Abstract: A method and a circuit are disclosed for amplifying the input signals of an electronic overcurrent release of low-voltage circuit breakers with a selectable amplification factor. The electronic overcurrent release includes at least one integrating condenser on the input side, and at least one pre-amplifier and a microprocessor. According to at least one embodiment of the invention, a resistance is coupled to a switch in series, parallel to an integrating condenser, and the switch is switched by way of the microprocessor in a pulsewidth-modulated manner. In this way, the effectively active resistance value of the inserted resistances is inversely increased proportionally to the pulsewidth repetition rate, thus obtaining an extremely wide regulating range.

Abstract: A three or four pole low-voltage power switch is disclosed wherein the switch is partly provided with a device for detecting ground faults. For this purpose, the current vectorial sum must be produced in the three or four conductors of a monitored network. For the switches of this type, output signals received from Rogowski coils are directed via resistances to an integration capacitor whose voltage forms an input signal of another measuring amplifier representing the current sum of a monitored network. The output signal of the measuring amplifier is, afterwards processed in a known manner in the microprocessor of an excess-current trip.

Abstract: A three or four pole low-voltage power switch is disclosed wherein the switch is partly provided with a device for detecting ground faults. For this purpose, the current vectorial sum must be produced in the three or four conductors of a monitored network. For the switches of this type, output signals received from Rogowski coils are directed via resistances to an integration capacitor whose voltage forms an input signal of another measuring amplifier representing the current sum of a monitored network. The output signal of the measuring amplifier is, afterwards processed in a known manner in the microprocessor of an excess-current trip.

Abstract: A circuit arrangement is disclosed for rapidly switching off low-voltage circuit breakers comprising an electronic tripping unit. According to an embodiment, a switching element which is operated in a short-circuit mode during normal operation and to which a fast trip magnet of the low-voltage circuit breaker is connected in parallel is impinged upon by a current that is proportionate to the current monitored by the low-voltage circuit breaker, and the short circuit of the switching element is bypassed when the current monitored by the low-voltage circuit breaker reaches a set threshold value. One respective transformer is serially connected to the power inputs of the electronic tripping unit, the secondary ends of the transformers being interconnected among each other on the direct voltage side while being serially connected to the switching element via bridge rectifiers.

Abstract: A method and a circuit arrangement are disclosed for rapidly switching off low-voltage circuit breakers by impinging a switching element which is operated in a short-circuit mode during normal operation and to which a fast trip magnet is connected in parallel, with a current that is proportionate to the current monitored by the low-voltage circuit breaker while the short circuit of the switching element is bypassed when the current monitored by the low-voltage circuit breaker reaches a set threshold value. The fast trip magnet is at least temporarily short-circuited once again as soon as the monitored current reaches a second given threshold value. A corresponding circuit can be designed such that the switching element is embodied as a switching transistor which can be controlled back into the conducting state by a second monitoring circuit for the current monitored by the low-voltage circuit breaker when a second given threshold value has been reached.

Abstract: An electrical power breaker includes an electronic protective device and an electronic memory. The memory is accommodated in the power breaker such that it is physically separated from said protective device, for operational data for the power breaker. Data security when using the additional electronic memory is increased by the electronic memory being connected to the protective device via a data bus, which can be used to transmit control signals for the purpose of activating or deactivating a write protection device of the electronic memory. The data bus is preferably an I2C bus, and the write protection device is controlled by an I/O module which is likewise controlled by the I2C bus.

Abstract: One problem during the detection of ground faults resides in the fact that the measuring amplifiers have a great amount of tolerance regarding the amplification factor thereof, resulting in a substantial error when errors are handled by means of software. According to the disclosure, the output signals of the measuring amplifiers are summed up phase by phase in a pulse-modulated manner in a summing amplifier. The duration of the pulses generated by the trip are controlled in accordance with the amplification factor of the respective associated measuring amplifier while the output of the summing amplifier represents a ground fault monitoring signal.

Abstract: An electrical power breaker includes an electronic protective device and an electronic memory. The memory is accommodated in the power breaker such that it is physically separated from said protective device, for operational data for the power breaker. Data security when using the additional electronic memory is increased by the electronic memory being connected to the protective device via a data bus, which can be used to transmit control signals for the purpose of activating or deactivating a write protection device of the electronic memory. The data bus is preferably an I2C bus, and the write protection device is controlled by an I/O module which is likewise controlled by the I2C bus.

