Abstract: A fiber optical measuring device for measuring a magnetic or electric field comprises an optical modulator influenced by the field. The optical properties of the modulator are dependent on the magnetic or electric field acting on the modulator. The optical property which is made use of is the field dependence of at least one absorption edge of the radiation absorption spectrum of the modulator material. Optical fibers may be used for feeding light into the modulator and for leading away light that has passed through the modulator.

Abstract: In a surge arrester comprising a stack of series-connected cylindrical ZnO-varistors in an insulating housing, the envelope surface of each varistor is provided with an insulating protection means, which overlap varistors positioned adjacent to each other. The protection means prevent the varistors from being mechanically damaged during handling, provides guiding for the varistors in the stack, and seals the stack of varistors, so that a local glow discharge or a fault in individual varistors will not lead to an arc flash-over along the stack.

Abstract: In an impedance-measuring device for impedance protection, the phase positions of a plurality of alternating-current quantities are compared with the aid of a phase comparator. From the output signal thereof it is clear whether the impedance in a fault loop with a voltage U and a current I lies inside or outside an impedance zone, which is defined by means of a model impedance, Z.sub.k =R+jX. The comparator is supplied with input quantities corresponding to IX, U.sub.k, I and preferably also U.sub.p, where U.sub.k =U-IZ.sub.k, whereas U.sub.p relates to a voltage which is phase-shifted -90.degree. with respect to U. Quantities corresponding to IX, U.sub.p and I are each supplied to one input of a second logic component. This second logic component also has an input which is connected, via a delay element, to the output of a first logic component, the two inputs of which are supplied with quantities corresponding to I and U.sub.k, respectively.

Abstract: In directional wave detector apparatus for electrical power line relay protection devices determining the direction to a fault, the current and voltage of the travelling waves generated by a fault point are combined at a measuring point and the sign of the combined signal is determined. A tripping or blocking signal is emitted depending on whether the sign of the combined signal indicates that the fault lies within or outside the range protection of the relay protection device.

Abstract: A reluctance machine comprises a rotor having a plurality of unwound salient rotor poles, and a stator with an even number of mutually equal groups of salient stator poles evenly distributed around the inner circumference of the stator unit, each stator pole being surrounded by a respective working coil. The stator poles belonging to the same group have the same polarity and also the same premagnetization. The polarity is determined by the working coils being distributed between at least two working windings which are each provided with a rectifying means. Between two stator poles, whose working coils belong to one and the same working winding, there is at least one stator pole which supports a working coil belonging to some other working winding.

Abstract: A diverter switch comprises at least two contact pairs, each pair having a fixed contact and a movable contact. The movable contacts are movably arranged on a pivoted current-carrying contact carrier. Each movable contact consists of two contact elements pressed by means of springs against the contact carrier on either side thereof. The current-carrying capacity of the movable contacts can be improved by means of silver plates arranged between the contact elements and the contact carrier.

Abstract: The present invention relates to an overvoltage protection device designed to protect electronic components against high energy transients. The protection device comprises a varistor, across which there is connected a voltage-dividing unit comprising a resistor and a voltage-limiting element, for example a varistor or a Zener diode. The voltage appearing across the voltage-limiting element controls the output signal of the protection device by being connected to the base of a transistor. The input signal to the transistor consists of the input signal of the circuit or the input signal voltage-divided across an input resistor.

Abstract: The invention relates to a fiber optical device for measuring physical magnitudes such as force, elongation, pressure, acceleration, temperature, etc., comprising a transducer unit and an electronic unit, in which the quantity to be measured is supplied to the transducer unit to affect the resonance frequency of an oscillating body included in the tansducer unit by changing the dimensions, mass, density, modulus of elasticity and/or mechanical stress of the body. A property of the body oscillation, such as frequency, phase position and/or amplitude, is used as a value of the quantity to be measured. The oscillations of the body are detected optically by means of a fiber optical position/movement detector.

Abstract: An apparatus for removing the lining of a crucible furnace comprises a tubular support which can be introduced into the furnace substantially in the axial direction of the latter. A power-driven tool, for example a pneumatically operated chisel, is movable along the tubular support in engagement with the lining to be removed. Drive means operable from outside the furnace is provided for moving the tool along the tubular support. A suction means is connected to the tubular support for the purpose of extracting, through the tubular support, dust and lining fragments produced during the operation of removing the lining.

Abstract: The invention relates to a fiber optical measuring device for measuring physical parameters of a medium, preferably the level thereof, and it comprises an electronic unit and a transducer unit interconnected by an optical fiber, the transducer including at least one light guide connected to the optical fiber. The light guide is adapted to be lowered or introduced into the medium, the level, or other parameters, of which is to be measured, the light guide having a core with a higher refractive index than the surrounding sheath. The sheath has one or more regions along the light guide that are light transparent by being uncovered or only very thinly covered. When the guide is immersed into the medium, it influences the channel such that light in the thinly covered or uncovered regions of the guide is transmitted from the core, which light is representative of the level, or other parameter, of the medium.

