CN117501396A

CN117501396A - Electric leakage detector circuit, electric leakage breaker and distribution board

Info

Publication number: CN117501396A
Application number: CN202280042464.1A
Authority: CN
Inventors: 毛翔; 宫川纮平; 中道义也
Original assignee: Panasonic Holdings Corp
Current assignee: Panasonic Holdings Corp
Priority date: 2021-06-14
Filing date: 2022-03-07
Publication date: 2024-02-02
Also published as: JP7526139B2; WO2022264544A1; JP2022190533A

Abstract

The problem to be solved by the invention is to protect a third contact (S3) for interrupting a power feeding path to a leakage detector (5) against an inrush current. The leakage detector circuit (1) includes first and second contacts (S1, S2), a leakage detector (5), a third contact (S3), and a surge absorber (61). The leakage detector (5) changes the first contact (S1) and the second contact (S2) from on to off when the generation of leakage current is detected. The third contact (S3) includes a first end (P1) and a second end (P2) opposite the first end (P1). The first end (P1) is connected to the first input node (71) or the second input node (72). The second end (P2) is connected to the leakage detector (5). The third contact (S3) switches itself on/off synchronously with the on/off of the first contact (S1) and the second contact (S2). The surge absorber (61) is connected between the first electrical path (C1) and the second electrical path (C2) without via a third contact (S3).

Description

Electric leakage detector circuit, electric leakage breaker and distribution board

Technical Field

The present disclosure relates generally to an earth leakage detector circuit, an earth leakage breaker, and a power distribution board, and more particularly to an earth leakage detector circuit, an earth leakage breaker, and a power distribution board each having an overcurrent protection function.

Background

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

In a circuit breaker such as the circuit breaker disclosed in patent document 1, an overcurrent generated by, for example, a lightning surge may flow through the second contact.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2020-167089

Disclosure of Invention

In view of the foregoing background, it is therefore an object of the present disclosure to provide an earth leakage detector circuit, an earth leakage breaker, and a distribution board, each having the ability to protect contacts for interrupting a feed path to the earth leakage detector against an overcurrent (surge current).

A leakage detector circuit according to an aspect of the present disclosure includes a first terminal, a second terminal, a third sheet, a fourth terminal, a first electrical path, a second electrical path, first and second contacts, a leakage detector, a third contact, and a surge absorber. The first terminal and the second terminal are connected to a first connection object, which is a power source or a load. The third terminal and the fourth terminal are connected to a second connection object that is the power source or the load and is different from the first connection object. The first electrical path connects the first terminal and the third terminal to each other. The second electrical path connects the second terminal and the fourth terminal to each other. The first contact and the second contact are provided for the first electrical path and the second electrical path, respectively. The leakage detector is connected between the first input node and the 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. The leakage detector changes the first contact and the second contact from on to off when generation of a leakage current is detected. The third contact has a first end and a second end opposite the first end. The first end is connected to the first input node or the second input node. The second end is connected to the leakage detector. The third contact switches its on/off state synchronously as the first contact and the second contact become on and off. The surge absorber is connected between the first electrical path and the second electrical path without via the third contact.

An earth leakage breaker according to another aspect of the present disclosure includes the above-described earth leakage detector circuit.

A power distribution panel according to still another aspect of the present disclosure includes the above-described earth leakage breaker.

Drawings

FIG. 1 is a schematic circuit diagram of a leakage detector circuit according to an exemplary embodiment;

FIG. 2 is a schematic circuit diagram of the leakage detector circuit;

FIG. 3 is a schematic circuit diagram of the leakage detector circuit;

fig. 4 is a schematic front view illustrating the inside of a power distribution board according to an exemplary embodiment;

fig. 5 is a schematic front view of an earth leakage breaker according to an exemplary embodiment;

fig. 6 is a schematic circuit diagram of a leak detector circuit according to a first modification;

fig. 7 is a schematic circuit diagram of a leak detector circuit according to a second modification; and

fig. 8 is a schematic circuit diagram of a leak detector circuit according to a third modification.

