Abstract: Asynchronous motors are controlled by way of two- or three-phase controllers that include at least two pair of thyristors connected in antiparallel and fired at certain intervals. According to the inventive method, a fundamental wave with the desired frequency is defined for the first phase and in the other phase a respective fundamental wave is defined that has the same frequency as that in the first phase, but phase-shifted by corresponding values. For every phase, firing intervals are marked that have the same polarity as the respective fundamental wave. Those intervals of the potential firing intervals are used for every phase at which there is a potential firing interval in one of the two other phases. These intervals are used as the actual firing intervals.

Abstract: A method for transmitting data via a traction current conductor which simultaneously conducts drive current for a vehicle and in which an interruption in the data transmission by an arc cccurring between a vehicle-end drive current collector and the traction current conductor is reliably avoided. The method for trandsmitting data via a traction current conductor, in which at the transmitter end at least two data signals including in each case the data in an identical form are fed into the traction current conductor with different frequency channels. In the event of an arc occurring at the receive end, the received data of that data signal or those data signals whose amplitude does not drop below a ratio necessary for achieving a specific bit error probability with respect to the amplitude of the interference signal S(f), is selected for evaluation.

Abstract: The aim of the invention is to provide a method, with which the load current and thus the load moment of an asynchronous motor that is controlled via a phase-controlled two-phase thyristor power controller can be easily influenced so as to allow a smooth starting operation. According to a first embodiment of the invention, the ignition point (tIgn+1) is determined in the controlled phase (L1 and L2) in order to adapt the flow angles of the subsequent current half waves. According to a second embodiment, the ignition point (tIgn) of the subsequent current half waves is brought forward in both controlled phases (L1 and L2).

Abstract: An electromagnetic switching device includes a contact arrangement with three contacts which couple a three-phase load to three phases of a three-phase power supply system, and disconnect the three-phase load from the three phases. Switching erosion takes place on the contacts. An overall erosion is determined for each contact, and is supplied to a drive circuit. The contact arrangement is operated by the drive circuit as a function of the overall erosion such that the overall erosion of the contacts are approximated to one another.

Abstract: A protection device includes a measurement device that is a current transformer which is based on a printed circuit, and an evaluation device that is a unit for early short-circuit identification. The current transformer, which is based on a as printed circuit board, is preferably a multiwinding transformer. The unit for early short-circuit identification operates on the basis of a so-called locus curve method, which uses instantaneous values of the current and current rate of change to identify a short circuit.

Abstract: The orthogonal frequency division multiplexing (OFDM) method is well-known for transmitting data on electrical power supply lines. According to this method, the items of information to be transmitted are distributed among numerous carriers, and the composite signal of the modulated carrier signals is transmitted in the form of an OFDM block. Standard OFDM methods are, however, highly sensitive to strong periodic pulse jammers. According to the invention, the method is thus devised such that the OFDM blocks to be transmitted have a length of approximately 85% of the interval between two periodic disturbing pulses. The carrier interval accordingly results from the reciprocal duration of the OFDM blocks. The transmitted OFDM blocks are synchronized with pulse-shaped periodic jammers in such a manner that one block at a time is located between two disturbing pulses. The pulse-shaped jammers can be gated at the receiver.

Abstract: A switching device includes a working circuit, to which an operating voltage can be or is applied to which has at least one electronic switching element. This switching element includes at least one control terminal for applying a switching signal and is switched off or switched on depending on the switching signal. At least one electronic protection element is for protecting the switching element in its switched state from excessive Joule losses in the event of danger, especially in the event of an overload or a short circuit. The protection element bears the predominant part of the operating voltage that is released at the working circuit.

Abstract: In order to control the run-down of an induction machine, whose stator is connected to a singe-phase or polyphase AC main power supply system via an AC power controller which can be controlled by phase gating, a phase gating angle is first increased in steps until an operating point is reached, which is defined on the basis of predetermined criteria. The phase gating angle is then controlled in order to ensure that the induction machine runs down in accordance with a predetermined control program.

Abstract: It is a known fact that even information signals in the kilohertz and megahertz range can be transmitted via the bus systems of power transmission networks. The invention provides a method and a system for improving the transmission behavior by feeding the signals not to the bus of the power supply but at the end of an outgoing line or a bus bar trunking system facing away from the power feed. The connection to the telecommunication system is made via a PLC bus line (10), said bus line (10) being connected to the bus bar trunking systems/outgoing lines (2, 2′, . . . ) via PLC bus elements (12, 12′, . . . ).

