JP3143205B2 - Circuit breaker for ground fault protection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a circuit breaker for protecting a ground fault by adding simple and inexpensive parts.
In addition, the present invention relates to a configuration in which a circuit can be interrupted even when abnormal heat is generated due to poor fastening of a terminal .

[0002]

2. Description of the Related Art FIG.
Conventionally, a ground fault / overload protection combined earth leakage breaker has a bimetal 1 attached as a part of the main conductor to at least one pole between the power supply side and the load side, and a contact device due to deflection of the bimetal 1 due to temperature rise due to overcurrent thereby separating the tripping has apparatus 2
There was something.

[0003] Although the bimetal 1 is required deformation force corresponding to the tripping load of the contact trip mechanism, the overcurrent
Only the amount of heat generated when flowing directly into the bimetal
No force for tripping the contact trip mechanism could be generated.

Therefore, in the case of abnormal heat generation of the terminal,
The circuit breaker did not perform the breaking operation.

[0005]

SUMMARY OF THE INVENTION In view of the above, the present invention uses a tripping device due to a ground fault for a circuit breaker for ground fault protection, and prevents a rise in temperature due to abnormal heat generation due to insufficient terminal tightening. It is configured by adding a simple and inexpensive means for detecting and generating a pseudo ground fault in the conductor through the zero-phase current transformer.

[0006]

[Function] A pseudo ground fault current is generated between the through conductors of the zero-phase current transformer due to a rise in the temperature of the conductor due to the heat generated due to insufficient tightening of the terminals and a rise in the temperature inside the circuit breaker. The contact is tripped and separated by a tripping device due to a ground fault.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a first embodiment embodying the present invention. FIG. 2 is an explanatory diagram of an operation in which a continuous rise in temperature due to a terminal fastening failure shown in FIG. 1 is detected. In FIG. 1, reference numeral 7 denotes a main conductor, which penetrates through the zero-phase current transformer 5, and a zero-phase current transformer 5 → amplifying unit 6 → tripping device due to an imbalance in the current flowing through the two-pole main conductor 7 due to a ground fault. In step 3, trip the circuit breaker.

Reference numeral 8 denotes an element which changes its shape depending on temperature, such as a bimetal or a shape memory alloy, according to the present invention, which is arranged in the vicinity of the main conductor 7 or at an appropriate position in the electrical connection terminal or the circuit breaker body. It is electrically connected to the main conductor 7 on the power supply side of the zero-phase current transformer 5 by soldering, screwing, spot welding, or the like, so that the zero-phase current transformer 5 does not penetrate, and the other end is connected to the zero-phase current transformer 5. Are arranged facing each other with a gap in the bare charging portion of the same main conductor 7 on the load side.

The effect of connecting the element 8 whose shape changes depending on the temperature is the same as above, that is, even if one end is connected to the main conductor on the load side of the zero-phase current transformer 5.

The gap 10 between the element 8 and the main conductor 7 is a normal end.
The main conductor 7 does not come into contact with the main conductor 7 when the element 8 is deformed due to a rise in temperature inside the housing due to current flow in the clamped state of the child. The gap is in contact with 7.

In FIG. 2, for example, when the terminal is not properly tightened , the temperature of the main conductor or the inside of the case further increases, and the element 8
Becomes large and comes into contact with the main conductor 7.

When the element 8 and the main conductor 7 contact each other, a bypass circuit is formed, and the current shown in FIG. 2 has a relationship of I1 + I2 = I3, but the element 8 does not pass through the zero-phase current transformer 5, The currents I1 and I3 passing through the phase current transformer 5 become unbalanced and the tripping device 3 trips the circuit breaker. In this case, it is necessary to select an element and a main conductor having a resistance value such that the current value of I2 is equal to or higher than the rated sensitivity current of the circuit breaker.

FIG. 3 shows a second embodiment, and FIG. 4 shows FIG.
FIG. 4 is an operation explanatory diagram in a state where the terminal is not properly tightened, but electrically connects an element 8 to a main conductor 7 on a power supply side of a zero-phase current transformer 5,
Without passing through the zero-phase current transformer 5, the other end is connected to the other end of the resistor 11 whose one end is electrically connected to the other main conductor 7 on the load side of the zero-phase current transformer. In the same manner as described above , the element 8 and the resistor are deformed by deformation of the element 8 due to a rise in temperature due to heat generated due to an abnormality such as an improper tightening of an electrical connection terminal .
11 make contact, a bypass circuit is formed, and the through currents I4 and I6 of the zero-phase current transformer 5 shown in FIG. 4 become unbalanced, and the circuit breaker is tripped.

