Leakage detector circuit, leakage circuit breaker and distribution board

Abstract

The problem to be solved by the present invention is to protect the third contact (S3) for interrupting the feeding path to the earth leakage detector (5) against a surge current. The earth leakage detector circuit (1) comprises a first contact (S1) and a second contact (S2), an earth leakage detector (5), a third contact (S3), and a surge absorber (61). The earth leakage detector (5) changes the first contact (S1) and the second contact (S2) from on to off upon detecting generation of a leakage current. The third contact (S3) comprises a first end portion (P1) and a second end portion (P2) opposite to the first end portion (P1). The first end portion (P1) is connected to a first input node (71) or a second input node (72). The second end portion (P2) is connected to the earth leakage detector (5). The third contact (S3) switches its on / off in synchronization with the first contact (S1) and the second contact (S2) being on and off. The surge absorber (61) is connected between a first electrical path (C1) and a second electrical path (C2) without passing through the third contact (S3).

Description

Technical Field

[0001] This disclosure generally relates to leakage current detector circuits, leakage current circuit breakers, and distribution boards, and more particularly to leakage current detector circuits, leakage current circuit breakers, and distribution boards, each having overcurrent protection functionality. Background Technology

[0002] Patent document 1 discloses a circuit breaker comprising: a first contact for interrupting a main circuit; a second contact for interrupting a feed circuit to a leakage detector for detecting leakage current; and a surge absorber through which an overcurrent generated by, for example, a lightning surge flows.

[0003] In circuit breakers such as those disclosed in Patent Document 1, an overcurrent generated by, for example, a lightning surge may flow through the second contact.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-167089 Summary of the Invention

[0007] In view of the foregoing background, the purpose of this disclosure is to provide a leakage current detector circuit, a leakage current circuit breaker, and a distribution board, each having the capability to interrupt the power supply path to the leakage current detector for overcurrent (surge current) protection.

[0008] A leakage current detector circuit according to one aspect of this disclosure includes a first terminal, a second terminal, a third terminal, a fourth terminal, a first electrical path, a second electrical path, a first contact and a second contact, a leakage current detector, a third contact, and a surge absorber. The first and second terminals are connected to a first connection object, which is a power source or a load. The third and fourth terminals are connected to a second connection object, which is the power source or the load and is different from the first connection object. The first electrical path connects the first and third terminals to each other. The second electrical path connects the second and fourth terminals to each other. The first and second contacts are respectively configured for the first and second electrical paths. The leakage current detector is connected between a first input node and a second input node. The first input node is disposed between the first contact and the first terminal. The second input node is disposed between the second contact and the fourth terminal. When the leakage current detector detects the generation of leakage current, it causes the first and second contacts to change from closed to open. The third contact has a first end and a second end opposite to the first end. The first end is connected to either the first or the second input node. The second end is connected to the leakage current detector. The third contact switches its on / off state synchronously with the first and second contacts as they become on and off. The surge absorber is connected between the first and second electrical paths without passing through the third contact.

[0009] According to another aspect of this disclosure, a residual current circuit breaker includes the aforementioned residual current detector circuit.

[0010] According to another aspect of this disclosure, the distribution board includes the aforementioned residual current circuit breaker. Attached Figure Description

[0011] Figure 1 This is a schematic circuit diagram of a leakage current detector circuit according to a typical embodiment;

[0012] Figure 2 This is a schematic circuit diagram of the leakage current detector circuit;

[0013] Figure 3 This is a schematic circuit diagram of the leakage current detector circuit;

[0014] Figure 4 This is a schematic front view illustrating the interior of a power distribution board according to a typical embodiment;

[0015] Figure 5 This is a schematic front view of a residual current circuit breaker according to a typical embodiment;

[0016] Figure 6It is a schematic circuit diagram of the leakage current detector circuit according to the first modification example;

[0017] Figure 7 It is a schematic circuit diagram of the leakage current detector circuit according to the second modification; and

[0018] Figure 8 This is a schematic circuit diagram of the leakage current detector circuit according to the third variation. Detailed Implementation

[0019] The leakage current detector circuit 1, leakage current circuit breaker 11, and distribution board 12 according to exemplary embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that the exemplary embodiments and variations thereof described below are merely examples of the present disclosure and should not be construed as limiting. Rather, the exemplary embodiments and variations thereof can be readily modified in various ways according to design choices or any other factors without departing from the true spirit and scope of the present disclosure. Note that the embodiments described below (including their variations) can be appropriately combined.

[0020] (1) Overview

[0021] First, refer to Figure 1 This section provides an overview of the leakage current detector circuit 1 according to a typical embodiment.

