JP2005050605A - Ground-fault interrupter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a space-saving ground-fault interrupter of a simple structure equipped with a switch for voltage withstanding test so as to be able to respond to a voltage withstanding test carried out after shipment. <P>SOLUTION: The ground-fault interrupter having an overcurrent and leakage protection functional parts mounted on a single body case 11 is equipped with a manual operation switch for voltage withstanding test turning on and off a power feeding circuit feeding interphase voltage of a main circuit to a leakage detecting circuit 7. The switch is structured of an electrode plate 22 for power supply mounted on a printed board 7a of the leakage detecting circuit 7 to be directly pressed against a main circuit conductor 1a (a primary conductor penetrating a zero-phase-sequence current transformer 6), and a switching operation piece 24 made of an insulating material intercalated between the electrode plate and the main circuit conductor for attaching and detaching the electrode plate to and from the main circuit conductor by a manual operation, with a knob part 24a of the switching operation piece made to faced a window hole opened to a cover of the interrupter case. Further, the leakage detection circuit is disconnected from the main circuit by the knob part drawn out to an OFF position at implementation of the voltage withstanding test. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an earth leakage breaker having an overcurrent protection function and a ground fault protection function applied to a low voltage distribution system, and more specifically, withstand voltage for disconnecting an earth leakage detection circuit from a main circuit when conducting a withstand voltage test of the earth leakage breaker. It relates to the assembly structure of the test switch.
[0002]
[Prior art]
Circuit breakers and earth leakage circuit breakers are well known as protection devices for low-voltage distribution systems. Current earth leakage circuit breakers currently used in Japan incorporate all overcurrent protection function parts and ground fault protection function parts in the main body case. The one with the configuration is common. Also, in recent earth leakage circuit breakers, in order to improve the usability on the customer side, the outer dimensions of the wiring breakers and earth leakage circuit breakers of the same frame are standardized, and the main parts to be incorporated in the main body case can be as much as possible. A single structure that is configured to be shared is the mainstream (see, for example, Patent Document 1).
Next, a circuit diagram of the above-described earth leakage breaker (for a three-phase power source) is shown in FIG. 6, and its assembly structure is shown in FIGS. First, in FIG. 6, 1 is an R, S, T phase main circuit, 2 is a main circuit contact, 3 is an opening / closing mechanism part of the main circuit contact 2, 4 is an operation handle, 5 is an overload current flowing through the main circuit, This is an overcurrent trip device that detects the short-circuit current and trips the switching mechanism.
[0003]
An earth leakage trip device that detects a ground fault in the distribution system and trips the circuit breaker is a zero-phase circuit that detects an unbalanced current in the main circuit 1 using the R, S, T phase main circuit 1 as a primary conductor. A current transformer 6, a leakage detection circuit (electronic circuit including IC) 7 that detects the occurrence of a ground fault from the secondary output level of the zero-phase current transformer 6, and an opening / closing mechanism 3 that receives the output from the leakage detection circuit 7 And a trip coil unit 8 for tripping. Here, the leakage detection circuit 7 feeds the inter-phase voltage of the main circuit 1 through the power supply line 9 and the rectifier circuit 10 wired between the main circuit 1 as its power source. In the illustrated example, the VT phase interphase voltage of the main circuit 1 is supplied to the leakage detection circuit 7. However, the R, S, and T phase voltages may be converted into direct current and supplied.
On the other hand, in FIGS. 7 and 8, 11 is a circuit breaker case comprising a lower case 11a and an upper cover 11b, 12, 13 are main circuit terminals on the power supply side and load side, 14 is a fixed contact for the main circuit contact 2, Reference numeral 15 is a movable contact, 16 is a rotary contact holder that supports the movable contact 15, and 17 is an arc extinguishing device. Further, as is well known, the opening / closing mechanism 3 includes a toggle link mechanism combining a toggle link 3a connecting the contact holder 16 and the operation handle 4 and an opening / closing spring 3b, and a latch 18 and a latch receiver. 19, an assembly with a latch mechanism combined with a trip cross bar 20, and the trip cross bar 20 includes an armature 5a which is an operation end of the above-described overcurrent trip device 5 and a trip coil unit 8 of an earth leakage trip device. The slider which is the operation end of is facing.
