JP2508463Y2 - Flux switching type trip device for circuit breaker - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic flux switching type trip device for a circuit breaker, and more particularly to the output of an electronic overcurrent relay provided in the circuit breaker and receiving the secondary current of a current transformer. A magnetic flux switching type trip device that operates.

[0002]

2. Description of the Related Art FIGS. 5 and 6 show a first prior art which is the background of the present invention. In particular, FIG. 5 is a block diagram showing an external circuit of a conventional circuit breaker. 6 is a side sectional view of the trip device 40.

In FIG. 5, the main circuit of the circuit breaker 1 is provided with a switching contact 2 and a current transformer 3 for detecting a current flowing through the main circuit. The output current of the current transformer 3 is input to the overcurrent relay 4, is rectified by the rectifying element 5, and is made into a constant voltage by the Zener diode 7 via the input resistor 6, and a constant voltage power supply is obtained. The constant voltage is applied to the arithmetic circuit 8 and the energy storage capacitor 9. When the output current value of the current transformer 3 exceeds a preset external operating current value, the arithmetic circuit 8 generates an external signal and makes the transistor 10 conductive.

When an external signal is generated from the arithmetic circuit 8,
The discharge current from the capacitor 9 and the rectified output current of the current transformer 3 serve as an external current and thus the external coil 4 of the external device 40.
1, the trip device 40 provided corresponding to the trip mechanism 11 of the circuit breaker 1 operates, and the trip mechanism 1
1 operates and the switching contact 2 opens.

In the external operation range of this overcurrent relay 4, the current flowing in the main circuit is 5 to 10% of the rated current of the circuit breaker.
Very wide, ranging from ground fault currents to short circuit currents of thousands of percent. Since the output current of the current transformer 3 is small when the operating current is a small current such as a ground fault current, the trip device 40 operates almost only by the current from the capacitor 9. But,
Since the energy stored in the capacitor 9 is small, a magnetic flux switching type trip device that can be operated with relatively small energy is often used as the trip device 40.

In this magnetic flux switching type tripping device, a movable part which is biased in the pulling direction by a spring force is adsorbed and held on a magnetic pole surface by a permanent magnet, and an external current is passed through a coil to make the permanent magnet. The magnetic flux is generated in a direction opposite to that of the magnetic flux, and the attraction force is weakened, and the movable portion is moved in the outward direction by the spring force. It is sufficient that this external current has a small energy such as the discharge current of the capacitor.

The conventional magnetic flux switching type trip device 40 shown in FIG. 5 is shown in a side sectional view in FIG. In FIG. 6, a magnetic pole surface 42 ′ integrally provided with a fixed armature is formed on one end side of the magnetic frame 42, and a fixed guide pin 43 made of a non-magnetic material is projected from the magnetic pole surface 42 ′.
It is planted in one. The movable core 4 is made so that one end of the movable core 44 made of a magnetic material corresponds to the magnetic pole surface 42 '.
A fixed guide pin 43 is inserted into a guide hole 44a provided at the center of the outer peripheral surface of the movable member 44, and a pull-out spring is provided between the magnetic pole surface 42 'and the movable core 44 so as to bias the movable core 44 in the outward direction. 45 is installed. The other end 44b of the movable core 44, in which the outer cylinder diameter is reduced stepwise, is arranged so as to pass through the through hole 46 of the magnetic frame 42, and the head projection 44c of the operating member is provided at the tip thereof. ing.

Further, an external coil 41 is arranged so as to surround the magnetic pole surface 42 ', and a pair of permanent magnets 47, 47 adjacent to the external coil 41 face each other on both sides of the body of the movable core 44. Is provided.

This trip device 40 has a trip mechanism 11 for the circuit breaker 1 whose head projection 44c is not shown in FIG.
Is mounted on the circuit breaker 1 so as to operate the.

In the conventional magnetic flux switching type trip device constructed as described above, the magnetic fluxes from the permanent magnets 47, 47 when the circuit breaker 1 is closed are movable core 44, magnetic pole surface 4.
2'and a magnetic circuit which returns to the permanent magnets 47, 47 through the magnetic frame 42 to form the movable core 44 on the magnetic pole surface 42 '.
6 is held at the suction position shown in FIG.