[0022] The leakage current detector circuit 1 includes a first terminal 41 and a second terminal 42, both of which are connected to a first connection object selected from a power source 2 and a load 3. In this embodiment, the first connection object may be, for example, the power source 2. Additionally, the leakage current detector circuit 1 includes a third terminal 43 and a fourth terminal 44, both of which are connected to a second connection object selected from the power source 2 and the load 3. In this embodiment, the second connection object may be, for example, the load 3. Alternatively, the first terminal 41 and the second terminal 42 may be connected to the load 3, and the third terminal 43 and the fourth terminal 44 may be connected to the power source 2.

[0023] The first terminal 41 and the third terminal 43 are connected to each other via the first electrical path C1. The second terminal 42 and the fourth terminal 44 are connected to each other via the second electrical path C2. That is, the first electrical path C1 and the second electrical path C2 are power supply paths from the power source 2 to the load 3. The first electrical path C1 and the second electrical path C2 are respectively provided with a first contact S1 and a second contact S2.

[0024] The leakage current detector circuit 1 also includes a leakage current detector 5, a third contact S3, and a surge absorber (first surge absorber 61).

[0025] A leakage current detector 5 is connected between a first input node 71, located between the first contact S1 and the first terminal 41, and a second input node 72, located between the second contact S2 and the fourth terminal 44. The leakage current detector 5 is activated by power supplied from the power source 2. The leakage current detector 5 monitors the current flowing between the power source 2 and the load 3 through the first electrical path C1 and the second electrical path C2. When leakage current is detected, the leakage current detector 5 changes the first contact S1 and the second contact S2 from ON to OFF. This allows power to be stopped from the power source 2 to the load 3 when leakage current is generated.

[0026] The third contact S3 has a first end (end P1) and a second end (end P2) opposite to the first end (end P1). In this embodiment, the first end P1 is connected to the first input node 71. The second end P2 is connected to the leakage detector 5. That is, the third contact S3 is connected between the first input node 71 and the leakage detector 5. Alternatively, end P1 can be connected to the second input node 72, and the third contact S3 can be connected between the second input node 72 and the leakage detector 5. The third contact S3 switches its on / off state synchronously with the first contact S1 and the second contact S2 becoming on and off. For example, in this embodiment, when the first contact S1 and the second contact S2 are on, the third contact S3 is also on. When the first contact S1 and the second contact S2 are off, the third contact S3 is also off. When the third contact S3 is on, power is supplied from the power source 2 to the leakage detector 5. On the other hand, when the third contact S3 is off, power is stopped from the power source 2 to the leakage detector 5.

[0027] The first surge absorber 61 is connected between the first electrical path C1 and the second electrical path C2 without passing through the third contact S3. Therefore, if a surge voltage is applied between the first electrical path C1 and the second electrical path C2 by, for example, lightning, the surge current will flow through the first surge absorber 61 without passing through the third contact S3. This makes it possible to protect the third contact S3 against surge current.

[0028] (2) Details

[0029] Next, refer to Figures 1 to 5 The leakage current detector circuit 1 and the leakage current circuit breaker 11 according to this embodiment will be described in detail.

[0030] (2.1) Structure of the leakage current detector circuit

[0031] Reference Figure 1 This will illustrate the structure of the leakage current detector circuit 1.

[0032] According to this embodiment, the leakage current detector circuit 1 includes a first terminal 41 to a fourth terminal 44. The first terminal 41 and the second terminal 42 are connected to a power supply 2. In this embodiment, the power supply 2 may be, for example, a commercial AC power supply. The third terminal 43 and the fourth terminal 44 are connected to a load 3. AC power is supplied from the power supply 2 to the load 3 through a first electrical path C1 for connecting the first terminal 41 to the third terminal 43 and a second electrical path for connecting the second terminal 42 to the fourth terminal 44. Note that the leakage current detector circuit 1 can also operate normally with the first terminal 41 and the second terminal 42 connected to the load 3 and the third terminal 43 and the fourth terminal 44 connected to the power supply 2. Such a connection state will be referred to below as the "reverse connection state".

[0033] The first electrical path C1 and the second electrical path C2 are respectively provided with a first contact S1 and a second contact S2. The operation of turning the first contact S1 and the second contact S2 on and off will be explained later.

[0034] The leakage current detector circuit 1 includes a leakage current detector 5, a third contact S3, and a first surge absorber 61. The leakage current detector circuit 1 also includes a tripping mechanism 8, a testing unit 9, and a zero-phase current transformer (ZCT) 10.

[0035] The leakage current detector 5 may include, for example, a rectifier circuit for rectifying the AC voltage supplied from the power source 2 into a DC voltage; a smoothing circuit for smoothing the output voltage of the rectifier circuit; and a computer system disposed after the smoothing circuit and including a processor and a memory. The computer system performs the function of the leakage current detector 5 by having the processor execute a program stored in the memory. In this embodiment, the program to be executed by the processor is pre-stored in the memory of the computer system. Alternatively, the program may be stored in a storage medium such as a memory card and then distributed or downloaded via a telecommunications line such as the Internet. Note that the leakage current detector 5 need not necessarily be implemented as a digital IC such as a processor, but may also be implemented as an analog IC.

