JP7020179B2 - Earth-leakage circuit breaker - Google Patents

Description

The present invention relates to an earth-leakage circuit breaker having an overcurrent and ground fault protection function applied to a low-voltage power distribution system, and more particularly to an earth-leakage circuit breaker in which an earth-leakage detection unit is incorporated in a main body case.

As described in Patent Document 1, for example, the earth leakage breaker includes an open / close contact of the main circuit, a zero-phase earth leakage device for detecting the earth leakage current of the main circuit, and an earth leakage from the secondary output of the zero-phase earth leakage device. An earth leakage detection circuit that determines the occurrence, an opening / closing mechanism that opens / closes the opening / closing contact, an opening / closing operation handle that manually operates the opening / closing mechanism, and an earth leakage trip that trips the opening / closing mechanism by receiving the output signal of the leakage detection circuit. It is equipped with.
The leakage trip is a magnetic holding type electromagnet equipped with a coil, permanent magnet and plunger. When the zero-phase current transformer detects the leakage current and the excitation current flows through the coil according to the command of the leakage detection circuit, the plunger is turned on. The magnetic force of the permanent magnet holding the restraint weakens, the plunger moves, and the opening / closing mechanism moves in the trip direction.

By the way, there is a model of the earth-leakage circuit breaker in which the earth-leakage detection unit is detachably incorporated in the main body case.
An earth-leakage circuit breaker incorporating such an earth leakage detection unit is equipped with an overcurrent, ground fault protection detector, open / close contact, open / close mechanism, and open / close operation handle in the main body case, and zero phase in the unit case of the earth leakage detection unit. It is equipped with a current transformer, an earth leakage detection circuit, and an earth leakage trip. Then, by appropriately selecting each component mounted on the leakage detection unit as a component corresponding to the size of the allowable current of the main circuit, it is possible to standardize the components incorporated in the main body case and cut off the leakage. It is possible to reduce the production cost of the vessel.

Japanese Unexamined Patent Publication No. 2008-159456

By the way, in the earth leakage detection unit of the earth leakage circuit breaker, an overcurrent, a ground fault protection part, a zero-phase current transformer, an earth leakage detection circuit and an earth leakage trip part are arranged in the unit case. The energizing conductor to be connected is also arranged in a state of extending in the vicinity of the earth leakage trip portion inside the unit case.
Here, when a large current such as a short-circuit current flows through the earth-leakage circuit breaker, a magnetic field is generated around the current-carrying conductor arranged inside the earth-leakage detection unit, and this magnetic field is arranged in the vicinity of the current-carrying conductor. By affecting the demagnetizing coil and the permanent magnet of the earth-leakage trip part, the earth-leakage trip part may malfunction.

Therefore, in the present invention, the energizing conductor arranged close to the earth leakage trip portion in the earth leakage detection unit is arranged inside the yoke of the earth leakage trip portion even if a magnetic field is generated due to the flow of a large current. It is an object of the present invention to provide an earth-leakage circuit breaker capable of preventing the influence of a magnetic field on a permanent magnet and a demagnetizing coil and preventing a malfunction of an earth-leakage trip portion.

In order to achieve the above object, the earth leakage breaker according to one aspect of the present invention is equipped with an open / close contact of a main circuit, an open / close mechanism for opening / closing the open / close contact, and an open / close operation handle mounted on the main body case. In the unit case of the leakage detection unit that is detachably incorporated in the case to detect leakage, overcurrent, and ground fault, there is a current leak that detects leakage, overcurrent, and ground fault, and leakage and excess from the detection results of the current changer. A detection circuit that discriminates the occurrence of current and ground fault, an earth leakage trip that trips the switching mechanism by receiving the output signal of the detection circuit, and an energizing conductor that is placed near the earth leakage trip and connects to the open / close contact. , Is an earth leakage breaker. The leakage trip portion is a magnetic holding type electromagnet in which a permanent magnet and a demagnetizing coil are arranged inside the yoke, and a magnetic field generated around the current-carrying conductor affects the permanent magnet and the demagnetizing coil in the yoke. The magnetic shield member is a magnetic shield member made of a ferromagnetic material surrounding the outer surface of the yoke, and the magnetic shield member is at least two divided members, and a plurality of magnetic shield members are provided. The portions of the split members adjacent to each other are fixed.

