Maschinenfabrik Reinhausen Gmbh

Pharmacia & Upjohn Company

Dieter Dohnal

Karsten Viereck

Silke Wrede

Wolfgang Albrecht

Christian Hammer

Hans-Henning Lessmann-Mieske

Josef Neumeyer

Oliver Brueckl

Albert Schmidbauer

Klaus Hoepfl

Leonhard Pillmeier

Reinhold Baertl

Gunter Kloth

Manfred Stadelmayer

Jochen Von Bloh

Klaus Hopfl

Christian Pircher

Volker Karrer

Christian Kotz

Rolf Lauterwald

Kurt Kugler

Rainer Frotscher

Jochen Ermisch

Reiner Brill

Mario Schmeckebier

Ansgar Hinz

Klaus Schlepp

Alexei Babizki

Peter Okanik

Axel Kraemer

Christian Heudecker

Franz Griesbacher

Michael Holmer

Klaus Krueger

Dieter Geiger

Klaus HÖPFL

Klaus KRÜGER

Disclosed is a device and method for reducing network feedback during operation of an electric-arc furnace (). The electric-arc furnace () has three lines () with one electrode () each. A sensor () for measuring the currently flowing current and a sensor () for measuring the currently applied voltage are provided in each line. A control and regulating unit () calculates an electrical actual value (E, E, E). A semiconductor tap changer () is assigned to the furnace transformer () such that, by suitably selecting three target winding taps (T, T, T) of a primary side (P) of the furnace transformer (), a target current (I, I, I) is adjustable in each line ().

Device and method for reducing network reactions when an electric arc furnace is in operation

An on-load tap changer has a load changeover switch insert having a switching tube rotatable about an axis, at least one switching module associated with the switching insert and having at least one switching segment fastened to the switching tube, an oil tank, and a resistor subassembly having a plurality of separate and identical resistors. An actuating arrangement associated with the switching module at an inner wall of the oil tank has a plurality of identical actuators associated with the switching module at the inner wall of the oil tank. The on-load tap changer is a load selector or a load changeover switch depending on the arrangement of the at least one identical switching segment, the resistor subassembly, and the mounting of the plurality of identical actuators at the inner wall of the oil tank.

On-load tap changer

The invention relates to a control transformer that is designed as a phase-shifting transformer, wherein semiconductor switching components are provided for each phase at a regulating winding with several partial windings. According to the invention, an additional connecting line with an additional electronic switching component is provided in each phase wherein each of these connecting lines connects a module of the respective phase with the end of the main winding of the adjacent phase.

Control transformer

A tap changer for uninterrupted switching over between winding taps of a tapped transformer has two load branches each for a respective phase to be switched. Each load branch has a vacuum switching contact acting as main contact and parallel thereto at least one series connection of a switch-over resistance and a respective further vacuum switching contact. The two load branches are connected with a common load shunt or connectable by mechanical switching elements. Two respective vacuum switching contacts of each load branch are constructionally combined to form a single vacuum switching tube with two separate movable contacts actuatable independently of one another and a common fixed contact. The common fixed contact is connected with the common load shunt or connectable mechanical switching contacts.

Tap changer and vacuum switching tube for such a tap changer

The invention relates to a transformer with a tap changer, wherein optionally the primary or secondary side can be regulated by the tap changer, and wherein, on the side of the transformer to be regulated, a main winding and at least one regulating winding, which is connectable by the tap changer, are provided. According to the invention, the main winding is divided into two main winding parts, and the at least one regulating winding and the tap changer () connecting the regulating winding are arranged electrically between the two main winding parts ().

Transformer with on-load tap changer

The invention relates to an on-load tap changer for switching among winding taps of a step transformer without interruption. According to the invention, in each auxiliary current branch of the on-load tap changer, which operates with vacuum switching tubes as switching elements, additional switches are provided in series with the vacuum switching tubes and the respective winding tap. Said additional switches cause a complete galvanic isolation of the vacuum switching tubes in the auxiliary current branches in steady-state operation.

The invention relates to an on-load tap changer comprising semiconductor switching elements for uninterrupted switching between winding taps of a tapped transformer. According to the invention, contact bars are provided which extend in the direction of the path of the fixed tap contacts and can be contacted using contact bridges that can be jointly moved by a contact slide in such a way that direct electrical connections to the charge diverter and electrical connections to the inputs and the output of the semiconductor switching elements can be established.

