JP2993129B2 - Switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switch. The term “switch” as used herein refers to a circuit breaker, a current limiter, an electromagnetic contactor, or the like that generates an arc in a container when current is interrupted.

[0002]

2. Description of the Related Art FIG. 6 is a side view showing a state in which a conventional circuit breaker disclosed in Japanese Utility Model Publication No. 59-21489 is opened. In the drawing, 1 is a movable contact, 2 is a movable contact fixed to one end of the movable contact 1, 3 is a fixed contact which comes into contact with and separates from the movable contact 2 by rotation of the movable contact 1, and 4 is fixed to one end The fixed contact 5 to which the contact 3 is fixed is a terminal portion connected to the other end of the fixed contact 4. Reference numeral 4a denotes a blow-out coil which forms the fixed contact 4 and generates a magnetic flux for driving an arc generated between the contacts 2 and 3 in the direction of the terminal portion 5. Reference numeral 6 denotes an arc-extinguishing plate, and 7 denotes an arc-extinguishing side plate that holds the arc-extinguishing plate 6. Reference numeral 8 denotes a mechanism for rotating the movable contact 1, reference numeral 9 denotes a handle for manually operating the mechanism 8, reference numeral 10 denotes another terminal, and reference numeral 11 denotes a conductor connecting the movable contact 1 and the terminal 10. is there. Reference numeral 12 denotes a container for accommodating them, and reference numeral 13 denotes an exhaust hole. FIG. 7 is a plan view seen from the line CC in FIG.

Next, the operation will be described. When the terminal unit 5 is connected to the power supply, the terminal unit 10 is connected to the load, and the handle 9 is operated in the state of FIG.
Rotates around a rotation center (not shown) provided at one end, the movable contact 2 comes into contact with the fixed contact 3, and power is supplied from the power supply to the load. In this state, the movable contact 2 is pressed against the fixed contact 3 with a specified contact pressure in order to ensure the reliability of energization. Here, when a short-circuit accident or the like occurs in the circuit on the load side of the circuit breaker and a large short-circuit current flows in the circuit, a current detecting unit (not shown) provided in the mechanism unit 8 operates the mechanism unit 8, By rotating the movable contact 1, the movable contact 2 and the fixed contact 3 are separated from each other, and an arc is generated between the contacts 2 and 3. However, usually, when a large current such as a short-circuit current flows, the electromagnetic repulsion at the contact surface between the contacts 2 and 3 and the electromagnetic force acting on the movable contact 1 due to the magnetic flux generated by the blowout coil 4a become very strong. In order to overcome the contact pressure applied to the movable contact 2, the movable contact 1 rotates without waiting for the operation of the mechanism section 8,
Opening of the contacts 2, 3 takes place. The generated arc is extended in the direction of the arc extinguishing plate 6 and cooled by the magnetic flux generated by the blowout coil 4a. As a result, the arc resistance increases, a current limit occurs in which the short-circuit current is reduced, and the arc is extinguished at the current zero point to complete the current interruption. Current limiting is very important to improve the protection function of the circuit breaker. In order to improve the current limiting performance, it is necessary to increase the arc resistance as described above.

[0004] In order to improve the current limiting performance in ordinary AC interruption, it is necessary to increase the arc resistance as described above, but this is because the current is still at the maximum immediately after the contacts 2 and 3 are opened. Needless to say, it has to be done before. Even if the arc resistance is increased after the current increases, the current is not easily limited due to the inertia effect of the current. On the contrary, since the current is large and the resistance is high, the arc energy generated in the circuit breaker becomes large, and the damage to the circuit breaker only becomes severe. Therefore, the opening speed of the movable contact 1 immediately after the contacts 2 and 3 are opened is increased, and at the same time, the arc is greatly extended with a strong electromagnetic force, and the arc is extended with a large current. It is necessary not to use electromagnetic force.

