CN2676394Y - A grating sheet arc-suppression chamber with gas-generating insulating material interlayer - Google Patents

Abstract

The utility model discloses a grid arc extinguishing chamber with a gas-generating insulating material interlayer applied to various low-voltage circuit breakers, including the grid arc extinguishing chamber of a traditional circuit breaker; Gas-producing insulating clips are inserted between two adjacent ferromagnetic grids, and the gas-producing insulating clips are respectively placed on both sides of each layer of ferromagnetic grids to form a gap in the middle; the moving contact is placed between the gaps. between. For the molded case circuit breaker, the moving contact can be moved in the middle. When the circuit breaker is disconnected, the arc contacts the sheet of insulating material, which is vaporized to produce a gas containing hydrogen. On the one hand, the arc is cooled, and on the other hand The pressure of the arc extinguishing chamber is increased to generate a gas driving force, which promotes the arc to enter the grid smoothly and extinguish it. In the laboratory, the model arc extinguishing chamber is used to do the comparative test of the grid arc extinguishing chamber with and without insulating sheet. When breaking the 2kA current, the former can reduce the peak value of the arc current by 15.3%, and the arcing time can be reduced by 40%. Therefore, the breaking performance is greatly improved.

Description

A grid interrupter with interlayer of gas-generating insulating material

technical field

The utility model belongs to the field of low-voltage electrical appliances and relates to an arc-extinguishing chamber of a low-voltage circuit breaker, in particular to a grid plate arc-extinguishing chamber with a gas-generating insulating material interlayer which can be widely used in low-voltage circuit breakers.

Background technique

The annual output value of low-voltage circuit breakers in my country has exceeded 10 billion yuan. With the increase of low-voltage power grid capacity, the demand is increasing rapidly. In particular, it is necessary to develop low-voltage circuit breakers with small size and high breaking performance. For circuit breakers, it is even more necessary to improve their current limiting characteristics. The traditional grid interrupter can no longer meet the requirements of breaking performance.

The structure of the low-voltage circuit breaker is shown in Figure 1a and Figure 1b. Its structure includes an arc extinguishing chamber 1 composed of multiple iron grids 2, a moving contact 5 and a static contact 6, a mechanism 8, and a release 9. The handle 10, the plastic shell 11, the upper outlet terminal 12 and the lower outlet terminal 13 are composed (see accompanying drawing 1), and the breaking characteristics of the circuit breaker are mainly determined by the contacts and the arc extinguishing system.

In the traditional grid arc extinguishing chamber, when the arc enters the grid, due to the sudden increase of the arc voltage and the high temperature in the rear area, that is, the arc track and the contact area, thermal breakdown in the rear area will occur, resulting in The arc runs out from the grid. This phenomenon is called arc back breakdown. This phenomenon occurs repeatedly, causing the arc voltage to drop many times, thus prolonging the arcing time of the current-limiting circuit breaker. With the increase of the capacity of the low-voltage power grid, it is necessary to develop low-voltage circuit breakers with small volume and high breaking performance, especially for miniature circuit breakers and molded case circuit breakers, it is necessary to improve their current-limiting characteristics.

Contents of the invention

In view of the defects or deficiencies in the above-mentioned prior art, the purpose of the present utility model is to provide a novel grid arc extinguishing chamber with a gas-generating insulating material interlayer.

The technical solution to achieve the above purpose is that the grid arc extinguishing chamber with interlayer of gas-producing insulating material includes the grid arc extinguishing chamber of the traditional circuit breaker; its characteristic is that the adjacent two pieces of ferromagnetic Gas-producing insulating clips are inserted between the grids, and the gas-producing insulating clips are respectively placed on both sides of each layer of ferromagnetic grids.

Other features of the utility model are that the ferromagnetic grid piece is U-shaped, and the gas-producing insulating clips placed on both sides of the ferromagnetic grid piece form a gap in the middle; the movable contact moves between the gaps. When the movable contact separates from the fixed contact and ignites an arc, the movable contact moves in the gap, and the generated arc contacts the gas-generating insulating clip, which is vaporized to generate a gas flow containing hydrogen.

