Full-resettable overvoltage overcurrent protection circuit and protection method

Abstract

Disclosed a automatic recover over-voltage over-current protective circuit and it's protecting method, comprises input line, output line, signal line and earth cord. Wherein, a positive temperature coefficient heat-variable resistor is connected between the input and output lines; a anti-surge arrester is connected between input and earth lines; a industrial frequency over-voltage protective unit is connected between output and earth lines; and a thermal deformation metal sheet switch is mounted between earth and signal lines. The invention reaches the over-voltage protection by utilizing the anti-surge arrester and the industrial frequency over-voltage protective units while the ant-surge arrester operates the over-voltage protection on the positive temperature coefficient heat-variable resistor; utilizing the positive temperature coefficient heat-variable resistor to operates over-current protection on the protected device as well as on the industrial frequency over-voltage protective units; utilizing the positive temperature coefficient heat-variable resistor to transfer heat to thermal deformation metal sheet switch, for controlling the thermal deformation metal sheet switch and signal line. Then, the protective units and thermal deformation metal sheet switch operates to be recovered automatically when the accident disappears.

Description

technical field [0001] The present invention relates to the field of electricity, in particular to a protection circuit, in particular to an overvoltage and overcurrent protection circuit and a protection method, in particular to a fully self-resetting overvoltage and overcurrent protection circuit used in various communication and control equipment and protection method Background technique [0002] In the prior art, communication and control equipment are in the primary stage of overvoltage and overcurrent protection technology from transmission lines, and communication and control equipment are either only equipped with overvoltage protection devices for lightning protection or overcurrent protection devices. Fuses, so the protection function is very imperfect, and communication and control equipment are often damaged by overvoltage and overcurrent from transmission lines. The problem of overvoltage and overcurrent protection in local telephone communication lines has be...

AI Technical Summary

Problems solved by technology

The security unit with manual recovery input line open-circuit structure solves the problem of outputting an alarm when the circuit is open, but the unit must add an action reset mechanism, which has a complex structure, and the open-circuit action produces arcing at high voltage and high current, and the contact performance deteriorates after reset. The reliability of the unit is reduced; after the line fault is eliminated, manual reset is required to eliminate the alarm and resume work, which fails to reduce the maintenance workload. In short, it is still not conducive to the smooth flow of communication lines

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