Leakage protection device

Abstract

The invention discloses a leakage protection device which can prevent electric shock accidents caused by faults of electric equipment and also can prevent the electric shock accidents caused by the fact that an earth wire is electrified accidently. The leakage protection device is also provided with a weak current detection sensor, a voltage comparator circuit and a one-way output circuit; an iron core of the weak current detection sensor is wound by a primary winding and a secondary winding; a detection circuit which is formed by serially connecting the primary winding with a current-limiting capacitance resistance element is connected between the earth wire and a neutral wire; a standard voltage obtained from a stable-voltage power supply is input into an input end of the voltage comparator circuit; an output end of the secondary winding of the weak current detection sensor and the other output end thereof are respectively connected with the other input end of the voltage comparatorcircuit and a cathode of the output end of a rectifying circuit; and the output end of the voltage comparator circuit is connected with a driving circuit of an electromagnetic coil through the one-way output circuit.

Description

technical field [0001] The invention relates to the technical field of electricity safety protection, in particular to an electric leakage protection device. Background technique [0002] Chinese patent document CN1142618C discloses a kind of earth leakage protection plug which can be opened and closed. The earth leakage protection plug is not only provided with a zero-sequence current transformer through which both the phase wire and the neutral wire pass, but also has a ground wire through which the earth wire passes. Line live detection sensor, so it can not only detect whether there is residual current between the phase line and the neutral line at the load end, when there is a residual current between the phase and neutral lines and reaches the preset threshold (for example: 10mA), it will It will trip immediately and cut off the phase wire, neutral wire and ground wire; and when the ground wire is accidentally electrified due to an abnormal grounding protection system,...

AI Technical Summary

Problems solved by technology

[0003] It can be seen from the above that the prerequisite for the existing leakage protection device to trip when the load end is faulty or the ground wire is accidentally electrified is that there must be a residual current between the load end phase and the neutral wire or there must be an accidental current flow on the load end ground wire. Therefore, the existing leakage protection device has the following defects: when in use, whether the ground wire of the grounding protection system is missing (for example: the ground wire of the socket is empty, resulting in no grounding) and the load end of the leakage protection device is insulated by electrical appliances When there is a fault leakage, or when the grounding protection system is abnormal (for example: short circuit of the phase wire and the ground wire) and the ground wire is accidentally electrified, it will cause the exposed metal parts of the electrical appliances to carry dangerous voltages, but they have not formed a loop, so there is no Therefore, although the exposed metal parts of electrical appliances have been charged with dangerous voltage, the existing leakage protection devices will not automatically trip in this case, only when the human body or livestock touch these When the exposed metal parts have been electrified, a loop is formed through the human body or livestock, resulting in residual current or ground wire accidental current, which makes the leakage protection device trip within 0.1S and disconnects the phase wire, neutral wire, and ground wire. Although it can be tripped in time to protect the life safety of people or livestock, in this case, the existing leakage protection device must first pass through the human body or livestock to generate residual current or ground wire accidental current and flow through the human body or livestock. It can trip and disconnect the phase wire, neutral wire and ground wire, so the existing leakage protection device will still cause electric shock accidents to human body or livestock

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