[0036] The leakage current detector 5 is connected between a first input node 71, located between the first contact S1 and the first terminal 41, and a second input node 72, located between the second contact S2 and the fourth terminal 44. Specifically, the leakage current detector 5 includes terminals T1 to T4. Terminal T1 is connected to the first input node 71. Terminal T2 is connected to the second input node 72. The leakage current detector 5 monitors the current flowing between the power supply 2 and the load 3 through the first electrical path C1 and the second electrical path C2 to detect leakage current.

[0037] The third contact S3 is connected between terminal T1 of the leakage current detector 5 and the first input node 71. Specifically, the third contact S3 has an end P1 and an end P2. End P1 is connected to the first input node 71. End P2 is connected to terminal T1. The on / off state of the third contact S3 is switched synchronously by the tripping mechanism 8 (described later) as the first contact S1 and the second contact S2 become on and off.

[0038] The first surge absorber 61 is a variable resistor used to protect the leakage current detector 5 against surge voltages generated by, for example, lightning, and can be implemented as a zinc oxide nonlinear resistor (ZNR). Note that the first surge absorber 61 does not necessarily have to be a variable resistor, but can also be, for example, a gas discharge tube (GDT) or an avalanche diode.

[0039] The first surge absorber 61 is connected between the first electrical path C1 and the second electrical path C2 without passing through the third contact S3. Specifically, the first surge absorber 61 has an end P3 and an end P4. End P3 is connected between the second input node 72 and the end P5 of the trip coil 81 (described later). End P4 is connected to the first input node 71. End P4 is also connected to the end P1 of the third contact S3. That is, end P3 is connected to the second input node 72, and end P4 is connected between the first input node 71 and the end P1 of the third contact S3. This allows the surge current generated between the first electrical path C1 and the second electrical path C2 to flow through the first surge absorber 61 without passing through the third contact S3. This enables surge current protection for the leakage current detector 5 and the third contact S3.

[0040] The tripping mechanism 8 is connected between terminal T2 of the leakage current detector 5 and the second input node 72. The tripping mechanism 8 has the ability to change the first contact S1, the second contact S2 and the third contact S3 from closed (tripping) to open when the leakage current detector 5 detects the generation of leakage current.

[0041] The tripping mechanism 8 includes, for example, a tripping coil 81, a switching unit 82, and a linkage unit 83.

[0042] The trip coil 81 is a coil connected between terminal T2 of the leakage current detector 5 and the second input node 72. Specifically, the trip coil 81 has end P5 and end P6. End P5 is connected to the second input node 72. End P6 is connected to terminal T2 of the leakage current detector 5.

[0043] When the leakage current detector 5 detects the generation of leakage current, the switching unit 82 switches the first contact S1 and the second contact S2 from closed to open. The switching unit 82 includes, for example, a movable iron core made of magnetic material; a push pin connected to the movable iron core; and a switching mechanism interlocked with the push pin for switching the first contact S1 and the second contact S2 from closed to open. When the generation of leakage current is detected based on the output of the zero-phase current transformer 10, the leakage current detector 5 allows a drive current to flow through the trip coil 81. This causes a change in the magnetic flux through the movable iron core housed in the coil spool of the trip coil 81, thereby causing the movable iron core to move in a direction that counteracts the change in magnetic flux. The push pin moves together with the movable iron core. The switching mechanism of the switching unit 82, in cooperation with the movement of the push pin, switches the first contact S1 and the second contact S2 from closed to open.

[0044] The linkage unit 83 synchronously changes the third contact S3 from closed to open as the switching unit 82 changes the first contact S1 and the second contact S2 from closed to open. In this embodiment, the tripping mechanism 8 includes a tripping coil 81, a switching unit 82, and a linkage unit 83. However, this is not a necessary structure for the tripping mechanism 8. Alternatively, the function of the tripping mechanism 8 can be performed by different structures.

[0045] Test unit 9 is connected between the first input node 71 and the second input node 72. Test unit 9 includes a test switch 91 and a resistor 92. Specifically, test switch 91 has end P7 and end P8. End P7 is connected to end P10 of resistor 92 (described later). End P8 is connected between end P1 of the first input node 71 and end P1 of the third contact S3. Test switch 91 is a normally open switch, but is turned on by the user when testing the leakage detection function of leakage current detector 5 and the tripping function of tripping mechanism 8. Resistor 92 has end P9 and end P10. End P9 is connected between end P5 of the second input node 72 and end P5 of tripping coil 81. End P10 is connected to end P7 of test switch 91. The test to be performed on the leakage detection function of leakage current detector 5 by test switch 91 will be described in detail later in the "(2.2.2) Test Operation" section.

