JPS60175336A - 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 a circuit breaker, and more particularly to reducing arc extinguishment of its contacts and improving its breaker performance.

[Prior art]

Figures 1 to 3 are cross-sectional views showing conventional circuit breakers.
Each shows a different operating state.

1 is a cover, ko is a base, and a container 3 is constituted by the cover/ and the pacco. A fixed contact is an electrical contact, and its fixed conductor! It has a fixed contact 6 at one end, and the other end is a terminal portion to be connected to an external conductor (not shown). A movable contact 7 is an electric contact, and has a movable contact D facing the fixed contact B at one end of its movable conductor g.

io is the movable contact device, /l is the movable arm, and the crossbar
12 and is configured to be opened and closed when each pole is spaced. /3 is an arc extinguishing chamber, and an arc extinguishing plate /<7 is held by a side plate /j-. 16 is a toggle link mechanism, which is composed of an upper link 17 and a lower link /I. Above link 1
One end of 7 is connected to the cradle l9, and the other end is connected to one end of the lower link l by shafts 20, 2/, respectively. The other end of the lower link tg is connected to the movable arm // of the movable contact device IO. Here is the tilting type operating handle 1. 23 is the operating spring, the shaft of the toggle link mechanism 16, 2
/ and the operation handle here. 2
+, , 2j- are thermal and electromagnetic tripping mechanisms, respectively, and when activated, the tripping mechanism 2g is rotated counterclockwise by a metal 26 and a movable iron core 27, respectively. Reference numeral 29 is a latch whose one end is locked to the trip bar 2F and the other end is locked to the fredle 19.

When the operating handle 2 is tilted to the closing position with the creno dollar 19 locked to the latch 29, the toggle link mechanism 16 is extended, the shaft 21 is locked to the freddle 19, and the movable contact is joined only to the fixed contact. This state is shown in FIG.

Next, if you tilt the operation non-dol 2 unit to the open position, the spike) y
The IJ link mechanism 16 bends to connect the movable contact 6 to the fixed contact 6.
The movable arm /l is further opened and locked to the fredl shaft 30. This state is shown in Figure 1.

Furthermore, if an overcurrent flows through the circuit in the closed state shown in FIG. , the fredle rotates clockwise around the fredle shaft 30 and is stopped by the stopper shaft 31. Since the connection point between the fredle 19 and the upper link 17 exceeds the line of action of the actuation spring 3, the toggle link mechanism 16 is bent by the spring force of the actuation spring 23, and each pole is interlocked by the crossbar 23. Automatically shuts off. This state is shown in FIG.

Next, the behavior of an arc generated when a circuit breaker interrupts current will be explained.

Now, when the movable contact 6 is in contact with the fixed contact 6, the power is transferred from the power supply side to the fixed conductor! , the fixed contact 6, the movable contact D, and the movable conductor g in order to be supplied to the load side. When a large current such as a short circuit current flows through this circuit in this state, the thermal tripping mechanism 2 or the electromagnetic tripping mechanism 2S operates to separate the movable contact 9 from the fixed contact 6, as described above. At this time, three arcs are generated between the fixed and movable contacts 6 and 9, and an arc voltage is generated between the fixed and movable contacts 6 and 9. This arc voltage increases as the separation distance of the movable contact from the fixed contact 6 increases, and at the same time, the arc 3 is attracted and expanded in the direction of the arc-extinguishing plate/+ by magnetic force, so that the arc voltage increases further. Rise.

In this way, the arc current reaches a current zero point and the arc 32 is extinguished, completing the interruption. During such a blocking operation, a large amount of energy is generated between the movable contact 9 and the fixed contact 6 by the arc 3.2 within a short period of time, ie within a few milliseconds. Therefore, the temperature of the gas inside the container 3 rises and the pressure also rises rapidly, but this high temperature and high pressure gas is released into the atmosphere from the outlet 33 formed in the side wall of the container 3 on the power supply side. be done.

In the operation of the circuit breaker as described above, arc resistance R is generally given by the following formula.

That is, R-ρ - where R: arc resistance (Ω) ρ: arc resistivity (Ω・cIrL) l: arc length (In) S: arc cross-sectional area (cd) However, generally at large currents of several KA or more, , and in a short arc 3.2 where the arc length l is less than or equal to Sθ, the arc space is occupied by as many metal particles as the fixed contact and the movable contact. Ejection occurs perpendicular to the contact surface. In addition, the ejected metal particles have a temperature close to the boiling point of the metal at 6° at the contact point, and as soon as they are injected into the arc space, they are injected with electrical energy, causing a high temperature island pressure. It becomes gas.