In this state, when the overcurrent relay 4 operates and an external current flows through the external coil 41, the permanent magnet 4
A magnetic flux is generated in a direction of canceling the magnetic flux created by 7, 47, the attraction force between the movable core 44 and the magnetic pole surface 42 'is reduced, and the acting force of the outer spring 45 becomes larger than the attraction force.
Separates from the magnetic pole surface 42 'and the head projection 44c moves linearly to operate the trip mechanism 11 of the circuit breaker 1 to open the switching contact 2.

[0012]

As described above, the operation of the overcurrent relay 4 when the tripping operation current value is relatively small has been described in the first conventional technique.

On the other hand, with respect to a large current such as a short circuit current, it is necessary to shorten the interruption time as much as possible even in milliseconds to protect the circuit breaker itself and the electric circuit. In this regard, as can be seen from the above description,
In the first prior art trip device 40, the trip spring 45 is provided after the movable core 44 is separated from the magnetic pole surface 42 ′ during trip.
Is only related to the trip mechanism 11 of the circuit breaker 1, and it is not possible to expect a sufficiently fast operation due to the inertia of the trip mechanism 11 and the moving parts of the trip device. High-speed operation can be expected by increasing the acting force of the external spring 45,
In order to stably attract and hold the movable core 44 on the magnetic pole surface 42 ', the permanent magnets 47, 47 having a strong magnetic force are required, and the capacitor 9 having a large capacity is also required to release the attraction. It becomes a large and expensive device.

Further, at a large current, the capacitor 9
In addition to the discharge current from the permanent magnets 47, 47, a large rectified current from the current transformer 3 flows into the external coil 41.
An excessive reverse magnetic flux exceeding the magnetic flux of
A suction force is generated in the direction of re-sucking the movable core 44 separated from 2 ', and the acting force of the external spring 45 is diminished. As a result, the moving speed of the movable core 44 is reduced and the circuit breaker 1 There is a drawback that the acting force on the trip mechanism 11 is reduced.

In order to eliminate such a drawback, a technique disclosed in Japanese Patent Laid-Open No. 62-272419 has been proposed as a second conventional technique. A side sectional view of the magnetic flux switching type trip device disclosed in this publication is shown in FIG. As shown in FIG. 7, the trip device is provided with a cylindrical movable core 53 that is movable between the first magnetic pole surface 51 and the second magnetic pole surface 52 at both ends of the magnetic frame 50. A magnetic gap G is formed between the first magnetic pole surface 51 and the second magnetic pole surface 52. The magnetic gap G is the trip stroke of the circuit breaker.

A guide pin 54 made of a non-magnetic material is axially inserted through the movable core 53 from the outer side on one side of the magnetic frame 50 and led out to the outer side on the other side of the magnetic frame 50. 55 is attached.

The movable core 53 and the guide pin 54 are tightened together by a set screw 56, and the movable core 53 and the first magnetic pole surface 51 of the movable core 53 are pulled out so as to urge the movable core 53 in the outward direction. A spring 57 is installed. At both ends of the magnetic frame 50, the first and second magnetic cores 50 are provided so as to surround the movable core 53.
External coil 58, 58 '. In addition, a pair of square-shaped permanent magnets 59, 5 are provided between the first and second external coils 58, 58 'at the axial center of the magnetic frame 50.
9 are provided so as to face each other with the movable core 53 interposed therebetween. The circuit configuration of the second conventional technique is the same as that of the first conventional technique shown in FIG. 5 except that two extraction coils are used in series or in parallel.

In the operation of the second prior art thus constructed, the movable core 53 is moved by the magnetic flux of the permanent magnets 59, 59 against the acting force of the external spring 57 when the circuit breaker is closed. It is attracted to the first magnetic pole surface 51. When an external current is supplied from the overcurrent relay 4 in this state, the magnetic flux generated from the first external coil 58 is combined with the magnetic flux of the permanent magnet 59 in the attracted portions of the movable core 53 and the first magnetic pole surface 51. Is a reverse magnetic flux as in the first prior art,
The movable core 53 separates from the first magnetic pole surface 51.