[0004]
Further, as shown in FIG. 8, a phase interval wall 11c is formed in the main body case 11 to insulate and isolate the components of each phase assembled in the main body case, and the above-described leakage detection circuit 7 is an IC or the like. Are mounted on the printed circuit board 7a and accommodated in a protective case, and then incorporated into the main body case 11 (the space between both sides of the zero-phase current transformer 6 and the side wall of the lower case 11a), and the main circuit A harness is wired as a power supply line 9 (see FIG. 6) between the two conductors.
The opening / closing operation of the earth leakage circuit breaker is well known, and when the operation handle 4 is moved to the ON / OFF position, the toggle link mechanism of the opening / closing mechanism unit 3 is reversed in conjunction with the operation handle 4 to move the movable contactor. 15 opens and closes. In the illustrated closing state in which the main circuit contact 2 is closed (ON), the latch 18 is locked to the latch receiver 19, and the latch receiver 19 is restrained by the trip cross bar 20 at this position. When overload current and short-circuit current flow in the main circuit from this state and the overcurrent trip device 5 operates, the trip crossbar 20 rotates counterclockwise via the armature 5a, and the latch receiver 19 and the latch 18 Release the engagement. As a result, the opening / closing mechanism 3 trips, and the movable contact 15 is separated from the fixed contact 14 to cut off the current of the main circuit. Similarly, when a ground fault current flows through the main circuit 1 and the trip coil unit 8 of the leakage trip device operates, the trip crossbar 20 is driven to the release position. As a result, the opening / closing mechanism 3 trips, and the movable contact 15 opens to disconnect the main circuit 1 in the same manner as the operation due to overcurrent. In order to reopen the circuit breaker after the trip operation, the operation handle 4 stopped at the trip position is temporarily returned from the trip position to the OFF position, the latch mechanism is reset, and the operation handle 4 is further turned off. The movable contact 15 is closed by moving to the ON position.
[0005]
By the way, it is stipulated in the standard that a product of an earth leakage breaker secures a predetermined dielectric strength, and for that purpose, a withstand voltage test is performed for each product to confirm that dielectric breakdown does not occur. This withstand voltage test is performed by applying a test voltage between the phases of the main circuit terminals with the main circuit contact of the earth leakage breaker turned off, and the test voltage is determined for each rated voltage of the earth leakage breaker. For example, the test voltage in an earth leakage breaker with a rated voltage of 400 to 600V is 2500V.
When performing this withstand voltage test, if the test is performed in the assembled state of the product in which the power supply line 9 is provided between the leakage detection circuit (IC) 7 and the main circuit 1 shown in FIG. A high test voltage applied between the two phases is applied to the leakage detection circuit 7 and the IC is destroyed. Therefore, a domestic circuit breaker maker performs a withstand voltage test at an assembly stage before connecting and wiring the power supply line 9 for supplying power to the leakage detection circuit 7 to the main circuit 1.
[0006]
On the other hand, the earth leakage circuit breakers produced in Europe and the United States are different in type from the domestic products with the single structure described above, and the independent earth leakage detection unit (zero-phase current transformer, earth leakage current) with a separate structure for the circuit breaker for wiring. It is common to use a combination of optional components that are equipped with a detection circuit.
[0007]
[Patent Document 1]
Japanese Patent No. 3246562 [Patent Document 2]
US Patent Application Publication No. 2001 / 0022713A1
[Problems to be solved by the invention]
As mentioned above, the earth leakage circuit breakers currently on the domestic market are not equipped with the withstand voltage test on the user side after product shipment. There is no withstand voltage test switch. Therefore, with regard to products that have obtained overseas standard certification, it is necessary to equip a withstand voltage test switch in order to be able to cope with the withstand voltage test performed locally in the export destination country.
By the way, the earth leakage circuit breaker having the single structure shown in FIGS. 7 and 8 has the common parts for the circuit breaker and the functional parts for the earth leakage protection incorporated in the main body case tightly without leaving any remaining space. . For this reason, in order to secure a new space for installing the withstand voltage test switch without changing the external size of the main body case (unified to the same size as the case of the circuit breaker for wiring) It is necessary to change the component parts and layout, which causes a problem of enormous development costs and time.