According to the earth-leakage circuit breaker according to the present invention, even if a magnetic field is generated by the flow of a large current in the current-carrying conductor arranged close to the earth-leakage trip portion in the earth-leakage detection unit, the inside of the yoke of the earth-leakage trip portion It is possible to prevent the influence of the magnetic field on the permanent magnet and the demagnetizing coil arranged in the earth, and prevent the malfunction of the earth leakage trip portion.

It is a circuit diagram of the earth-leakage circuit breaker of 1st Embodiment which concerns on this invention. It is a figure which shows the earth-leakage circuit breaker of 1st Embodiment in which the earth-leakage detection unit is detachably attached to a part of the main body case. It is a figure which showed the leakage detection unit of 1st Embodiment from the side which connects to the open / close contact of a main body case. It is a figure which showed the leakage detection unit of 1st Embodiment from the side which connects to a load. (A) is a view showing the earth leakage trip portion arranged inside the earth leakage detection unit of the first embodiment from the front side on which the plunger protrudes, and (b) is a view showing the earth leakage trip part on the back side side. It is a figure shown from. It is a figure which shows the state which arranged the magnetic field cutoff part (magnetic insulation seal and magnetic shield member) on the outer periphery of the earth leakage trip part.

Next, a first embodiment of the present invention will be described with reference to the drawings. In the description of the drawings below, the same or similar parts are designated by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the plane dimensions, the ratio of the thickness of each layer, etc. are different from the actual ones. Therefore, the specific thickness and dimensions should be determined in consideration of the following explanation. In addition, it goes without saying that parts having different dimensional relationships and ratios are included between the drawings.
Further, the first embodiment shown below exemplifies an apparatus and a method for embodying the technical idea of the present invention, and the technical idea of the present invention is the material, shape, and structure of the constituent parts. , Arrangement, etc. are not specified to the following. The technical idea of the present invention may be modified in various ways within the technical scope specified by the claims described in the claims.

[Earth-leakage circuit breaker configuration]
FIG. 1 is a circuit diagram showing an earth-leakage circuit breaker 1 according to the first embodiment.
The earth leakage breaker 1 of the first embodiment is connected between a three-phase four-wire type power supply and a load, and the earth leakage of the main circuit 2 with the open / close contact 3 of the main circuit 2 and the main circuit 2 as the primary conductor. A zero-phase earth leakage device 4 that detects an electric current, an earth leakage detection circuit 5 that determines the occurrence of an earth leakage from the secondary output of the zero-phase earth leakage device 4, an opening / closing mechanism 6 that opens / closes the main circuit 2, and a manual opening / closing mechanism 6. It is provided with an earth leakage operation handle 7 for performing an operation, an earth leakage trip unit 8 for tripping the earth leakage mechanism 6 in response to an output signal of the earth leakage detection circuit 5, a power supply circuit 9 for the earth leakage detection circuit 5, and an earth leakage test switch 10. ing.

Further, the zero-phase current transformer 4, the leakage detection circuit 5, the leakage trip unit 8, the power supply circuit 9, and the leakage test switch 10 surrounded by the two-dot chain line in FIG. 1 are integrated as the leakage detection unit 11. There is. In the earth leakage detection unit, as an overcurrent and ground fault protection detector, a current transformer that detects overcurrent and ground fault, and a detection circuit that discriminates overcurrent and ground fault from the detection result of the current transformer are installed. By providing it, it is possible to obtain an earth leakage breaker having not only an electric leakage but also an overcurrent and a ground fault protection function.
FIG. 2 is an external view of the earth leakage circuit breaker 1 of the first embodiment, and the earth leakage detection unit 11 is attached to and detached from a part of the main body case 12 on which the opening / closing contact 3, the opening / closing mechanism 6 and the opening / closing operation handle 7 are mounted. It is freely attached.

[Leakage detection unit]
3 and 4 show a specific external shape of the earth leakage detection unit 11, and inside the unit case 13 having a substantially rectangular parallelepiped shape, a zero-phase current transformer 4, an earth leakage detection circuit 5, and an earth leakage trip portion are shown. 8. The power supply circuit 9 and the leakage test switch 10 are arranged.
The first connection terminals 14a1 to 14d1 of the energizing conductors 14a to 14d (see FIG. 1) are arranged on the first wall surface 13a of the substantially rectangular parallelepiped unit case 13, and these first connection terminals 14a1 to 14d1 leak electricity. When the detection unit 11 is attached to the main body case 12, it is connected to each connection terminal of the open / close contact 3. Further, the second connection terminals 14a2 to 14d2 of the energizing conductors 14a to 14d are arranged on the second side surface 13b on the back surface with respect to the first wall surface 13a of the unit case 13, and these second connection terminals 14a2 to 14d2 are arranged. Is connected to each connection terminal of the load.

