JPS6219013B2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Application) The present invention relates to a circuit breaker that protects a circuit from breaking when an excessive current such as a short circuit current or an overload current flows, and particularly relates to an arc extinguishing device thereof. .

(Problems with the prior art) Recent circuit breakers are required to be smaller and have a higher capacity. The arc is extinguished in parts, and the now safe arc gas is discharged from the exhaust port to the outside of the vessel.

In such an arc extinguishing device, there is a problem that the grid block itself that extinguishes the arc in sections acts as a fluid resistance against the arc, which increases the pressure within the arc extinguishing chamber and impedes the arc's movement. Furthermore, if an arc enters the grid block, the amount of gas discharged is limited by the exhaust hole, and therefore the pressure behind the grid block increases, which may push the arc back toward the contact. In such a case, there is a risk that not only the current limiting characteristics will be deteriorated, but also the circuit or the disconnector itself will be damaged due to the pressure increase in the arc extinguishing chamber.

On the other hand, as a method to improve arc running, insulating plates are placed upright on both sides of the upper and lower arc running plates, a space is provided between these plates and the side walls of the device stand, and this space allows gas to circulate to the arcing part. Some use a recirculation method. This is less effective when an arc enters the grid block, and is less effective in reducing the pressure within the arc extinguishing chamber.

(Purpose) The present invention was made in view of the above-mentioned points. When the arc is traveling, the pressure in front of the arc is made smaller than the pressure in the back of the arc. When the arc enters the grid block, the pressure in the back of the arc is reduced. let it rise;
The object of the present invention is to provide an arc extinguishing device for circuits and disconnectors that has good current limiting characteristics.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

1 is the main body of the cutter, which is composed of a synthetic resin container stand 2 and an upper lid 3. Reference numeral 4 denotes a power supply terminal device installed at one end of the device stand 2, and 5 a terminal connection frame drawn out from the power supply terminal device 4, which is connected to one (upper) arc running plate 7 provided with a fixed contact 6. . Therefore, the portion of the upper arc traveling plate 7 where the fixed contact 6 is provided serves as a fixed contact. Note that the circulation hole provided in the upper arc traveling plate 7 will be described later. 20 is a movable contact 19 that comes into contact with and separates from the fixed contact 6
These fixed and movable contacts constitute an arcing part X. 8 is the other (lower) arc running plate opposite to the upper arc running plate 7, and is seated along the bottom wall 2a of the device stand 2.

Reference numeral 9 denotes a grid block in which a plurality of grids 10 are stacked with a certain space interposed between them, and the portions of the upper and lower arc travel plates 7 and 8 that are farther away from the arcing portion X are located at the uppermost and lowermost stages. Therefore, the upper and lower arc travel plates 7 and 8 draw the arc generated at the arcing portion X into the grid block 9. 11 is grid 10
an insulated side plate 12 supporting the grid block 9;
This is a back plate having an exhaust hole 13 located immediately behind the.

Reference numeral 17 denotes a ceiling wall that constitutes the circulation chamber 16 on the side where the grid block 9 is not located, together with the upper arc travel plate 7. In this circulation chamber 16, a gas path is determined by a guide chamber and a circulation hole of the upper arc travel plate 7, which will be described later.

Reference numeral 14 denotes an exhaust port provided at the upper corner of the main body 1, through which the gas that has passed through the grid block 9 is discharged to the outside of the main body. Reference numeral 15 denotes a space interposed between the grid block 9 and the exhaust port 14, and the space 15
6, the gas that has passed through the grid block 9 is directed approximately at right angles and drawn into the exhaust port 14.

