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 an on-load tap changer having an energy storage mechanism for changing over, without any interruptions, between different winding taps of a tap-changing transformer on load. According to the invention, the energy storage mechanism has one or more compression springs, which are tensioned at the beginning of a changeover operation. In comparison with the tensile springs used to date with such energy storage mechanisms, the compression springs have markedly greater long-term strength.

Abstract: The present invention relates to a device for system components of a high-voltage impulse test system, preferably for quality assurance of power transformers. According to the invention, a common base frame having only one main electrode common to the system components is proposed for the spatial collection of the system components.

Abstract: The invention relates to a switching arrangement with two operational settings for switching over a winding during transformer operation, wherein during the switching-over a transient current commutates from one current path to another current path. In that case fixed contacts are arranged in several horizontal planes around a rotatable switching shaft and on an insulating-material frame and have upper and lower contact fingers that can be pressed apart and with which electrical connection can be made by an electrically conductive rail as movable switching contact.

Abstract: A pressure-relief valve has a housing having an annular flange defining a pressure-vent hole centered on an axis and having an axially directed end face and a radially outwardly directed outer surface. A cap can fit axially over the flange in a closed position and has a skirt radially juxtaposed with the outer surface in the closed position. A spring braced axially between the cap and the housing urges the cap into the closed position. A first annularly continuous seal secured to the end face axially bears on and hermetically engages the cap in the closed position. A second annular seal secured to the outer surface has an outer edge elastically engaging the skirt in the closed position and formed with a notch through which fluid trapped between the first and second seals in the closed position can drain.

Abstract: The invention relates to a method for controlling a heatable dehumidifier. The heating of the dehumidifier is to be actuated only when several congruent time windows within which a temperature gradient is greater than or equal to 0 could be determined during a certain period of time, i.e. the heating is to be actuated only when no air flows into the interior of the expansion vessel of the transformer.

Abstract: The invention relates to a mechanical switching contact having an insulating material support (1), on which fixed contacts (4, 5, 6) are arranged. Furthermore, a switching lever (2) is mounted such that it can rotate on the insulating material support (1) and has a pivoting arm (22). In addition, a pivotable contact housing (3) is also mounted on the insulating material support (1), which contact housing bears parallel contact fingers (9, 10), which surround the respectively connected fixed contacts (4, 5, 6) on both sides when contact is made.

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 an energy store for a load tap changer with a longitudinally movable lifting carriage and an also longitudinally movable snap-action carriage which follows the movement of the lifting carriage after being triggered and whose longitudinal movement is converted into a rotary movement of an output shaft that actuates the load tap changer. In order to do so, two rolls which are guided in an especially geometrically designed guide rail are disposed on the snap-action carriage. Only one of the two rolls is positively guided in the guide rail during the first part of each movement of the snap-action carriage while the other roll can be moved freely. The second roll that could previously be moved freely is then positively guided during the second part of the movement while the roll which was previously guided can be moved freely. The roll which was initially guided is positively guided once again during the third part of the movement.

Abstract: The invention relates to an energy store for a load tap changer with a longitudinally movable lifting carriage and an also longitudinally movable snap-action carriage which follows the movement of the lifting carriage after being triggered and whose longitudinal movement is converted into a rotary movement of an output shaft that actuates the load tap changer. In order to do so, two rolls which are guided in an especially geometrically designed guide rail are disposed on the snap-action carriage. Only one of the two rolls is positively guided in the guide rail during the first part of each movement of the snap-action carriage while the other roll can be moved freely. The second roll that could previously be moved freely is then positively guided during the second part of the movement while the roll which was previously guided can be moved freely. The roll which was initially guided is positively guided once again during the third part of the movement.

Abstract: A tap changer has an insulating housing and a plurality of annular arrays of contacts fixed in the housing. A vertical switching shaft in the housing carries contacts positioned to engage the fixed contacts of the respective array on rotation of the shaft. A tap-changer head closes an upper end of the housing, and a head flange above the tap-changer head is formed with threaded fastening bores. A geneva transmission on the tap-changer head has an output connected to the shaft and an input shaft projecting vertically upward from the head into the head flange. An upper transmission stage boltable to the bores on the head flange is connectable to the input shaft. A handwheel drive has a flange with an upper cover through which the input shaft extends and a handwheel or hex fitting on an upper end of the input shaft.

Abstract: A dehumidifier for an electrical-equipment air intake has an outer housing wall and a floor of a material with a high specific thermal conductivity downwardly closing the outer housing wall, having a downwardly tapering funnel-shaped inner surface formed with a central downwardly open port, and having a rounded edge where the surface meets the port. An inner air-permeable housing inside the outer housing wall holds a moisture-absorbing mass so that air drawn in through the port can pass through the mass and then into a space between the inner and outer housings. A moisture sensor is provided between the housings and a heater in the mass. A controller connected between the heater and the sensor energizes the heater and cooks moisture out of the mass such that the moisture condenses on the floor and runs over the edge out through the port.

Abstract: A pressure-relief valve has a flange formed with a throughgoing port. A spring plate spaced outward from the port is mounted on a rigid post fixing the spring plate relative to the flange. A valve body between the plate and the flange can shift between a closed position engaging the seal and closing the port and an open position spaced outward from the port and permitting flow through the port; A spring braced between the spring plate and the valve body urges the valve body into the closed position. A cup-shaped housing covering the valve body, spring plate, post, and springs has an end wall spaced from the flange and a side wall projecting from the end wall toward the casing and formed with a vent opening.

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: The invention relates to a novel energy accumulator for a load step switch for rapid, continuous switching between various winding tappings. Said energy accumulator comprises a lifting carriage and a jumping carriage, which follow the movement of the jumping carriage in a jumping manner. Both of the carriages are guided along three parallel guiding rods. The lifting carriage and the jumping carriage comprise, respectively, three linear roller bearings which respectively surround one of the three guiding rods.

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 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 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.