RO96925B1 - Circuit for protecting and signalling shorts to load - Google Patents

Abstract

The invention relates to a circuit for protection and signaling of short-circuits on load at inductive proximity limiters LN, consisting of a resistor connected to the ultimate transistor of the limiter E, commanded by a transistor which rectifies the oscillations of a limiting oscillator; the voltage drop produced on this resistor at the time of occurrence of a short circuit at the load terminals consisting of a relay controlled by the final transistor becomes large enough to bring into conduction an overcurrent overcurrent transistor characterized in that the overcurrent siren transistor command , by means of a resistor (R 2), the wearing of a thyristor (Th) which is thus primed, brings in saturation conduction another transistor (T2), whose collector-emitter junction is connected in parallel, through a resistive divider with the base-emitter junction of the end transistor of the limiter (2) it blocks, thus canceling the current through the load, signaling the protection action being achieved by an LED (L) that lights up, the thyristor (Th) remaining still primed, to remove the short circuit and return to the initial situation by a disconnection-connection maneuver from and to a power supply, respectively.