Abstract: A puffer type circuit breaker is provided with a pump means consisting of a piston and a cylinder for producing a blast of arc-extinguishing gas. The piston is joined to one contact of the circuit breaker and the cylinder to the other contact. Both contacts are connected to an operating device which is adapted, during the first part of a breaking operation, to move the contacts in opposite directions away from each other, whereupon one contact and the piston joined thereto are returned to the initial position.

Abstract: The invention relates to a memory circuit in a relay protection device with a phase-locked loop, a monitoring circuit and an updating circuit. When a fault detector, a phase-change detector and/or an amplitude-change detector monitoring an a.c. network to which the protection device is connected supply an output signal indicative of a fault in the network, no updating of a storing member in the loop takes place.

Abstract: A method of manufacturing stainless ferritic-austenitic steel having good corrosion properties, above all a good resistance to intercrystalline corrosion, a high yield strength and good hot-workability, which contains up to 0.10 percent of C, up to 4.0 percent of Si, up to 2.0 percent of Mn, from 20 to 30 percent of Cr, from 3 to 8 percent of Ni, from 1.0 to 6.0 percent of Mo, up to 0.5 percent of V and up to 4.0 percent of Cu, the remainder being iron and unavoidable impurities in unimportant amounts. The method includes the steps of preparing a melt of the steel with a nitrogen content higher than about 0.10 percent, preferably from about 0.15 to about 0.80 percent, and an austenite content not less than about 20 percent, preferably from about 20 percent to about 50 percent, gas atomizing said melt to form a powder, compacting said powder into a body, preferably employing an isostatic or semiisostatic compaction procedure, heat-treating said body at a temperature of from about 950.degree. to about 1250.

Abstract: An apparatus for simultaneously firing a plurality of series-connected thyristors having a control pulse transformer for each thyristor. Each transformer has first and second primary windings, with the first windings being connected in series with each other, and the series combination being connected through an auxiliary thyristor to a capacitor which is charged from a DC voltage source. The second primary windings are also connected in series with each other with the series combination being connected to a DC source through a transistor switch means. In half of the transformers the two primary windings have the same polarities, while in the other half they have opposite polarities. To fire the thyristors, the auxiliary thyristor is caused to be fired causing the transformers to provide a steep pulse with a high amplitude to the thyristors.

Abstract: A high voltage direct current transmission apparatus having a DC carrying line (L1, K, L2) and including voltage-limiting members (A1, A2) which are arranged so that the limiting level is higher for a line voltage (u.sub.D) of one polarity than for a line voltage of an opposite polarity, and so that for both polarities the limiting level is other than zero.

Abstract: An inverter connection has an inverter bridge which, in series with a controllable valve, is connected between terminals for connection to a direct voltage source. A turn-off circuit is arranged for simultaneous turn off of the thyristors of the inverter. The turn-off circuit comprises a capacitor connection and a thyristor connection which is controllable in both directions. The latter is connected, in series with at least one capacitor, between a point which is located between the valve and the bridge, and at least one of the terminals. An inductor is arranged in at least two of the three current paths between said point and the terminals.

Abstract: A gas-cooled rotor assembly for use with a turbogenerator type device, wherein a coil side is positioned within a winding slot formed in the rotor core, such that a pair of cooling channels extend between opposite sides of the coil side and adjacent wall portions of the winding slot. Positioning devices of insulating material are positioned adjacent to radially inner-most and outer-most end portions of the coil side, with the positioning devices electrically insulating the coil side from confronting surface portions of the slot walls, while at the same time transmitting tangential forces therebetween.

Abstract: A high voltage power converter has a number of thyristors interconnected. Symmetrical voltage dividers maintain equal voltage distribution across the thyristors. Each thyristor has a plurality of inductors associated therewith for reducing rapid current increases through the thyristors during firing which might injure the components and generate radio frequency interference.

Abstract: A deflector roll for a strip mill is divided axially into sections to be able to measure the distribution of the strip tension across the strip width. To avoid transmitting the measuring signals from movable parts, the sections of the deflector roll are supported by rollers journalled in stationary holders, the force-measuring transducers being built into the holders.

Abstract: A two-pole overcurrent protection device, intended for connection into a current-carrying conductor, comprises a normally conducting thyristor having members for firing the thyristor at low off-state voltage. The thyristor has a member for turning off the thyristor by short-circuiting one of its injecting junctions. Voltage-sensing members sense the on-state voltage drop across the thyristor and influence the short-circuiting member for turning off the thyristor when the on-state voltage drop reaches a pre-determined level. The overcurrent protection device may be constructed integrally with one single semiconductor plate.