Abstract: The invention relates to a method for monitoring contact consumption in multiple contact switches of the load-switching type, wherein the selection and the switching is carried out in one step by the movement of switching contacts and which therefore do not have a separate diverter switch. Every time the multiple contact switch is actuated, the load current is measured. The corresponding, previously stored rated stage voltages for the current switching and information on whether it was shifted “up” or “down”, are used to calculate the switching currents of the breaking contacts, the consumption rates are determined on the basis thereof and the volume consumption is accumulated. Said accumulated value is compared with a previously determined threshold value; once this threshold value is reached, warning messages or other messages are generated.

Abstract: The invention relates to an oil filter installation for cleaning or cleaning and dessication of the oil in a tap changer at a power transformer or a plunger core coil, wherein a measuring device for detecting the volume flow of the throughflowing oil is provided and the electric pump motor is influenced by way of an interposed frequency converter in accordance with the result of a comparison of this measured value with a target value.

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: A tap changing assembly for power transformers having vacuum interrupters each of which is associated with a radio interrogated surface wave sensor capable of detecting whether the respective vacuum interrupter opens circuit in a timely manner. The sensors are interrogated by an interrogating unit transmitting high-frequency signals to the sensors and associated with a monitoring circuit responsive to signals received by the interrogating unit for signalling the status of the vacuum interrupter.

Abstract: A thyristor transformer has a mechanical tap selector and a diverter switch with thyristors. The tap selector is mounted in the oil-filled housing or tank of the transformer and the diverter switch is mounted in a separate housing laterally attached to the tank.

Abstract: The invention relates to an oil filter installation for cleaning or cleaning and dessication of the oil in a tap changer at a power transformer or a plunger core coil, wherein a measuring device for detecting the volume flow of the throughflowing oil is provided and the electric pump motor is influenced by way of an interposed frequency converter in accordance with the result of a comparison of this measured value with a target value.

Abstract: A tap changing assembly for power transformers having vacuum interrupters each of which is associated with a radio interrogated surface wave sensor capable of detecting whether the respective vacuum interrupter opens circuit in a timely manner. The sensors are interrogated by an interrogating unit transmitting high-frequency signals to the sensors and associated with a monitoring circuit responsive to signals received by the interrogating unit for signalling the status of the vacuum interrupter.

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 thyristor tap changer that comprises a mechanical tap selector and a diverter switch with thyristors as the switching means. The inventive tap changer is further characterized in that only the tap selector is mounted in the oil-filled transformer tank while the diverter switch is externally mounted in a laterally attached separate housing.

Abstract: A method of controlling a step switch. From the measured values of current, voltage and phase angle at an electric drive motor during actuation of the step switch the individual picked-up active output is calculated. From the active output the corresponding torque at the drive motor is calculated. The torque in the step switch which is crucial for controlling is determined on the basis of the torque by using a specifically calculated transfer function. The transfer function is newly determined every time the switch is actuated, with the values of the preceding switch operation or the preceding switch operations being taken as a basis of the new calculation.

Abstract: A method of monitoring contact burnoff in tap changers operating under load in which the load current is measured and for nominal variation of the voltage of the particular tap parameters are stored which are used to calculate the burnoff rate per contact per switching operation. From these values the cumulative burnoff rate of both the switching contact and resistance contact are determined and compared with limits or threshold values.

Abstract: A position indicator for step switches and tap selectors of transformers and the like has a contact array connected to the motor drive and connected by a plug to the plug of a connector which, in turn, is connected by plugs to the information-generating module which outputs to the display. One of the pairs of plugs between the contact array and the connector or between the connector and the module can be reversed relative to the other to signal a different sense of rotation of the motor drive.

Abstract: A method of monitoring contact burnoff in tap changers operating under load in which the load current is measured and for nominal variation of the voltage of the particular tap parameters are stored which are used to calculate the burnoff rate per contact per switching operation. From these values the cumulative burnoff rate of both the switching contact and resistance contact are determined and compared with limits or threshold values.

Abstract: A position indicator for a motor drive for actuating a step switch, tap changer, or dipping coil, has a display board having front and back faces and a first circular array of symbols on the front face corresponding to individual switching phases traversed during changeover of the motor drive from one operational position into another neighboring operational position. A first shaft extending through the board centrally of the first array and defining a first axis carries a pointer at the front face rotatable about the first axis through positions aligned with the symbols. A second circular array of symbols on the front face is associated with individual possible stationary operational positions of the step switch, the tap changer, or the dipping coil. A second pointer shaft projecting through the board centrally of the second array and defining a second axis carries a second pointer at the front face rotatable about the second axis through positions aligned with the symbols of the second array.

Abstract: A tap selector for a power transformer switchable under load is monitored by detecting the effective values of current and voltage of the drive motor of the tap changer. The power is calculated and from that the instantaneous torque and the latter is compared with setpoint values either of the torque and position of the tap selector or in terms of characteristic segments of the torque versus time graph with normalized segments of a setpoint graph so that, with serious deviation an immediate shutdown of tap selector operations is ensured or information can be generated as to trends or the need for maintenance.

Abstract: A method of monitoring a tap changer in which measured values representing the status of the tap change operation are associated with positions of the tap changer and the position range or time range for the tap change is subdivided into partial intervals for which characteristic values of the measurement are calculated by a calculating rule, e.g. averaging. These characteristic values are compared with stored parameter data and operation categories are established which are then used exclusively for the further information processing.

Abstract: A tap changer has a bypass switch with a rotary pair of movable contacts engaging arc segmental fixed contacts of a length greater than the spacing between the movable contact which spacing is greater than the spacing between the fixed contacts of the bypass switch.

Abstract: The invention relate to a position signaling layout for a motor drive which also serves to activate an on-load tap changer, an off-circuit tap changer or a plunger core coil. Position signaling devices of this kind detect the position at a given time of the on-load tap changer or similar and transmit this information in the form of an electric signal. According to the invention, the device consists essentially of a board on which there are fixed signaling contacts and a pivoted cam disc which connects said fixed contacts electrically and links them to a terminal lead via a spring operated switch, activating the spring operated switch by means of its front cam contour.

Abstract: A multiphase reactor-switching tap selector has a single geneva mechanism operating three shafts which traverse phase plates carrying all of the contacts and the vacuum switching cell and rapid release mechanism for each of the phases. The geneva mechanism operates the tap selection contacts directly through its shaft and is coupled to other shafts for operating the preseslector contacts, the bypass contacts and the vacuum switching cells. All three shafts traverse all of the phase plates.

Abstract: The invention concerns a switching arrangement for load change-over switches of step switches and for selector switches, wherein two switching contacts movable in two directions are present. The first switching contact is in the form of a main switching contact and is connected to the load derivation by means of a first vacuum switchgear cell. The second switching contact is in the form of a resistance switching contact which is likewise connected to the load derivation by means of a series connection comprising a second vacuum switchgear cell and a transition resistor. Both the main and the resistance switching contacts can be moved independently of one another and without mutual coupling or influence. The main switching contact always reaches the new fixed contact abruptly and independently of the switching direction before the resistance switching contact leaves the previous fixed contact.