Next, to explain the circulation hole of the upper arc running plate 7, when the arc is drawn from the arcing part X into the grid block 9,
A reflux hole 18 communicating with the reflux chamber 16 at a passing position.
is provided. Therefore, the gas path in the reflux chamber 16 is from the reflux hole 18 to the reflux chamber 16 to the guide chamber 15.
There are two possible cases in which the fluid flows: → the exhaust port 14, and another where it flows from the grid block 9 → the guide chamber 15 → the circulation chamber 16 → the circulation hole 18 → the grid block 9. It is preferable that the upper arc traveling plate 7 constituting the circulation chamber 16 be inclined so that it approaches the lower arc traveling plate 8 on the arcing part X side and moves away from the guide chamber 15 side. By doing this,
The area of the reflux chamber 16 in the portion communicating with the guide chamber 15 can be gradually reduced, and it is possible to suppress the arc from slipping out of the reflux chamber 16.

A manual handle 21 is connected to the movable contact 20 via links 22 and 23 to turn it on and off. 24 is a latch fitting, link 2
It has two and twenty-three shafts 25 and guide grooves 26. 27
2 is a tripping metal whose arm 27a engages with the latch piece 24a of the latch 24, 28 is a bimetal, and 29 is an electromagnetic device. When an excessive current flows, the bimetal 28 or the electromagnet 29 activates the tripping metal 27. The movable contact 20 is turned off.

(Operation) Figure 3 shows the initial stage of arc generation, that is, the state in which the arc is traveling from the arcing part
It flows through both routes: → guide chamber 15 → exhaust port 14, circulation hole 18 → circulation chamber 16 → guide chamber 15 → exhaust port 14. Therefore, both paths lead to the exhaust port 14, making the pressure in front of the arc lower than the pressure behind the arc, facilitating arc travel (drawing into the grid block 9).

FIG. 4 shows a state in which the arc enters the grid block 9 and arc division is performed, and gas flows along the route from the guide chamber 15 to the exhaust port 14, and the gas pressure on the side of the arcing part X decreases. Therefore, it also flows along the route of guide chamber 15 → circulation chamber 16 → circulation hole 18 → grid block 9. Therefore, the pressure behind the arc is increased and the arc is prevented from being pushed back toward the arcing portion X side.

Such an operation provides a preferable arc-extinguishing effect and provides good current-limiting characteristics. In addition, it is possible to prevent the re-ignition phenomenon and the like, thereby making it possible to perform stable shedding.

[Effects of the Invention] Since the arc extinguishing device for circuits and breakers of the present invention is configured as described above, when the arc is running, the pressure in front of the arc is made smaller than the pressure behind the arc, and the arc enters the grid block. If this occurs, the pressure behind the arc will increase, resulting in better current limiting characteristics.

[Brief explanation of the drawing]

Fig. 1 is a cutaway plan view showing an embodiment of the present invention, Fig. 2 is a vertical cross-sectional view thereof, Fig. 3 is an explanatory diagram of the state in which the arc is running, and Fig. 4 is an illustration of the state in which the arc is running. FIG. 3 is an explanatory diagram of the state in which the grid block has been entered. DESCRIPTION OF SYMBOLS 1...Shipping breaker main body, 2...Device stand, 3...Fixed contact, 7, 8...Upper and lower arc running plates, 9...Grid block, 14...Exhaust port, 15...Guide chamber, 16... ... Circulation room, 17... Ceiling wall, 18...
Circulation hole, X... arcing part.

Claims (1)

[Claims] 1. An arcing part consisting of a movable contact with a movable contact and a fixed contact with a fixed contact, a grid block made of a plurality of grids stacked in a fixed space, and a grid block located at the top and bottom of the grid block and separated from the arcing part. Upper and lower arc running plates that draw arc gas into the grid block, the bottom wall of the pedestal on which the lower arc running plate sits, a ceiling wall that forms a circulation chamber on the side where the grid block is not located together with the upper arc running plate, and the grid block. It is a space interposed between the exhaust port and the guide chamber that communicates with the reflux chamber, and the upper arc traveling plate has a reflux chamber at the position where the arc passes when it is drawn from the arcing part into the grid block. An arc extinguishing device in a circuit or disconnector that is provided with a circulation hole that communicates with the chamber.