However, the blowout coil 4a described above
In the configuration (1), at the time of a large current, there is no effect of reducing the electromagnetic force for extending the arc, and the arc energy generated in the circuit breaker is insignificantly increased, so that the breaker is severely damaged. At the time of a large current, the movable contact 1 normally rotates to the maximum as shown in FIG. In FIG. 8, 14
Is the center of rotation provided on the movable contact 1, and the arc-extinguishing plate 6 and the arc-extinguishing side plate 7 are omitted. In this state, when an electromagnetic force for extending the arc in the direction of the terminal portion 5 is applied, a large amount of the hot gas H of the elongated arc A is discharged from the exhaust hole 13 as indicated by an arrow in the drawing. Become.
This is very dangerous as it may cause a ground fault or fire outside the circuit breaker. Originally, the electromagnetic force due to the current flowing through the movable contact 1 is a force for extending the arc toward the terminal portion 5, and the addition of the electromagnetic force in the same direction by the blowout coil 4 a further increases the risk. .

In order to remedy this drawback, Japanese Patent Application Laid-Open No. 62-163234 proposes a blowout coil as shown in FIGS. FIG. 9 shows the movable contact 1 in a closed state, and FIG. 10 shows the movable contact 1 in an open state. As is apparent from these figures, the electromagnetic force for extending the arc by the blowout coil 4a toward the terminal portion 5 acts only immediately after the contacts 2, 3 are opened. Therefore, immediately after the contacts 2 and 3 for which the arc resistance must be increased, an electromagnetic force for extending the arc toward the terminal portion 5 is applied to improve the current limiting performance, and the movable contactor 1 rotates to the maximum. In the moving state, the electromagnetic force for extending the arc toward the terminal portion 5 decreases, so that the emission of hot gas and damage due to the arc energy can be reduced.

[0007]

As the arc is elongated, the arc resistance increases, as described above. This means that the voltage applied to the contacts 2 and 3 increases. Therefore, if the distance between the contacts 2 and 3 is short, there is a risk that insulation breakdown may occur between the contacts. For this reason, in order to improve the current limiting performance, it is necessary not only to extend the arc, but also to increase the rotation speed of the movable contact and rapidly increase the insulation distance between the contacts. However, in the configuration of the blowout coil shown in FIG. 9, the magnetic flux generated by the blowout coil is used only for extending the arc immediately after the contacts 2 and 3 are opened. Accordingly, the rotation speed of the movable contact 1 is smaller than that of the movable contact 1 having the blowout coil having the configuration shown in FIG. For this reason, there is a problem that the current limiting performance cannot be improved as expected.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a switch which has excellent current limiting performance, and is less likely to be damaged by arc energy and to emit hot gas to the outside. The purpose is to gain.

[0009]

In the switch according to the present invention, when the direction in which the movable contact is separated from the fixed contact is set to be upward, the blow-out coil is at least at the center side of the movable contact. It has two current paths that are substantially parallel to the movable contact at the time of contact closure and currents flow in mutually opposite directions,
Together during the contact closing current path current one in the current in the same direction of flow in the movable contact of these current paths are flow is above the said movable contact, the other current path below the moving contact Wherein the movable contact is located above a current path above the blowout coil when the contact is opened.

[0010] Further, the fixed conductor is a fixed contact in which the connection conductor has a substantially loop shape, a terminal portion is connected to one end thereof, and a fixed contact is fixed inside the loop at the other end to form a blowout coil. A slit is provided in a portion of the connection conductor located above the surface to which the fixed contact is fixed so as not to hinder at least the opening operation of the movable contact.

[0011]

In the switch of the present invention, the blowout coil generates an electromagnetic force for extending the arc immediately after the contact is opened in the direction of the terminal, and the current flowing on the upper side of the blowout coil is a movable contact. The current flowing through the current path below the blowout coil is substantially parallel to and opposite to the current flowing through the movable contact, and repels each other. These are all directions in which the movable contact is opened. Accordingly, the moving speed of the movable contact is increased. Therefore, even if a high voltage is applied between the contacts, no dielectric breakdown will occur,
Excellent current limiting performance is exhibited. Moreover, when the movable contact is maximally separated, the electromagnetic force of the blowout coil acting on the arc located above the current path above the blowout coil extends the arc in a direction opposite to the fixed contact connection terminal side. Since the force is a force, it is possible to weaken the electromagnetic force that tends to extend the arc due to the current flowing through the movable contact toward the terminal. As a result, the amount of hot gas released from the exhaust hole is reduced. Further, even if the current increases, the arc in this portion is less prolonged and the generated arc energy is small, so that damage in the circuit breaker can be reduced.

