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

Abstract

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.

Dependencies are inferred from the claim text.