On-load tap changer comprising semiconductor switching elements

The invention relates to the arrangement of a stepping switch on a control transformer, wherein either only the mechanical contact system () of the stepping switch or also its load changeover switch () is or are arranged within the tank () of the transformer, under the transformer cover () and above the iron yoke ().

Arrangement of a stepping switch on a control transformer

The invention relates to an on-load tap changer comprising semiconductor switching elements for uninterrupted switching between fixed tap changer contacts which are electrically connected to winding taps of a tapped transformer. Each of the fixed tap changer contacts can be connected to a charge diverter either directly or, during switching, via the semiconductor switching elements that are connected therebetween. According to the invention, the charge diverter has fixed, divided diverting contact pieces in order for the semiconductor switching elements to be electrically isolated from the transformer winding during stationary operation.

An on-load tap changer with semiconductor IGBT switching elements for uninterrupted switching over between winding taps of a tapped transformer, has two load branches connectable with the respective winding taps and each load branch is electrically connected with a common load output line through a respective series circuit consisting of two oppositely connected IGBTs. A diode is connected parallel to each IGBT, and the two diodes in each load branch are connected oppositely to one another. A respective mechanical switch is connected in series with the series circuit of IGBTs and parallel diodes in each load branch. A respective varistor is connected parallel to each parallel circuit of IGBT and diode, and the varistors are so dimensioned that the respective varistor voltages are lower than the maximum blocking voltage of the respective parallel IGBTs but higher than the maximum instantaneous value of the tap voltage.

Tap switch with semiconductor switching elements

The invention relates to a method for switching without any interruption between two winding taps (tap n, tap n+1) of a tap-changing transformer, wherein each of the two winding taps is connected to the common load output line via in each case one mechanical switch (Ds) and a series circuit, arranged in series thereto, comprising two IGBTs (Ip, In) which are switched in opposite directions.

Method for switching without any interruption between winding taps on a tap-changing transformer

An apparatus for regulating electrical voltage in multiphase power mains has a control transformer having for each phase of the power mains a primary winding and a control winding having three taps. The second tap is connected centrally between the first and third taps and to one of the ends of the primary winding. This control winding has winding lengths between the first and second taps and second and third taps equal to a whole-number multiple of a winding length of the primary winding. Three circuit elements have inputs connected to the taps. A reactor winding has ends connected to outputs of the first and second circuit elements, while the output of the third circuit element electrically connected to the output of the first circuit element. A further circuit element is connected across the reactor winding, and an output is connected to a center of the reactor winding.

Device for regulating electrical voltage

The invention relates to a tap changer having a switching monitoring device, which is arranged above the upper transmission stage in a housing. For monitoring purposes, two cam switches are provided which are actuated by a cam disk which is connected to the contact-bearing switch column of the tap changer. The cam disk has a horizontally split contour at its end face, wherein one of the two cam switches runs on each partial contour.

Tap changer having a switching monitoring device

A contact arrangement for use on an insulating rod having an upper fastening bore and a lower fastening bore has a U-shaped contact having a pair of limbs each formed with an upper bore and a lower bore. The contact is fittable around the rod with the limbs flanking the rod and the upper and lower bores of the limbs aligned with the respective upper and lower bores of the rod. Respective upper and lower contact holders each have a pair of mounts flanking the rod and respectively downwardly and upwardly engaging the limbs of the contact. The mounts of the contact holders are formed with bores aligned with the bores of the rod and with the bores of the respective limbs. Dielectric upper and lower pins extend through the bores of the mounts of the holders, the bores of the limbs, and the bores of the rod.

Contact arrangement

The invention relates to a method for dehumidifying air and to an air dehumidifier. To this end, a filter element is provided that is filled with granular material that can be regenerated by baking out. For effecting this baking out, a heating device is provided that is only actuated when both a humidity sensor indicates that a humidity limit value has been exceeded as well as a relative pressure sensor or a comparable technical means indicates that, at the moment, no flow toward the oil expansion tank is recorded.

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Lappersdorf, Germany

Dieter Dohnal