Siemens Aktiengesellschaft

Holger Hochgraef

Wolfgang R&ouml;hl

Ulrich Baumgaertl

Reinhard Maier

Gerd Griepentrog

Henry Franke

Andreas Pancke

Aron-Ernst Musiol

Gerhard Tietz

Hans Rehaag

Wolfgang Roehl

Manfred Schiller

Jeffery C Mizener

Ulrich Baumg&auml;rtl

Thomas M&uuml;ller

Jeffrey C Mizener

Mario Wegener

Michael Jankowiak

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.

Low-voltage power breaker with a rating plug

The circuit contains a primary coil on the core () of a magnetic circuit with an air gap and switchable into a line carrying the measurement current. A secondary compensation coil (), with an order higher winding count and mounted on the core, is connected to the output of a controllable compensation current source (). The output of a Hall element () in the air gap is connected to the control input of the compensation source. A further coil () on the core is connected to an additional controllable current generator () whose control input () is driven by a measurement device () for the compensation current via a control and evaluation circuit (). USE/ADVANTAGE&#x2014;Measuring a.c. and d.c. Can be produced at low cost and all drift occurring during measurement can be compensated.

Method for reproducing direct currents and a direct current transformer for carrying out said method

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.

Low-voltage circuit breaker comprising a data memory

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.

Method and circuit for measuring a current

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 &ldquo;fuse&rdquo; 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.

Electronic tripping device for a circuit breaker

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.

Method for preventing making on electrical short circuits existing in branches and corresponding device

Circuit arrangement for detecting the current of a current conductor in

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Ganzer/Wusterhausen, Germany

Holger Hochgraef