Detailed Description

The electric leakage detector circuit 1, the electric leakage breaker 11, and the distribution board 12 according to an exemplary embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that the exemplary embodiments to be described below and modifications thereof are merely examples of the present disclosure, and should not be construed as limiting. Rather, the exemplary embodiment and its variants can be readily modified in various ways, depending on design choices or any other factors, without departing from the true spirit and scope of the present disclosure. Note that the embodiments (including modifications thereof) to be described below may be employed in combination as appropriate.

(1) Summary of the invention

First, an outline of the leak detector circuit 1 according to the exemplary embodiment will be described with reference to fig. 1.

The leakage detector circuit 1 includes a first terminal 41 and a second terminal 42, both of the first terminal 41 and the second terminal 42 being connected to a first connection object that is one selected from the power supply 2 and the load 3. In this embodiment, the first connection object may be, for example, the power supply 2. In addition, the leakage detector circuit 1 further includes a third terminal 43 and a fourth terminal 44, both of the third terminal 43 and the fourth terminal 44 being connected to a second connection object that is the other selected from the power supply 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 supply 2.

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

The leakage detector circuit 1 further includes a leakage detector 5, a third contact S3, and a surge absorber (first surge absorber 61).

The leakage detector 5 is connected between a first input node 71 provided between the first contact S1 and the first terminal 41 and a second input node 72 provided between the second contact S2 and the fourth terminal 44. The leakage detector 5 is activated by the power supplied from the power supply 2. The leakage 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. Upon detecting the generation of the leakage current, the leakage detector 5 changes the first contact S1 and the second contact S2 from ON (ON) to OFF (OFF). This makes it possible to stop the supply of electric power from the power source 2 to the load 3 when the leakage current is generated.

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, the end P1 may be connected to the second input node 72, and the third contact S3 may be connected between the second input node 72 and the leakage detector 5. The third contact S3 switches its on/off state in synchronization 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 turned on, the third contact S3 is also turned on. When the first contact S1 and the second contact S2 are opened, the third contact S3 is also opened. When the third contact S3 is turned on, electric power is supplied from the power supply 2 to the leakage detector 5. On the other hand, when the third contact S3 is opened, the supply of electric power from the power source 2 to the leakage detector 5 is stopped.

The first surge absorber 61 is connected between the first electrical path C1 and the second electrical path C2 without via the third contact S3. Thus, 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 enables protection of the third contact S3 against an inrush current.

(2) Details of the

Next, the electric leakage detector circuit 1 and the electric leakage breaker 11 according to this embodiment will be described in detail with reference to fig. 1 to 5.

(2.1) Structure of leakage Detector Circuit

The structure of the leak detector circuit 1 will be described with reference to fig. 1.

The leakage detector circuit 1 according to this embodiment includes first to fourth terminals 41 to 44. The first terminal 41 and the second terminal 42 are connected to the power source 2. In this embodiment, the power source 2 may be, for example, a commercial AC power source. The third terminal 43 and the fourth terminal 44 are connected to the 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 detector circuit 1 may also operate normally in a state in which 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. Such a connection state will be referred to as a "reverse connection state" hereinafter.

The first and second electrical paths C1 and C2 are provided with first and second contacts S1 and S2, respectively. The operation of turning the first contact S1 and the second contact S2 on and off will be described later.

The leakage detector circuit 1 includes a leakage detector 5, a third contact S3, and a first surge absorber 61. The leakage detector circuit 1 further includes a trip mechanism section 8, a test section 9, and a zero-phase current transformer (ZCT) 10.