[0009]
Therefore, the object of the present invention is standard for conventional products for single-unit earth leakage circuit breakers equipped with overcurrent protection and leakage protection functional parts in the body case with the same outer size as the circuit breaker for wiring. An earth leakage circuit breaker that is equipped with an additional switch for withstand voltage test so that it can easily cope with withstand voltage tests conducted after product shipment without changing the various functional parts and layout. It is to provide.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a leakage current including a switching mechanism for a main circuit contact, an overcurrent tripping device, a zero-phase current transformer having the main circuit as a primary conductor, and a leakage detection circuit in the case. An earth leakage circuit breaker with a trip unit and equipped with a manually operated withstand voltage test switch that turns on and off the power supply circuit that feeds the interphase voltage of the main circuit to the leakage detection circuit. ,
(1) The above-mentioned withstand voltage test switch is pulled out from the printed circuit board of the leakage detection circuit, and the power supply electrode plate whose end is directly pressed against the main circuit conductor, and an interrupt is interposed between the electrode plate and the main circuit conductor. And an open / close operation piece with a knob made of an insulator that allows the power supply electrode plate to be brought into and out of contact with the primary conductor by manual operation from the outside. It arrange | positions facing the window hole opened to the cover (Claim 1).
[0011]
(2) A power electrode plate for pulling out the withstand voltage test switch from the main circuit conductor and pressing the tip of the switch on the power supply terminal provided on the printed circuit board of the leakage detection circuit, and the electrode plate and the power terminal It consists of an open / close operation piece with an insulating knob that allows the electrode plate to be brought into and out of contact with the power supply terminal of the printed board by manual operation from the outside with an interrupt in between. Is arranged so as to face a window hole opened in the case cover of the circuit breaker (claim 2).
(3) Here, the electrode plate is formed of a tongue-shaped conductive material having a spring property, and is pressed and urged toward the abutting counterpart member (Claim 3).
In the above configuration, in the normal use state of the earth leakage circuit breaker, the knob portion of the opening / closing operation piece is set to the ON position. As a result, the power supply electrode plate of the withstand voltage test switch comes into contact with the main circuit conductor as a counterpart member or the power supply terminal of the printed board, and the interphase voltage of the main circuit is supplied to the leakage detection circuit. On the other hand, when conducting the withstand voltage test, if the switch operation knob is pulled out of the window hole opened in the case of the circuit breaker body and switched to the OFF position, the open / close operation piece (insulator) follows the power supply electrode. The leakage detection circuit is disconnected from the main circuit by interrupting between the piece and the abutting counterpart member and separating between the two. Thereby, the withstand voltage test voltage can be safely tested without being applied to the leakage detection circuit.
[0012]
In addition, when the switch is OFF, the main circuit conductor and the leakage detection circuit are insulated with an insulating opening / closing operation piece interposed therebetween, so there is no need to secure an insulation distance corresponding to the test voltage. The withstand voltage test switch can be saved in space, and the withstand voltage test switch can be incorporated by utilizing a small space remaining in the breaker case without changing the main components and layout of the earth leakage breaker.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on the examples shown in FIGS. In addition, in the figure of an Example, the same code | symbol is attached | subjected to the member corresponding to FIGS. 6-8, and the detailed description is abbreviate | omitted.
[Example 1]
An embodiment corresponding to claim 1 of the present invention will be described with reference to FIGS. First, FIG. 3 shows a circuit diagram of the leakage breaker. In FIG. 3, reference numeral 21 denotes a withstand voltage test switch additionally provided in the earth leakage circuit breaker according to the present invention. The switch is arranged in a power supply circuit for supplying the interphase voltage of the main circuit 1 to the earth leakage detection circuit 7 to withstand the withstand voltage test. In this case, the power supply circuit is disconnected by turning off the switch.
[0014]
Here, the withstand voltage test switch 21 is installed in the lower case 11a of the circuit breaker case 11 from above as shown in FIG. The circuit 7 is combined as follows.
