JPS5999625A - 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] The present invention provides a method for reducing the
The present invention relates to a circuit breaker that uses the magnetic driving force of the magnetomotive flux generated by the large current to transfer the arc to the arc extinguishing device side, or that current-limits the arc using a current-limiting resistor.

[Background technology]

A first conventional example of this kind of magnetically driven arc is disclosed in Japanese Patent Laid-Open No. 55-53839. That is, the movable contact plate and the fixed contact plate are arranged in parallel so that the current directions are opposite to each other, and the arc is magnetically driven toward the arc extinguishing device by the magnetomotive flux of the large current.

Since this first conventional example uses a so-called self-induction system in which the magnetic driving force is dependent on the current passing through the movable contact plate and the fixed contact plate, a very strong driving force cannot be expected.

Therefore, as a second conventional example, U.S. Patent Specification No. 3815
Publication No. 0F19 exists. That is, the coil is inserted in series in the circuit extending from the power supply side terminal fitting to the load side terminal fitting. Specifically, the connection is inserted between the movable contact plate and the load side terminal fitting.

In this second conventional example, since the coils are connected in series in the circuit, current flows through the coils even at the rated current, which causes problems with heat generation, especially in large-capacity circuit breakers.

Further, as a third conventional example, there is a Japanese Utility Model Publication No. 56-36037, in which the generated arc first transfers to the induction arc plate through a space, and then the coil J When this large current flows, it is magnetically driven by a single electromotive flux. The disadvantage of this third conventional example is that it takes time for the arc to transfer to the arc induction plate, and according to experiments, it took 2 to 3 m5ec.

The key point of this method using auxiliary contacts is how quickly the arc generated at the main contact can be extinguished. (The arc on the auxiliary contact side was extinguished first), and the problem that the arc on the main contact was not extinguished or transitioned in a short time became apparent.

[Purpose of the invention]

The present invention has been made in view of the above points, that is, the main contacts share the rated current, the auxiliary contacts share the large current through large current time limiting elements, etc. The purpose of this is to quickly transfer the arc of the main contact to the side of the arc device.

[Disclosure of the invention]

(Example) The present invention will be described below based on ν1WII listed as an example. l is a breaker main body, which is made up of a container stand 2 and a top lid 3 made of synthetic wood. 4) Exhaust hole formed at one end of the main body 1, 5 (power supply side terminal fitting installed at one end of the main unit 2), 6 (Masono power supply (when connecting the base end 63 to all terminal fittings 5) This is a fixed contact plate in which one of the main contacts 7, which is a fixed contact, is fixed to a free end 6b extending along the two-piece heat exchanger base 2I. 8 is an insulator inserted into the folded part to prevent the free end 6a from hanging down. 9 is the other main contact of the movable contact A (the other main contact, which is connected to the load side terminal metal part). It is fixed to the contact plate 10.
The reason why the free end 6b of the fixed contact plate 6 is folded back into a U-shape is that the current direction is opposite to that of the movable contact plate lO.
This is because when a large current is applied, an electromagnetic repulsive force acts due to the electromotive flux, thereby improving the opening speed of the movable contact plate 10. 11 is an auxiliary contact electrically connected to the main contact 7 on the fixed contact side;
12 is an auxiliary contact electrically connected to the main contact 9 on the movable contact side.

First, the electrical connection between the main contact 7 and the auxiliary contact 11 on the fixed contact side is made via a current limiting element 13 such as a coil or a resistance wire. That is, one end 13@ of the current limiting element 13 is connected to the free end 6@ of the fixed contact plate 6, the other end 13b is connected to the arc traveling plate/relay terminal plate 14, and the auxiliary contact 11 is connected to the relay terminal plate 14. is fixed. Also, the main contact 9 on the movable contact side
and the auxiliary contact 12 are connected via the auxiliary movable contact plate 15, the U-shaped braided wire 16, and the electromagnetic part X. That is, an L-shaped piece 10m is provided at the free end of the main contact side movable contact plate 10, and a similar L-shaped piece 15B is also provided on the auxiliary movable contact plate 15, with the vertical pieces 10b and 15b facing each other to form a thin braided wire. 16 are connected with brazing on the inner surface, and the currents are in opposite directions to each other and an electromagnetic repulsion force is exerted to press the auxiliary movable contact 42 into the fixed auxiliary contact 11 and prevent it from floating up. At this time, the vertical pieces 10b and 15b of the five-shaped pieces 10a and 151N serve as holders to prevent the U-shaped braided wire 16 from spreading. The auxiliary movable contact plate 15 is pivotally supported by a shaft 17.

In order to improve the electrical connection of this pivot, the braided wire 1
6 exists, and the auxiliary movable contact plate 15 has the auxiliary contact 1.
2 is fixed. This auxiliary movable contact plate 15 has a tension spring 1 suspended between the auxiliary movable contact plate 15 and the movable contact plate 10.
8, it is always pressed so as to be connected to the auxiliary contact 11 on the fixed contact side.