The leakage detector 5 may include, for example: a rectifier circuit for rectifying an AC voltage supplied from the power supply 2 into a DC voltage; a smoothing circuit for smoothing an output voltage of the rectifier circuit; and a computer system which is provided to a subsequent stage of the smoothing circuit and includes a processor and a memory. The computer system performs the function of the leakage detector 5 by causing the processor to execute a program stored in the memory. In this embodiment, a program to be executed by the processor is stored in advance in a memory of the computer system. Alternatively, the program may be distributed after being stored in a storage medium such as a memory card or the like or downloaded via a telecommunication line such as the internet or the like. Note that the leak detector 5 need not necessarily be implemented as a digital IC such as a processor or the like, but may be implemented as an analog IC.

The leakage detector 5 is connected between a first input node 71 provided between the first contact S1 and the first terminal 41 and a second input node 72 provided between the second contact S2 and the fourth terminal 44. Specifically, the leakage detector 5 includes terminals T1 to T4. Terminal T1 is connected to first input node 71. Terminal T2 is connected to second input node 72. The leakage 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.

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

The first surge absorber 61 is a varistor for protecting the leakage detector 5 against surge voltages generated by, for example, lightning, and may be implemented as a zinc oxide nonlinear resistor (ZNR). Note that the first surge absorber 61 does not necessarily have to be a varistor, but may be, for example, a Gas Discharge Tube (GDT) or an avalanche diode.

The first surge absorber 61 is connected between the first electrical path C1 and the second electrical path C2 without via the third contact S3. Specifically, the first surge absorber 61 has an end P3 and an end P4. The end portion P3 is connected between the second input node 72 and an end portion P5 of a trip coil 81 (to be described later). The end P4 is connected to the first input node 71. The end P4 is also connected to the end P1 of the third contact S3. That is, the end portion P3 is connected to the second input node 72, and the end portion P4 is connected between the first input node 71 and the end portion P1 of the third contact S3. This causes 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 protection of the leakage detector 5 and the third contact S3 against an inrush current.

The trip mechanism portion 8 is connected between the terminal T2 of the leakage detector 5 and the second input node 72. The trip mechanism 8 has the capability of changing (tripping) the first contact S1, the second contact S2, and the third contact S3 from on to off when the leakage current generation is detected by the leakage detector 5.

The trip mechanism section 8 includes, for example, a trip coil 81, a switching unit 82, and a linking unit 83.

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

The switching unit 82 changes the first contact S1 and the second contact S2 from on to off when the leakage current generation is detected by the leakage detector 5. The switching unit 82 includes, for example: a moving core made of a magnetic material; a push pin coupled to the moving core; and a switching mechanism interlocked with the push pin for changing the first contact S1 and the second contact S2 from on to off. Upon detecting generation of a leakage current based on the output of the zero-phase current transformer 10, the leakage detector 5 allows a driving current to flow through the trip coil 81. This causes a change in magnetic flux of the moving iron core accommodated in the coil bobbin passing through the trip coil 81, thereby causing the moving iron core to move in a direction to cancel the change in magnetic flux. The push pin moves with the moving core. The switching mechanism of the switching unit 82 changes the first contact S1 and the second contact S2 from on to off in cooperation with the push pin movement.

The interlocking unit 83 changes the third contact S3 from on to off in synchronization with the switching unit 82 changing the first contact S1 and the second contact S2 from on to off. In this embodiment, the trip mechanism portion 8 includes a trip coil 81, a switching unit 82, and a linkage unit 83. However, this is not an essential structure of the trip mechanism portion 8. Alternatively, the function of the trip mechanism portion 8 may be performed by a different structure.

The test section 9 is connected between the first input node 71 and the second input node 72. The test section 9 includes a test switch 91 and a resistor 92. Specifically, the test switch 91 has an end P7 and an end P8. The end P7 is connected to an end P10 of a resistor 92 (to be described later). The end P8 is connected between the first input node 71 and the end P1 of the third contact S3. The test switch 91 is a normally off switch, and is turned on by a user when testing the leak detection function of the leak detector 5 and the trip function of the trip mechanism portion 8. Resistor 92 has an end P9 and an end P10. The end P9 is connected between the second input node 72 and the end P5 of the trip coil 81. The end P10 is connected to the end P7 of the test switch 91. The test to be performed by the test switch 91 on the electric leakage detection function of the electric leakage detector 5 will be described in detail later in the "(2.2.2) test operation section.