First, the leakage detection circuit 7 is arranged in a U-shaped case 7b in which a printed board 7a divided into two left and right parts is placed so as to straddle over the zero-phase current transformer 6 from above and below the breaker case 11 It is incorporated in the case 11a. Then, with respect to the assembly of the leakage detection circuit 7, the main circuit conductor 1 a (primary passing through the zero-phase current transformer 6) is drawn forward from the printed boards 7 a arranged side by side and connected to the load side terminal 13 at the tip. The power supply electrode plate 22 (movable contact of the withstand voltage test switch) arranged so as to be in direct contact with the conductor surface of the conductor) and the power supply electrode plate 22 and the main circuit conductor 1a are interrupted. A withstand voltage test switch is constituted by the open / close operation piece 24 made of an insulating material (resin molded product). Reference numeral 23 denotes a wiring harness that connects between the leakage detection circuit 7 and the trip coil 8 (see FIG. 3) of the leakage breaker.
[0015]
Next, the detailed assembly structure of the withstand voltage test switch and the opening / closing operation thereof will be described with reference to FIGS. 4 (a) and 4 (b). First, the power electrode plate 22 is formed by bending a conductive material piece having a spring property into an L shape, and fixing the base to the printed board 7a and connecting it to the power input terminal of the leakage detection circuit 7. Is pulled out in front of the case 7b so as to be in direct contact with the end face of the main circuit conductor 1a. Reference numeral 25 denotes a coil spring added to press and urge the electrode plate 22 from the back toward the main circuit conductor 1a.
Further, as shown in FIG. 1, the opening / closing operation piece 24 has a gate shape, and a knob portion 24a is formed on the upper end thereof, and a partition wall portion 24b corresponding to the electrode plate 22 is formed on the lower left and right sides. Then, as shown in FIG. 2, the knob 24a faces the slit-shaped window hole 11b-1 opened in the upper cover 11b of the circuit breaker case 11, and is arranged so as to be moved in and out by the manual operation. ing.
[0016]
Then, as always shown in FIG. 4A, the knob 24a is pushed in the direction of the arrow to set the opening / closing operation piece 24 at the ON position. In this state, the partition wall 24b of the opening / closing operation piece 24 is retracted downward, and the electrode plate 22 is in contact with the main circuit conductor 1a. In this state, the interphase voltage of the main circuit 1 is supplied to the leakage detection circuit 7 in FIG.
On the other hand, when conducting a withstand voltage test at the site where the earth leakage circuit breaker is delivered, as shown in FIG. 4B, prior to the test, the knob 24a of the opening / closing operation piece 24 is manually pulled up to turn it off. Move to position. As a result, the partition wall 24b of the opening / closing operation piece 24 is interrupted between the electrode plate 22 and the main circuit conductor 1a, and the electrode plate 22 is detached. In this state, the leakage detection circuit 7 of FIG. 3 is completely disconnected from the main circuit 1, so that the withstand voltage test can be performed safely. In the state where the switch is OFF in FIG. 4B, the electrode plate 22 and the main circuit conductor 1a are separated from each other with the partition wall portion 24b (made of an insulating material) 24b of the opening / closing operation piece 24 interposed therebetween. Yield strength can be secured.
[0017]
After the withstand voltage test is completed, the switching operation piece 24 is returned to the ON position in FIG. 4A, so that the interphase voltage of the main circuit 1 is again supplied to the leakage detection circuit 7, and the leakage breaker is cut off. The instrument returns to normal use.
[Example 2]
Next, FIG. 5 shows a configuration of another embodiment according to claim 2 of the present invention. FIGS. 5A and 5B are diagrams showing the ON / OFF state of the withstand voltage test switch corresponding to FIGS. 4A and 4B of the previous embodiment. Contrary to the first embodiment, a power supply electrode plate 26 made of a conductive material having a spring property is fixedly installed on the main circuit conductor 1a, and the tip of the electrode plate 26 is provided on the printed board 7a of the leakage detection circuit 7. The power supply terminal 27 is disposed so as to be pressed. The opening / closing operation piece 24 is interposed between the electrode plate 26 and the power supply terminal 27 in the same structural arrangement as in FIG.
[0018]
In the above configuration, when the knob 24a of the opening / closing operation piece 24 is pushed into the ON position as shown in FIG. 5A, the partition wall 24b retreats downward, and the power supply terminal 27 provided on the printed board 7a is provided with the electrode plate 26. In this state, the interphase voltage of the main circuit 1 in FIG. 3 is supplied to the leakage detection circuit 7.
