JPS62157629A - Arc extinguisher of circuit breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an arc extinguishing device for a so-called de-ion grid type circuit breaker.

[Technical Background of the Invention and Problems Therewith] A conventional configuration of an arc extinguishing device for this type of circuit breaker will be described with reference to FIGS. 7 and 8. First, in FIG. 7, 1 is a circuit breaker, 2 is its main body case, 3 is a cover, 4 is a fixed contact, 5 is a movable contact, and 6 is a fixed contact by rotating the movable contact 5. 7 is a circuit opening/closing mechanism for bringing the movable contact 5 into contact with and separating from the fixed contact 4.

That is, it is an arc extinguishing device for extinguishing the arc generated between these fixed and movable contacts 4 and 5 during a breaking operation. As shown in FIG. 8, this arc extinguishing device 7 includes a grid plate 9 made of magnetic material in which a substantially V-shaped notch 8 is formed, and side portions 9a, 9a on both left and right sides of the grid plate 9 are arranged as shown in FIG. A pair of left and right side plates 10 made of an insulating material are placed on both sides of the fixed and movable recontactors 4 and 5 at a predetermined interval, and a plurality of plates, seven in this case, are arranged so as to leave a gap between them in the vertical direction. 10. This arc extinguishing device 7 combines the magnetic flux generated by the arc and the grid plate 9 when the arc generated between the fixed and movable liquid contactors 4 and 5 runs through the space in the notch 8 when the circuit is interrupted. By the cooperative action of these, the arc is drawn to the back of the notch 8 and stretched out, and each grid plate 9 cools the arc, divides it, and extinguishes it. However, in this case, especially in the initial stage of arc generation, the edges of the notch 8 in the grid plate 9, that is, the side portions 9a, 9a, are affected by the high temperature arc heat.
(the molten metal is locally melted and the molten part is indicated by diagonal lines in FIG. 8 for convenience), the molten metal floats between the fixed contact 4 and the movable contact 5, obstructing the movement of the arc, and reducing the arc voltage. This is causing the rate of increase to worsen. In addition, the molten metal on the grid plate 9 tends to scatter, and if it adheres to the grid plate 9 or the side plate 10 that supports the grid plate 9, this will also worsen the rate of increase in arc voltage, and if it adheres to the circuit opening/closing mechanism 6, it will Furthermore, if the scattered molten metal adheres to the inner surface of the main body case 2 or the cover 3, the insulation resistance decreases and the circuit breaker 1 has a disadvantage of having a poor withstand voltage.

To deal with this, for example,
469 and Utility Model Application Publication No. 52-2166 have been devised. This item is specifically shown in Figures 9 and 1.
As shown in FIG. 0, insulation is provided inside the left and right sides 11a, 11a of each grid plate 11 to shield the side sides 11a of each grid plate 11 from the fixed and movable recontactors 4, 5. The configuration includes shielding plates 12 and 12 made of wood, so that the arc heat of the arc generated between the fixed and movable liquid contactors 4 and 5 is shielded by the shielding plate 12, and the side portions of the grid plate 11 are This is to prevent melting and scattering of 11a. However, in this case, the grid plate 11
The space above and below the side portion 11a is also covered by the shielding plate 12.
Therefore, there was a risk that the internal pressure of the circuit breaker 1 would rise due to the arc heat and the main body case 2 and cover 3 would be damaged.

[Object of the Invention] The present invention has been made in view of the above circumstances, and its purpose is to prevent grid plates from melting and scattering due to arc heat, and to alleviate the increase in internal pressure of a circuit breaker due to arc heat. To provide a circuit breaker arc extinguishing device that can.

[Summary of the Invention] The present invention provides a grid plate made of a magnetic material having side portions located at a predetermined interval on both sides of a fixed contact and a movable contact that approaches and separates from the fixed contact at the center. In the case where a plurality of grid plates are arranged with gaps between them, the grid plate is placed on the inner side of both sides of one of the plurality of grid plates that extends from the vicinity of the fixed contact to the middle part in the grid plate arrangement direction. A shielding plate made of insulating material is provided to shield the sides of the grid plate from the fixed and movable re-contactors. The grid plate was shielded from arc heat by a shielding plate, and the sides of the grid plate, which were away from the fixed contact and were difficult to melt, were not shielded by a shielding plate, and the spaces between the grid plates were left open. Add a characteristic to a place.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. However, parts that are the same as those in the conventional configuration are designated by the same reference numerals. That is, in FIG. 1, 1 is a circuit breaker, 2 is a main body case, 3 is a cover, 4 is a fixed contact, 5 is a movable contact, and 6 is a circuit opening/closing mechanism.

Now, 13 is an arc extinguishing device, which will be described below.

Reference numeral 14 designates a grid plate made of magnetic material in which a substantially V-shaped notch 15 is formed, as shown in FIGS. 2 and 3, and side portions 14a on both left and right sides thereof.

14a are located at a predetermined interval on both sides of the fixed and movable recontactors 4.5, and a plurality of left and right insulating materials are arranged so that a plurality of sheets, seven in this case, are vertically spaced apart from each other. It is supported and arranged by side plates 16.16.