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 a coil 102 is wound around a part of a toroidal core 101. The coil 102 is connected between the terminals T3 and T4 of the leakage detector 5. The first electrical path C1, the second electrical path C2, and the third electrical path C3 pass through the holes of the toroidal core 101. In this embodiment, the third electrical path C3 is an electrical path connecting 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 in such a way that current flows through these electrical paths C1, C2 in two opposite directions. The operation of the zero-phase current transformer 10 will be described in detail later in the "(2.2.1) leakage detection operation" section.

Further, in this embodiment, the leakage detector circuit 1 further includes a second surge absorber 62 provided separately from the first surge absorber 61. The second surge absorber 62 has an end P11 and an end P12. The end P11 is connected between the end P6 of the trip coil 81 and the terminal T2 of the leakage detector 5. The end portion P12 is connected between the end portion P2 of the third contact S3 and the terminal T1 of the leakage detector 5.

(2.2) operation of the leakage Detector Circuit

Next, respective operations of the leak detector circuit according to this embodiment will be described with reference to fig. 1 to 3.

(2.2.1) leakage detection operation

First, how the leak detector circuit 1 performs a leak detection operation will be described with reference to fig. 1.

If the first contact S1, the second contact S2 and the third contact S3 are all on, no leakage current is generated, and power is normally supplied from the power source 2 to the load 3, the current I1 flowing through the first electric path C1 and the current I2 flowing through the second electric path C2 will be equal to each other. In this embodiment, the first electrical path C1 and the second electrical path C2 pass through the inside of the toroidal core 101 of the zero-phase current transformer 10, so that currents I1 and I2 flow through the first electrical path C1 and the second electrical path C2 in mutually opposite directions. Thus, the magnetic fluxes generated by the currents I1 and I2 cancel each other out, which results in no current flowing through the coil 102. On the other hand, if a leakage current is generated, the currents I1 and I2 are no longer in balance, thereby causing a current corresponding to the difference between these currents I1 and I2 to flow through the coil 102. The leakage detector 5 may detect generation of leakage current by sensing current flowing through the coil 102.

Upon detecting that the leakage current is generated, the leakage detector 5 allows the driving current to flow through the trip coil 81, thereby causing the trip mechanism portion 8 to change the first contact S1, the second contact S2, and the third contact S3 from on to off. When the first contact S1, the second contact S2, and the third contact S3 are changed from on to off, the supply of electric power from the power source 2 to the load 3 is cut off, thereby enabling protection of the load 3.

(2.2.2) test operation

Next, how the test section 9 tests the leakage detection function and the trip function will be described with reference to fig. 2.

The test section 9 is configured such that the pseudo leakage current I3 flows through the third electrical path C3 passing through the inside of the annular core 101, thereby causing the trip mechanism section 8 to change the first contact S1, the second contact S2, and the third contact S3 from on to off.

If the first contact S1, the second contact S2, and the third contact S3 are all on, no leakage current is generated, and power is normally supplied from the power supply 2 to the load 3, the user of the leakage detector circuit 1 may perform a test to see whether the leakage detection function and the trip function of the leakage detector circuit 1 are operating normally.

As shown in fig. 2, the user to be tested changes the test switch 91 from off to on. When the test switch 91 is changed from off to on, a current flows from the power supply 2 via the test switch 91 and the resistor 92, thereby causing a pseudo leakage current I3 to flow through the third electrical path C3 through the inside of the toroidal core 101. In this case, the currents I1 and I2 flowing through the first and second electrical paths C1 and C2 are in balance. However, as the pseudo leakage current I3 flows through the third electrical path C3, the currents I1 and I2 and the pseudo leakage current I3 are unbalanced. As a result, a current corresponding to the pseudo leakage current I3 flows through the coil 102. The leakage detector 5 can detect a pseudo leakage current by sensing the current flowing through the coil 102.