Further, the fixed conductor has a connection conductor having a substantially loop shape, a terminal portion connected to one end thereof, and a fixed contact fixed to the inside of the loop at the other end to form a blowout coil. If the configuration is such that a slit that does not hinder at least the opening operation of the movable contact is provided in the portion of the connection conductor located above the surface to which the fixed contact is fixed, manufacture is easy. is there.

[0013]

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway sectional view of an embodiment of the present invention, showing a contact closed state.
The fixed contact 4 is made of a conductor constituting the blowout coil 4a. As shown in an enlarged manner in FIG. 3, the blowout coil 4a further includes current paths 41, 42, 43,
44 and are formed integrally with the terminal portion 5. In this example, the current paths 42 and 43 are provided with slits 441 so as not to hinder the rotation, that is, the separating operation of the movable contact. Fixed contact 3 of blowout coil 4a
The current path 44 and the current path 42 to which are fixed extend to the rotation center side almost in parallel with the movable contact 1, and as shown by the arrow in the figure, the movable contact 1 The current flows in the same direction, and the current flows in the opposite direction in the lower current path 44. When the contacts are closed, the current path 44 is located below the movable contact 1, and the current path 42 is located above the movable contact 1. Reference numeral 6 denotes an arc-extinguishing plate having a notch at a locus of rotation of the movable contact 1. FIG. 2 is a partially cutaway sectional view showing one embodiment of the present invention, and shows a state when the contacts of the switch of FIG. 1 are opened. When the contacts are opened,
The current path 42 above the blowout coil 4 a is configured to be located below the movable contact 2. In addition,
In FIGS. 1 and 2, the mechanism and the like are omitted.

Next, the operation will be described. Conventionally, when a large current such as a short-circuit current flows, the movable contact 1 rotates without waiting for the operation of the mechanism, the contacts 2 and 3 are separated, and an arc is generated between the contacts 2 and 3. Is the same as Contacts 2, 3
The magnetic flux generated by the blowout coil 4a acts on the arc generated in between, and is extended toward the terminal portion 5 side, so that the arc resistance increases. The current path 42 on the upper side of the blowout coil 4a attracts each other because the flowing current is substantially parallel to and the same direction as the current flowing through the movable contact 1, and the current flowing through the lower current path 44 on the blowout coil 4a is ,
Since it is almost parallel to and opposite to the current flowing through the movable contact 1,
Repel each other. These are all directions in which the movable contact 1 is rotated. Therefore, the opening speed of the movable contact, that is, the rotation speed is increased. Therefore, even if a high voltage is applied between the contacts 2 and 3, no dielectric breakdown occurs, and excellent current limiting performance is exhibited.

Next, as shown in FIG. 2, when the movable contact 1 is rotated to the maximum, the electromagnetic force of the blowout coil 4a acting on the arc located above the current path 42 above the blowout coil 4a. The force is a force for extending the arc in a direction opposite to the terminal portion 5 side. As a result, it is possible to reduce the electromagnetic force that tends to extend the arc due to the current flowing through the movable contact 1 to the terminal portion 5 side. As a result, the amount of hot gas released from the exhaust holes 13 is reduced. Further, even if the current increases, the arc in this portion is less elongated, so that the generated arc energy is small, so that damage in the circuit breaker can be reduced.

Embodiment 2 FIG. The blowout coil 4a
Is configured as shown in FIG. 3, the fixed contact 3
Since the fixed contact 4 and the terminal portion 5 having the current paths 41, 42, 43, and 44 can be relatively easily formed from a single conductive material by bending or the like, an inexpensive blowout coil can be provided. However, the present invention is not limited to this, and an exhaust slit 442 for exhausting gas generated by an arc may be provided in a part of the current path 41 on the terminal portion 5 side as shown in FIG.