At this time, the second external coil 58 'has a magnetic gap G between the movable core 53 and the second magnetic pole surface 52.
Since it is arranged around the second external coil 58 '
The magnetic flux due to acts on the movable magnetic core 53 in a direction of separating it from the first magnetic pole surface 51 and adsorbing it to the second magnetic pole surface 52. The movable core 53 has the first magnetic pole surface 5
After separating from 1, the movable core 53 and the second magnetic pole surface 5
Since the second magnetic gap G becomes smaller, the attraction force to the second magnetic pole surface 52 becomes stronger, and the second magnetic pole surface 52 moves acceleratingly in the outward direction.

However, in such a second conventional technique, when the current of the current transformer 3 is excessively large, it is considerably improved, but there is a problem similar to the first conventional technique. That is,
Of the excessive magnetic flux generated by the first external coil 58 arranged near the surface where the movable core 53 is attracted to the first magnetic pole surface 51 and the magnetic flux generated by the second external coil 58 ′, Part of the magnetic flux passing through the attracting surface acts on the attracting force in the direction of re-adsorbing the movable core 53 after being separated.

Therefore, the main object of the present invention is to reliably operate the circuit breaker even if the current flowing through the main circuit of the circuit breaker is a small current if an external signal is generated, and stabilize the circuit breaker even with a large current. It is another object of the present invention to provide a magnetic flux switching type trip device for a circuit breaker that is small in size and inexpensive and that can be disconnected at high speed.

[0022]

According to the present invention, there is provided a first movable core which is composed of a first magnetic pole surface and a magnetic body and which is linearly movable, a circuit breaker and a first movable core which is in a closed state. A first magnetic frame having a permanent magnet attracted to the magnetic pole surface of the first magnetic core and a first external coil wound around the first movable core inside, and coaxially with the first movable core made of a magnetic material. A second movable core which is integrally connected to the first movable core and which is linearly movable, and a predetermined gap between the second movable core and the second movable core in a direction for operating the trip mechanism of the circuit breaker when the circuit breaker is closed. A second magnetic frame having a second magnetic pole surface disposed therein and a second external coil wound around the second magnetic pole surface, and the first and second movable cores. Equipped with a trip spring that biases the trip mechanism of the circuit breaker Composed of Te. Then, the first and second magnetic frames are coupled to each other through a high magnetic resistance member, and the direction of the magnetic flux by the first coil is opposite to the direction of the magnetic flux of the permanent magnet on the first magnetic pole surface when tripping. The first coil is excited so that it is oriented, and the second coil is excited so that the second movable core is attracted to the second magnetic pole surface.

[0023]

In the magnetic flux switching type trip device according to the present invention, the first movable core is attracted and held on the first magnetic pole surface by the action of the permanent magnet when the circuit breaker is closed. Since the magnetic flux generated in the first trip coil during tripping is in the opposite direction to the magnetic flux of the permanent magnet on the first magnetic pole surface, the attraction force with the first magnetic pole surface weakens, and the first movable core Is separated from the first magnetic pole surface by the acting force of the external spring. Upon tripping, the second trip coil is excited together with the first trip coil, and its magnetic flux acts to attract the second movable core to the second magnetic pole surface. First
Since the second movable core and the second movable core are coaxially and integrally connected to each other, the acting force of the external spring and the acting force of the magnetic flux of the second coil are superposed, and the external mechanism of the circuit breaker can be operated at high speed. Move in the direction to activate.

Further, since the first magnetic frame and the second magnetic frame are coupled to each other through the high magnetic resistance member, the magnetic fluxes generated by the internal pull-out coils are mutually transmitted to the other magnetic frames. Don't shunt. Therefore, the magnetic flux generated by the second extraction coil acts only to attract the second movable core to the second magnetic pole surface, and is shunted to the first magnetic frame to move the first movable core to the first magnetic core. It does not affect the magnetic pole surface of No. 1 by causing it to be attracted.

[0025]

1 and 2 show a first movable core 1 of a magnetic flux switching type trip device 12 according to an embodiment of the present invention.
FIG. 6 is a side sectional view of the first suction surface 24 in a suction state and a separated state.