Abstract: A protection device includes a measurement device and a downstream evaluation device. The evaluation device is a unit for early short-circuit identification which actuates a semiconductor switch, which is preferably produced based on silicon carbide. The unit for early short-circuit identification preferably operates with switching thresholds which can be predetermined for the product of the current and the current rate of change, or on the basis of tolerant locus curves. In the latter case, different power factors (0.1<cos100 <0.9) are used in the locus curves in a locus curve representation of the current and current rate of change. The semiconductor switch preferably contains two back-to-back series-connected switching elements based on silicon carbide.

Abstract: Asynchronous motors are controlled by way of two- or three-phase antiductors that comprise at least two pair of thyristors connected in antiparallel and fired at certain intervals. According to the inventive method, a fundamental wave with the desired frequency is defined for the first phase and in the other phase a respective fundamental wave is defined that has the same frequency as that in the first phase but phase-shifted by corresponding values. For every phase, firing intervals are marked that have the same polarity as the respective fundamental wave. Those intervals of the potential firing intervals are used for every phase at which there is a potential firing interval in one of the two other phases. These intervals are used as the actual firing intervals.

Abstract: The invention relates to a method for transmitting a control signal to a vehicle which is driven using an electrical drive current which is fed into a traction current conductor at a drive current feed point. In order to ensure that the transmission of the control signal is very largely unaffected by interference frequency components included in the drive current, according to the invention one current sensor, which is located outside the line section, is used to receive the control signal.

Abstract: A method is for preventing tapping into existing short circuits in branches. A power supply momentarily is connected in a test circuit at a defined instant of the power supply voltage and at least the current in the test time period is detected and evaluated as a criterion for a short circuit. The short-circuit current is limited by the use of an additional test resistor which is arranged in the test circuit in series preferably with a semiconductor switch. Solely the test current and/or the test voltage is used for identification of the short circuit. In the associated arrangement, a test resistor having a defined resistance, whose resistance is significantly greater than the power supply impedance, is arranged in the test circuit in series with the semiconductor switch.

Abstract: In a method and device for determining the torque of an induction machine, stator terminal voltages and the stator terminal currents are integrated and then high-pass filtered to determine a space vector of the concatenated stator flux. The torque is calculated therefrom by multiplication by a complex correction factor.

Abstract: A method for performing a short-circuit and overload disconnection with a semiconductor component includes the steps of providing a semiconductor component having a drain, a source and a gate. The semiconductor component has a gate-source voltage applied thereto, a current flowing therethrough, and a voltage dropping between the source and the drain. The gate-source voltage at the semiconductor component is adjusted, in dependence of the current flowing through the semiconductor component, such that, after charge carriers in the semiconductor component are depleted, the voltage dropping between the source and the drain assumes a highest possible value still uncritical for the semiconductor component and for a circuit to be disconnected. An algorithm is used for the step of adjusting the voltage dropping between the source and the drain.

Abstract: In order to measure the rotation speed of an induction machine whose stator is connected via a controllable AC controller to a single-phase or polyphase AC power supply system, the stator is disconnected from the AC power supply system for at least a predetermined time period (&Dgr;t). This is preferably achieved by opening active devices in the AC controller, with at least one stator voltage, which is induced in the stator by the rotary movement of the rotor, being measured in this time period (&Dgr;t). The measured values are used to determine the frequency of the stator voltage and to derive the rotation speed of the induction machine.

Abstract: Torque measurement is required in motors, in particular. It is already known to generate response signals in an axially offset manner at least at two points on a torque shaft by irradiating light onto the rotating torque shaft. An azimuthal offset of those signals produced by the torque over and above a rotary movement must be determined for evaluation purposes. An apparatus according to the invention for torque measurement on rotating torque shafts uses a continuous light beam to generate signals. A torsion-induced deflection of the light beam is geometrically amplified before an evaluation and an azimuthal offset is determined accurately therefrom as a time signal. The apparatus includes a device for generating optical response signals from at least two axially offset reflector systems at the torque shaft of the machine, which have individual concave mirrors in each case.

Abstract: A method for identifying short circuits in a low-voltage network includes the step of determining a first envelope and a second envelope for a plurality of locus curves of a current steepness as a function of a current in a low voltage network, the first and second envelopes including all switching angles, the first envelope being determined for a lower power factor, the second envelope being determined for an upper power factor. Additionally a third envelope is determined taking into account rated-current switching operations between the lower power factor and the upper power factor. A resultant envelope is formed from a combination of the first, second, and third envelopes by overlaying the first, second, and third envelopes. The resultant envelope defines a tolerant locus curve criterion indicating a short circuit for values outside the tolerant locus curve criterion. A configuration for identifying short circuits is also provided.