Embodiment 3 FIG. Further, as shown in FIG. 5, the opening / closing slit 441 and the exhaust slit 442 may be connected to form a single slit 443.

Embodiment 4 FIG. Further, in each of the first, second, and third embodiments, the blowout coil 4a has less than one turn, but may be wound many times.

Embodiment 5 FIG. In the above embodiment, the arc extinguishing plate 6 is used.
Has been shown outside the blowout coil 4a so as to surround the blowout coil 4a, but the present invention is not limited to this.
And the arc extinguishing plate 6 may not be provided.

Embodiment 6 FIG. In the above embodiment, the case of a circuit breaker has been described. However, another switch such as a load switch or an electromagnetic contactor may be used, and the same effects as those of the above embodiment can be obtained.

[0021]

As described above, according to the present invention, when the direction in which the movable contact is separated from the fixed contact is set to the upper direction, the blow-out coil is connected to the contact at least at the center side of the movable contact. It has two current paths which are substantially parallel to the movable contact at the time of closing and flow currents in opposite directions to each other. with a current path that flows is above than the movable contactor and the other current path located below the said movable contact, when the contact opening above the movable contact lies above the current path of the upper side of the blow-out coil With such a configuration, there is an effect that a switch having excellent current limiting performance and less damage due to arc energy and emission of hot gas can be obtained.

Further, the fixed conductor is a fixed contact in which the connection conductor has a substantially loop shape, a terminal portion is connected to one end thereof, and a fixed contact is fixed inside the loop at the other end to form a blowout coil. If the slit is provided in the portion of the connection conductor located above the surface to which the fixed contact is fixed so as not to hinder at least the opening operation of the movable contact, the work is easy.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration view of a main part showing a movable contact of a switch according to a first embodiment of the present invention in a closed state.

FIG. 2 is a cross-sectional configuration diagram of a main part of the switch according to the first embodiment of the present invention shown in FIG. 1, showing a movable contact in an open state;

FIG. 3 is an enlarged perspective view showing a fixed contact of FIG. 1;

FIG. 4 is an enlarged perspective view showing a fixed contact according to a second embodiment.

FIG. 5 is an enlarged perspective view showing a fixed contact according to a third embodiment.

FIG. 6 is a cross-sectional configuration diagram showing a conventional switch.

FIG. 7 is a plan view of the switch of FIG. 6 as viewed from the line CC.

FIG. 8 is a cross-sectional configuration diagram illustrating an operation of the switch of FIG. 6;

FIG. 9 is a side configuration diagram of a main part showing a movable contact of a switch according to another conventional example in a closed state.

FIG. 10 is a side view of a main part of the conventional switch shown in FIG. 9, showing a movable contact in an open state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Movable contact 2 Movable contact 3 Fixed contact 4 Fixed contact 4a Blow-out coil 42 Upper current path 44 Lower current path 5 Terminal part

Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) H01H 9/30-9/40 H01H 73/18

Claims (2)

(57) [Claims] 1. A movable contact having a movable contact fixed to an end thereof, a fixed contact having a fixed contact detachable from the movable contact at one end of a connecting conductor, and a fixing of the connecting conductor. A terminal connected to the other end where the contact is not fixed, and a blowout for generating a magnetic field such that the connection conductor extends and drives the arc generated between the contact toward the terminal. In a switch forming a coil, when the direction in which the movable contact is separated from the fixed contact is set to an upward direction, the blow-out coil is closed at least at a central portion side of the movable contact when the contact is closed. A current path in which current flows in the same direction as the current flowing in the movable contact on one of the current paths when the contacts are closed. Is the above movable contact And the other current path is located below the movable contact, and when the contact is opened, the movable contact is located above the current path above the blowout coil. Switch. 2. A fixed contact in which a connection conductor has a substantially loop shape, a terminal portion is connected to one end thereof, and a fixed contact is fixed inside a loop at the other end to form a blowout coil. 2. The switch according to claim 1, wherein a slit is provided in a portion of the connection conductor located above a surface to which the fixed contact is fixed, so as not to hinder at least an opening operation of the movable contact.