Abstract: A rating plug may be provided with an electrical coding such that unsuitable identification of the rating plug is not transmitted to the trigger unit, but rather the attempt to make use of such a rating plug leads to a signal. The signaling unit is arranged on the housing of the low-voltage power breaker, or on the trigger unit. Thus, if the rating plug is the wrong rating plug, wrong contact connection and a defective rating plug may be recorded.

Abstract: The circuit contains a primary coil on the core (2) of a magnetic circuit with an air gap and switchable into a line carrying the measurement current. A secondary compensation coil (5), with an order higher winding count and mounted on the core, is connected to the output of a controllable compensation current source (6). The output of a Hall element (11) in the air gap is connected to the control input of the compensation source. A further coil (14) on the core is connected to an additional controllable current generator (15) whose control input (16) is driven by a measurement device (13) for the compensation current via a control and evaluation circuit (17). USE/ADVANTAGE—Measuring a.c. and d.c. Can be produced at low cost and all drift occurring during measurement can be compensated.

Abstract: A power circuit breaker includes break contacts for main current circuits and a connection device for auxiliary current circuits that interacts with a contact device mounted in a fixed manner. Signaling switches are placed on a withdrawable rack, which accommodates the power circuit breaker, and are provided for detecting and signaling the position of the power circuit breaker located inside said withdrawbable rack. The signaling switches are structurally assigned in a direct manner to an interface subassembly that processes signals, which are transmitted out of the contact device and by the signaling switches and to be relayed to a field bus system.

Abstract: Data memories are used to represent the characteristic values of the properties of the circuit-breaker and the associated current transformer. A cable harness uses a writeable electronic memory module which is inserted into one of the interconnecting cables between the current transformer(s) and the overcurrent trip as the data memory.

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: The overall characteristic curve for an overload trip should fall monotonically, which isn't always the case for certain choices of set values. According to the invention, the characteristic curve of an overload trip in the overload region (I), for a section of the curve situated before the short-delayed short-circuit region (II), may be set with the delay time (tsdi), which is independent of current and dependent on the short delay time (tsd) and which is at least as big as the short delay time (tsd). The above is particularly advantageous in the case of current measurement by means of Rogowski coils.

Abstract: Data memories are used to represent the characteristic values of the properties of the circuit-breaker (10) and the associated current transformer (17). Known assemblies requires a large number of plug and socket connections and are limited with regard to the number of parameters that can be stored. The inventive assembly uses a writeable electronic memory module which is inserted into one of the interconnecting cables (1) between the current transfomer(s) and the overcurrent trip (18) as the data memory.

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 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: A circuit arrangement for detecting the current of a current conductor in order to activate electronically controllable tripping devices, having a line voltage supply unit, with the operating voltage generated by the line voltage supply unit being compared to a reference voltage and the tripping device being activated by a limit voltage that forms when an overcurrent occurs. The a.c. voltage transmitted via secondary phase windings is rectified and supplied to a microprocessor device in the form of an operating voltage by the phases that are not in the measuring state. The processor-controlled phase measurement is performed without load, producing a precise measurement result.