Here, although not specifically shown, a zero-phase current transformer 4 is arranged under the leakage trip unit 8 inside the leakage detection unit 11, and energization passes through the zero-phase current transformer 4. A part of the conductors 14a to 14d is arranged in the vicinity of the earth leakage trip portion 8.
Further, in the opening 15 formed in the first wall surface 13a, the plunger 20 of the earth leakage trip portion 8 built in the unit case 13 is arranged so as to be able to project to the outside.

[Leakage trip part]
5 (a) and 5 (b) and FIG. 6 show the structure of the earth leakage trip portion 8.
The leakage tripping portion 8 is a magnetic holding type electromagnet, and as shown in FIGS. 1 and 5 (a), a rectangular body-shaped yoke 17, a permanent magnet 18 and a demagnetizing coil arranged inside the yoke 17 are demagnetized. 19, the above-mentioned plunger 20, the tripping coil spring 21 which is arranged around the plunger 20 on the outside of the yoke 17 and exerts a spring force to push outward to the plunger 20, and the terminal block 22 of the demagnetizing coil 19. And have.
Then, the trip crossbar 16 is arranged close to the plunger 20 of the earth leakage trip portion 8, and the operation of the opening / closing mechanism 6 is transmitted to the plunger 20 via the trip crossbar 16.

As shown in FIGS. 5A and 5B, the outer periphery of the yoke 17 of the earth leakage trip portion 8 is covered with a flexible insulating seal 23 which is formed of a material such as synthetic resin and blocks a magnetic field. There is. That is, assuming that the surface on which the plunger 20 on the outer periphery of the yoke 17 protrudes is the front surface 17a, the insulating seal 23 is attached to the upper surface, the lower surface, the left and right side surfaces, and the rear surface other than the front surface 17a via an adhesive.
Further, a magnetic shield member 24 is arranged on the outer periphery of the yoke 17 while covering the insulating seal 23.
The magnetic shield member 24 is composed of a first divided component 25 that surrounds the lower surface, left and right side surfaces, and a rear surface of the yoke 17, and a second divided component 26 that is coupled to the first component 25 and surrounds the upper surface of the yoke 17. .. The first and second divided parts 25 and 26 are ferromagnetic steel sheets such as SPCC (cold rolled steel sheet).

The first divided component 25 includes a rectangular lower surface shield plate 25a that surrounds the lower surface of the yoke 17, and a pair of side surface shield plates 25b and 25c that rise in parallel with each other from the opposite sides of the lower surface shield plate 25a. It is provided with a rear surface shield plate 25d rising from another edge of the lower surface shield plate 25a between the side surface shield plates 25b and 25c.
Each of the pair of side shield plates 25b and 25c has a pair of protruding deformed portions 27b and 27c on both sides of the connecting recess 27a and the connecting recess 27a in a part of the side edge portion on the opposite side to the rear shield plate 25d. Is formed.
Further, a connecting plate 28 is formed upright on the upper surface of the rear shield plate 25d, and a positioning recess 28a is formed on the upper side edge portion of the connecting plate 28.

The second divided component 26 includes a rectangular upper surface shield plate 29 that surrounds the upper surface of the yoke 17, and a pair of connecting plates 30 and 31 extending in a direction perpendicular to the upper surface shield plate 29 from one side of the upper surface shield plate 29. , Is equipped. The pair of connecting plates 30 and 31 are formed with connecting projections 32 and 33 that enter into the connecting recesses 27a formed in the pair of side shield plates 25b and 25c of the first divided component 25.
Further, a positioning convex portion that enters the positioning recess 28a of the connecting plate 28 rising from the rear shield plate 25d of the first divided component 25 on the side facing the side forming the pair of connecting plates 30 and 31 of the upper surface shield plate 29. 34 is formed.

The procedure for assembling the magnetic shield member 24 having the above configuration to the yoke 17 will be described with reference to FIG.
First, the lower surface, the left and right side surfaces, and the rear surface of the yoke 17 of the earth leakage trip portion 8 covered with the insulating seal 23 are surrounded by the first partition component 25.
Next, the positioning protrusion 34 of the second division component 26 is inserted into the positioning recess 28a of the connecting plate 28 rising from the rear shield plate 25d of the first division component 25. Then, the connecting projections 32 and 33 formed in the pair of connecting plates 30 and 31 of the second divided component 26 are fitted into the connecting recesses 27a formed in the pair of side shield plates 25b and 25c of the first divided component 25. ..