Under such circumstances, contact point 6. Contact point 6. This will lead to melting and wear and tear of the device. Therefore, as shown in Figures 4'A and +B, the fixed conductor 3
An arc runner 3'l is disposed on the rear side of the fixing position of the fixed contact base. The main purpose of this is to protect both contacts 6° by quickly transferring the legs of the 3 arcs generated between the contacts 6 and 9 on the fixed contact 6 side to the 3 arc runners.

However, in the above case, even if the arc 32 is dislocated to the arc runner 3t, it is difficult to completely separate from the fixed contact 6, and the arc current at the time of this dislocation is Since the arc current flows from the base end of the arc current around the fixed contact 6 side to the arc liner 3da, the fixed contact 6 is overheated due to the passage of the arc current, and therefore the fixed contact 6 is easily worn out.

In order to eliminate such inconveniences, a fixed contactor Sl as shown in FIG. S is formed. The fixed contact Sl is
It consists of a fixed conductor S and a fixed contact 6. Fixed conductor! r
The tip sides S and tO of the U are formed into a substantially U-shape with the arc 32 side open, and the vertical piece on the load side of this substantially U-shaped tip SSO! The tip of the contact fixing piece 521 extends toward the power source side (base end side).

However, in the above case, the gas g accompanying the generation of the arc 3.2 stays in the inner space S of the U-shaped tip 320, and because of this gas, the fixed contact 6 may also close to the tip side 320 of the fixed conductor 5.2. The corner between and the base end side S22! ; Since the legs of the three arcs are prevented from moving to 22a, there was a drawback that the breaking performance deteriorated.

[Summary of the invention]

This invention was made for the purpose of eliminating the above-mentioned drawbacks, and includes providing a gas outlet hole in at least one of the pair of vertical pieces and the connecting piece in the substantially U-shaped tip portion, and By providing a protrusion for guiding the outflow of gas in the corner of the inner space of the U-shaped tip, a circuit breaker with less wear on contacts and excellent breaking performance is provided.

[Embodiments of the invention]

Hereinafter, one embodiment of the circuit breaker of the present invention will be described based on the drawings. 6 to 9 are perspective views and sectional views showing one embodiment of the present invention, and FIGS.
The same or corresponding parts as those in the figures are given the same reference numerals, and the explanation thereof will be omitted.

For example, the connecting piece of the approximately U-shaped tip S2Q! i
As shown in FIGS. 6A and 6B, a gas outflow hole 53 is formed in -〇b, and the approximately U-shaped tip 3.20
Vertical piece on the load side! As shown in FIGS. 7A and 7B, a vertical wall Sda is formed on the PESCO opposite to 20&.

The vertical wall 5 is designed to direct the gas flow g from the gas outlet hole S3 upward. In addition, the approximately U-shaped tip S
Vertical piece on the power supply side of 20! Gas outflow hole in r20 c! r
A through hole 53a is provided which is continuous to 3. This through hole j,? A is provided with a mold protrusion 100 in which a part of the PESCO protrudes into the inner space S.

Next, the operation of the circuit breaker with the above configuration will be explained.

The opening/closing operations by the fixed and movable contacts 51 and 7 are the same as those of the prior art, and their explanation will be omitted.

With the opening operation of the movable contactor 70, the contacts 6 and 9
An arc 32 is generated between the arc 3λ and the arc 3λ.
Since it is attracted by the magnetic force of F and begins to expand, the corner 5, 251 between the distal end side S20 and the proximal end side, t, 2.2 of the fixed conductor S2 is heated by the arc 3λ, and here The foot of the arc 32 is in a state where it is easy to shift (FIG. 7A).

In this state, the fixed conductors 11-. The gas g caused by the generation of the arc 32 tends to stay in the inner space S (FIG. 7A) of the tip S: t of the tip S:t.
Connecting piece at O! j; 20b and the gas outflow hole 53 are formed, and the mold protrusion 100 is provided at the corner of the inner space S where the gas g tends to stay, so that the gas g does not enter the inner space S. The gas is sequentially discharged from the left gas outlet hole 3 without stagnation. For this reason, Ark 3 is
Without being hindered by the gas g, it moves to the fixed conductor S side as shown in FIG. 7B and is further extended. Especially the vertical piece on the load side of the U-shaped optical end SSO! ;Since a standing wall S-hiro is formed opposite to 20a, it is a gas outflow hole! The gas g from 3 is a flow path formed by the vertical wall sq! 3 and pushes out the arc 3.2 from the back side (load side), contributing to the elongation of the arc 32.