The material of the gas insulating clip is polyoxymethylene or nylon.

The utility model grid sheet arc extinguishing chamber with a gas-generating insulating material interlayer, because the gas-generating insulating clip is provided, the gas-generating insulating clip generates a gas flow containing hydrogen, which cools the running arc and the contact area, Thus, the phenomenon of arc back breakdown can be suppressed.

Description of drawings

Figure 1 is a structural diagram of a low-voltage circuit breaker; Figure 1a is a cross-sectional view, and Figure 1b is a perspective view;

Fig. 2 is a schematic diagram of the structure of the utility model; wherein (a) is a superposition diagram of a ferromagnetic grid sheet and a gas-producing insulating clip, and (b) is a diagram of an arcing state when the moving contact moves away from the static contact, ( c) is the shape diagram of the ferromagnetic grid, and (d) is a schematic diagram of the gas-generating insulating clip stacked on the ferromagnetic grid.

Fig. 3 is the waveform diagram of the arc voltage without the gas producing clip;

Fig. 4 is an arc voltage waveform diagram with a gas producing clip;

Figure 5 and Figure 6 are schematic diagrams of two structures of the insulating clip.

Detailed ways

Below in conjunction with accompanying drawing and the embodiment that the utility model person provides, the utility model is described in further detail.

Referring to Fig. 1, according to the above-mentioned technical scheme, the grid arc extinguishing chamber with a gas-producing insulating material interlayer includes a ferromagnetic grid arc extinguishing chamber 1 of a traditional circuit breaker; two adjacent ferromagnetic grid arc extinguishing chambers 1 Gas-generating insulating clips 3 are inserted between the ferromagnetic grid pieces 2, and the gas-generating insulating clips 3 are respectively placed on both sides of each layer of ferromagnetic grid pieces 2. The ferromagnetic grid piece 2 is U-shaped, and the gas-producing insulating clips 3 placed on both sides of the ferromagnetic grid piece 2 form a gap 4 in the middle; the movable contact 5 moves between the gaps 4 . For a molded case circuit breaker, when the moving contact 5 leaves the static contact 6 and ignites the arc 7, the moving contact 5 moves in the gap 4, and the generated arc 7 contacts the gas-producing insulating clip 3, making it gas This gas flow can not only cool the arc, but also generate the driving force to drive the arc (see Figure 2).

The grid arc extinguishing chamber 1 composed of a layer of gas-producing insulating sheet 3 and a layer of ferromagnetic grid 2 is a "sandwich" structure, which combines the insulator wall gas-generating cooling arc and grid extinguishing There are two arc extinguishing measures, and the function of the gas-producing insulating interlayer is manifested in the following aspects:

When the contacts are opened to ignite the arc, the arc needs to stay on the contacts for a period of time before moving. This period is called the arc stagnation time. Reducing the arc stagnation time is not only beneficial to reduce the burning loss of the arc to the contacts, but also allows the arc to enter the arc extinguishing chamber as soon as possible, which is conducive to improving the breaking performance. Previous studies have pointed out that gas production on the wall can reduce the arc stagnation time.

The slit formed by the gas-generating insulating sheet makes the arc closely contact with it, and the sheet is gasified under the high temperature of the arc to generate gas. The gas generated by materials such as polyoxymethylene (POM) or nylon (Nylon) contains hydrogen. Composition, can have a good cooling effect on the arc, thus improving the arc voltage and current limiting performance, and improving the dielectric recovery strength when the arc crosses zero.

As the gas-generating insulating material 3 produces gas, the pressure of the arc extinguishing chamber increases during the breaking process, and a stream of air and air blowing force driving the arc is formed from the gas outlet of the arc extinguishing chamber to promote the arc to enter the grid arc extinguishing chamber and be extinguished quickly.

