JP2011198586A - Circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a second movable contactor from being driven in a pole-closing direction by a magnetic field due to current flowing in a lead wire.SOLUTION: A circuit breaker includes a first movable contactor 4, a second movable contactor 5, a lead wire 8 with one end connected to the other end of the second movable contactor 5, and a power supply side terminal 2 with the other end of the lead wire 8 electrically connected. In the circuit breaker, a magnetic shielding material 12 made of a magnetic substance is fitted between the lead wire 8 and the second movable contactor 5.

Description

  The present invention relates to a circuit breaker such as a circuit breaker for wiring, an earth leakage breaker, and the like, and more particularly, to a repulsive circuit breaker in which a contactor double-opens when a short-circuit current is interrupted.

  As this type of repulsive circuit breaker, a circuit breaker disclosed in Patent Document 1 is known. 3 is a longitudinal sectional view of a main part showing a closed state of a conventional repulsive three-pole circuit breaker, FIG. 4 is a perspective view around the second movable contact shown in FIG. 3, and FIG. It is operation | movement explanatory drawing which shows the ON state of the circuit breaker shown in FIG. FIG. 6 is a cross-sectional view taken along the line B-B in FIG. 5B and shows an electromagnetic force acting between the second movable contact and the lead wire during the opening operation.

  In the figure, 1 is a main body case composed of a case and a cover, 2 is a power supply side terminal composed of a terminal conductor fixed to the main body case 1, 3 is a load side terminal composed of a terminal conductor fixed to the main body case 1, and 4 is one end. A first movable contact 5 having a first movable contact 4a, 5 is a second movable contact having a second movable contact 5a that contacts the first movable contact 4a at one end, and 6 is each pole. The first movable contact 4 is pivotally supported by a fulcrum pin 4b and is a holder connected to an opening / closing mechanism (not shown), and is rotatably supported by the main body case 1.

Reference numeral 7 denotes a flexible lead wire having one end connected to the other end of the first movable contact 4, and the other end is connected to the load side terminal 3 via an overcurrent tripping device (not shown). .
8 is a flexible lead wire having one end connected to the power supply side terminal 2 and the other end connected to both side surfaces of the other end of the second movable contact 5, respectively. This is a U-shaped support frame that rotatably supports the other end of the movable contact 5 by a fulcrum pin 5c.

  Reference numeral 10 denotes a contact spring formed of a torsion spring that presses the second movable contact 5 toward the first movable contact 4, and a pin having one end penetrating the second movable contact 5 as shown in FIG. 4. The other end is engaged with the support frame 9.

  Reference numeral 11 denotes an arc extinguishing device having a plurality of magnetic plates arranged so as to surround the first and second movable contacts 4, 5, and 12 denotes the holder 6 and the first movable contact 4 via an opening / closing mechanism (not shown). This is an operation handle for opening and closing.

  In the configuration described above, as shown in FIG. 5A, the current i is supplied from the power supply side terminal 2, the lead wire 8, the second movable contact 5, the second movable contact 5a, the first movable contact 4a, It flows to the overcurrent tripping device (not shown) and the load side terminal 3 via the first movable contact 4 and the lead wire 7.

  The opening / closing operation of such a circuit breaker is well known. When the operation handle 12 is opened / closed, the holder 6 and the first movable contact 4 are opened / closed via the opening / closing mechanism, and the contact is turned on / off.

  Further, when a large current such as a short circuit current flows in the ON state of the circuit breaker shown in FIG. 5A, an electromagnetic repulsive force F1 is generated between the first movable contact 4 and the second movable contact 5. , F2 are generated, and both contacts are opened in a direction away from each other as shown in FIG. Here, the second movable contact 5 is rotated counterclockwise in the figure against the contact spring 10 and separated from the first movable contact 4. Further, the first movable contact 4 is rotated in the clockwise direction in the drawing, and is held at the opening position of the first movable contact 4 by the tripping opening / closing mechanism.

  When the current is interrupted, an arc arc is generated between the contacts 4a and 5a of the first movable contact 4 and the second movable contact 5, and the arc arc is stretched toward the arc extinguishing device 11 and is divided by the magnetic plate. It disappears due to the cathode / anode drop and cooling action.