Reference numeral 17 denotes a shielding plate made of an insulating material such as a white mica plate or a glass fiber plate, which has a rectangular plate shape, and is arranged in the grid plate arrangement direction (vertical direction) from the vicinity of the fixed contact 4 among the seven grid plates 14. ).

That is, the left and right sides 14a in the fourth page from the bottom in FIGS. 1 and 3.

They are provided inside the grid plate 14a so as to shield the side portions 14a of the grid plate 14 from both the fixed and movable liquid contactors 4 and 5, respectively. Also, in this case, seven grid plates 14
As for the top three grid plates 14 except for those whose side edges 14a are shielded by the shielding plate 17, the surfaces of the left and right side edges 14a, 14a are coated with, for example, ceramic, as shown in FIG. An insulating coating 18 is applied.

In the above configuration, when the circuit is interrupted, that is, when the movable contactor 5 separates from the fixed contactor 4, an arc is generated between the fixed and movable liquid contactors 4 and 5. Then, by the magnetic flux generated by the arc and each grid plate 14, the arc is drawn to the depths of the notch 15 of each grid plate 14 and stretched out, and the arc is cooled and divided, thereby extinguishing it. be done. Here, the arc heat generated at the beginning of the arc is high temperature, and the grid plate 14 near the fixed contact 4 is likely to melt due to the high temperature arc heat, but in this embodiment, the fixed contact Since both sides 14a, 14a of the fourth grid plate 14 from the bottom existing near the child 4 are shielded by the shielding plates 17.17, both sides 14a of these grid plates 14,
14a are shielded from arc heat, thereby preventing the side portions 14a of these grid plates 14 from melting and scattering. In addition, the second three grid plates 14 are not shielded, and the upper grid plates 14 are not shielded from each other. Since the space is in an open state, the internal pressure of the circuit breaker 1 is reduced due to arc heat, compared to a case where the side portions 11a of all the grid plates 11 are shielded by the shielding plates 12. The rise can be alleviated, and damage to the main body case 2 and cover 3 can therefore be prevented.

Moreover, especially in the case of this embodiment, since the insulation coating 18 is applied to the surface of the side part 14a of the upper three grid plates 14 whose side parts 14a are not shielded by the shielding plate 17, The grid plate 14 can also be reliably prevented from melting and scattering due to arc heat, and therefore the grid plate 14 can be further reliably prevented from melting and scattering due to arc heat.

It should be noted that the present invention is not limited to the above-mentioned embodiment. For example, as shown in FIGS. 5 and 6 as different embodiments of the present invention, the shielding plate 17 having a flat plate shape may be replaced with a U-shape. The shielding plates 19 and 19 may be arranged so as to surround the side portions 14a of the grid plates 14, and other modifications may be made as appropriate without departing from the scope of the invention. be.

[Effects of the Invention] As is clear from the above description, the present invention provides shielding plates to protect the sides of the grid plate near the fixed contacts, which are easily melted by arc heat during the initial stage of arc generation, from arc heat. The sides of the grid plate, which are away from the fixed contact and are difficult to melt, are not covered by a shield plate.
Since the mutual space between the grid plates was left open,
It has the excellent effect of preventing the grid plate from melting and scattering due to arc heat, and also mitigating the increase in internal pressure of the circuit breaker due to arc heat, thereby preventing damage to the main body case and cover of the circuit breaker. .

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention, in which FIG. 1 is a sectional view of the main parts of the circuit breaker, FIG. 2 is a plan view of the arc extinguishing device part of the circuit breaker, and FIG. 4 is a perspective view of the arc extinguishing device, FIG. 4 is a plan view of a grid plate whose side parts are coated with insulation, and FIGS. 5 and 6 show different embodiments of the present invention. The figure is a perspective view of the shielding plate, and FIG. 6 is a front view of the arc extinguishing device. 7 and 8 show the conventional configuration, FIG. 7 is a diagram corresponding to FIG. 1, FIG. 8 is a plan view of the arc extinguishing device, and FIG. 9 and 10 are different conventional configurations. The configuration is shown, and FIG. 9 is a diagram corresponding to FIG. 1, and FIG. 10 is a diagram corresponding to FIG. 2. In the drawing, 1 is a circuit breaker, 4 is a fixed contact, 5 is a movable contact, 13 is an arc extinguisher, 14 and 14a are a grid plate and its side parts, 17 is a shielding plate, 18 is an insulating coating, 19
is a shielding plate. Applicant Toshiba Corporation Figure 1 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] 1. A plurality of grid plates made of magnetic material each having a fixed contact and a movable contact moving toward and away from the fixed contact in the center and side portions located on both sides at a predetermined interval. The grid plates are arranged so that there are gaps between them, and the grid plates are arranged on the inner side of both sides of one of the plurality of grid plates extending from the vicinity of the fixed contact to the middle part in the grid plate arrangement direction. 1. An arc extinguishing device for a circuit breaker, characterized in that a shielding plate made of an insulating material is provided to shield the side portions of the contactor from both the fixed and movable contacts. 2. The circuit breaker according to claim 1, wherein the surfaces of both sides of the grid plates other than the grid plates shielded by the shielding plate are coated with an insulating coating. arc extinguishing device. 3. The arc extinguishing device for a circuit breaker as set forth in claim 1, wherein the shielding plates have a U-shape and are arranged so as to surround the side portions of the grid plates.