1 and 2, the trip device according to this embodiment comprises an outer shell, two movable cores, two trip coils and a permanent magnet. The outer shell has a cross section
Two sets of rectangular cylinder-shaped first magnetic frames 1 configured by fastening two character-shaped magnetic bodies with screws so that the inner sides face each other.
3 and the second magnetic frame 14 are formed by sandwiching the non-magnetic block 15 and connecting them by a non-magnetic screw (not shown). Both of the two movable cores are magnetic materials, and
The movable core 16 has a bottomed cylindrical shape with an opening formed at one end and a screw hole formed at the other end, and the second movable core 17 has a columnar shape having a screw hole formed at one end. To be done. The first and second movable cores 16 and 17 are connected by a screw hole formed in each of them and a common linear movement rod 18 attached to the screw hole, and the first and second movable cores 16 and 17 are connected to each other. It can be moved in the connecting direction.

In the state where the first movable core 16 is attracted to the first magnetic pole surface, the holes formed in the respective surfaces 13a and 14a of the first and second magnetic frames facing each other are respectively formed. The side surfaces of the first and second movable cores 16 and 17 are arranged so as to face each other so that the magnetic fluxes passing through the surfaces 13a and 14a of the first and second magnetic frames can easily pass through the respective movable cores. It has become.

Inside the first magnetic frame 13, from the surface 13b facing the surface 13a to the surface 13a, the magnetic pole plates 22,
A permanent magnet 19, a magnetic pole plate 23, and a first external coil 21 wound around a coil bobbin 20 are provided coaxially with the first movable core 16 so as to be stacked, and an operating rod is provided at the center of the magnetic pole plate 22. The hole through which 18 can be inserted is the permanent magnet 1.
A hole through which the first movable core 16 can be inserted is formed in the center of the magnetic pole plate 23 and the coil bobbin 20.

The coil bobbin 20 of the insulating molded product is formed into a cylindrical shape with a flange, and the hole at the center is formed so as to serve as a guide when the first movable core 16 moves. further,
A stepped cylindrical end portion 20a is formed at one end of the coil bobbin 20, and the pole plate 22, the permanent magnet 19 and the pole plate 23 are formed.
Is inserted.

The pole plate 22 has a cylindrical shape with a collar, and has a surface 1
A first magnetic pole surface 24 is formed on a surface that is not in contact with 3b and can contact one end of the first movable core 16. Pole plate 2
The first movable core 16 is provided between the cylindrical recess formed in the central portion of the first movable magnetic core 24 on the second magnetic pole surface 24 side and the bottom of the hollow portion of the first movable core 16. An extension spring 25, which is a compression coil spring biased in a direction away from, is installed. The permanent magnet 19 has a cylindrical shape, and one magnetic pole surface is in contact with the flange portion of the magnetic pole plate 22 and the other magnetic pole surface is in contact with the magnetic pole plate 23.

Inside the second magnetic frame 14, a second external coil 27 wound around a coil bobbin 26 of an insulating molded product is provided. The coil bobbin 26 has a flanged cylindrical shape, and a hole through which the second movable core 17 can be moved is formed in the center of the coil bobbin 26. On the surface 14b facing the surface 14a, a cylindrical fixed core 28 is provided integrally with the surface 14b and inserted in the middle of the hole of the coil bobbin 26 so as to be coaxial with the second movable core 17. The end of the fixed core 28 forms a second magnetic pole surface 29, and a predetermined gap G is provided between one end of the second movable core 17 and the second magnetic pole surface 29.

A "U" -shaped pin holding metal fitting 30 is attached to the end of the operating rod 18, and an operating pin 31 is provided over the opposite sides of the "U" shape in detail in FIGS. 1 and 2 of the circuit breaker. It is provided so as to face a rotatable operation lever 32 included in a trip mechanism not shown in FIG. The trip mechanism of the circuit breaker trips when the operation lever 32 is rotated while the operation pin 31 moves downward by the dimension G.

In this trip device, when the circuit breaker is opened, the reset plate 33 included in the opening / closing mechanism of the circuit breaker, the details of which are not shown in FIGS. 1 and 2, engages with the operating pin 31. Then, the operating pin 31 is pulled up and reset until the first movable core 16 is attracted to the first magnetic pole surface 24.