[0046] The zero-phase current transformer 10 includes a toroidal core 101 and a coil 102. The zero-phase current transformer 10 has a structure in which the coil 102 is wound around a portion of the toroidal core 101. The coil 102 is connected between terminals T3 and T4 of the leakage current detector 5. A first electrical path C1, a second electrical path C2, and a third electrical path C3 pass through holes in the toroidal core 101. In this embodiment, the third electrical path C3 is the electrical path that connects the end P10 of the resistor 92 to the end P7 of the test switch 91. In this case, the first electrical path C1 and the second electrical path C2 pass through these electrical paths C1 and C2 in two opposite directions. The operation of the zero-phase current transformer 10 will be described in detail later in the section “(2.2.1) Leakage Detection Operation”.

[0047] Furthermore, in this embodiment, the leakage current detector circuit 1 also includes a second surge absorber 62, which is separately disposed from the first surge absorber 61. The second surge absorber 62 has an end P11 and an end P12. End P11 is connected between the end P6 of the trip coil 81 and the terminal T2 of the leakage current detector 5. End P12 is connected between the end P2 of the third contact S3 and the terminal T1 of the leakage current detector 5.

[0048] (2.2) Operation of the leakage current detector circuit

[0049] Next, refer to Figures 1 to 3 The various operations of the leakage current detector circuit according to this embodiment will be explained.

[0050] (2.2.1) Leakage current detection operation

[0051] First, refer to Figure 1 This will explain how leakage current detector circuit 1 performs leakage current detection.

[0052] If all three contacts—first contact S1, second contact S2, and third contact S3—are closed, no leakage current is generated, and power is normally supplied from power source 2 to load 3, then the current I1 flowing through the first electrical path C1 and the current I2 flowing through the second electrical path C2 will be equal. In this embodiment, the first electrical path C1 and the second electrical path C2 pass through the inner side of the toroidal core 101 of the zero-phase current transformer 10, causing currents I1 and I2 to flow through the first electrical path C1 and the second electrical path C2 in opposite directions. Therefore, the magnetic flux generated by currents I1 and I2 cancels each other out, resulting in no current flowing through coil 102. On the other hand, if a leakage current is generated, currents I1 and I2 are no longer in balance, resulting in a current corresponding to the difference between these currents I1 and I2 flowing through coil 102. The leakage current detector 5 can detect the generation of leakage current by sensing the current flowing through coil 102.

[0053] When a leakage current is detected, the leakage current detector 5 allows the drive current to flow through the trip coil 81, thereby causing the trip mechanism 8 to change the first contact S1, the second contact S2, and the third contact S3 from closed to open. When the first contact S1, the second contact S2, and the third contact S3 change from closed to open, the power supply from the power source 2 to the load 3 is cut off, thereby protecting the load 3.

[0054] (2.2.2) Test Operation

[0055] Next, refer to Figure 2 This will explain how the testing department 9 tests the leakage current detection function and the tripping function.

[0056] The test unit 9 is configured to allow the spurious leakage current I3 to flow through the third electrical path C3 passing through the inner side of the ring core 101, thereby causing the tripping mechanism 8 to change the first contact S1, the second contact S2 and the third contact S3 from closed to open.

[0057] If all three contacts S1, S2, and S3 are connected, no leakage current is generated, and power is supplied normally from power source 2 to load 3, then the user of leakage current detector circuit 1 can perform tests to check whether the leakage current detection function and tripping function of leakage current detector circuit 1 are working properly.

[0058] like Figure 2 As shown, the user performing the test switches test switch 91 from open to closed. When test switch 91 switches from open to closed, current flows from power supply 2 through test switch 91 and resistor 92, causing a dummy leakage current I3 to flow through the third electrical path C3 passing through the inner side of the toroidal core 101. In this situation, the currents I1 and I2 flowing through the first electrical path C1 and the second electrical path C2 are in balance. However, as the dummy leakage current I3 flows through the third electrical path C3, the currents I1 and I2, as well as the dummy leakage current I3, become unbalanced. As a result, a current corresponding to the dummy leakage current I3 flows through coil 102. The leakage current detector 5 can detect the dummy leakage current by sensing this current flowing through coil 102.

[0059] If the leakage current detector 5 and the tripping mechanism 8 are operating normally, the leakage current detector 5 allows the drive current to flow through the tripping coil 81 when it detects a false leakage current, and the tripping mechanism 8 causes the first contact S1, the second contact S2, and the third contact S3 to change from closed to open. This allows the user to check whether the leakage current detection function and the tripping function are working properly.

[0060] (2.2.3) Surge voltage absorption operation

[0061] Next, refer to Figure 3 This explains how leakage current detector circuit 1 absorbs surge voltage.

