A system protector against loss of current to ground intended to be used with a system of alternate current polifastico. (Machine-translation by Google Translate, not legally binding)

摘要

A protective system against losses of current to ground, intended to be used with a polyphase alternating current system, comprising current transformer means for deriving an output current that varies with the current to ground in said system, an electric input circuit that it has an input connected to said current transforming means and having output terminals to produce a first output signal at said output terminals when said ground current exceeds a predetermined value, time delay means having an input connected to it. Said output terminals of said input circuit and output terminals to produce a second output signal at said output terminals after a predetermined time delay upon the occurrence of said first output signal, an output circuit having an input connected to said output circuit; the output terminals of said time delay means and terminals of s alida to produce a third output in response to said second output signal, a delay enabling circuit including a delay disabling circuit, having an input connected to said input electrical circuit and an output connected to said time delay means to produce, normally, an additional output signal when said electrical input circuit produces said first output signal, said additional output signal being effective to activate said time delay means, to produce said second output signal substantially instantaneously on the occurrence of said first output signal, said system being characterized in that said delay enabling circuit includes an inhibitor circuit connected to said delay disabling circuit and adapted to respond to an external training signal to prevent said disabling circuit from producing said additional output signal. When said circuit the input electric signal produces said first output signal, so as to ensure that said time delay means produce said second output signal only after said predetermined time delay, when said first output signal occurs, and a disabling circuit connected to said output signal. Said output circuit and having an input, intended to receive a disabling signal, preventing said output circuit from producing said third output signal when said disabling signal is applied to the input of said disabling circuit. (Machine-translation by Google Translate, not legally binding)