Then, as shown in FIG. 6, the pair of projecting deformation portions 27b and 27c sandwiching the connecting projection 33 fitted in the connecting recess 27a of the side shield plate 25c are plastically deformed by the caulking force of F1 and F2. Further, although not shown, the pair of protruding deformed portions 27b and 27c of the side shield plate 25b sandwiching the connecting projection 33 fitted in the connecting recess 27a of the side shield plate 25b are also plastic due to the caulking force of F1 and F2. Transform.
By caulking and joining the first divided component 25 and the second divided component 26 in this way, the magnetic shield member 24 is assembled around the yoke 17.

Here, the magnetic field blocking portion described in the present invention corresponds to the insulating seal 23 and the magnetic shield member 24, and the member divided into at least two parts of the magnetic shield member described in the present invention is the first divided component. It corresponds to 25 and the second divided part 26. The caulking joint sites of the plurality of split members described in the present invention are the connecting recesses 27a of the first split component 25, the protruding deformed portions 27b and 27c, and the connecting protrusions 32 and 33 of the second split component 26. It corresponds to. The magnetic insulating member described in the present invention corresponds to the insulation seal 23, the current transformer described in the present invention corresponds to the zero-phase current transformer 4, and the detection circuit described in the present invention. Corresponds to the leakage detection circuit 5.

[Operation of earth-leakage circuit breaker]
In the earth-leakage circuit breaker 1 of the first embodiment, when the opening / closing operation handle 7 is operated to the reset position, the movement of the opening / closing mechanism 6 is pulled into the yoke 17 by the plunger 20 of the earth-leakage trip portion 8 via the trip crossbar 16. It is transmitted as a movement, and the plunger 20 is restrained and held by the magnetic force of the permanent magnet 18. In this state, the tripping coil spring 21 is compressed by the movement of the plunger 20 and the spring force is stored.
Then, when a ground fault occurs in the distribution system and the zero-phase current transformer 4 detects the leakage current of the main circuit 2, the leakage detection circuit 5 in which the leakage current detection signal is input from the zero-phase current transformer 4 An exciting current that demagnetizes the magnetic force of the permanent magnet 18 is passed through the demagnetizing coil 19 of the earth leakage trip portion 8. As a result, the magnetic force of the permanent magnet 18 that restrains and holds the plunger 20 weakens, and the plunger 20 moves outward due to the spring force stored in the tripping coil spring 21, so that the opening / closing mechanism is via the trip crossbar 16. 6 moves in the trip direction and the opening / closing contact 3 opens.

[Effect of earth-leakage circuit breaker]
Next, the effect of the earth-leakage circuit breaker 1 of the first embodiment will be described.
Inside the unit case 13 of the earth leakage detection unit 11, a zero-phase current transformer 4, an earth leakage detection circuit 5, an earth leakage trip unit 8, a power supply circuit 9, and an electric leakage test switch 10 are arranged, and an energizing conductor 14a is arranged. ~ 14d (see FIG. 1) are arranged. Further, a part of the energizing conductors 14a to 14d is arranged in the vicinity of the earth leakage trip portion 8.
Here, when a large current such as a short-circuit current flows through the earth-leakage circuit breaker 1, a magnetic field is generated around the energizing conductors 14a to 14d arranged in the earth-leakage detection unit 11. An earth leakage trip portion 8 is arranged in the vicinity of the energizing conductors 14a to 14d where a magnetic field is generated.

The permanent magnet 18 and the demagnetizing coil 19 are arranged inside the yoke 17 in the leakage trip portion 8, but the outer periphery of the yoke 17 is surrounded by a magnetic shield member 24 made of a ferromagnetic material, and is a conductor for energization. Since the magnetic shield member 24 absorbs the magnetic field of the magnetic field generated in 14a to 14d, the permanent magnet 18 and the demagnetizing coil 19 are not affected by the magnetic field.
Further, the outer periphery of the yoke 17 is surrounded by the magnetic shield member 24 via the insulating seal 23, and the magnetic flux that passes through the magnetic shield member 24 and tries to flow into the inside of the yoke 17 is blocked by the insulating seal 23. Therefore, the magnetic field shielding performance for the permanent magnet 18 and the demagnetizing coil 19 inside the yoke 17 is enhanced.