[0062] Assuming that the first contact S1, the second contact S2, and the third contact S3 are all connected and power is supplied from the power source 2 to the load 3, a surge voltage is applied between the first electrical path C1 and the second electrical path C2 by, for example, lightning.

[0063] The surge voltage applied between the first electrical path C1 and the second electrical path C2 is also applied to the first surge absorber 61. In this case, if the surge voltage is greater than the voltage across the first surge absorber 61, which is implemented as a variable resistor, the resistance of the first surge absorber 61 drops sharply, causing a surge current Is to flow through the first surge absorber 61. The surge current Is flowing through the first surge absorber 61 flows toward the power supply 2 via either the first electrical path C1 or the second electrical path C2. This makes it possible to prevent the surge current Is from flowing through the leakage current detector 5. Furthermore, in this case, the surge current Is can flow without passing through the third contact S3. This makes it possible to protect the third contact S3 against the surge current Is.

[0064] Alternatively, the leakage current detector 5 can also be configured to detect the generation of surge current Is. In this case, when the leakage current detector 5 detects the generation of surge current Is, it allows the drive current to flow through the trip coil 81 and causes the trip mechanism 8 to change the first contact S1, the second contact S2, and the third contact S3 from closed to open.

[0065] (2.3) Reverse connection

[0066] According to this embodiment, the leakage current detector circuit 1 includes a third contact S3. This enables the leakage current detector circuit 1 to operate normally even in a reverse connection state where the first terminal 41 and the second terminal 42 are connected to the load 3 and the third terminal 43 and the fourth terminal 44 are connected to the power supply 2.

[0067] Assume that the leakage current detector circuit 1 does not include the third contact S3. In this case, if the load 3 connected to the first terminal 41 and the second terminal 42 in the reverse connection state causes, for example, a ground fault, the ground fault current may flow through the leakage current detector 5 even when the first contact S1 and the second contact S2 are open.

[0068] Conversely, the leakage current detector circuit 1 according to this embodiment includes a third contact S3, so if the first contact S1 and the second contact S2 are open, the third contact S3 is also open. This prevents ground fault current from flowing through the third contact S3 even if the load 3 causes, for example, a ground fault, thereby improving reliability.

[0069] (2.4) Residual current circuit breaker

[0070] Next, refer to Figure 1 , Figure 4 and Figure 5 To illustrate the residual current circuit breaker 11, which includes the residual current detector circuit 1.

[0071] The residual current circuit breaker 11 includes a residual current detector circuit 1, and therefore has the ability to interrupt the current flowing through the first electrical path C1 and the second electrical path C2 (wherein, power is supplied from the power source 2 to the load 3 through the first electrical path C1 and the second electrical path C2) when any leakage current is detected. Figure 4 As shown, the residual current circuit breaker 11 can be used, for example, in a distribution panel 12 to be installed in a residential building. Note that the distribution panel 12 does not necessarily have to be installed in a residential building, but can also be installed in a non-residential building such as an office, shop, factory, or hospital. The residual current circuit breaker 11 is mounted on the mounting surface 131 of a DIN rail 13 provided inside the panel of the distribution panel 12. The mounting surface 131 can be, for example, the side of the DIN rail 13 facing the residual current circuit breaker 11.

[0072] The residual current circuit breaker 11 can be used as a branch circuit breaker or a main circuit breaker; either is suitable. For example... Figure 4 As shown, among the multiple residual current circuit breakers 11 mounted on the DIN rail 13 of the distribution panel 12, for example, the rightmost residual current circuit breaker 11 (11M) can be used as the main circuit breaker, and the other residual current circuit breakers 11 (11B) can be used as branch circuit breakers. Note that in Figure 4 The wiring diagram inside the distribution board 12 is omitted in the text.

[0073] like Figure 5 As shown, the residual current circuit breaker 11 includes a first terminal 111 and a second terminal 112 at its upper end, and a third terminal 113 and a fourth terminal 114 at its lower end. Additionally, the residual current circuit breaker 11 also includes an operating handle 115 and a test button 116 on its operating surface 110.

[0074] The first terminal 111 to the fourth terminal 114 are respectively connected to Figure 1 The first terminal 41 to the fourth terminal 44 of the leakage current detector circuit 1 shown correspond to each other. That is, the first terminal 111 and the second terminal 112 are connected to the power supply 2, while the third terminal 113 and the fourth terminal 114 are connected to the load 3. Alternatively, the leakage current circuit breaker 11 can operate normally even if the first terminal 111 and the second terminal 112 are connected to the load 3 and the third terminal 113 and the fourth terminal 114 are connected to the power supply 2.

