Abstract: A semiconductor component for electrical generation of optical radiation, for example an LED, is provided. The component includes a semiconductor body that contains a first region of material of a first conductivity, a second region of material of a second conductivity type adjacent to the first region; and a PN junction between these regions. The first region has a central part of a material with a first band gap and a peripheral part laterally surrounding the central part of the first region. The material of the peripheral part has a band gap larger than the bang gap of the central part of the first region. The material of the second region has a larger band gap than the band gap of the central part of the first region.

Abstract: A method of containing radioactive or other dangerous material separately or intermixed with a bonding compound of a material, resistant to leaching by water, in a gas-tight container and of converting the material by hot isostatic pressing (HIP) into a dense body. The material is filled into a cylindrical container having a corrugated bellows-like wall. The dangerous material is prevented from filling up the annular spaces formed by the corrugations, by means of a barrier means placed inside the container. A metallic netting combined with a paper-like sheet of ceramic material makes a suitable barrier means.

Abstract: To protect electrical three-phase machines from damage on the appearance of an unbalanced load between the phases, so-called negative sequence current protection is used. Conventional measurement of the negative sequence current takes place in filters which contain frequency dependent LC components. Frequency variations in a three-phase supply, because of an unbalanced frequency response for harmonics in the three phase filters, may lead to an erroneous indication of negative sequence current. The invention provides a novel method for determining both the positive sequence and the negative sequence currents to a three-phase load. For grounded systems the zero-sequence current is eliminated. Measuring each phase current (I.sub.R, I.sub.S, I.sub.T) and the phase sequence, the positive sequence and/or negative sequence current are/is determined as the solution of an equation derived in advance from the electrical relationships between the phase currents.

Abstract: A method for improving the electrical insulation of an electrode in a power transformer included in a converter plant of a high voltage direct current (HVDC) transmission system. The method involves winding around the electrode, layers of tape of woven or non-woven fibrous structure of non-conducting cellulose material, inorganic plastics material, or inorganic insulating material. This means that ions approaching the electrode, which are migrating under the influence of a high d.c. field outside the electrodes, do not sense the porous tape insulation as any noticeable obstacle, while at the same time the insulating layer is sufficiently dense to increase the breakdown value in the case of electrical surges.

Abstract: A method for manufacturing a railway wheel with a base material, a more wear-resistant layer at the part of the flange facing the wheel tread, and a layer in the tread which gives a high friction between wheel and rail which is relatively independent of the weather. The method is characterized in that a prefabricated component is manufactured from members of the base material and from the more wear-resistant materials, respectively, which members are given such a shape as to fit closely against each other, and which, after turning or other machining and cleaning from oxide and other impurities, are put together and welded together at the outer surfaces of the component in such a way that admission of air between said members is prevented, the component thereafter being hot-worked to form a finished or near finished wheel blank with a good bond between the different members defining the tread and/or flange regions thereof.

Abstract: A network impedance protection device operates in dependence on the quotient of voltage and current at a measuring point and is set to initiate a protective action when the measured impedance is lower than an impedance level set in the device. Known designs comprise analog components and functions both as regards quotient formation, comparison and compensation etc. An impedance relay constructed according to the invention utilizes the same principles as the analog design, but all units and functions are digitized. Incoming voltage and current signals are converted in an A/D converter, filtered in tuned filters, rectified in rectifiers, and so on, and deliver an output signal, via summators, when the measured impedance is lower than a set impedance value.

Abstract: A static electrical converter for high voltage DC is provided with at least one valve assembly which has one or more valves electrically connected in series. Each of these valves includes a plurality of valve modules carried by a carrier for dependent mounting. The valve modules are connected to the carrier with the aid of resilient members allowing vertical spring movement between the valve modules and the upper portion formed for suspension of the carrier.

Abstract: An edge-region heating device for use in the hot rolling of metallic strip after some cooling of the strip has occurred, employs an induction heater to preferentially raise the temperature of the edge-regions of the strip to compensate for the faster cooling of these edge regions whereby a more uniform temperature is obtained over the cross-section of the strip when a later hot rolling operation is performed.

Abstract: A linear resistor is serially connected to a voltage-dependent metal oxide varistor and the series-connected resistor elements are connected in parallel with the series capacitor of a high voltage network to provide an overvoltage protection circuit for the series capacitor. A spark gap is also connected in parallel with the series-connected resistor elements in case of overload thereof. The voltage across the linear resistor triggers device for firing the spark gap when the voltage across the linear resistor exceeds a predetermined voltage. The resistance of the linear resistor and that of the varistor is dimensioned such that the predetermined voltage constitutes the smaller part of the voltage across the capacitor.

Abstract: A device for monitoring the arc of a plasma burner employs a photo-sensitive device to receive light from the plasma arc via at least one narrow band filter, the wavelength range of the filter being centered on the spectral response characteristic of a material in the burner or the plasma nozzle. A monitoring circuit detects when the output of the photo-sensitive device increases, indicating fault conditions in the arc.

