Abstract: A device having two opposite terminals interconnected by material layers for switching between a current conducting state and a state blocking transport of charge carriers between the terminals upon applying a voltage there across has as the material layers a first layer made of intrinsic diamond and a second layer arranged next to the first layer. The device switches to the conducting state by providing free charge carriers in the second layer for transport through the diamond layer through the voltage and the blocking state by stopping providing the free charge carriers for the transport. The diamond layer is adapted to take a major part of the voltage across the terminals in the blocking state.

Abstract: A photoconductive switch comprises a first layer (1) of a first material sandwiches between two contact layers (2,3). The first layer is adapted to be conducting upon applying a voltage across said contact layers when irradiated by light (5) of an energy high enough for lifting charger carriers from the valence band to the conduction band of the first material. A first (2) of the contact layers is provided with apertures (4) for allowing light applied on the switch to reach said first layer there for making the switch conducting upon applying a voltage across the two contact layers. A thin second layer (7) is arranged on the side of the first contact layers, at least covering the surfaces of the first layer exposed through said apertures and forming an interface to said first layer in said apertures. The second layer is made of a material being able to form a well ordered interface to said first material and having the same or a larger band gap than the latter.

Abstract: A device for non-contacting measurement of a measuring object is provided. The device includes at least one pair of associated coils, including a transmitter coil and a receiver coil. The transmitter coil generates a time varying magnetic field. In the receiver coil, a voltage is induced. The voltage is dependent on the location of the transmitter coil, the receiver coil and a measuring region of a measuring object. The device comprises a U-shaped structure with two branches. A retaining part is arranged between these branches. The transmitter and receiver coils are fixed to the branches of the U-shaped structure and the measuring object is intended to be arranged centrally in the opening of the U-shaped structure.

Abstract: The present invention relates to a transformer with superconducting primary and secondary windings (1, 2), concentrically wound around a core limb (3), between which windings there is a concentric tubular space, the main channel, with insulation material (10) for insulation between the two windings. Cylindrical screens (11, 12) of a magnetic material with a high relative permeability are concentrically introduced into the insulation material at the two ends of the main channel.

Abstract: A method for detection of misfiring of an internal combustion engine, wherein the torque of the internal combustion engine is measured with the aid of a torque sensor mounted on the crankshaft of the internal combustion engine and wherein a torque signal is sampled speed-synchronously with the aid of a sensor. A digital filtering of the torque signal is carried out with a digital filter with a finite impulse response which blocks or damps a selection of integer or half-integer multiples of the speed of the internal combustion engine. The selection of speed multiples is substantially dependent on the number of cylinders of the internal combustion engine.

Abstract: A device for transferring electric signals comprises a first unit having a bus and electrical and mechanical interconnections of this bus and a bus of another device at at least one side of the unit. A second unit has terminals electrically connected to the bus for external connection of the device to, and signal exchange with, electrical arrangements. The device further comprises two different carriers on which the bus unit and the terminal unit, respectively, are arranged, and members for releasable mechanical connection of the two carriers to each other, and adapted to allow separation of the terminal unit from the bus unit with maintained connection thereof to the bus unit of an adjacent device.

Abstract: A plant for transmitting electric power comprises at least one VSC-converter (1). It comprises also at least one DC/DC-converter (33, 34) having two current valves connected in series and an inductance connected to a midpoint therebetween. The DC/DC-converter is through said inductance connected to a first of the poles of the direct voltage side of the converter and through a first output terminal connected to one of the current valves to the second of the poles so as to obtain an unbalanced step-up-transformation of the direct voltage between the two poles while obtaining a potential having a higher value on the second output terminal (27) of the DC/DC-converter connected to the second current valve than on said first output terminal (28).

Abstract: An arrangement with a conductor (15) intended to be on a high potential and a part (12) connected to ground and separated therefrom by at least a voltage receiving air gap (16, 17), comprising an insulating envelope (18) surrounding said conductor and at least a first member (9) of electrical insulating material arranged to screen off said ground part from said conductor. Said air gap is dimensioned to get such a high electrical field strength by possible sudden, strong voltage raises of said conductor, that air molecules in said air gap will be ionized. Said insulating envelope (18) and the insulating member (9) have surfaces arranged to receive electrical charges generated through said ionizing for creating a voltage over their thicknesses and decreasing the voltage drop in the air gap between the conductor (15) and the ground part (12).

Abstract: To provide for fast switching at high powers while relieving stress on a mechanical switch, an electric switching device comprising a mechanical electric switch and an irradiation source and at least one switching element sensitive to irradiation is adapted to create an electrically well conducting current path by-passing the mechanical switch upon irradiation of the switching element by the irradiation source. The switching element assumes an electrically insulating state in the absence of irradiation thereof. The switching element includes rectifiers adapted to be reverse biased when not irradiated and conducting as a consequence of generation of free charge carriers therein through irradiation by the irradiation source.

Abstract: A torque transducer comprising a shaft (1) with a circularly polarized ring (2) which, when loading the shaft with a torque, generates an axial static magnetic field in the shaft and wherein the ring is concentrically surrounded by a stationary tubular shell (3) which is freely arranged in relation to the shaft and which is provided with at least one winding (4, 8, 9) for magnetization of the shaft with a given frequency. A phase-sensitive detector (5) connected to the winding supplies a signal corresponding to the content of those voltages with even harmonics which are induced in the winding to the frequency of a controller (6). The controller generates a direct current which is proportional to the signal and is connected to the winding with such a polarity that it counteracts the static magnetic field generated in the shaft. This direct current constitutes a measure of the torque with which the shaft is loaded.