Therefore, the outer circumference of the yoke 17 of the leakage trip portion 8 arranged in the leakage detection unit 11 is covered with the insulation seal 23, and the outer circumference of the insulation seal 23 is surrounded by the magnetic shield member 24. Since the magnetic shield structure is such that the magnetic field from the outside is cut off from the permanent magnet 18 and the demagnetizing coil 19 inside the yoke 17, a large current such as a short-circuit current flows through the earth leakage breaker 1, and the earth leakage is disconnected. Even if a magnetic field is generated around the energizing conductors 14a to 14d arranged in the vicinity of the part 8, the permanent magnet 18 and the demagnetizing coil 19 are prevented from being affected by the magnetic field, and the earth leakage trip part 8 is prevented from malfunctioning. can do.

On the other hand, the insulating seal 23 is a flexible member, and is covered with an adhesive on the upper surface, the lower surface, the left and right side surfaces, and the rear surface of the yoke 17 other than the front surface 17a on which the plunger 20 protrudes. Further, the magnetic shield member 24 is composed of a first divided component 25 that surrounds the lower surface, left and right side surfaces, and a rear surface of the yoke 17, and a second divided component 26 that surrounds the upper surface of the yoke 17. Then, the connecting projections 32 and 33 of the second divided component 26 are inserted into the connecting recess 27a of the first divided component 25, and the protruding deformed portions 27b and 27c formed around the connecting recess 27a are used for connecting. By plastically deforming to the protrusions 32 and 33, the first divided part 25 and the second divided part 26 are caulked and joined.

Therefore, a flexible insulating seal 23 is attached to the outer periphery of the yoke 17 with an adhesive to cover it, and the magnetic shield member 24 is arranged by caulking and joining the first divided component 25 and the divided component 26. The magnetically shielded structure of the removing portion 8 can be easily and inexpensively formed.

1 Leakage breaker 2 Main circuit 3 Open / close contact 4 Zero-phase current transformer 5 Leakage detection circuit 6 Open / close mechanism 7 Open / close operation handle 8 Leakage trip part 9 Power supply circuit 10 Leakage test switch 11 Leakage detection unit 12 Main body case 13 Unit case 13a 1st wall surface 13b 2nd wall surface 14a to 14d Conductor for energization 14a1 to 14d1 1st connection terminal 14a2 to 14d2 2nd connection terminal 15 Opening 16 Trip crossbar 17 York 18 Permanent magnet 19 Demagnetization coil 20 Plunger 21 Detachment coil spring 22 Terminal block 23 Insulation seal 24 Magnetic shield member 25 First division part 26 Second division part 25a Bottom shield plate 25b, 25c Pair of side shield plates 25d Rear shield plate 27a Connection recess 27b, 27c Projection deformation part 28 Connection plate 28a Positioning recess 29 Top shield plate 30, 31 Pair of connecting plates 32, 33 Connecting protrusion 34 Positioning convex portion

Claims (4)

The main body case is equipped with an open / close contact for the main circuit, an open / close mechanism for opening / closing the open / close contact, and an open / close operation handle.
In the unit case of the leakage detection unit that is detachably incorporated in the main body case to detect leakage, overcurrent, and ground fault, an earth leakage device that detects leakage, overcurrent, and ground fault, and an electric leakage from the detection result of the current changer. A detection circuit that discriminates the occurrence of overcurrent, ground fault, and an earth leakage trip portion that trips the earth leakage mechanism in response to the output signal of the detection circuit, and an earth leakage trip portion that is arranged near the earth leakage trip unit and is located at the open / close contact. In the earth leakage breaker on which the current-carrying conductor to be connected is mounted,
The leakage trip portion is a magnetic holding type electromagnet in which a permanent magnet and a demagnetizing coil are arranged inside a yoke, and a magnetic field generated around the current-carrying conductor is generated in the yoke in the permanent magnet and the demagnetizing coil. A magnetic field blocking part is provided to prevent the influence of
The magnetic field blocking portion is a magnetic shield member made of a ferromagnet that surrounds the outer surface of the yoke.
The magnetic shield member is a divided member that is divided into at least two parts, and is characterized in that a plurality of parts adjacent to each other of the divided members are fixed to each other . The earth-leakage circuit breaker according to claim 1 , wherein the plurality of divided members are fixed to each other by caulking . The earth-leakage circuit breaker according to claim 1 or 2 , wherein a magnetic insulating member is arranged between the outer surface of the yoke and the inner surface of the magnetic shield member. The earth-leakage circuit breaker according to claim 3 , wherein the magnetically insulating member is a flexible sheet-like member and is attached to the outer surface of the yoke.

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