If the leakage detector 5 and the trip mechanism portion 8 are operating normally, the leakage detector 5 allows the driving current to flow through the trip coil 81 when the pseudo leakage current is detected, and the trip mechanism portion 8 changes the first contact S1, the second contact S2, and the third contact S3 from on to off. This enables the user to check whether the leakage detection function and the trip function are functioning properly.

(2.2.3) Surge Voltage absorbing operation

Next, how the leakage detector circuit 1 performs an operation of absorbing surge voltage will be described with reference to fig. 3.

It is assumed that in the case where the first contact S1, the second contact S2, and the third contact S3 are all on 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.

A 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 varistor voltage of the first surge absorber 61 implemented as a varistor, the resistance of the first surge absorber 61 drops sharply to cause the 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 the first electric path C1 or the second electric path C2. This makes it possible to prevent the surge current Is from flowing through the leakage detector 5. In addition, in this case, the surge current Is may flow without passing through the third contact S3. This enables protection of the third contact S3 against the surge current Is.

Alternatively, the leakage detector 5 may also be configured to detect the generation of the surge current Is. In this case, the leakage detector 5 allows the driving current to flow through the trip coil 81 when the generation of the surge current Is detected, and causes the trip mechanism portion 8 to change the first contact S1, the second contact S2, and the third contact S3 from on to off.

(2.3) upon reverse connection

The leakage detector circuit 1 according to this embodiment comprises a third contact S3. This enables the leakage detector circuit 1 to operate normally even in a reverse connection state in which 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.

It is assumed that the leakage 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 current may flow through the leakage detector 5 even when the first contact S1 and the second contact S2 are opened.

In contrast, the leakage detector circuit 1 according to this embodiment includes the third contact S3, and thus if the first contact S1 and the second contact S2 are open, the third contact S3 is also open. This makes it possible to prevent a ground fault current from flowing through the third contact S3 even if the load 3 causes a ground fault, for example, thereby improving reliability.

(2.4) leakage Circuit breaker

Next, the earth leakage breaker 11 including the earth leakage detector circuit 1 will be described with reference to fig. 1, 4, and 5.

The earth leakage breaker 11 includes the earth leakage detector circuit 1, and thus has the capability of shutting off the current flowing through the first and second electric paths C1 and C2 (wherein the electric power is supplied from the power source 2 to the load 3 through the first and second electric paths C1 and C2) when any earth leakage current is detected. As shown in fig. 4, the earth leakage breaker 11 may be used, for example, in a distribution board 12 to be installed in, for example, a house. Note that the distribution board 12 need not necessarily be installed in a house, but may be installed in a non-house such as an office, a store, a factory, or a hospital. The earth leakage breaker 11 is fitted to a fitting surface 131 of the DIN rail 13 provided inside the panel of the distribution board 12. The mounting surface 131 may be, for example, a surface of the DIN rail 13 facing the leakage breaker 11.

The earth leakage breaker 11 may be used as a branch breaker or a main breaker, whichever is appropriate. As shown in fig. 4, among the plurality of earth leakage breakers 11 mounted on the DIN rail 13 of the distribution board 12, for example, the rightmost earth leakage breaker 11 (11M) may be used as a main breaker, and the other earth leakage breakers 11 (11B) may be used as branch breakers. Note that in fig. 4, illustration of wiring inside the distribution board 12 is omitted.

As shown in fig. 5, the earth leakage 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. The residual current circuit breaker 11 further includes an operation handle 115 and a test button 116 on the operation surface 110.

The first to fourth terminals 111 to 114 correspond to the first to fourth terminals 41 to 44 of the leak detector circuit 1 shown in fig. 1, respectively. That is, the first terminal 111 and the second terminal 112 are connected to the power source 2, and the third terminal 113 and the fourth terminal 114 are connected to the load 3. Alternatively, 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 source 2, the electrical leakage breaker 11 can operate normally.