Also in this case, the connection between the element 8 and the resistor 11 may be reversed from the above. Further, it is necessary to select an element and a resistor having a resistance value such that the current value of I5 is equal to or greater than the age sensitivity current of the circuit breaker.

FIG. 5 is a block diagram of the third embodiment. Reference numeral 13 denotes a circuit element or means such as a thermistor whose resistance value decreases when the temperature rises, and one end of which is connected to the power supply side of the zero-phase current transformer 5. The other end of the zero-phase current transformer 5 is electrically connected to the other main conductor 7 on the load side without passing through the zero-phase current transformer 5.

The temperature of the main conductor 7 or the terminal or the inside of the housing further rises due to the heat generated due to an abnormality such as a poor fastening of the electric connection terminal, and the resistance value of the circuit element or the means 13 arranged near the main conductor 7 or the terminal 13 decreases. When a current equal to or greater than the sensitivity current flows through this circuit element or means 13, the zero-phase current
Of the breaker is unbalanced, and the breaker is tripped.

In this case, the circuit element or means at the detected temperature
It is necessary to select the low resistance value of 13 such that the current value flowing through the circuit element or the means 13 is equal to or higher than the rated sensitivity current value.

FIG. 6 shows a modification of the second embodiment, and FIG.
Is a modified configuration example of the third embodiment, and the operation and effect are the same even when connected in this manner.

[0020]

As described above, according to the present invention, there is provided a means for generating a pseudo ground fault current due to abnormal heat generation inside the circuit breaker body, so that it is simpler than the conventional ground fault protection circuit breaker. Addition of parts to the terminal , inexpensive, abnormal heating due to poor terminal tightening
To provide a ground fault protection circuit breaker that operates
You.

Incidentally, in the illustrated example, the two-pole type is illustrated.
The same effect can be obtained with a circuit breaker for pole and quadruple ground fault protection.

Further, the temperature detecting pseudo-ground fault generating means according to the present invention can be applied to different types of circuit breakers having different rated currents, and can be standardized to any type of ground fault protective circuit breaker. There is also an effect that an inexpensive one can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of an operation in a terminal heating state in FIG.

FIG. 3 is a configuration diagram of a second embodiment of the present invention.

FIG. 4 is an explanatory diagram of an operation in a terminal heating state in FIG. 3;

FIG. 5 is a configuration diagram of a third embodiment of the present invention.

FIG. 6 shows a modified configuration example of the second embodiment.

FIG. 7 shows a modified barrel example of the third embodiment.

FIG. 8 is a configuration diagram showing the structure of a conventional earth leakage / overload protection / ground fault circuit breaker.

[Explanation of symbols]

1 Bimetal 2 Tripping device due to overload 3 Tripping device due to ground fault 4 Amplifying unit 5 Zero-phase current transformer 6 Contact device 7 Main conductor 8 Element whose shape changes according to temperature according to the present invention 9 Load 10 Temperature according to the present invention Gap between the element whose shape changes and the main conductor 11 Resistor 12 Gap between the element whose shape changes due to temperature and the resistor according to the present invention 13 Circuit element or means whose resistance value decreases when humidity increases 13 Symbols represent the same parts

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01H 83/02

Claims (4)

(57) [Claims] A contact device, a mechanism for opening and closing the contact device, a zero-phase current transformer for detecting a ground fault current, an amplifying unit, and a contact device in a body constituted by a base and a cover. placed earth leakage breaker for ground protection with tripping device for releasing
Means for detecting a rise in the temperature of the main conductor, the terminal, or the body due to abnormal heat generation due to improper tightening of the electrical connection terminal, and generating a pseudo ground fault. A circuit breaker for ground fault protection, characterized in that the circuit breaker is tripped by a tripping device that separates a flow device, an amplifier, and a contact device. 2. The means for generating a quasi-ground fault includes an element whose shape changes according to temperature, a power supply side and a load side of a zero-phase current transformer of one of the main conductors penetrating through the zero-phase current transformer. 2. The circuit breaker for ground fault protection according to claim 1, wherein the circuit breaker is connected in a path that does not pass through the zero-phase current transformer, and the pseudo-short-circuit current passes through the zero-phase current transformer. 3. The means for generating a pseudo ground fault comprises connecting an element and a resistor, the shapes of which change with temperature, between different types of penetrating main conductors of a zero-phase current transformer. 2. The circuit breaker for ground fault protection according to claim 1, wherein the circuit breaker is configured to penetrate the device. 4. The means for generating a pseudo ground fault comprises connecting a circuit element or means whose resistance value decreases due to a rise in temperature between different poles of a penetrating main conductor of a zero-phase current transformer. Claims: It is configured to penetrate a zero-phase current transformer.
Circuit breaker for ground fault protection as described in 1. [0001]