초록 ▼

A device for detecting a persisting electrical overload in an electrical system includes means for monitoring an electrical parameter in the electrical system and for generating an electrical signal whose magnitude represents the instantaneous absolute value of the parameter, reference means which g

A device for detecting a persisting electrical overload in an electrical system includes means for monitoring an electrical parameter in the electrical system and for generating an electrical signal whose magnitude represents the instantaneous absolute value of the parameter, reference means which generates an output signal of predetermined value and which develops, in cooperation with the monitoring means, an electrical signal whose magnitude represents the amount by which the magnitude of the absolute value signal exceeds the predetermined value, integrator means to integrate the aforementioned electrical signal and 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; and comparator means to continuously compare the magnitude of the integrator output signal with a second preselected value and which generates an indicative output whenever the integrator output signal exceeds the second preselected value.

대표청구항 ▼

A device for determining the occurrence of an electrical overload in an electrical system comprising: a. means for monitoring an electrical parameter in an electrical system and for generating an output signal representative of the instantaneous absolute value of the monitored electrical parameter;

A device for determining the occurrence of an electrical overload in an electrical system comprising: a. means for monitoring an electrical parameter in an electrical system and for generating an output signal representative of the instantaneous absolute value of the monitored electrical parameter; b. threshold control means for developing an electrical output signal of predetermined time-invariant value; c. adder means connected to receive the output signals from said monitoring means and from said threshold control means and to receive a feedback signal, said adder means being operative to generate an output signal representative of the summation of said three received signals; d. integrator means connected to receive said summation signal from said adder means and to generate an output signal representative of the integral of said summation signal; e. feedback means coupled between the output of said integrator means and the input to said adder means for feeding said integrated signal back to said adder means with a predetermined gain; and f. comparator means connected to receive the integrated signal from said integrator means and operative to generate an indicative overload signal whenever the magnitude of said integrated signal exceeds a second predetermined value.