Abstract: The invention relates to a tap changer for switching among winding taps of a step transformer without interruption, said step transformer having an oil-filled transformer tank, wherein the tap changer does not have a separate housing or a housing that completely encloses the tap changer and is arranged on the outside of or inside the transformer tank connected to the oil filling of the step transformer.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The invention relates to the arrangement of a stepping switch on a control transformer, wherein either only the mechanical contact system (8) of the stepping switch or also its load changeover switch (7) is or are arranged within the tank (1) of the transformer, under the transformer cover (4) and above the iron yoke (3).

Abstract: 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.

Abstract: 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.

Abstract: The invention relates to a tap switch for uninterrupted changeover between two winding taps (tap n, tap n+1) of a tapped transformer, wherein each of the two winding taps is connected to the common outgoing load line via in each case a mechanical switch (Ds) and a series circuit which is arranged in series therewith and which is composed of two oppositely connected IGBTs (Ip, In). According to the invention, each IGBT is bridged by in each case a specially dimensioned varistor (Vp, Vn) connected in parallel therewith.

Abstract: 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.

Abstract: The abstract relates to an arrangement of an oil-filled power transformer having an oil-filled stepping switch, wherein only a single oil expansion vessel is provided, this oil expansion vessel being connected both to the oil volume of the stepping switch and also to the transformer tank, which is likewise oil-filled, via corresponding flanges.

Abstract: 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.

Abstract: 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.

Abstract: The invention relates to a device for regulating the electrical voltage in power mains, comprising a regulating transformer. Optionally interconnecting only three winding taps and a separate reactor winding with a total of four switching elements, enables five different voltage levels to be set.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The invention relates to a multipoint switch for continuously switching different coil branches of a step-down transformer. According to said invention, at least one torque motor associated to various drive configurations carries out different driving functions for individual groups, thereby substituting a conventional motor.

Abstract: The invention relates to an arrangement for automatically influencing a mains supply. A voltage transformer is provided as a pilot transformer which detects the real value of the voltage which is to be adjusted and which transmits said value to a motor drive via an individual electric measuring circuit in which means are provided for comparing said real value to a set point value and for producing an adjustment command which is dependent upon said comparison. The invention also relates to a correspondingly equipped motor drive provided with an additional control module which directly actuates an electric motor independently from the direction of rotation when required. Said electric motor drives a step-switching mechanism on the variable-voltage transformer, whereby the voltage is adjusted, thereby influencing the mains supply.

Abstract: The invention relates to a contact arrangement in which an electrical contact of U-shaped construction is fixed in common by two contact holders, which surround it at the top and bottom, and selectably also upper and lower screening caps, by means of two pins which go through corresponding bores not only of the described components, but also of the insulating rod at which the fastening shall take place.

Abstract: 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.