Therefore, the transition from arc 3 to the power supply side is smooth.
(After this arc 3.2 was greatly extended,
The arc is extinguished at the current zero point.

In other words, the gas flow g in the inner space S of the U-shaped tip S2Q of the fixed conductor 5.2 is quickly discharged through the gas outlet hole S3, so that the arc 3 is not obstructed by the gas flow g. , quickly separates from the fixed contact 6, etc., and wear and tear on the fixed contact 6, etc. is reduced.

Furthermore, in this example, the tip of the fixed conductor octopus! Since the gas outflow hole S3 is provided in the connecting piece s and 2ob of 20, for example, when the fixed contact 6 is welded and fixed, if the outflow hole S3f is used as a through hole for the welding electrode (not shown), it will be able to connect to the contact B (~ This has the advantage that the electrodes can be sandwiched from above and below, making the work easier.

In the above embodiment, the gas outflow hole s3 was formed in the connecting piece s2b of the tip end 52° of the fixed conductor octopus.

As shown in FIG. gB, the gas outflow hole 53 may be formed in the left λ (7a) of the load side vertical piece.

Also, connect the gas outflow hole s3 to the load side vertical piece! r20a
FIG. 9A shows another embodiment in which the structure is formed as follows.

It is shown in FIG. 9B. In this example, a fixed conductor! An insulating plate that protrudes toward the load side on the contact fixing piece jt2/ of -! This is the one that has R. This insulating plate j[ prevents the gas generated in the load side space of the arc 3 from moving downward, so that the gas g in the inner space S of the approximately U-shaped tip Sλ0 flows into the left gas outlet hole 3. It is discharged smoothly. That is, in this case, it is not necessary to form the standing wall Sa at the base λ as in the above embodiments (the arc 3.2 can be effectively transferred to the power source side and extended). However, the mold protrusion 10θ is provided at the corner of the inner space S, and the gas flow g in the inner space S is efficiently directed to the outflow hole 53.
is discharged from. In addition, the gas outflow hole S3 is a pair of vertical pieces! Of course, it is possible to selectively provide a plurality of pieces among the 2°a, 32□C and the connecting piece S2θb.

〔Effect of the invention〕

As explained above, according to the circuit breaker of the present invention, gas flows into at least one of the pair of vertical pieces and the connecting piece at the substantially U-shaped tip of the conductor of one electric contact. By providing a hole and a protrusion at the corner of the inner space of the approximately U-shaped tip to guide the outflow of gas, there is less wear and tear on the contact (and it has the advantage of excellent breaking performance. .

[Brief explanation of the drawing]

Figures 1 to 3 are cross-sectional views of a conventional circuit breaker in different operating states, and Figures 4'A and 4'A and QB are perspective views of a fixed contact with an arc runner and Figure S is a perspective view of a fixed contact of a conventional circuit breaker, and Figures 6A and 6B each show a fixed contact incorporated in an embodiment of the circuit breaker according to the present invention. A perspective view and a sectional view, FIG. 2A. 7B is an explanatory diagram of the operation of the same circuit breaker, FIG. FIG. B is a cross-sectional view that also serves to explain the operation of essential parts of still another embodiment of the present invention. 3. Container, 6. ?・・Contact, 7, 51・・Electric contact, g, s; t・・Conductor, /4′・・Arc-extinguishing plate, 3:l・・
Arc, S3...Gas outflow hole, SSO...Roughly U-shaped tip! ;,20a,! ;,lOc...vertical piece,! 2/
...Contact fixing piece, left 3a...through hole, ioo...mold protrusion, g...gas flow, S...inner space. Note that the same reference numerals in the figures indicate the same or corresponding parts. 8A drawing 9A drawing 8B drawing 9B drawing

Claims (1)

[Claims] (1) At least one pair of electrical contacts consisting of a conductor and a contact fixed thereto, which open and close within the container, and for extinguishing the arc that occurs between the contacts when the electrical contacts open and close. a plurality of arc-extinguishing plates arranged in the container, and the tip side of the conductor of one of the l pairs of electric contacts is opened to the arc side of the conductor. In a circuit breaker which is formed into a U-shaped tip and has the tip of the vertical piece on the load side of the substantially U-shaped tip extending toward the power supply side as a contact fixing piece, the substantially U-shaped tip of the conductor is pressed against the l pair. A gas outflow hole is provided in at least one of the vertical piece and the connecting piece, and a protrusion for guiding gas outflow is provided in a corner of the inner chamber of the substantially U-shaped tip. A circuit breaker featuring: