JP4395134B2 - Breaker - Google Patents

Description

  The present invention relates to a circuit breaker structure.

  Various proposals have been made to improve the current-carrying capacity between contacts when a short-circuit current is generated in a circuit breaker. For example, what is disclosed in Japanese Patent Application Laid-Open No. 6-89650 has a current-carrying portion including a stator having a fixed contact, a mover having a movable contact, and a shunt conductor extending between the mover and the terminal, In a circuit breaker in which a magnetic flux generated due to a current flowing through the shunt conductor and an electromagnetic force due to the current act to direct the movable contact toward the fixed contact, a high permeability member in the magnetic path of the magnetic flux And the magnetic flux that has passed through the magnetic permeability member is configured to interlink with the current.

  As a result, the magnetic flux concentrates on the high permeability member, and the short-circuit current is linked with the magnetic flux concentrated on the high permeability member. Will improve. However, according to the above-described conventional configuration, the electromagnetic force applied between the contacts is increased, and there is an effect of increasing the pressing force between the movable and fixed contacts and improving the current carrying capacity. There is a problem that a certain amount of space is required due to the installation of the magnetic permeability member.

  The present invention has been made in view of the above points, and without increasing the number of parts and without requiring space, increases the force for pressing between the movable and fixed contacts while maintaining a small size. The purpose is to improve the short-term energization capacity of the circuit breaker.

In order to achieve the above object, a circuit breaker according to the present invention includes a stator having a fixed contact, a mover having a movable contact that is supported by a shaft and tilts and contacts and separates from the fixed contact, and A shunt conductor having one end fixed to the rear end side opposite to the movable contact with respect to the shaft and the other end connected to a terminal, and a magnetic flux generated due to a current flowing through the shunt conductor; In the circuit breaker configured to act on the mover so that an electromagnetic force due to the current is directed to the movable contact side toward the fixed contact side, the length of the rear end side of the mover is defined as the shaft. The distance between the movable contacts in the horizontal direction is set to be twice or more, and the distance between the shaft and the joining screw is set to be 1.3 times or more in the horizontal direction between the axis and the movable contacts. One end of the conductor along the rear end of the mover Are fixed in contact with each other.

  Each of the poles is provided with a fixed contact, a movable member that is supported by a shaft, tilts and has three or more movable contacts that contact and separate from the fixed contact, and the movable member. A shunt conductor having one end fixed to the rear end side in the direction opposite to the movable contact with respect to the shaft and the other end connected to a terminal, and a magnetic flux generated due to a current flowing through the shunt conductor and the current In the circuit breaker configured to act on the movable element so that the electromagnetic force by the magnetic force moves the movable contact toward the fixed contact side, the width viewed from the plane direction of the movable element adjacent to the other pole is It is made narrower than the width of the other mover.

  Each of the poles is provided with a fixed contact, a movable member that is supported by a shaft, tilts and has three or more movable contacts that contact and separate from the fixed contact, and the movable member. A shunt conductor having one end fixed to the rear end side in the direction opposite to the movable contact with respect to the shaft and the other end connected to a terminal, and a magnetic flux generated due to a current flowing through the shunt conductor and the current In the circuit breaker configured to act on the mover so that the electromagnetic force by the magnetic head moves the movable contact toward the fixed contact, the mover on the side adjacent to the other pole corresponds to the movable contact of the mover. The fixed contact to be installed is shifted from the center of the movable element group.

  Since the movable contact strengthens the force that presses the fixed contact, it is possible to realize a small circuit breaker with a large current carrying capacity for a short time.

Embodiment 1 FIG.
Embodiments of the present invention will be described below with reference to the drawings. 1 is a side sectional view of a circuit breaker according to the present invention, FIG. 2 is a diagram conceptually showing a stator and a mover portion thereof, and FIG. 3 is a diagram showing an enlarged main part of FIG. It is. The circuit breaker according to the present invention includes a box 1. In the box 1, a stator (conductor) 3 having a fixed contact 2, a mover 5 having a movable contact 4 contacting and separating from the fixed contact 2, a contact arm 6 supported by a shaft 8, and a mover 5 are supported. The movable shaft 7, the terminal 9, the shunt conductor 10 that electrically connects the terminal 9 and the movable shaft 7 , and the movable element 5 and the box 1 are installed between the movable element 5 and the movable element 5. A contact pressure spring 11 for applying an urging force to the actuator, an opening / closing mechanism section 12, a shaft 13, a tripping relay section 14, and an arc extinguishing chamber 15 are provided.

  FIG. 2 conceptually shows the stator 3 and the mover 5 taken out, and FIG. 3 shows an enlarged main part of FIG. These drawings show a state in which the movable contact 4 is in contact with the fixed contact 2. The shunt conductor 10 that connects the terminal 9 and the mover 5 is a flexible conductor in which many thin copper plates are laminated. One end of the shunt conductor 10 is fixed to the terminal 9 by a screw or the like, and the other end is fixed to the movable element 5 by a fixing portion A. As will be described later, the fixing portion A usually uses a fixing screw 20. The mover 5 is a substantially rod-shaped member that tilts about a shaft 7 as a fulcrum, and is provided with a fixed contact 4 on the tip side (right side in FIG. 2) from the shaft 7 and on the rear end side (left side in FIG. 2). ) Is connected and fixed to the shunt conductor 10.

  The connection / fixed portion between the shunt conductor 10 and the mover 5 will be described in detail. The front end portion of the shunt conductor 10 made of a laminated conductor is brought into contact with the lower surface on the rear end side of the movable element 5, that is, the surface on the side where the movable contact 4 is provided. Is fixed to the movable element 5 by screwing. The front end portion of the shunt conductor 10 is firmly fixed between the stopper 16 and the rear end side of the shaft 5 of the movable element 5, and also keeps close contact with the movable element 5 electrically. The stopper 16 has a length substantially equal to the length in which the tip of the shunt conductor 10 is in contact with the mover 5.

  The feature of the present invention described in the first embodiment is that, in the above configuration, the distance between the rear end of the movable element 5 and the shaft 7 is set larger than the distance between the shaft 7 and the movable contact 4. Specifically, when the distance in the horizontal direction between the center of the shaft 7 and the movable contact 4 is D1, and the distance between the center of the shaft 7 and the rear end of the movable element 5 is D2, D2 is set to be twice or more of D1. ing.

  When a short-circuit current flows from the terminal 9 to the stator 3 through the shunt conductor 10, the movable element 5, the movable contact 4, and the fixed contact 2, a magnetic flux is generated by this current, and the shunt conductor 10 and the terminal 9 are During this time, an electromagnetic repulsive force is generated, and this electromagnetic repulsive force acts on the movable element 5 so as to press the movable contact 4 against the fixed contact 2 with the shaft 7 as the rotation center. On the other hand, a repulsive force due to electromagnetic force acts between the movable contact 4 and the fixed contact 2 (hereinafter referred to as a contact repulsive force to distinguish it from the electromagnetic repulsive force acting between the terminal 9 and the shunt conductor 10). A force is applied to weaken the pressure contact between the movable contact 4 and the fixed contact 2. However, by setting D2 to be twice or more of D1, the moment around the axis 7 due to D2 greatly exceeds the moment around the axis 7 due to D1, so that the contact pressure between the movable contact 4 and the fixed contact 2 is increased. The energization capacity is improved for a short time, greatly exceeding the contact repulsive force.