FIG. 3 is a circuit diagram of a circuit breaker using an embodiment of the present invention. The circuit breaker shown in FIG.
It is almost the same as FIG. 5 described above, but the two external coils 2
1, 27 are connected in parallel, the first external coil 21 is supplied with an external current from the output side of the input resistor 6, and the second external coil 27 is supplied with an external current from the input side of the input resistor 6. They differ in that they are connected as supplied.

The operation of the magnetic flux switching type trip device of the circuit breaker of this embodiment, which is constructed as described above, will be described.
In FIG. 1, the first movable core 16 resists the acting force of the external spring 26 by the magnetic force of the permanent magnet 19 and the magnetic pole plate 22.
Is attracted to the first magnetic pole surface 24 of the. At this time, the magnetic flux of the permanent magnet 19 is the magnetic pole plate 22, the first movable core 16 and the magnetic pole plate 2 as shown by the dotted line φ1 in FIG.
3 is the magnetic path.

In this state, when a predetermined current flows in the main circuit of the circuit breaker 1 shown in FIG. 3 and an external signal is generated in the overcurrent relay 4, the transistor 10 is turned on and the capacitor 9 causes the first The first pull-out current is supplied to the pull-out coil 21. The magnetic flux generated in the first external coil 21 by this external current is the one-dot chain line φ in FIG.
2, the first magnetic frame 13, the first movable core 16 and the magnetic pole plate 22 are used as magnetic paths, and the permanent magnets 19 are provided on the attracting surfaces of the first movable core 16 and the first magnetic pole surface 24. The opposite of the magnetic flux of. As a result, the attraction force becomes smaller than the acting force of the outer spring 25, the first movable core 16 is separated from the first magnetic pole surface 24, and the acting force of the outer spring 25 causes the first movable core 16 to move together with the second movable core 17. It moves in the direction of the fixed core 28.

At the same time that the first external current is supplied, the rectified secondary output current of the current transformer 3 is supplied to the second external coil 27 as the second external current.

This external current causes the second external coil 2 to
The magnetic flux generated in 7 uses the second magnetic frame 14, the fixed core 28, the predetermined gap G and the second movable core 17 as the magnetic path, as indicated by the chain double-dashed line φ3 in FIG.
This magnetic flux causes the second movable core 17 to move to the fixed core 2
The second magnetic pole surface 29 of No. 8 is acted on. This acting force becomes larger in the direction in which the first movable core 16 is separated from the first magnetic pole surface 24, and becomes larger as the gap between the second movable core 17 and the second magnetic pole surface becomes smaller. The moving speed and the acting force of are increased at an accelerating rate. Furthermore, the acting force of the external spring 25 is also superimposed on this acting force.

When the first and second movable cores 16 and 17 move in the direction of the second magnetic pole surface 29, the operating pin 31 rotates the operating lever 32 to operate the trip mechanism of the circuit breaker to open and close it. Open the contact. FIG. 2 shows a state where the second movable core 17 is in contact with the second magnetic pole surface 29.

The larger the current flowing in the main circuit of the circuit breaker, the larger the magnetic flux φ3 generated by the second external coil 27 has a greater effect on the second movable core 17, and the magnetic flux φ3 has a large magnitude such as a short circuit current. At the current, the second movable core 17 is moved together with the first movable core 16 at an extremely high speed and with a large force. Even in the case of such a large current, the magnetic flux generated by the second external coil 27 is magnetically separated by the non-magnetic block 15 between the first magnetic frame 13 and the second magnetic frame 14, Since it does not act in the vicinity of the attracted portion of the first movable core 16 and the permanent magnet 19, it does not act in the direction of re-attracting after separation.

FIG. 4 is a side sectional view showing another embodiment of the present invention. The embodiment shown in FIG. 4 has a movable core 3
4 is a single unit, but since both ends thereof are located in the first and second magnetic frames 13 and 14, respectively, the magnetic flux generated by the first and second extraction coils 21 and 27 is Clearly, the light passes through the magnetic path of FIG. 4 and produces the same effect as in the first embodiment. Further, in this embodiment, the first magnetic frame and the second magnetic frame are arranged with a gap and are joined by the non-magnetic plate 35, but they are joined by sandwiching the non-magnetic block as in the first embodiment. It is clear that the effect does not change because the magnetic path is not different from that in the case of

Further, although not shown, even if the first magnetic frame and the second magnetic frame are arranged upside down, the first magnetic frame and the second magnetic frame are substantially magnetically separated. It is easy to see that the same effect is produced if this is done.