Therefore, even if the main contacts 7 and 9 are opened, the spring 18 acts so that the co-auxiliary movable contact plate 15 hangs down to some extent.
Opening will be delayed by that amount. That is, this auxiliary contact 11.12
Since an arc is generated on the side, these contacts 11 and 12 are made of high melting point metal scrap, such as tungsten, or its alloy to reduce the generation of metal vapor and improve the breaking conditions by reducing the vapor density. are doing. 19 is an arc extinguishing device located on the side of the arc extinguishing hole 4. In the drawings of the embodiment, a plurality of grids 20 are stacked at regular intervals, and the lowermost grid 20 and the relay terminal It is connected to the plate 14. The arc is transferred through this relay terminal plate 14. Of course, the arc extinguishing device is not limited to this.
Other means may also be used. 21 is an insulating frame for fixing the grid 20, and 22 is a U-shaped yoke when the current limiting element 13 is used as a coil, which is used to make the magnetic flux strong. 2
Reference numeral 3 designates a horseshoe-shaped grid, one end 23m of which is fixed to the arc traveling plate/relay terminal plate 14, and the main contacts 7 and 9 are located in the opening 23b of the free end. Therefore, the arc generated between the main contacts 7 and 9 quickly moves from the relay terminal plate 14 to the arc extinguisher 19 side via the horseshoe-shaped grid 23.

(Operation) Next, to explain the operation of the circuit breaker of the present invention, in Figure J81, the main contact 7.9 and the auxiliary contact 11.12 are connected to each other, and the auxiliary contact 11.12 is connected to the main contact 7.9. They are parallel to each other.

In this state, since the current limiting element 13 is inserted, the resistance is higher on the auxiliary contacts 11 and 12 side, the current flows through the main contacts 7 and 9 side, and the heat generation is extremely small.

Subsequently, when a large current such as a short circuit current or an overload current flows, the movable contact plate IO on the main contact side first performs an opening operation as shown in FIG. Then, the opening operation is started so that the auxiliary contacts 12 are also included, but at this time, both auxiliary contacts 11.
12 is joined.

Therefore, a large current flows through the fixed contact plate 6 - current limiting element 13 - relay terminal plate 14 - auxiliary contact 11° 12 - auxiliary movable contact plate 15 - braided wire 16 - movable contact plate 10 as shown by the arrow in the figure.
The current limiting element 13 limits the large current. Of course, if the current limiting element 13 is a coil, a strong magnetomotive flux is generated, and the magnetomotive flux acts to magnetically drive the arc generated between the auxiliary contacts 11 and 12 toward the arc extinguishing device 19.

Thereafter, as shown in FIG. 4, the arc current flows through the arc extinguishing device and is quickly extinguished.

In this case, the arc generated between the main contacts 7 and 9 is quickly transferred to the horseshoe-shaped grid 23, transferred to the relay terminal plate 14, and extinguished in parts by the arc extinguisher M19.

〔effect〕

As described above, the main contacts 7 and 9 of the present invention are electrically connected to each other as a pair, and are connected together with the main contacts 7 and 9 at the rated current. and an auxiliary contact 11.12 which opens with a delay after the main contact 7.9 opens, and one electrical connection between the main contacts 7, 9 and the auxiliary contact 11.12 '6-current limiting. A relay terminal plate 1 that performs parallel operation via the element 13, further fixes the fixed side auxiliary contact ti, and transfers the arc to the arc extinguishing device 19.
4 and a horseshoe-shaped grid 23 with one end fixed to this relay terminal plate 14 and the main contacts 7.9 located in the opening 23b of the free end, the arc generated at the main contacts 7, 9 is It is transposed to the horseshoe-shaped grid 23 and quickly disappears, which has the effect of solving the problem of the system in which the auxiliary contact and the main contact are connected in parallel via a current limiting element.

[Brief explanation of drawings]

The open plane shows one embodiment of the present invention, and FIG. 1 is a cross-sectional front view;
FIG. 2 is a plan view, and FIGS. 3 and 4 are operational diagrams. 7.9...Main contact, 11...12...Auxiliary contact,
13...Current limiting element, 14...Medium #blade plate, 19...
- Arc extinguishing device, 23...horseshoe-shaped grid. Patent Applicant Matsushita Electric Works Co., Ltd. Representative Patent Attorney Toshimaru Takemoto (and 2 others) Figure 2 141 No. 3 [4 R Figure 4 f3 22 6' 2ja 2j

Claims (1)

[Claims] fi+ The main contacts facing each other so as to match each other are electrically connected to each other as a pair, and during the rated forward flow, they are connected together with the main contacts and pull, and after the main contacts open, there is a delay. An auxiliary contact that cross-opens, a current-limiting element that electrically connects one of the main contact and the auxiliary contact in parallel, and an arc generated at the delayed ISF and auxiliary contact that is polarized. In a circuit breaker made up of an arc extinguishing device that extinguishes the arc in parts by retracting, the fixed side contacts of the auxiliary contacts have the same character, and a relay terminal board that transfers the arc to the arc extinguishing device, and this relay terminal board. 1. A circuit breaker characterized in that it is made of a horseshoe-shaped grid, which is fixed to the circuit breaker, has an open free end, and has a main contact located in the opening.