Abstract: An electric device comprising at least one core (5, 10) of magnetic material and a high-voltage winding (16) in the form of an electric conductor wound around the core, and a method for manufacturing such a device is described. The device comprises a first insulating layer (14) of a solid, electrically insulating material which encloses the core (10) and which is arranged b between the core (10) and the high-voltage winding (16), and a second insulating layer (18) of a solid, electrically insulating material which encloses the high-voltage winding (16). a semiconductive layer is arranged on both sides of each of the electrically conductive layers.

Abstract: The invention relates to an electric circuit breaker. The circuit breaker comprises at least one mobile contact with operating means (2) for operating the same. An electric motor (6) is arranged for driving the operating means (2). The motor (6) is powered from a current source (50) via a current converter (40). According to the invention, the motor (6) and/or current converter (40) are greatly under-dimensioned in relation to the output the current converter is designed to deliver. This is possible because the operating duration is so brief. Under-dimensioning results in extensive cost-savings. The invention also relates to an electric plant equipped with such a circuit breaker. The invention further relates to the use of such a circuit breaker and a method for breaking electric current in the corresponding fashion.

Abstract: The invention relates to an electric circuit breaker that includes at least one mobile contact. The contact is connected to operating means that includes an electric motor (6). Movement converting means (16, 17) are provided for converting rotary movement of the motor (6) to translatory movement for linear movment of the mobile contact. The object is to provide an improved movement conversion means. According to the invention, the movement conversion means includes a first body, such as a screw (17), and a second body, such as a nut (16). The threads of the screw (17) and the nut (16) co-act in engagement with each other. The invention also relates to an electric plant that is equipped with such a circuit breaker, to the use of the breaker for breaking electric current, and to a method of breaking electric current with the aid of the inventive circuit breaker.

Abstract: An electric switching device for fast closing of a high current in a power network comprising a first electrode (1), a second electrode (2), a movable contact element (3) closing said first and second electrodes, and an operating device. The operating device comprises a helically wound first coil (6) secured to the first electrode. The movable contact element comprises a flange (4) making contact with the coil. A current pulse flowing through the coil forms a repulsive force between the coil and the flange, said repulsive force throwing the movable contact element to the second electrode and completing the closing operation.

Abstract: A controllable inductor comprises at least a tubular core, a main winding surrounding the core and a control winding passing substantially axially through the core. A yoke of a material having a high magnetic permeability is arranged to extend outside the core and the main winding and together with the core form a closed loop having at the most small air gaps for a main magnetic flux generated in the core by a current in the main winding and extending substantially axially to the core. The control winding comprises first plates of a material having a good electric conductivity extending substantially axially through the core.

Abstract: A controllable inductor comprises at least a tubular core (3), a main winding (1) surrounding the core and a control winding (4) passing substantially axially through the core. It also comprises a yoke (19) of a material having a high magnetic permeability arranged to extend outside the core and the main winding and together with the core form a closed loop having at the most small air gaps for a main magnetic flux generated in the core by a current in said main winding and extending substantially axially to the core. The control winding comprises first plates of a material having a good electric conductivity extending substantially axially through the core.

Abstract: An electric coupling device for connecting, disconnecting or limiting the current in an electric circuit. The electric coupling device includes a variable resistor. This resistance is variable between a very low value corresponding to a conducting state and a very high value corresponding to a substantially insulating state. Switching between the states takes place continually and in a very short time. The invention relates to an electric circuit provided with such an electric coupling device and a method performed in accordance with the function of the electric coupling device.

Abstract: A tubular core (6) for a controllable inductor with a main winding (1) surrounding the core and a control winding (7) passing substantially axially through the core. The core (6) is capable of receiving a magnetic flux from the main winding (1) running substantially axially therethrough and having a plurality of core rings (8) stacked co-axially on top of each other and connected to a rigid unit. The core rings (8) are connected to each other forming a walled construction. The core (6) also has an inner envelope (18) with an outer cross-section that is substantially equal to the inner cross-section of the core ring walled construction. The walled construction has joints (16) between the core rings (8) in an axial direction which are overlapped by a part of the envelope (18).

Abstract: A controllable inductor comprises at least a tubular core, a main winding (1) surrounding the core and a control winding (3) passing substantially axially through the core. It is adapted for connection to a three phase alternating current network and has for this sake for each phase (14-16) a main winding (1) for connection to the phase, a core and a control winding, and the control windings of the three phases are electrically connected in series to each other.

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: A controllable inductor including a tubular core, a main winding (1) surrounding the core, a control winding running substantially axially to the core and an element (3) surrounding the core and arranged to support the main winding wound outside thereof in radial layers. The element includes means arranged to provide channels (19) partly defined by the radially inner turn of the main winding. Said channels are communicating with spacings between said layers (2). A member is arranged to generate a flow of air in the channels and through the spacings of the layers for cooling the main winding.