Abstract: A trip device is for an electrical power breaker, for tripping on a short-circuit. It is embodied as an analogue electrical circuit. The circuit components and devices necessary for tripping on a short circuit form a discrete module, completely independent of other trip devices on the power breaker. A direct current is provided by transformers together with rectifiers which flows through a power semiconductor switched to conduct in the normal operating state of the power breaker. A measurement and control circuit is controlled by way of a voltage generated across a measuring resistance through which the direct current flows and closes the power semiconductor when a threshold value is exceeded. The current is then commutated from the power semiconductor to the trip magnet which opens the switch contacts with a particularly small delay.

Abstract: A method and circuit arrangement for measuring a current are described, which can be used in electrical engineering to precisely trigger electronic tripping devices in circuit breakers. The current is measured according to magnitude and phase in such a way that only the fundamental wave of the current between precisely determined current zero crossings is sampled at a low sampling rate, and the root mean square is calculated on the basis of the measured phase angle and amplitude. The exact phase angle is measured using a conventional PLL circuit with a downstream zero switch.

Abstract: An electronic tripping device for a circuit breaker contains circuitry for simulating the response curve of a fuse. This circuitry can be controlled by a single setting mechanism representing the nominal currents or rated currents of fuses. This improves the coordination of protection in sophisticated power supply equipment containing both circuit breakers and fuses. Tripping devices equipped with microprocessors or operating in an analog fashion can be configured for the mode of operation. The new protection system achieves particularly safe operation for the user in that the setting mechanism is combined with a rating plug for the “fuse” mode, thus directly setting the tripping device to one current value. In a manner similar to a true fuse, consequently, the setting mechanism is provided with appropriate labeling. The simulated curves may contain a point of inflection below a limit in a lagging manner, to increase the nominal switching capacity and selectivity limit of a circuit breaker.

Abstract: A partition arrangement for a self-supporting body of a motor vehicle has a partition which is arranged at the forward end of a rear space and extends in the transverse direction of the vehicle and along a portion of its height between rear wheel houses of the motor vehicle. The arrangement is detachably fastened to boundary walls of the rear space. The partition extends along almost the entire height of the rear space and is arranged approximately in an upright transverse plane of the vehicle. The partition, moreover, is constructed as a supporting device stiffening the vehicle body against deformation.

Abstract: A circuit arrangement is described for monitoring an electronic tripping device for low-voltage switches having a microprocessor device which, in conjunction with a digital-analog converter, evaluates an overcurrent so that line power supply system. The microprocessor device (MPE) has a zero crossing comparator with which a constant test current pulse is transmittable, at zero crossings, to the electronic tripping device via an additional current transformer winding to measure the amplitude. In the case of deviations from the setpoint value, (re)calibration or actuation of the line tripping contacts, with an alarm signal being emitted, takes place.

Abstract: An undervoltage circuit breaker has an electromagnet for triggering a switching device and a driver circuit that supplies power to the electromagnet. The driver circuit contains a pulse generator for generating a holding current for the electromagnet and a capacitance dimensioned so that delayed triggering of the electromagnet is possible. Due to the variable pulse duty factor of the pulse generator, the energy content of the capacitance is utilized favorably. An elevated operating voltage can also be selected and therefore a smaller capacitor may be selected to advantage.

Abstract: A circuit configuration for supplying power to electronic tripping devices from a current-transforming device. A switched-mode power supply unit, in particular a choke/step-up transforming device having a pulse-width voltage control, is connected downstream of a charging capacitor. Once a set point of the output voltage at an output capacitor is reached, only a very high pulse duty factor is provided. Particularly, maximum power point control is provided during an initial charging phase. Circuit configurations of this kind serve the power supply of overvoltage tripping devices in low-voltage and medium-voltage systems.

Abstract: A voltage transformer with increased electric strength has a resistance divider made of ohmic resistances as well as a working amplifier and an inductive transformer. The secondary side of the inductive transformer forms the undervoltage side of the voltage transformer. Since high electric strength resistances are cheap to obtain, this voltage transformer is particularly useful in cases where an inductive voltage cannot be used because of its size and price, for example in low voltage power switches with voltage display or voltage measurement.

Abstract: An intrinsically safe power supply arrangement with a current regulator is provided with a controlled semiconductor, coupled to a clock generator and coupled between a rectifier and a primary winding of a transformer, for periodically interrupting a DC current in response to a clock signal. A short-circuit switch is disposed between a secondary winding of the transformer and an output of the power supply arrangement. A choke is coupled to the short-circuit switch, and a voltage limiter is coupled to the choke. A current regulator, coupled between the voltage limiter and the output of the power supply arrangement, has a retrogressive current-voltage characteristic and a delay stage for producing a time-delayed rise of a selectable combination of current and voltage. A circuit element supplies a selectable input and output signal of the current regulator to an input of a voltage regulator. An output of the voltage regulator is coupled to the clock generator.