Abstract: A device for compensation of the reactive power consumption of an industrial load, preferably an electric arc furnace or a plant for rolling of metallic materials, supplied from a three-phase (a, b, c) electric ac network, comprises a first compensation device for controllable consumption of reactive power and a second compensation device for generation of reactive power. The first compensation device comprises an inductor connected in series with a semiconductor connection controllable in dependence on a control order (.alpha.ref) supplied thereto. Control equipment is supplied with measured values of voltage (Ua, Ub, Uc) and current (Ia, Ib, Ic), respectively, at the load. The control equipment comprises devices for determination of the instantaneous consumption of active and reactive power by the load, and a control device which forms the control signal to the first compensation device in dependence on the consumption of reactive power and active power by the load.

Abstract: A device for pressure treatment of wood elements comprises a pressure chamber for accommodating the wood elements which are to be treated. The pressure chamber also accommodates a pressure medium which surrounds the wood elements on more than one side and, at least before the pressurization, a secondary medium in the form of a fluid. When the pressure medium is pressurized, the wood elements are subjected to a multilateral pressure, whereby they are permanently compressed. Furthermore, the pressure chamber is provided with elements for controlling the quantity of secondary medium which penetrates into the wood during the treatment. These elements may include evacuating valves or casings which surround the wood elements and which are impenetrable to the secondary medium.

Abstract: A device for manufacturing a rotor for an electric machine, for example, a permanent-magnet excited rotor for a high-speed a.c. machine, the rotor including an inner part constituting a rotor body and an outer part including a capsule tube which, when the rotor is completed, surrounds the rotor body with a shrinkage fit, the device including a counter-support (6) for fixing one of the first and second parts of the rotor in the vertical direction, and a guide channel (7) through which the other of the two parts moves due to gravity against the fixed part.

Abstract: Apparatus and method for limiting current in a direct voltage network of a HVDC power distribution system. A direct voltage network is connected to an alternating voltage network through a VSC-converter. At least one parallel connection including a semiconductor switching element is connected in series with the direct voltage network. A surge diverter is connected in parallel with the semiconductor switching element. During a high current condition in the direct voltage network, the switching element is switched off interrupting the current flow which is then diverted through the surge diverter which reduces the current flowing in the direct voltage network. By inserting a plurality of parallel connections, and selectively turning off a number of the semiconductor switching elements, a number of different levels of over current conditions in the direct voltage network may be controlled.

Abstract: An active filter (2) is connected to a dc circuit (L1, L2) in a converter (SR1) in an installation for transmission of high-voltage direct current. Control equipment (5) generates, in dependence on a control signal, a control order (SCF) for the active filter which, in dependence thereon, generates and supplies to the dc connection one of a filter voltage (UF) and a filter current (IF) for reducing at least one tone of a chosen tone frequency in a current (Id) in the dc connection. The control equipment comprises a controlling unit which forms a controller signal in dependence on a supplied current measurement value (IM) of the current in the dc connection, and an identification unit. The identification unit forms a first compensating parameter in dependence on the current measurement value and on an excitation signal generated by the control equipment and added to the control order.

Abstract: A first MOS transistor of a specific conductive type and a second MOS transistor of the specific conductive type are combined in an electrostatic circuit protection. In the first MOS transistor, a drain thereof is connected to an output terminal or an input terminal and a source thereof is connected to a first power terminal. The first MOS transistor is turned on/off by a signal received by a gate or ordinarily turned off by holding the gate at a specific potential. In the second MOS transistor of the specific conductive type, a drain thereof is connected to the output terminal or the input terminal and a source thereof is connected to a gate of the first MOS transistor. The second MOS transistor is ordinarily turned off by connecting a gate thereof to the first power terminal.

Abstract: A compact gear system that includes an input shaft (28), an output shaft (1) and gear wheel means which drivingly connect the same, wherein the output shaft (1) is journalled in a gear housing (2). The output shaft (1) is hollow and has pins (5a) which project radially outwards in a normal plane and each of which carries a gear wheel (6). Provided on each side of the pins is a respective crown wheel (11, 12) journalled on the output shaft (1) and having a toothed ring (17, 18) in engagement with the gear wheel (6). Each crown wheel also has a cylindrical toothed ring (19, 20) which coacts at different transmission ratios with a respective toothed ring (25, 26) on an eccentric shaft (21) which extends parallel with the output shaft (1) and which is rotatably journalled in the housing (2), wherein the eccentric shaft (21) is driven by the input shaft (28).

Abstract: In a method and apparatus used for detecting and handling a short circuit in a circuit having a plurality of power semiconductors connected in series the voltage is divided across the electrodes and each power semiconductor and the magnitude of a small proportion of the voltage is measured. The magnitude of the voltage is compared to a reference voltage at least from when the power semiconductor is turned on. The reference voltage is higher than the maximum voltage across the power semiconductor during normal operation. A short circuit is detected when the magnitude of the measured voltage exceeds the reference voltage.

Abstract: A plant for transmitting electric power between a direct voltage network and an alternating voltage network through a power station. A converter of a station has two current valves connected in series, each having one turn-on and turn-off type breaker and a diode connected anti-parallel therewith. Circuits are provided to detect the direction and the intensity of the current through the converter, as well as the current valve through which it flows to actuate the control apparatus on the basis of the detected current level and the identity of the valve carrying the current. The control apparatus operates to commutate current through the valve which is not carrying current when a detected current level in the current carrying valve exceeds a first predetermined level.

Abstract: A plant for transmitting electric power is provided. The plant has a direct voltage network connected to at least one alternating voltage network through a station. The station transmits electric power between the direct voltage network and the alternative voltage network and has at least one converter for converting direct voltage to alternating voltage and for converting alternating voltage to direct voltage. The plant comprises a DC/DC converter connected between the poles of the direct voltage network. The DC/DC converter is adapted to create a higher voltage between the poles on the station remote side of the DC/DC converter than on the station near side.