[0075] The operating handle 115 forms part of the linkage unit 83 of the tripping mechanism section 8, and switches between the on and off states when the first contact S1 and the second contact S2 are switched. For example, when the first contact S1 and the second contact S2 are on, the operating handle 115 rotates upward (i.e., rotates to the on position). On the other hand, when the first contact S1 and the second contact S2 become off, as... Figure 5 As shown, the operating handle 115 is rotated downwards (i.e., rotated to the off position). Furthermore, the third contact S3 is configured to switch between the on and off positions as the operating handle 115 switches between the on and off positions. Specifically, when the operating handle 115 is switched to the on position, the third contact S3 is on. When the operating handle 115 is switched to the off position, the third contact S3 is off. Therefore, when the leakage current detector circuit 1 detects, for example, a leakage current, the first contact S1, the second contact S2, and the third contact S3 change from on to off, and the operating handle 115 also changes from the on position to the off position. Furthermore, switching the operating handle 115 from the on position to the off position when the first contact S1, the second contact S2, and the third contact S3 are on allows the first contact S1, the second contact S2, and the third contact S3 to become off. Therefore, by preemptively switching the operating handle 115 to the off position before being struck by, for example, lightning, surge current can be prevented. Furthermore, when the first contact S1, the second contact S2, and the third contact S3 are open, switching the operating handle 115 from the open position to the closed position allows the first contact S1, the second contact S2, and the third contact S3 to become closed. Therefore, for example, if, after the leakage current detector circuit 1 has switched the first contact S1, the second contact S2, and the third contact S3 from closed to open, and the cause of, for example, leakage current has been determined and safety has been ensured, the user can rotate the operating handle 115 to restore power supply from the power source 2 to the load 3.

[0076] A test button 116 is provided to turn the test switch 91 of the leakage current detector circuit 1 on and off. The user of the leakage current circuit breaker 11 can press the test button 116 to turn the test switch 91 on and perform tests to check whether the leakage current detection function and tripping function of the leakage current detector circuit 1 are working properly.

[0077] (3) Variations

[0078] Note that the above embodiments are merely typical embodiments among the various embodiments of this disclosure and should not be construed as limiting. Instead, these typical embodiments can be readily modified in various ways, depending on design choices or any other factors, without departing from the scope of this disclosure. The function of the leakage current detector circuit 1 according to the above typical embodiments can also be implemented, for example, as a method for controlling the leakage current detector circuit 1, a computer program, or a non-transitory storage medium storing a computer program.

[0079] Next, variations of the typical embodiments will be listed one by one. Note that the variations described below can be appropriately combined.

[0080] (3.1) First variation

[0081] In the first variation, such as Figure 6 As shown, the end P4 of the first surge absorber 61 is connected between the first contact S1 and the third terminal 43, which differs from the typical embodiment described above. In the following description, any constituent elements in this first variation that have the same function as the corresponding part in the typical embodiment described above will be designated by the same reference numerals as those corresponding to the corresponding parts, and their description will be omitted herein.

[0082] In this first variation, such as Figure 6 As shown, the third input node 73 is disposed between the first contact S1 and the third terminal 43, and the end P4 of the first surge absorber 61 is connected to the third input node 73. The end P3 of the first surge absorber 61 is connected to the second input node 72, and the first surge absorber 61 is connected between the second input node 72 and the third input node 73. The leakage current detector circuit 1 according to this first modification having this structure achieves, for example, the advantage of enabling withstand voltage testing of the first contact S1 and the second contact S2 by means of the following method.

[0083] In the leakage current detector circuit 1, during the withstand voltage test of the first contact S1 and the second contact S2, a pulse voltage of, for example, several kV can be applied between the first terminal 41 and the second terminal 42, which are short-circuited to each other, and the third terminal 43 and the fourth terminal 44, which are short-circuited to each other. At this time, the first contact S1 and the second contact S2 have been pre-connected and then disconnected. This allows the user to check whether any dielectric breakdown has occurred when the first contact S1 and the second contact S2 are disconnected.

[0084] According to the first variation, end P3 of the first surge absorber 61 is connected to the second input node 72, and end P4 is connected to the third input node 73, thereby preventing pulse voltage from being applied to the first surge absorber 61 during the withstand voltage test.

[0085] (3.2) Second variation

[0086] In the second variation, such as Figure 7 As shown, the end P3 of the first surge absorber 61 is connected between the second contact S2 and the second terminal 42, which is different from the typical embodiment and the first variant described above.

[0087] In the second variation, such as Figure 7As shown, the fourth input node 74 is disposed between the second contact S2 and the second terminal 42, and the end P3 of the first surge absorber 61 is connected to the fourth input node 74. The end P4 of the first surge absorber 61 is connected to the first input node 71, and the first surge absorber 61 is connected between the first input node 71 and the fourth input node 74. The leakage current detector circuit 1 according to this second modification with this structure achieves the advantage of enabling withstand voltage testing of the first contact S1 and the second contact S2 by the same method as that described for the first modification.