  As shown in FIG. 6, a magnetic field φ <b> 1 is generated in the lead wire 8 by a current i flowing through the lead wire 8, and the second movable contact 5 has the second movable contact 5. The magnetic field φ2 is generated by the current flowing through the.

Japanese Patent Laid-Open No. 3-11518

  By the way, in the conventional circuit breaker, the power supply side terminal 2 and the second movable contact 5 are connected by a flexible lead wire 8, and the second power supply terminal 2 is connected via the lead wire 8 to the second circuit breaker. A current is passed through the movable contact 5.

  However, as shown in FIG. 5B, since the direction of the current flowing through the second movable contact 5 and the direction of the current flowing through the lead wire 8 are opposite, as shown in FIG. The magnetic field φ1 generated by the current flowing through 8 and the magnetic field φ2 generated by the current flowing through the second movable contact 5 are opposite to each other.

  Thereby, an upward electromagnetic force F3, that is, a force for driving the second movable contact 5 in the closing direction is generated in the second movable contact 5. Since the electromagnetic force F3 is opposite to the electromagnetic force F2 described with reference to FIG. 5A, the opening speed of the second movable contactor 5 is reduced and the overcurrent current is reduced when the current is interrupted. Depending on the value, the second movable contact may not be driven in the opening direction, and the current breaker performance of the circuit breaker may be reduced.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a circuit breaker that prevents the second movable contact from being driven in the closing direction by a magnetic field caused by a current flowing through a lead wire when the current is interrupted. .

  In order to achieve the above object, according to the present invention, a first movable contact that has a first movable contact and is driven to open and close by an opening and closing mechanism, and a second contact that contacts the first movable contact. A second movable contact having a movable contact at one end and being urged toward the first movable contact by a contact spring, and one end at the other end of the second movable contact. In a circuit breaker comprising: a lead wire connected so that the current is opposite to that of the second movable contact; and a terminal conductor to which the other end of the lead wire is electrically connected; A magnetic shield material is provided between the lead wire and the second movable contact.

  In the above circuit breaker, it is preferable that the magnetic shield material has a U shape and is arranged so as to surround the second movable contact. Further, the magnetic shield material or the lead wire may be insulated.

  According to the present invention, since the magnetic shield material made of a magnetic material is provided between the second movable contact and the lead wire, the magnetic field caused by the current flowing through the lead wire can be magnetically shielded by the magnetic shield material. When the current is interrupted, the second movable contact can be prevented from being driven in the closing direction by the current flowing through the lead wire.

BRIEF DESCRIPTION OF THE DRAWINGS It is a circuit breaker which shows embodiment of this invention, (a) is principal part sectional drawing which shows an ON state, (b) is principal part sectional drawing which shows an OFF state. AA arrow sectional view of FIG. Longitudinal longitudinal sectional view showing a closed state of a conventional repulsive three-pole circuit breaker FIG. 3 is a perspective view around the second movable contact shown in FIG. It is operation | movement explanatory drawing of the circuit breaker shown in FIG. 3, (a) is operation | movement explanatory drawing which shows the ON state of a circuit breaker, (b) is operation | movement explanatory drawing which shows an OFF state. BB arrow sectional drawing of FIG.5 (b)

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2.
1A and 1B show an embodiment of the present invention, in which FIG. 1A is a cross-sectional view of a main part showing an ON state of a repulsive circuit breaker, and FIG. 2 is a cross-sectional view taken along arrow AA in FIG. In addition, in the figure of an Example, the same code | symbol is attached | subjected and demonstrated to the member corresponding to FIGS. 3-6.

  In the figure, reference numeral 2 denotes a power supply side terminal made of a terminal conductor fixed to a main body case (not shown), and 4 denotes a first movable contact having a first movable contact 4a at one end and rotating around a fulcrum pin 4b. 5 has a second movable contact 5a that contacts the first movable contact 4a at one end, and a second movable contact that rotates around a fulcrum pin 5c, and 7 a first movable contact 4 The other end of the flexible lead wire is connected to the load side terminal via an overcurrent tripping device (not shown).

  8 has one end connected to the power source side terminal 2 and the other end connected to both side surfaces of the other end of the second movable contact 5, and the current is opposite to that of the second movable contact 5. The flexible lead wires 10 are arranged so as to be a contact spring composed of a torsion spring that presses the second movable contact 5 toward the first movable contact 4.

