JPH0982209A - Plug type earth leakage circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to turn off a plug-type ground leakage circuit breaker by operating in a remote position. SOLUTION: A zero-phase-sequence current transformer 1A incorporated in a plug-type ground leakage circuit breaker is equipped with a tripping coil 82 to which a current is supplied from the outside through a signal wire 81 of a four-conductor cable 70. When the plug-type ground leakage circuit breaker is wanted to be turned off in a remote position therefrom, if a current of a predetermined value is fed into the signal wire 81, the plug-type ground leakage circuit breaker interpretes it as a leakage current, causing a relay contact 5 to open and a power source is disconnected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth leakage breaker for detecting an earth leakage on a load side of a distribution line, and more particularly to a plug type earth leakage breaker having a plug portion which is inserted into an outlet to be inserted into a main circuit. .

[0002]

2. Description of the Related Art An earth leakage circuit breaker is installed for the purpose of detecting a leakage or a ground fault in a distribution line and shutting off the main circuit to protect it. Is used by inserting it into a power outlet at home, etc.
The purpose of the present invention is to protect an electric device to which the plug type earth leakage breaker is connected or prevent an electric shock of a user. Therefore, it is required to be compact and inexpensive.

FIG. 2 is a circuit diagram of a plug type earth leakage breaker. In this figure, the earth leakage breaker comprises a zero-phase current transformer 1, an electronic circuit 2, a relay contact 5 and a trip coil 3, and a power-side electric wire 62 penetrates the zero-phase current transformer 1, The power supply side electric wire 62 is connected to the load side electric wire 61 via the relay contact 5. In a normal state in which no electric leakage occurs, the relay contact 5 is closed because the relay is not driven, but when the ground fault is detected by the zero-phase current transformer 1, the trip coil 3 of the relay is excited. Then, the relay contact 5 is opened and the current is cut off. The power supply of the electronic circuit 2 is taken from the power supply side electric wire 62 side. This is because it is necessary to operate the electronic circuit 2 for resetting as will be described later even after the main circuit is cut off by the electric leakage.

The zero-phase current of the main circuit is detected by the detection coil 21 wound around the zero-phase current transformer 1 and amplified by the electronic circuit 2. At the same time, when the value of the detected current exceeds a predetermined value, an electric leakage occurs. It is determined that the current is generated, and a current is passed through the trip coil 3 of the relay via the electric wire 23 to drive the relay. In the figure, the relay is driven and the relay contact 5 is opened, but it is in the off state, but when the main circuit is in a normal state, the relay contact 5 is closed and is in the on state. It ’s true. Although the number of turns of the detection coil 21 is shown as one turn, it is actually a plurality of turns, and the detection sensitivity of the leakage current is about 20 mA.

In addition to the detection coil 21, the zero-phase current transformer 1 is provided with another coil, that is, an inspection coil 43. This inspection coil is connected to the load-side electric wire 61 via a series circuit of a limiting resistor 42 and a test switch 41. When the test switch 41 is manually turned on in order to inspect whether the earth leakage breaker operates normally, the current set by the limiting resistor 42 is applied to the inspection coil 4
Flow to 3. This current is the same as the leakage current flowing in the main circuit for the zero-phase current transformer 1, so that the electronic circuit 2 outputs the current to open the relay contact of the relay. When there is an abnormality in either the electronic circuit 2 or the relay and normal operation cannot be performed, the abnormality is found by such inspection.

The reset switch 22 provided in the electronic circuit 2 is for operating the reset switch 22 to open the relay contact 5 again when the relay contact 5 is opened. That is, when the reset switch 22 is turned on, the output line 23 of the electronic circuit 2
A drive current flows through the relay contact to bring it into a reset state. The drive current for turning off and the drive current for turning on have the opposite current directions.

[0007]

By the way, it is possible to change the relay contact from the closed state to the open state except when the leakage is detected, by operating the test switch 41, and more simply, the plug type earth leakage breaker. Pull out from the outlet. However, in any case, there is a problem that the plug-type earth leakage circuit breaker must be operated close to it, and this may be difficult depending on the electric device equipped with the plug-type earth leakage circuit breaker.

An object of the present invention is to solve such a problem and to provide a plug type earth leakage breaker capable of performing an interruption operation by operating from the outside apart from the plug type earth leakage breaker.