The operation handle 115 forms a part of the interlocking unit 83 of the trip mechanism portion 8, and is switched when the first contact S1 and the second contact S2 are switched between the on and off states. For example, when the first contact S1 and the second contact S2 are on, the operation handle 115 is rotated upward (i.e., rotated to the on position). On the other hand, when the first contact S1 and the second contact S2 become open, as shown in fig. 5, the operation handle 115 is turned downward (i.e., turned to the open position). In addition, the third contact S3 is also configured to become on and off as the operation handle 115 is switched between the on and off positions. Specifically, when the operation handle 115 is switched to the on position, the third contact S3 is turned on. When the operation handle 115 is switched to the open position, the third contact S3 is opened. Thus, when the leakage current is detected by the leakage detector circuit 1, for example, the first contact S1, the second contact S2, and the third contact S3 are changed from on to off, and the operation handle 115 is also switched from the on position to the off position. Further, switching the operation handle 115 from the on position to the off position when the first, second, and third contacts S1, S2, and S3 are on allows the first, second, and third contacts S1, S2, and S3 to become off. Thus, the operation handle 115 is switched to the off position in advance before being hit by, for example, lightning, which can prevent generation of an inrush current. Further, switching the operation handle 115 from the off position to the on position when the first, second, and third contacts S1, S2, and S3 are off allows the first, second, and third contacts S1, S2, and S3 to become on. Thus, for example, if the cause of, for example, the leakage current is determined and the safety is ensured after the electric leakage detector circuit 1 changes the first contact S1, the second contact S2, and the third contact S3 from on to off, the user can turn the operation handle 115 to resume the supply of electric power from the power source 2 to the load 3.

A test button 116 is provided to turn on and off the test switch 91 of the leak detector circuit 1. The user of the earth leakage breaker 11 can press the test button 116 to turn the test switch 91 on, and thereby perform a test to see whether the earth leakage detection function and the trip function of the earth leakage detector circuit 1 are operating normally.

(3) Modification examples

Note that the above-described embodiments are merely typical embodiments among various embodiments of the present disclosure, and should not be construed as limiting. Rather, the exemplary embodiment can be readily modified in various ways, depending on design choices or any other factors, without departing from the scope of the present disclosure. The functions of the electric leakage detector circuit 1 according to the above-described exemplary embodiments may also be implemented as a method for controlling the electric leakage detector circuit 1, a computer program, or a non-transitory storage medium storing a computer program, for example.

Next, modifications of the exemplary embodiment will be listed one by one. Note that modifications to be described below may be employed in combination as appropriate.

(3.1) first modification example

In the first modification, as shown in fig. 6, an end portion P4 of the first surge absorber 61 is connected between the first contact S1 and the third terminal 43, which is different from the above-described exemplary embodiment. In the following description, any constituent element in the first modification having the same function as the corresponding portion of the above-described exemplary embodiment will be designated by the same reference numeral as the corresponding portion, and the description thereof will be omitted herein.

In this first modification, as shown in fig. 6, the third input node 73 is provided between the first contact S1 and the third terminal 43, and the end portion 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 detector circuit 1 according to the first modification example having such a structure achieves, for example, an advantage of enabling the withstand voltage test of the first contact S1 and the second contact S2 by the following method.

In the leakage detector circuit 1, when the first contact S1 and the second contact S2 are subjected to the withstand voltage test, a pulse voltage of, for example, several kV may be applied between the first terminal 41 and the second terminal 42 that are short-circuited to each other and the third terminal 43 and the fourth terminal 44 that are short-circuited to each other. At this time, the first contact S1 and the second contact S2 have been changed from on to off in advance. This enables the user to see if any dielectric breakdown occurs when the first contact S1 and the second contact S2 are open.

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

(3.2) second modification example

In the second modification, as shown in fig. 7, an end portion P3 of the first surge absorber 61 is connected between the second contact S2 and the second terminal 42, which is different from the exemplary embodiment and the first modification described above.