  This situation will be described with a graph obtained as a result of the experiment. FIG. 4A shows a representative example of the two-phase current waveforms of the A-phase and B-phase of the three-phase circuit breaker when a short-circuit current is generated. FIG. 4 shows the first half wavelength of the short-circuit current, where time is plotted on the horizontal axis, current value is plotted on the vertical axis, A-phase current is S, and B-pole current is T. At this time, the floating force R (due to the contact repulsive force) and the pressing force P (due to the electromagnetic repulsive force and the contact pressure spring force) of the mover generated at the contact portion are calculated from electromagnetic force analysis by a finite element method or the like. 4B and 4C (time is plotted on the horizontal axis and force is plotted on the vertical axis). In the conventional configuration in which D2 does not reach twice that of D1, as shown in (b), there is a place where the buoyant force and the holding force are balanced, which prevents the contacts from being pressed together and satisfies the current-carrying performance for a short time. There was a case that could not be done. On the other hand, when the dimension D2 of the mover 5 is twice that of D1, as shown in FIG. 4C, the restraining force P exceeds the floating force R, and the restraining force is improved.

Embodiment 2. FIG.
5 and 6 show a mover and a stator part of a circuit breaker according to Embodiment 2 of the present invention. In this embodiment, in the drawing, a fixing portion A that fixes the end of the shunt conductor 10 that is press-contacted along the rear end side of the mover 5 to the mover 5 is provided near the rear end of the mover 5. It is characterized by that. The fixed portion A has the same structure as that of the first embodiment. Usually, the end portion of the shunt conductor 10 that is in contact with the rear end side of the mover 5 is sandwiched between the stoppers 16 and the fixing screw 20 is inserted into the mover. 5 is fixed by screwing. In this case, when the distance in the horizontal direction between the shaft 7 and the movable contact 4 is D1, and the distance between the shaft 7 and the fixing screw 20 is D3, D3 is set to 1.3 times or more of D1. Other configurations are the same as those of the first embodiment.

  As described in the first embodiment, if the distance D2 between the rear end of the movable element 5 and the shaft 7 is set to be twice or more the distance D1 between the movable contact 4 and the shaft 7, the shunt conductor 10 and the terminal 9 are used. The force of pressing the movable contact 4 against the fixed contact 2 with the shaft 7 as the center of rotation is strengthened by the action of the electromagnetic repulsive force generated between them. However, when the fixing position of the mover 5 and the shunt conductor 10 by the fixing screw 20 is close to the shaft 7 and D3 is 1.2 or less of D1, the resultant electromagnetic repulsive force acting on the mover 5 is There are cases where it is diminished due to play or transmission time delay due to elasticity or the like. However, as in the present embodiment, the end portion of the shunt conductor 10 is aligned with the rear end side of the mover 5, and D3 is 1.3 times D1 near the rear end of the stator 5 by the fixing screw 20. If fixed in the above position, the play width between the shunt conductor 10 and the stator 5 is suppressed, and the force acting toward the fixed contact 2 side of the movable contact 4 is generated without time delay or play width, The result that the current carrying capacity was improved for a short time was obtained.

Embodiment 3 FIG.
FIG. 7 is a plan view (a) and a side view (b) showing a group of movers of a circuit breaker according to Embodiment 3 of the present invention, and the figure shows, for example, six movable elements arranged in parallel with one pole of three phases. An example composed of children is shown. The number of movers increases and decreases depending on the capacity of the circuit breaker and the like, and is not limited to six. Each of the movers 51 to 56 is supported on the shaft 7 and fixed to the shunt conductor 10 with a fixing screw 20. Each movable element 51 to 56 is provided with a movable contact 4. On the other hand, as for the fixed contact that contacts the movable contact 4, the movable contacts 4 of the three adjacent movable elements 51 to 53 commonly face the horizontally long fixed contact 2 a, and the other three movable elements 54 to 56. The movable contact 4 is commonly opposed to the horizontally long fixed contact 2b. The form of the fixed contact is not limited to this example, and one fixed contact may be opposed to one movable contact, or one common fixed contact may be opposed to six movable contacts. In this case, as an example, the movable contact width is set to about 1.0 with respect to the fixed contact width 1.5.