[0009]

In order to solve the above-mentioned problems, according to the present invention, a zero-phase current transformer for detecting a zero-phase current of a main circuit and an output signal of a detection coil of this zero-phase current transformer are provided. An electronic circuit that amplifies and outputs a drive current when the value of the output signal exceeds a predetermined value, and a plug equipped with a relay that opens the relay contact inserted in the main circuit when the trip coil is excited by this drive current In the earth leakage circuit breaker, the trip coil is connected to the zero-phase current breaker when it is desired to switch it off at a position away from the plug type earth leakage breaker by providing a trip coil to which current is supplied from the outside. If a current of a predetermined value is applied to the wire, the plug type earth leakage breaker will shut off the relay contact, assuming that the earth leakage current has flowed.

Further, when the electric wire connected to the trip coil is drawn into the plug type earth leakage breaker together with the electric wire on the power source side of the main circuit by the four-core cable, the electric wire is easily routed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. FIG. 1 is a circuit diagram of an earth leakage circuit breaker showing an embodiment of the present invention, and the same components as those in FIG. 2 are designated by the same reference numerals to omit redundant description. 1 is different from FIG. 2 in that a trip coil 82 is added to the zero-phase current transformer 1 and the zero-phase current transformer 1 is added.
The signal line 81 drawn out from the trip coil 82 is taken out together with the load side electric wire 61 by the four-core cable 70.

When a current is passed through the trip coil 82, the electronic circuit 2 judges that a leakage current has flowed, and outputs a drive current to close the relay contact 5, just as when a current is passed through the detection coil 43. . Therefore, when a current is applied to the signal line 81 drawn out by the four-core cable 70, the plug-type earth leakage breaker turns off the main circuit. Therefore, for example, a signal is transmitted to an electric device to which the four-core cable 70 is connected. If a circuit for supplying a current to the wire 81 is provided, it is possible to cut off the power supply by the plug type earth leakage breaker from the electric equipment side.

For example, when the electric device is provided with a function of protecting the device by turning off the power when the device falls, a circuit breaker may be separately provided by providing a circuit for detecting the falling and supplying a current to the signal line 81. The purpose can be achieved without additionally providing. The signal line 81 and the load-side electric wire 61 do not necessarily have to be combined in the four-core cable 70.
For example, when the trip coil 82 is provided for the purpose of turning off the power by the plug type earth leakage breaker at a position different from the electric device to which the cable is connected, the signal line 81 is different from the load side electric wire 61. It is better to use a cable. However, as described above, since it is general to provide a circuit for supplying a current to the trip coil 82 in the electric device to which the conventional two-core cable 7 is connected, in such a case, the four-core cable 70 is used. By doing so, the number of cables can be reduced and the wiring can be simplified.

[0014]

As described above, the present invention provides the zero-phase current transformer with the trip coil to which an electric current is externally supplied, so that the trip coil is connected at a position distant from the plug type earth leakage breaker. It is possible to obtain the effect that the main circuit can be cut off from the outside by passing a current of a predetermined value through the existing electric wire.

Further, when the electric wire connected to the trip coil is drawn into the plug type earth leakage breaker together with the electric wire on the power source side of the main circuit by the four-core cable, the handling such as inserting into an outlet is the same as before. If a circuit that allows a current to flow is provided in an electrical device that is connected via a four-core cable, the plug-type earth leakage breaker can be easily turned off from this electrical device, and the wiring can be simplified. To be

[Brief description of drawings]

FIG. 1 is a circuit diagram of a plug type earth leakage breaker showing an embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional plug type earth leakage breaker.

[Explanation of symbols]

1 ... Zero phase current transformer, 2 ... Electronic circuit, 21 ... Detection coil, 2
2 ... Reset switch, 23 ... Output line, 24 ... Power line,
3 ... Trip coil 41 ... Test switch, 42 ... Limiting resistance, 43 ... Inspection coil, 5 ... Relay contact, 61 ... Power supply side electric wire, 62 ... Load side electric wire, 7 ... Two core cable, 70 ...
4-core cable, 81 ... Signal line, 82 ... Tripping coil,

Claims (2)

[Claims] 1. A zero-phase current transformer for detecting a zero-phase current of a main circuit,
An electronic circuit that amplifies the output signal of the detection coil of this zero-phase current transformer and outputs a drive current when the value of the output signal exceeds a predetermined value.The trip coil is excited by this drive current and inserted into the main circuit. Plug-type earth leakage circuit breaker having a relay for opening an open relay contact, characterized in that a zero-phase current transformer is provided with a trip coil to which current is externally supplied. . 2. The plug type earth leakage circuit breaker according to claim 1, wherein the electric wire connected to the trip coil is drawn out together with the load electric wire by a four-core cable.