In the second modification, as shown in fig. 7, the fourth input node 74 is provided between the second contact S2 and the second terminal 42, and the end portion 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 detector circuit 1 according to the second modification example having such a structure achieves an advantage of enabling the withstand voltage test of the first contact S1 and the second contact S2 by the same method as that described for the first modification example.

(3.3) third modification example

In the third modification, as shown in fig. 8, the end portion 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 detector 5, which is different from the exemplary embodiment and the first modification and the second modification described above. In this case, the terminal T1 of the leakage 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. In addition, in this case, the terminal T2 of the leak detector 5 is connected to the first input node 71. That is, the trip mechanism portion 8 is connected between the terminal T2 and the first input node 71. Note that, even if the end P1 of the third contact S3 is connected to the second input node 72 as in this third modification, the leak detector 5 can normally operate with AC power supplied from the power supply 2.

(3.4) other modifications

Next, other modifications of the exemplary embodiment will be listed one by one. Note that modifications to be described below may be employed in combination as appropriate.

The leakage detector 5 of the leakage detector circuit 1 according to the present disclosure comprises a computer system. The computer system may include a processor and memory as its main hardware components. The function of the leakage detector 5 of the leakage detector circuit 1 according to the present disclosure may be performed by causing a processor to execute a program stored in a memory of a computer system. The program may be stored in advance in a memory of the computer system. Alternatively, the program may be downloaded via a telecommunication line, or distributed after being recorded in some non-transitory storage medium, such as a memory card, an optical disk, or a hard disk drive (any of which is readable by a computer system), etc. The processor of the computer system may be constituted by a single or a plurality of electronic circuits including a semiconductor Integrated Circuit (IC) or a large scale integrated circuit (LSI). As used herein, an "integrated circuit" such as an IC or LSI is referred to by different names depending on the degree of integration thereof. Examples of integrated circuits include system LSIs, very large scale integrated circuits (VLSI), and ultra large scale integrated circuits (ULSI). Alternatively, a Field Programmable Gate Array (FPGA) to be programmed after the LSI is manufactured or a reconfigurable logic device that allows connection or circuit part inside the LSI to be reconfigured may also be employed as the processor. These electronic circuits may be integrated together on a single chip or distributed across multiple chips, whichever is appropriate. These multiple chips may be aggregated together in a single device or distributed among multiple devices without limitation. As used herein, a "computer system" includes a microcontroller that includes one or more processors and one or more memories. Thus, a microcontroller may also be implemented as a single or multiple electronic circuits including a semiconductor integrated circuit or a large scale integrated circuit.

Further, in the above-described embodiment, the plurality of functions of the leakage detector circuit 1 are aggregated together in a single housing. However, this is not an essential configuration of the leak detector circuit 1. Alternatively, the individual constituent elements of the leakage detector circuit 1 may be distributed in a plurality of different housings. Still alternatively, at least some functions of the leakage detector circuit 1 (e.g., some functions of the leakage detector 5) may also be implemented as a cloud computing system. In contrast, as in the earth leakage breaker 11 according to the above-described exemplary embodiment, the plurality of functions of the earth leakage detector circuit 1 may be aggregated together in a single housing.

(4) Summarizing

As can be seen from the foregoing description, the leakage 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 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 is 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 which is a power source (2) or a load (3) and which is different from the first connection object. A first electrical path (C1) connects the first terminal (41) and the third terminal (43) to each other. A 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 provided for the first electrical path (C1) and the second electrical path (C2), respectively. The leakage detector (5) is connected between a first input node (71) and a second input node (72). The first input node (71) is arranged between the first contact (S1) and the first terminal (41). A second input node (72) is disposed between the second contact (S2) and the fourth terminal (44). When the leakage current is detected to be generated, the leakage detector (5) changes the first contact (S1) and the second contact (S2) from on to off. The third contact (S3) has a first end (P1) and a second end (P2) opposite the first end (P1). The first end (P1) is connected to the first input node (71) or the second input node (72). The second end (P2) is connected to the leakage detector (5). The third contact (S3) switches its on/off state in synchronization with the first contact (S1) and the second contact (S2) becoming on and off. The surge absorber (61) is connected between the first electrical path (C1) and the second electrical path (C2) without via a third contact (S3).