On the other hand, when the withstand voltage test is performed, when the knob 24a of the opening / closing operation piece 24 is pulled up to the OFF position shown in FIG. 5 (b), the partition wall 24b enters between the electrode plate 26 and the power terminal 27, Leave between. As a result, the withstand voltage test switch is turned off as described in the first embodiment, and the main circuit 1 and the leakage detection circuit 7 are disconnected. After the endurance test, the switching operation piece 24 is returned to the ON position in FIG. 5 (a), so that the interphase voltage of the main circuit 1 can be supplied again to the leakage detection circuit 7, and the leakage breaker Returns to normal use.
[0019]
【The invention's effect】
As described above, according to the configuration of the present invention, in the earth leakage circuit breaker having a single structure integrally configured to the same external size as the circuit breaker for wiring, the overload protection, the earth leakage protection functional component incorporated in the case, and It is possible to add an additional withstand voltage test switch without changing the layout, and after turning off the withstand voltage test switch and disconnecting the leak detection circuit from the main circuit, after the product has been shipped It can be easily adapted to the withstand voltage test to be performed.
In addition, it is possible to configure a withstand voltage test switch simply by adding a simple power supply electrode plate and open / close operation piece parts to a conventional earth leakage circuit breaker product. Space saving of the switch can be achieved by arranging it in combination with the printed circuit board and the main circuit conductor (primary conductor of the zero-phase current transformer).
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of essential parts of an earth leakage breaker according to Embodiment 1 of the present invention. FIG. 2 is a plan view of the earth leakage breaker of FIG. 4 is an explanatory view of the structure and operation of a withstand voltage test switch in FIG. 1, in which (a) and (b) are cross-sectional side views showing the ON and OFF states of the switch, respectively. FIG. FIG. 6 is a cross-sectional side view showing the ON / OFF state of the switch, respectively, according to the structure and operation of the withstand voltage test switch according to FIG. Fig. 7 is a conventional circuit diagram of the circuit breaker. Fig. 7 is a cross-sectional view of the configuration of the earth leakage breaker shown in Fig. 6;
DESCRIPTION OF SYMBOLS 1 Main circuit 1a Main circuit conductor 3 Switching mechanism part 5 Overcurrent trip device 6 Zero phase current transformer 7 Leakage detection circuit 7a Print board 7b Case 11 Earth leakage circuit breaker case 11a Lower case 11b Upper cover 11b-1 Window hole 21 Withstand voltage test switches 22, 26 Electrode plate 24 for power supply Opening / closing operation piece 24a Knob 27 Power supply terminal

Claims (3)

An earth leakage circuit breaker with a single structure that incorporates an open / close mechanism for the main circuit contact, an overcurrent trip device, a zero-phase current transformer with the main circuit as the primary conductor, and an earth leakage trip device including a leakage detection circuit in the case. With a manually operated withstand voltage test switch that turns on and off the power supply circuit that feeds the interphase voltage of the main circuit to the leakage detection circuit,
The withstand voltage test switch is pulled out from the printed circuit board of the leakage detection circuit, and the power supply electrode plate is directly pressed against the main circuit conductor, and an interrupt is interposed between the electrode plate and the main circuit conductor. It consists of an open / close operation piece with an insulating knob that allows the power supply electrode plate to be brought into contact with and separated from the primary conductor by operation, and the knob of the open / close operation piece faces the window hole opened in the case cover of the circuit breaker. An earth leakage circuit breaker characterized by An earth leakage circuit breaker with a single structure that incorporates an open / close mechanism for the main circuit contact, an overcurrent trip device, a zero-phase current transformer with the main circuit as the primary conductor, and an earth leakage trip device including a leakage detection circuit in the case. With a manually operated withstand voltage test switch that turns on and off the power supply circuit that feeds the interphase voltage of the main circuit to the leakage detection circuit,
The above-mentioned withstand voltage test switch is pulled out from the main circuit conductor and its tip is pressed against the power supply terminal provided on the printed circuit board of the leakage detection circuit, and an interrupt is provided between the electrode plate and the power supply terminal. It is composed of an open / close operation piece with an insulating knob that allows the power supply electrode plate to be brought into contact with and separated from the power terminal of the printed board by manual operation. The handle of the open / close operation piece is covered with the case cover of the circuit breaker. An earth leakage circuit breaker characterized by being placed facing a window hole opened in the window. 3. The earth leakage circuit breaker according to claim 1, wherein the electrode plate is made of a conductive material having a spring property.

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