Abstract: A device for monitoring the condition of a high voltage circuit-breaker comprises as current-sensing members a number of reed contacts, which are located in such a way in relation to the current path through the circuit-breaker that the contacts are activated at different current levels. The reed elements control a pulse train to a counter, which takes place with different dignity for the different elements. With the aid of a position transducer connected to the contact device of the circuit-breaker, the pulse train is started simultaneously with the opening of the circuit-breaker, the contents of the counter thus being a measure of the contact wear. The contact position transducer is also used for measuring the opening speed, and if said speed falls below a certain value, alarm is triggered.

Abstract: A casting (e.g. of aluminum or aluminum alloy) is made at least approximately free from pores by being subjected, in heated state, to isostatic compression in a liquid pressure medium. A rapid pressing operation of under one minute can be achieved if the casting is placed in a container, the container and the casting are heated to the required compression temperature before they are thereafter placed in a press chamber of a fast-acting press. When liquid pressure medium is fed to the press chamber and the necessary pressure is applied thereto, the pressure medium flows into the interior of the container via a number of channels in its wall and is simultaneously heated to the necessary temperature, prior to its contacting the casting.

Abstract: A tool holder for an industrial robot intended to permit a programmed automatic replacement of tools. The holder and the tool are formed with connecting elements adapted to each other. The holder includes a cylinder housing, in which two pistons, interconnected by a connecting member, are slidably located. This connecting member is formed with a radially oriented, axially elongated opening with two different widths. On either side of the narrower opening part the connecting member is formed with camming surfaces which are inclined relative to an axial plane through the pistons.

Abstract: An absorber plate designed to be located in a gap between fuel rod bundles in the core of a boiling water reactor is manufactured by anchoring a burnable neutron-absorbing material to at least one sheet by spraying the absorbing material in finely-divided melted or plastically-formable state onto the sheet, to create a solidified layer of the absorbing material, and by enclosing the absorbing material, thus anchored, in a protective casing.

Abstract: A light-generating element, for example an LED, a semiconductor laser or a body of photoluminescent material is arranged to have a temperature-independent output power characteristic by providing it with an optical filter having such a frequency-dependent transmission curve that the amplitude of the signal, emitted by the element, is, after passage through the filter, substantially independent of the temperature of the element.

Abstract: In a cloud height measuring device, the attenuation caused by deposits on the output and/or receiver windows of the device (e.g. by rain and/or dirt) are compensated for by measuring the degree of reflection of light from the window(s) when illuminated by light pulses. By means of a special measuring sequence in a processor unit included in the cloud height measuring device, light pulses separate from those used for the cloud height measurement itself, can be employed to assess the extent of the fouling. The measurement energy can then be controlled during the cloud height measurement proper, so that the total attenuation, caused by rain and dirt on the windows, is properly compensated for.

Abstract: Electrically powered trolley vehicles in headings of mines are provided with a current collector pick-up unit having contact-sensing means, current collectors, position sensors and guide wheels. The power supply for the pick-up unit comprises an array of elongated guide rails and at least two conductor bars. The connecting method comprises running the vehicle slowly forwards, by means of its own energy source, in the direction of the elongated conductor bars and vertically raising the pick-up unit by means of an arm mounted on the vehicle so that a contact-sensing frame for sensing contact in a vertical direction is brought into engagement with one or both of the guide rails. During a continued vertical movement, the contact-sensing frame is turned down towards the rest of the pick-up unit and when the contact-sensing frame reaches its lower end limit position, this is indicated by a position sensor.

Abstract: A press is adapted for the press tool it is to operate, by means of at least one pad of force-transmitting material formed in situ on a surface adapted to transmit the forming force to the press tool. The pad is formed by locating a tool substitute in the space intended for the tool, defining at least one volume between the tool substitute and the said surface adapted to transmit the forming force with a sealing means and injecting the pad forming material in liquid state into the said volume to allow the same to harden there preferably under a force equivalent to that which will be used in forming a blank when the substitute tool is replaced by the press tool.

Abstract: For use in low-voltage switchgear there is provided a plug-in contact device for connecting two bars, each of which has two confronting parallel contact surfaces. The contact device includes two co-acting elongated contact fingers which form two electrically parallel-connected current paths between the two bars. At the two end portions of the contact device the current paths intersect each other, whereas in a relatively long middle portion of the contact device the current paths are parallel and lie relatively close to each other, thus obtaining an electrodynamic contact pressure increase.

Abstract: The temperature-measuring transducer of a temperature-measuring system that includes a device for emitting energizing radiation, a temperature-measuring transducer which, upon excitation by the energizing radiation, will emit luminescent light, a detector for detecting the luminescent light emitted by the temperature-measuring transducer, and at least one optical fiber interconnecting the various elements is made of a crystalline sensor material which contains luminescent ions, at least some of these luminescent ions being so located in the crystal lattice of the sensor material that for each of said at least some luminescent ions each immediately adjacent anion substantially shows inversion symmetry in relation to that luminescent ion.