This aspect may protect the third contact against an inrush current (S3).

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

This aspect may protect the third contact against an inrush current (S3).

In the leakage detector circuit (1) according to the third aspect, which can be implemented in combination 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).

This aspect enables the withstand voltage test of the first contact (S1) and the second contact (S2) by applying a voltage between the first terminal (41) and the second terminal (42) that are short-circuited to each other and the third terminal (43) and the fourth terminal (44) that are short-circuited to each other.

In a leakage detector circuit (1) according to a fourth aspect, which may be implemented in combination with the first or 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).

The earth leakage breaker (11) according to the fifth aspect includes the earth leakage detector circuit (1) according to any one of the first to fourth aspects.

This aspect may protect the third contact against an inrush current (S3).

The earth leakage breaker (11) according to the sixth aspect, which can be realized in combination with the fifth aspect, includes a switching mechanism that turns on and off the first contact (S1), the second contact (S2), and the third contact (S3) as the operation handle (115) is switched.

This aspect enables a user of the earth leakage breaker (11) to arbitrarily turn on and off the first contact (S1), the second contact (S2), and the third contact (S3).

The distribution board (12) according to the seventh aspect includes the earth leakage breaker (11) according to the sixth aspect.

This aspect may protect the third contact against an inrush current (S3).

Note that the constituent elements according to the second to fourth aspects are not essential constituent elements of the leak detector circuit (1), but may be omitted as appropriate.

Note that the constituent element according to the sixth aspect is not an essential constituent element of the earth leakage breaker (11), but may be omitted as appropriate.

Description of the reference numerals

1. Leakage detector circuit

2. Power supply

3. Load(s)

5. Leakage detector

61. Surge absorber

11. Leakage circuit breaker

12. Distribution board

41. First terminal

42. Second terminal

43. Third terminal

44. Fourth terminal

71. First input node

72. Second input node

115. Operating handle

C1 First circuit path

C2 Second electrical path

P1 first end

P2 second end

S1 first contact

S2 second contact

S3 third contact

Claims

1. A leakage detector circuit, comprising:

a first terminal and a second terminal, both of which are connected to a first connection object, the first connection object being a power source or a load;

a third terminal and a fourth terminal, both of which are connected to a second connection object that is the power source or the load and is different from the first connection object;

a first electrical path connecting the first terminal and the third terminal to each other;

a second electrical path connecting the second terminal and the fourth terminal to each other;

a first contact and a second contact provided for the first electrical path and the second electrical path, respectively;

a leakage detector connected between a first input node and a second input node, the first input node being disposed between the first contact and the first terminal, the second input node being disposed between the second contact and the fourth terminal, the leakage detector being configured to change the first contact and the second contact from on to off upon detection of generation of a leakage current;

a third contact having a first end portion and a second end portion, and configured to switch its on/off state in synchronization with the first contact and the second contact becoming on and off, the first end portion being connected to the first input node or the second input node, the second end portion being opposite to the first end portion and connected to the leakage detector; and

a surge absorber connected between the first electrical path and the second electrical path without via the third contact.

2. The leakage detector circuit of claim 1, wherein,

one end of the surge absorber is connected to the first end of the third contact.

3. The leakage detector circuit of 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 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. An earth leakage breaker comprising the earth leakage detector circuit according to any one of claims 1 to 4.

6. The earth leakage breaker of claim 5, comprising a switching mechanism configured to turn the first, second, and third contacts on and off as an operation handle is switched.

7. A distribution board comprising the earth leakage breaker according to claim 6.