ELECTRONIC OVERLOAD DETECTING DEVICE

摘要

A device for detecting a persisting electrical overload in an electrical system includes a sensor for monitoring the current in the electrical system and for generating an electrical signal whose magnitude represents the instantaneous absolute value of the current. A threshold control generates an output signal of predetermined value and develops, in cooperation with the sensor, an electrical signal whose magnitude represents the amount by which the magnitude of the absolute value signal exceeds the predetermined value. An integrator integrates the aforementioned electrical signal to generate an output whose magnitude includes a component representative of the product of the electrical signal and a time-increasing value that represents the duration that an overload has persisted. A comparator continuously compares the magnitude of the integrater output signal with a second preselected value and generates an indicative output whenever the integrator output signal exceeds the second preselected value.