Siemens Aktiengesellschaft

Josef Götz

Richard Schmidt

Thomas Kiendl

Jörg Weiss

Frank Jucht

Cornelia Prechtl

A power supply is disclosed for an electronic tripping unit and, in particular a circuit breaker for low voltages, which is connected on the outgoer side to a load via whose load resistance a direct current or alternating current flows. An electronic tripping unit initiates the disconnection of the associated contact elements in the event of an overcurrent and/or short-circuit current, and a voltage tap taps off a voltage on the conductor in order to supply power to the tripping unit. In order to ensure that power is always supplied to the tripping unit, the power supply includes, in at least one embodiment, an inductance between the load and the voltage tap, which inductance is connected in the conductor and is of such a magnitude that, when the current changes over time during the course of a short circuit, the voltage which is tapped off as the voltage drop across the inductance ensures the supply of electrical power to the tripping unit at least for a minimum time.

Power supply for an electronic tripping unit for a switch, in particular a circuit breaker for low voltages, and a switch having a power supply such as this

In one embodiment of the present invention, a circuit breaker and a method for triggering a circuit breaker are disclosed, particularly a low voltage circuit breaker, including an electronic overload trigger, particularly for the protection against a short circuit, wherein the current is compared to a predetermined limit current and evaluated and the circuit breaker is triggered by the overload trigger, in case a short circuit is present according to the evaluation. In order to be able to reliably detect short circuits, the current is sampled with a predetermined sampling frequency and digitized. The wavelet coefficients of at least two segmentation levels are calculated for a predetermined number of digital current values in direct succession via a wavelet transformation. At least two wavelet coefficients, that is, one wavelet coefficient per segmentation level, are compared quantitatively to each other if the last of the current values in direct succession is larger than the limit current. The circuit breaker is triggered if the wavelet coefficient of a higher segmentation level is larger than the wavelet coefficient of a lower segmentation level.

Growing community of inventors

Freudenberg-Aschach, Germany

Josef Götz