Abstract: A controllable inductor including at least one tubular core (10), a main winding (5) surrounding the core and a control winding (11) running substantially axially through said core and returning substantially axially outside thereof between said core and said main winding. The control winding is divided into a plurality of separate part control windings (12). The cross section of the part control windings is formed in a way that at least some adjacent part control windings inside the core are separated by means of a spacing (20, 26), which is at least partly defined by substantially parallel surfaces (16, 17) of these part control windings.

Abstract: A fault current limiter in which a resistor is inserted by a running arc. The arc is allowed to burn in a commutating unit until the current zero-crossing. Upon the passage through zero the arc is extinguished and the current is commutated to a shunt resistor. The commutating unit comprises a gap-formed nozzle, in which the arc is burning. The nozzle is defined by two nozzle halves of a material which gives off gas under the influence of the arc. Close to the nozzle inlet is a pressure accumulating chamber, in which an overpressure is built up during the arcing time. After current zero-crossing, the hot arc residues are effectively vented by means of the overpressure in the pressure accumulating chamber. For cooling the gas in the chamber and for guiding the gas flow, the chamber is divided into small sub-volumes defined by metal plates.

Abstract: The switching device has a fixed contact which cooperates with a movable contact secured to a movable contact carrier. The contacts are connected to runner rails for the arc that is created upon the contact opening. The runner rail connected to the movable contact consists of a movable commutating conductor which, during the initial stage of the contact opening, is at least approximately stationary, and then moves together with the movable contact to the open position of the switching device.

Abstract: The switching device has a contact arm which is fixed on a shaft in the form of a thick-walled tube and is turnable between a closed position and an open position under the influence of a torsion rod spring. At one of its ends the spring is fixedly connected to the contact arm and at its other end to a percussion hammer. In the closed position the spring is arrested in tensioned condition by means of a latch. When releasing the latch for opening of the switching device, the spring energy is transformed to rotation energy in the hammer and is transferred to the shaft by impact against a projection on the shaft. In this way the contacts of the switching device immediately attain a great separation velocity.

Abstract: A current limiter for high voltage utilizes the high migration velocity of an arc for rapidly inserting at least one pair of resistive runner rails upon a short-circuit in a circuit. To be able simultaneously to fulfil the demands for a high energy absorption capacity and sufficient resistance per unit of length of the runner rails, the runner rails are made of a relatively thin, insulated tape of an electrically conductive material, which is folded and packed to form a solid resistance package. Between the two runner rails in each pair of rails there extend two parallel walls of insulating material, which form between them a narrow gap for the arc. The magnetic field in the gap is reinforced with the aid of a magnetic core and/or current loops.

Abstract: A magnetoelastic force transducer with temperature-compensated sensitivity is produced by equally exciting a measuring transducer and a reference transducer having cores of the same material and the same design and in good thermal contact. A spring loads the core of the reference transducer with a constant force. The output signal of the reference transducer is rectified in a phase-sensitive rectifier, the output signal of which is compared with a constant reference voltage. The difference signal resulting from this comparison controls the phase position of the control voltage of the rectifier in such a way that the output signal of the rectifier is brought into agreement with the reference voltage. The output signal of the measuring transducer is also rectified in a phase-sensitive rectifier, which is controlled by said control voltage and the output signal of which constitutes the temperature-compensated measured signal.

Abstract: Force measuring equipment has a magnetoelastic transducer with an excitation winding supplied with alternating current, which generates a primary flux in a magnetic core of the transducer, and a measuring winding in which a signal voltage is induced, the signal voltage giving a measure of the force applied to the transducer core. The signal voltage is supplied to signal processing members which are arranged to form an output signal by phase-sensitive rectification of the signal voltage. Control members sense when the primary flux passes a positive and a negative reference level, and switch polarity reversing members at the times during each period of the AC supply when the primary flux with a certain sign of its time rate of change passes the positive reference level and with the opposite sign of its time rate of change passes the negative reference level.

Abstract: Method and apparatus for attaching a transducer to an object having characteristics to be measured. At least two attachment elements each including a number of pointed members are interconnected by a sensing element. Each attachment element includes a movable wedge member and at least one fixed wedge member whereby initial movement of the movable wedge member with respect to the fixed wedge member subjects said pointed members to a pressure force of a specified magnitude to press the pointed members into the surface of the object. Further movement of the movable wedge member with respect to the fixed wedge member generates a holding force on the pointed members less than the initial pressure force to hold each attachment element in engagement with the object regardless of transverse forces acting on the attachment elements.