[0088] (3.3) Third variation

[0089] In the third variation, such as Figure 8 As shown, the end P1 of the third contact S3 is connected to the second input node 72, and the third contact S3 is connected between the second input node 72 and the leakage current detector 5. This differs from the typical embodiment and the first and second modifications described above. In this case, the terminal T1 of the leakage current detector 5 is connected to the second input node 72, and the third contact S3 is connected between the terminal T1 and the second input node 72. Additionally, in this case, the terminal T2 of the leakage current detector 5 is connected to the first input node 71. That is, the tripping mechanism 8 is connected between the terminal T2 and the first input node 71. Note that even though the end P1 of the third contact S3 is connected to the second input node 72 as in this third modification, the leakage current detector 5 can still operate normally using AC power supplied from the power supply 2.

[0090] (3.4) Other variations

[0091] Next, other variations of the typical embodiments will be listed one by one. Note that the variations described below can be appropriately combined.

[0092] The leakage detector 5 of the leakage detector circuit 1 according to this disclosure includes a computer system. The computer system may include a processor and memory as its main hardware components. The leakage detector 5 of the leakage detector circuit 1 according to this disclosure can function by causing the processor to execute a program stored in the memory of the computer system. The program may be pre-stored in the memory of the computer system. Alternatively, the program may also be downloaded via a telecommunications line or distributed after being recorded on a non-transitory storage medium such as a memory card, optical disc, or hard disk drive (any of which is readable by the computer system). The processor of the computer system may consist of one or more electronic circuits including semiconductor integrated circuits (ICs) or large-scale integrated circuits (LSIs). As used herein, "integrated circuit," such as IC or LSI, is referred to by different names depending on its degree of integration. Examples of integrated circuits include system LSIs, very large-scale integrated circuits (VLSIs), and ultra-large-scale integrated circuits (ULSIs). Alternatively, a field-programmable gate array (FPGA) that is programmed after the LSI is manufactured, or a reconfigurable logic device that allows reconfiguration of connections or circuitry within the LSI, may also be used as the processor. These electronic circuits can be integrated together on a single chip or distributed across multiple chips, whichever is appropriate. These multiple chips can be aggregated together in a single device or distributed across multiple devices, without limitation. As used herein, a "computer system" includes a microcontroller comprising one or more processors and one or more memories. Thus, a microcontroller can also be implemented as a single or multiple electronic circuits comprising semiconductor integrated circuits or large-scale integrated circuits.

[0093] Furthermore, in the above embodiments, multiple functions of the leakage current detector circuit 1 are integrated into a single housing. However, this is not a necessary configuration for the leakage current detector circuit 1. Alternatively, the various components of the leakage current detector circuit 1 can be distributed in multiple different housings. Alternatively, at least some functions of the leakage current detector circuit 1 (e.g., some functions of the leakage current detector 5) can also be implemented as a cloud computing system. Conversely, as in the leakage current circuit breaker 11 according to the above exemplary embodiment, multiple functions of the leakage current detector circuit 1 can be integrated into a single housing.

[0094] (4) Summary

[0095] As can be seen from the foregoing description, the leakage current detector circuit (1) according to the first aspect includes a first terminal (41), a second terminal (42), a third terminal (43), a fourth terminal (44), a first electrical path (C1), a second electrical path (C2), a first contact (S1) and a second contact (S2), a leakage current detector (5), a third contact (S3), and a surge absorber (61). Both the first terminal (41) and the second terminal (42) are connected to a first connection object that serves as a power source (2) or a load (3). Both the third terminal (43) and the fourth terminal (44) are connected to a second connection object that serves as a power source (2) or a load (3) and is different from the first connection object. The first electrical path (C1) connects the first terminal (41) and the third terminal (43) to each other. The second electrical path (C2) connects the second terminal (42) and the fourth terminal (44) to each other. The first contact (S1) and the second contact (S2) are respectively provided for the first electrical path (C1) and the second electrical path (C2). A leakage current detector (5) is connected between a first input node (71) and a second input node (72). The first input node (71) is located between a first contact (S1) and a first terminal (41). The second input node (72) is located between a second contact (S2) and a fourth terminal (44). When the leakage current detector (5) detects the generation of leakage current, it causes the first contact (S1) and the second contact (S2) to change from closed to open. A third contact (S3) has a first end (P1) and a second end (P2) opposite to the first end (P1). The first end (P1) is connected to either the first input node (71) or the second input node (72). The second end (P2) is connected to the leakage current detector (5). The third contact (S3) synchronously switches its closed / open state as the first contact (S1) and the second contact (S2) become closed and open. The surge absorber (61) is connected between the first electrical path (C1) and the second electrical path (C2) without passing through the third contact (S3).

[0096] This aspect can be addressed for the third contact (S3) of surge current protection.

[0097] In the leakage detector circuit (1) according to the second aspect, which can be implemented in conjunction with the first aspect, one end of the surge absorber (61) is connected to the first end (P1) of the third contact (S3).