In the above-mentioned embodiment, the first magnetic frame and the second magnetic frame are rectangular cylinders in which magnetic plates each having a "U" -shaped cross section are combined. Other shapes such as a cylindrical shape may be used as long as components can be arranged and the above-mentioned magnetic paths φ1, φ2, and φ3 can be secured.

[0044]

As described above, according to the present invention, since two external coils are provided and the magnetic frames surrounding them are connected by the high magnetic resistance member, the magnetic flux generated in each coil is a movable core. , And each magnetic frame serves as a main magnetic path, and is not shunted to other magnetic frames. Therefore,
The current of the first external coil for separating the movable core from the magnetic pole surface may have a small energy, and may be a capacitor having a small capacity. In addition, the magnetic flux generated in the second extraction coil acts only to attract the movable core to the second magnetic pole surface because the magnetic path is in the second magnetic frame, and the moving speed of the movable core increases. Since the circuit breaker can be cut off at a higher speed and the acting force of the circuit breaker with respect to the trip mechanism is increased, a circuit breaker that can obtain a stable trip operation can be provided, and a wide circuit can be protected from a small current to a large current. Further, for this reason, a large permanent magnet, a capacitor, etc. are not required, and the device can be made compact and inexpensive.

[Brief description of drawings]

FIG. 1 is a side sectional view of a magnetic flux switching type trip device in a suction state according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of a magnetic flux switching type trip device according to a first embodiment of the present invention in a separated state.

FIG. 3 is a diagram showing a circuit configuration using the magnetic flux switching type trip device of the first and second embodiments of the present invention.

FIG. 4 is a side sectional view of a magnetic flux switching type trip device in a suction state according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a circuit configuration of a first conventional technique.

FIG. 6 is a side sectional view of a first conventional magnetic flux switching type trip device.

FIG. 7 is a side sectional view of a second conventional magnetic flux switching type trip device.

[Explanation of symbols]

 1 Circuit Breaker 2 Switching Contact 3 Current Transformer 4 Overcurrent Relay 5 Rectifying Element 6 Input Resistance 7 Zener Diode 8 Arithmetic Circuit 9 Capacitor 10 Transistor 11 Trip Mechanism 12 Flux Switching Type External Device 13 First Magnetic Frame 14 2nd Magnetic frame 15 non-magnetic block 16 first movable core 17 second movable core 18 operating rod 19 permanent magnet 21 first external coil 22,23 magnetic pole plate 24 first magnetic pole surface 25 external spring 27 second External coil 28 fixed core 29 second magnetic pole surface 34 movable core 35 non-magnetic plate

Claims (2)

(57) [Scope of utility model registration request] 1. A first magnetic pole surface, a first movable core made of a magnetic material and capable of moving linearly, and a circuit breaker attracts the first movable core to the first magnetic pole surface in a closed state. A first magnetic frame having a permanent magnet and a first external coil wound around the first movable core therein, and a magnetic body integrally formed coaxially with the first movable core A second movable core which is connected and is capable of moving linearly, and a predetermined gap is provided between the second movable core and the second movable core in a direction for operating the trip mechanism of the circuit breaker when the circuit breaker is closed. A second magnetic frame having therein a second magnetic pole surface provided and a second external coil wound around the second magnetic pole surface; and the first and second movable cores. An tripping device that biases the tripping mechanism of the circuit breaker in the direction in which it operates. The first and second magnetic frames are coupled to each other via a high magnetic resistance member, and when tripped, the direction of the magnetic flux by the first coil is the permanent magnet at the first magnetic pole surface. The first coil is excited so that the direction of the magnetic flux of the magnet is opposite,
A magnetic flux switching type trip device for a circuit breaker, wherein the second coil is excited so that the second movable core is attracted to the second magnetic pole surface. 2. A magnetic flux switching type trip device for a circuit breaker according to claim 1, wherein said first and second cores are integrated to form a single movable core.