  Here, in this embodiment, a magnetic shield material 12 made of a magnetic material is provided between the second movable contact 5 and the lead wires 8 and 8. As shown in FIG. 2, the magnetic shield material 12 has a U shape having both sides 12a and 12a, surrounds the second movable contact 5 inside the U shape, and has a U shape. It arrange | positions in a main body case so that the lead wires 8 and 8 may be located in the outer side of both sides 12a and 12a.

  In the configuration described above, as shown in FIG. 1A, the current i is generated from the power supply side terminal 2, the lead wire 8, the second movable contact 5, the second movable contact 5a, the first movable contact 4a, It flows through the first movable contact 4 and the lead wire 7 to an overcurrent tripping device (not shown) and a load side terminal.

  Further, as shown in FIG. 2, a current flows from the back of the paper surface to the front of the second movable contact 5, and a current flows through the lead wire 8 from the front to the back of the paper surface. In addition, a magnetic field φ <b> 2 is generated in the second movable contact 5 by the current flowing through the second movable contact 5.

  Here, as shown in FIGS. 1A and 2, a reverse current flows between the lead wire 8 and the second movable contact 5, but according to the present embodiment, the lead By providing the magnetic shield material 12 between the wire 8 and the second movable contact 5, the magnetic field generated by the current flowing through the lead wire 8 is magnetically shielded by the magnetic shield material 12.

Accordingly, the electromagnetic force F3 acting on the second movable contact 5 from the lead wire 8 shown in FIG. 6 is greatly reduced.
As a result, the second movable contact 5 opens in the opening direction due to the electromagnetic repulsive force F2 generated between the first movable contact 4 and the second movable contact 5 when the current is interrupted. The second movable contact 5 is not driven in the closing direction by the magnetic field generated by the current flowing through the lead wire 8.

  As described above, according to the present embodiment, since the magnetic shield material 12 is provided between the lead wire 8 and the second movable contact 5, the second movable contact 5 is opened when the current is interrupted. The extreme speed is not lowered, and excellent current limiting performance can be exhibited.

  In the present embodiment, the magnetic shield material 12 is formed in a U-shape. However, the present invention is not limited to this, and a plate-like magnetic field is formed between the second movable contact 5 and the lead wire 8. You may make it arrange | position a shielding material, respectively.

  Further, the lead wires 8, 8 connected to the second movable contact 5 are displaced along with the opening / closing operation of the second movable contact 5, but the lead wires 8, 8 contact the magnetic shield material 12. In order to prevent this, an insulating treatment such as a heat-resistant resin, for example, an unsaturated polyester resin as a thermosetting resin, is applied to the outside of both side surfaces 12a and 12a of the magnetic shield material 12 corresponding to the lead wires 8 and 8. It is preferable to electrically insulate between the lead wires 8 and 8 and the magnetic shield material 12.

  The insulation treatment may be provided inside or inside the both side surfaces 12a, 12a of the magnetic shield material 12, or the entire magnetic shield material 12 may be insulated. Further, a heat-resistant insulating tape may be provided on the lead wires 8 and 8 side so as to cover the lead wires 8 and 8 instead of the magnetic shield material 12 side to perform an insulation treatment.

  The insulation treatment may be performed on the magnetic shield material 12 or the lead wire 8, or may be performed on both the magnetic shield material 12 and the lead wire 8.

2 Power supply side terminal 4 First movable contact 4a First movable contact 5 Second movable contact 5a Second movable contact 8 Lead wire 10 Contact spring 12 Magnetic shield material

Claims (3)

A first movable contact having a first movable contact and driven to open and close by an opening and closing mechanism;
A second movable contact that has a second movable contact that contacts the first movable contact at one end, and that is urged toward the first movable contact by a contact spring;
One end is connected to the other end of the second movable contact, and the lead wire is arranged so that the current is opposite to that of the second movable contact;
In a circuit breaker comprising a terminal conductor to which the other end of the lead wire is electrically connected,
A circuit breaker comprising a magnetic shield material provided between the lead wire and the second movable contact.   2. The circuit breaker according to claim 1, wherein the magnetic shield material has a U-shape and is disposed so as to surround the second movable contact. The circuit breaker according to claim 1 or 2, wherein an insulation treatment is applied to the magnetic shield material or the lead wire.

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