The feature of the third embodiment relates to the distance between adjacent movable elements 51 to 56 having the same shape and the same dimensions provided in parallel (FIG. 7 is arranged between the three-phase A pole and C pole. The distance between the movers 51 and 56 adjacent to the other poles and the movers 52 and 55 adjacent to these other poles is n1 , and the other movers 52 and 53, 53 and 54, 54 are shown. When the interval between and 55 is n2 , the interval n1 is smaller than the interval n2 . That is, the position of the fixed contact 2 is provided assuming that all the movable elements are provided at equal intervals, whereas the movable elements 51 and 56 on both sides are arranged closer to the center of the movable element group. It has been done. When the fixed contacts (width 1.5) are provided independently one by one with respect to the movable contact 4 (width 1.0), the movable contacts 4 of the movers 52 to 55 are located between the fixed contact and the center. Whereas the movable contacts 4 of the movable elements 51 and 56 are provided so as to face each other, the movable elements 4 are movable so that the center line is shifted by 0.5 from the central line of the fixed contacts toward the center of the movable element group. Place.

FIG. 8 is a graph showing the surface current distribution of the first to sixth movers in a three-phase B pole composed of, for example, an A pole, a B pole, and a C pole. As shown in FIG. 8, a large surface current concentrates on the first and sixth movers located at both ends. This is due to the eddy current that occurs due to the influence of the adjacent mover and the adjacent pole. Accordingly, the contact repulsive force acting on the mover adjacent to the other pole in the mover group of each pole due to the current and the electromagnetic force in the other pole direction (outside lateral direction) become conspicuous as compared with the other. Various electromagnetic forces act on each mover depending on the magnitude of the current flowing through it, and in particular, the mover on the side adjacent to the other pole has a lateral electromagnetic force toward the outside, a fixed contact, The resultant force of the contact repulsion force, which is the repulsion force between the movable contacts, is applied, so that the movable contact does not come into contact with the fixed contact on the original contact surface, so-called stepping off occurs, and the current carrying capacity is reduced for a short time. However, as in this embodiment, the movable contacts 51 and 56 on the side adjacent to the other pole are arranged inward from the interval n2 to n1 , so that the movable contact 4 until the stepping off occurs is the fixed contact 2. It is possible to secure a margin for moving up, to prevent stepping off, and to secure a sufficient energization capacity for a short time.

Embodiment 4 FIG.
FIG. 9 is a plan view showing a mover of a circuit breaker according to Embodiment 4 of the present invention, and FIG. 9 shows an example constituted by six movers in which three phases are arranged in parallel, for example. The number of movers increases or decreases depending on the capacity of the circuit breaker, and is not limited to six. Each of the movable elements 51 to 56 is supported on the shaft 7 and fixed to the shunt conductor 10 with a fixing screw 20. The structure of the fixed contact is the same as that of the third embodiment.

  The feature of the fourth embodiment is that the widths of the movable elements 51 to 56 in the movable element groups 51 to 56 viewed from the plane direction of the movable elements 51 and 56 adjacent to the other poles are the widths of the other movable elements 52 to 55. It is narrower. In FIG. 9, when the width of the mover of the movers 52 to 55 is t1, the width of the movers 51 and 56 adjacent to the other pole is set to t2 smaller than t1, and the current path cross-sectional area of this portion is reduced. Impedance is increased. In FIG. 9, for reasons of processing, the width of the movers 51 and 56 from the connecting portion to the tip of the shunt conductor 10 is set to t2, which is smaller than t1, but in principle, the connecting portion to the shunt conductor 10 is used. To at least the movable contact 4 may be narrowed.

  The current distribution of each mover when the widths of the movers 51 to 56 are all the same is as shown in FIG. Due to the current distribution, as described in Embodiment 3, there is a tendency that a large surface current flows and a large electromagnetic force acts on the mover adjacent to the other pole. The repulsive force between the contacts and the electromagnetic force in the lateral direction toward the other pole are remarkably applied to the movable elements 51 and 56 on both sides. As a result, the force with which the movable contact is pressed against the fixed contact weakens, and at the same time, the movable contact does not come into contact with the fixed contact on the original contact surface, so-called stepping off occurs, and the current carrying capacity is reduced for a short time.