[0098] This aspect can be addressed for the third contact (S3) of surge current protection.

[0099] In the leakage current detector circuit (1) according to the third aspect, which can be implemented in conjunction with the first aspect, one end of the surge absorber (61) is connected between the first contact (S1) and the third terminal (43), and the other end of the surge absorber (61) is connected to the second input node (72).

[0100] This aspect enables the first contact (S1) and the second contact (S2) to be subjected to withstand voltage tests by applying voltage between the first terminal (41) and the second terminal (42) that are shorted to each other and the third terminal (43) and the fourth terminal (44) that are shorted to each other.

[0101] In the leakage detector circuit (1) according to the fourth aspect, which can be implemented in combination with the first aspect or the second aspect, one end of the surge absorber (61) is connected between the second contact (S2) and the second terminal (42), and the other end of the surge absorber (61) is connected to the first input node (71).

[0102] This aspect enables the first contact (S1) and the second contact (S2) to be subjected to withstand voltage tests by applying voltage between the first terminal (41) and the second terminal (42) that are shorted to each other and the third terminal (43) and the fourth terminal (44) that are shorted to each other.

[0103] The residual current circuit breaker (11) according to the fifth aspect includes a residual current detector circuit (1) according to any one of the first to fourth aspects.

[0104] This aspect can be addressed for the third contact (S3) of surge current protection.

[0105] The residual current circuit breaker (11) according to the sixth aspect, which can be implemented in conjunction with the fifth aspect, includes a switching mechanism that causes the first contact (S1), the second contact (S2) and the third contact (S3) to become closed and open as the operating handle (115) is switched.

[0106] This aspect allows the user of the residual current circuit breaker (11) to arbitrarily turn the first contact (S1), the second contact (S2), and the third contact (S3) on and off.

[0107] The distribution board (12) according to the seventh aspect includes the residual current circuit breaker (11) according to the sixth aspect.

[0108] This aspect can be addressed for the third contact (S3) of surge current protection.

[0109] Note that the components of the second to fourth aspects are not necessary components of the leakage current detector circuit (1) and can be appropriately omitted.

[0110] Note that the constituent elements according to the sixth aspect are not necessary constituent elements of the residual current circuit breaker (11) and can be appropriately omitted.

[0111] Explanation of reference numerals in the attached figures

[0112] 1. Leakage detector circuit

[0113] 2 power supplies

[0114] 3 loads

[0115] 5 Leakage Detectors

[0116] 61 Surge Absorber

[0117] 11 Residual Current Circuit Breaker

[0118] 12 Distribution Board

[0119] 41 First terminal

[0120] 42 Second terminal

[0121] 43 Third terminal

[0122] 44 Fourth terminal

[0123] 71 First Input Node

[0124] 72 Second Input Node

[0125] 115 Operating handle

[0126] C1 First electrical path

[0127] C2 Second electrical path

[0128] P1 First end

[0129] P2 Second end

[0130] S1 First Contact Point

[0131] S2 Second Contact

[0132] S3 Third Contact Point

Claims

1. A leakage current detector circuit, comprising: The first terminal and the second terminal are both connected to a first connection object, which is a power source or a load. The third and fourth terminals are both connected to a second connection object, which is the power source or the load, and is different from the first connection object; A first electrical path connects the first terminal and the third terminal to each other; A second electrical path connects the second terminal and the fourth terminal to each other; The first contact and the second contact are respectively set for the first electrical path and the second electrical path; A leakage current detector is connected between a first input node and a second input node, the first input node being disposed between a first contact and a first terminal, and the second input node being disposed between a second contact and a fourth terminal. The leakage current detector is configured to change the first contact and the second contact from closed to open when leakage current is detected. A third contact has a first end and a second end, and the third contact is configured to synchronously switch its on / off state as the first contact and the second contact become on and off, the first end being connected to the first input node or the second input node, and the second end being opposite to the first end and connected to the leakage detector. as well as A surge absorber is connected between the first electrical path and the second electrical path without via the third contact.

2. The leakage current detector circuit according to claim 1, wherein, One end of the surge absorber is connected to the first end of the third contact.

3. The leakage current detector circuit according to claim 1, wherein, One end of the surge absorber is connected between the first contact and the third terminal, and The other end of the surge absorber is connected to the second input node.

4. The leakage current detector circuit according to claim 1 or 2, wherein, One end of the surge absorber is connected between the second contact and the second terminal, and The other end of the surge absorber is connected to the first input node.

5. A residual current circuit breaker, comprising a residual current detector circuit according to any one of claims 1 to 4.

6. The residual current circuit breaker according to claim 5, comprising a switching mechanism configured to switch the first contact, the second contact and the third contact to be on and off as the operating handle is switched.

7. A distribution board comprising the residual current circuit breaker according to claim 6.

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