuits. The flux in one magnetic circuit of each element is shifted in phase by a first lag coil on an outer leg of the core to generate the opening and closing torque, respectively.

Abstract: A steel sheet (10) having a stress-relief annealed, structure with a plurality of magnetic domains (12) is made by drilling a plurality of closely spaced, small holes (15) through the entire thickness of the steel sheet, where the drilling is effective to form additional domain walls (17) and subdivide the magnetic domains.

Abstract: A tamper-resistant three-phase padmounted transformer is provided including a tank having electrical connections mounted on one wall thereof, and a cabinet fixedly attached to the tank forming a cabinet-to-tank interface therebetween. An elongated P-shaped gasket is positioned at the interface so as to completely fill such interface, and a rib is secured to the cabinet for overlying the interface to form a tamper-resistant cabinet-to-tank interface which prevents the intrusion of extraneous objects into the interior of the cabinet.

Abstract: A method for transmitting data in the form of a sequence of data words according to PLBus communications protocol in a channel (20) carrying data transmitted, according to a different protocol, in the form of timed bursts of a signal, comprising: producing (16) a carrier which is continuous at least for the duration of each data word; angularly modulating (14, 16) the carrier in accordance with the information contained in each data word; and transmitting the angularly modulated carrier in the channel (20).

Abstract: Automatic metal inert-gas-shielded arc welding of such apparatus as large transformer casings with stainless steel welding filler wire fed to the work through a torch from a spool. A series of seam welds are produced on each casing. The torch and spool are mounted on a movable arm of an electrically operated robot. The robot has sensing means responsive to electrical conduction through the work and the wire to position the wire in the correct location for producing each weld. The tip of the wire is oxidized during each weld of the series precluding the electrical conduction necessary to locate the wire for the next weld of the series. In accordance with the disclosure, there is provided a wire cutter displaced from work. After each weld, the robot arm positions the wire in the cutter. This positioning of the wire automatically triggers a proximity switch which actuates a high speed rotary grinder to sever the oxidized tip of the wire.

Abstract: The square wave phase comparison signals generated for each phase of a power distribution system by phase comparison relays at each end of a protected three phase transmission line segment are combined to generate a single, multi-level signal with discrete values for each instantaneous combination of square wave signals. The single, multi-level signal is used to modulate a carrier signal which is transmitted over a single channel of a two-way communications link to the other terminal where the carrier signal is demodulated to reproduce the multi-level signal. The reproduced multi-level signal is then decoded to generate remote square wave signals which are compared with the phase of locally generated square wave signals to generate trip signals for circuit breakers at the respective terminals. Square waves representative of priority functions, such as direct transfer trips, can be integrated into the single, multi-level signal transmitted to the other terminal.