The ferromagnetic grid is composed of the main body and two legs. The legs mainly play the role of enhancing the magnetic field, but when the arc is in contact with it, metal vapor will be generated and affect the arc extinguishing. The grid structure proposed in this application, the legs of the ferromagnetic grid The inner side of the part is isolated from the arc by the gas-producing insulating sheet, thus eliminating this defect.

In the traditional grid arc extinguishing chamber, when the arc enters the grid, due to the sudden increase of the arc voltage, the temperature in the rear area, that is, the arc track and the contact area is very high, so the thermal breakdown of the rear area will occur, causing the arc Running out of the grid, this phenomenon is called arc back breakdown. This phenomenon occurs repeatedly, causing the arc voltage to drop many times, thus prolonging the arcing time of the current-limiting circuit breaker. The grid plate arc extinguishing chamber proposed by the utility model cools the arc track and the contact area due to the gas production in the insulating interlayer, so that the phenomenon of arc back breakdown can be suppressed.

In order to confirm the effect of the new grid interrupter, the applicant made a model interrupter, using the oscillation circuit as the breaking test power supply, when the interrupter is used with and without gas-producing insulating material clips, take the capacitor When the charging voltage is 200V and the expected short-circuit current is 2011A, the breaking test is carried out, and the test results are shown in Table 1.

Table 1 Comparison of breaking test with and without gas-producing material clips Interrupter Current limiting peak (A) Arcing time (ms) Heat let-through energy (A ² S) Arc energy (J) The number of obvious drops in arc voltage Without gas clip 1380.98 2.584 2547.3 452.6 1 With gas clip 1169.56 1.527 1971.6 376.7 6

It can be seen from the data in Table 1 that the current-limiting peak value is reduced by 15.3% and the arcing time is reduced by 40% when the thickness of the interlayer grid is used.

Fig. 3 and Fig. 4 are the oscillograms of the breaking tests of two kinds of arc extinguishing chambers respectively. The arc voltage waveform (see Fig. 3) without the gas-producing clip has obvious repeated drop phenomenon, while with the gas-producing clip The arc voltage waveform of the sheet (see Figure 4) is relatively smooth.

Figure 5 and Figure 6 show two derivative structures of the gas-generating insulating clip respectively. The gas-generating insulating clip in Fig. 5 is shorter, which is beneficial to prevent the hot air from reaching the top of the grid to reflect and enter the gap area, causing heat shock in the rear area wear. The structure of accompanying drawing 6 is that the gap formed by the gas-generating insulating clip gradually widens at the upper part, which is beneficial to fully utilize the cutting effect of the upper end of the grid on the arc.

Claims (4)

1. the grating arc-extinguishing chamber of the band gas producing lamination of insulation material of a low-voltage circuit breaker comprises the ferromagnetic grating arc-extinguishing chamber [1] of conventional circuit breaker; It is characterized in that be inserted with aerogenesis insulation intermediate plate [3] between adjacent two ferromagnetic grid sheets [2] of ferromagnetic grating arc-extinguishing chamber [1], aerogenesis insulation intermediate plate [3] is put in the both sides of the ferromagnetic grid sheet of each layer [2] respectively.

2. the grating arc-extinguishing chamber of band gas producing lamination of insulation material as claimed in claim 1 is characterized in that, described ferromagnetic grid sheet [2] is the U type, and the aerogenesis insulation intermediate plate [3] that is placed on the both sides of ferromagnetic grid sheet [2] forms a slit [4] in the centre; Moving contact [5] is between slit [4].

3. the grating arc-extinguishing chamber of band gas producing lamination of insulation material as claimed in claim 2, it is characterized in that, when described moving contact [5] is lighted electric arc leaving fixed contact [6], moving contact [5] moves in slit [4], electric arc [7] the contact aerogenesis insulation intermediate plate [3] that produces makes edge intermediate plate [3] gasification of drawing last breath produce the gas stream of hydrogen composition.

4. the grating arc-extinguishing chamber of band gas producing lamination of insulation material as claimed in claim 1 or 2 is characterized in that, the material of described aerogenesis insulation intermediate plate [3] is polyformaldehyde or nylon.

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