  However, by making the widths of the movable elements 51 and 56 adjacent to the other poles narrower than the other movable elements 52 to 55 as in the present embodiment, the energization cross-sectional area of the movable elements 51 and 56 is reduced and the impedance is reduced. Increases and acts to cancel the current distribution drift shown in FIG. As a result, the surface current flowing through the movers 51 and 56 adjacent to the other poles is reduced, the remarkable lateral electromagnetic force received by these movers is reduced, the contact can be prevented from being stepped off, and the contact repulsive force is also reduced. As a result, the short-time energization capacity is improved.

FIG. 1 is a side view showing a circuit breaker according to the present invention.
FIG. 2 is a conceptual diagram showing a stator and a mover part of the circuit breaker according to Embodiment 1 of the present invention.
FIG. 3 is an enlarged view showing the main parts of the stator and mover part of the circuit breaker according to Embodiment 1 of the present invention.
FIG. 4 is a graph for explaining the operation of the first embodiment.
FIG. 5 is a conceptual diagram showing a stator and a movable part of a circuit breaker according to Embodiment 2 of the present invention.
FIG. 6 is an enlarged view showing the main parts of the stator and mover part of the circuit breaker according to Embodiment 2 of the present invention.
FIG. 7 is a plan view (a) and a side view (b) showing a stator portion of a circuit breaker according to Embodiment 3 of the present invention.
FIG. 8 is a graph for explaining the operation of the third embodiment.
FIG. 9 is a plan view (a) and a side view (b) showing a mover portion of a circuit breaker according to Embodiment 4 of the present invention.

Claims (3)

A stator having a fixed contact; a mover having a movable contact that is tilted by being supported by a shaft; and is movable toward and away from the fixed contact; and a rear end of the mover in a direction opposite to the movable contact with respect to the shaft A shunt conductor having one end fixed to the side by a joining screw and the other end connected to a terminal, and a magnetic force generated due to a current flowing through the shunt conductor and an electromagnetic force due to the current cause the movable contact to In the circuit breaker configured to act on the movable element so as to be directed toward the fixed contact side, the length of the rear end side of the movable element is twice the horizontal distance between the shaft and the movable contact. In addition, the distance between the shaft and the joining screw is set to be 1.3 times or more the horizontal distance between the shaft and the movable contact, and one end of the shunt conductor is placed on the rear end side of the movable element. Characterized by being abutted and fixed along Circuit breaker. Each pole is provided with a fixed contact, three or more movable elements arranged in parallel, each having a movable contact that is supported and tilted by a shaft and contacts and separates from the fixed contact, and the shaft of the movable element. On the other hand, a shunt conductor having one end fixed to the rear end side in the direction opposite to the movable contact and the other end connected to a terminal, and a magnetic flux generated due to a current flowing through the shunt conductor and an electromagnetic by the current In the circuit breaker configured to act on the mover so that the force moves the movable contact toward the fixed contact, the mover on the side adjacent to the other pole is fixed to the movable contact of the mover. A circuit breaker characterized in that the circuit breaker is shifted from the contact point toward the center of the movable element group. Each pole is provided with a fixed contact, three or more movable elements arranged in parallel, each having a movable contact that is supported and tilted by a shaft and contacts and separates from the fixed contact, and the shaft of the movable element. On the other hand, a shunt conductor having one end fixed to the rear end side in the direction opposite to the movable contact and the other end connected to a terminal, and a magnetic flux generated due to a current flowing through the shunt conductor and an electromagnetic by the current In the circuit breaker configured to act on the mover so that the force moves the movable contact toward the fixed contact side, the width viewed from the plane direction of the mover on the side adjacent to the other pole, A circuit breaker characterized by being narrower than the width of the mover.

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