JPS5981822A - Circuit breaker - Google Patents

Abstract

(57) [Abstract] 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 to prevent
[Background technology] Related to a circuit breaker that moves the arc to the arc extinguishing device side using the magnetic driving force of the magnetomotive flux generated by the large current, or that limits the current by a current limiting resistor [Background technology] As a circuit breaker that magnetically drives this type of arc, First, as a first conventional example, there is 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. Pat.
No. 5059 exists. That is, the coils are inserted in series in the circuit 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.

Therefore, 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. .

In addition, as a third conventional example, there is Japanese Utility Model Publication No. 56-36037, which first transfers the generated arc to the induction arc plate through space, and then transfers the arc and the induction arc plate to the coil. As current flows, it is magnetically driven by magnetomotive 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.

[Purpose of the invention]

The present invention has been made in view of the above points, and its purpose is to share the rated current at the main contact, and share the large current at the auxiliary contact via a large current timing element, etc. do.

[Disclosure of the Invention] (Example) The present invention will be explained based on the drawings as an example. 1 is a breaker main body, a synthetic resin container stand 2 and an upper lid 3.
I'm talking about it. Reference numeral 4 indicates an exhaust hole formed at one end of the main body 1, 5 indicates a power supply side terminal fitting provided at one end of the instrument base 2, and 6 indicates a connection of the base end 6a to the power supply side terminal fitting 5, and also connects the base end 6a to the power supply terminal fitting 5. This is a fixed contact plate in which one main contact 7 serving as a fixed contact is fixed to a free end 6b extending along the base 2. The free end 6a is formed into a folded U-shape.

8 is an insulator inserted into the folded portion to prevent the free end 6a from hanging down. Reference numeral 9 designates the other main contact serving as a movable contact, which is fixed to a movable contact plate 10 connected to the load side terminal fitting. Thus, the free end 6b of the fixed contact plate 6 is
The reason why the movable contact plate 10 is folded back in the shape of a letter is because the direction of the current is opposite to that of the movable contact plate 10, and when a large current is generated, an electromagnetic repulsive force acts due to the electromotive flux, improving the opening speed of the movable contact plate 10. be. 11 is an auxiliary contact electrically connected to the main contact 7 on the fixed contact side, and 1 and 2 are auxiliary contacts 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 13a of the current limiting element 13 is connected to the free end 6a of the fixed contact plate 6, the other end 13b is connected to the relay terminal plate 14, and the auxiliary contact 11 is fixed to this relay terminal t&14. Further, the main contact 9 and the auxiliary contact 12 on the movable contact side are connected via the auxiliary movable contact plate 15, the U-shaped braided wire 16, and the electromagnetic portion X. That is, an L-shaped piece 10a is provided at the free end of the main contact side movable contact plate IO, and a similar L-shaped piece 15a is also provided on the auxiliary movable contact plate 15, and the vertical pieces 10b and 15b are faced to each other and braided. The wires 16 are brazed and connected on the inner surface, and the currents are in opposite directions to produce electromagnetic repulsion, thereby pressing the auxiliary movable contact 12 into the fixed auxiliary contact 1■ and preventing it from rising. At this time, the vertical pieces 10 of the L-shaped pieces 10a and 15a
b, L5b serves as a holder to prevent the U-shaped braided wire 16 from spreading. In addition, as shown in Fig. 4, the branch 1
By making 0a of a magnetic material and extending it to the movable contact plate 10, it also functions as a yoke piece 10c. 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 contact 12 is fixed to the auxiliary movable contact plate 15. The auxiliary movable contact plate 15 is always pressed by a tension spring 8 suspended between the auxiliary movable contact plate 15 and the movable contact plate 10 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 to cause the co-auxiliary movable contact plate 15 to hang down to some extent, and the contact is opened. That is,
Since an arc is generated at these auxiliary contacts 11, 121j, 1, these contacts 11, 12 are made of a high melting point metal such as tungsten or an alloy thereof to reduce the generation of metal vapor and reduce the vapor density. By doing so, we are improving the new conditions. j9 is an arc extinguishing device located on the side of the arc extinguishing hole 4, and in the drawings of the embodiment, it is formed by stacking a plurality of grids 20 at regular intervals, and the lowermost grid 20 and the relay terminal board 14 are connected. Of course, the arc extinguishing device is not limited to this, and other means may be used.

21 is an insulating frame for fixing the grid 20, and 22 is a square-shaped yoke when the current limiting element 13 is a coil, which is used to make the magnetic flux strong.

(Operation) Next, to explain the operation of the circuit breaker of the present invention, in FIG. It is parallel to 7.9.

In this state, since the current limiting element 13 is inserted, the resistance is higher on the auxiliary contact 11.12 side, the current flows through the main contact 7.9 side, and the heat generation is extremely small.Subsequently, short circuit current and overload When a large current such as a current flows, the movable contact plate 10 on the main contact side first performs the opening operation as shown in FIG. At this time, both auxiliary contacts 11 and 12 are still connected by the spring 18, so the large current flows as shown by the arrow in the figure: fixed contact plate 6 - current limiting element 13 - relay terminal plate I4 - auxiliary contact 1112 - auxiliary The current flows through the movable contact plate 15, the braided wire 16, and the movable contact plate 10, and the large current is limited by the current limiting element 13.Of course, if the current limiting element 13 is a coil, a strong magnetic flux will be generated, and its The magnetic flux acts to magnetically drive the arc generated between the auxiliary contacts 11 and 12 toward the arc extinguisher 19 side.

Thereafter, as shown in FIG. 3, the arc current begins to flow through the arc extinguishing device and is quickly extinguished.

In this case, the auxiliary contact plate 15 is connected to the relay terminal plate 1 on the fixed side.
4 and the current direction is opposite to each other (of course, auxiliary contact 1
A similar phenomenon appears in microscopic observation of the surface of 1.12. ) An electromagnetic repulsive force acts to open the auxiliary movable contact 12, but as shown in FIG. 12 is pushed into the fixed side auxiliary contact 11 side to prevent it from floating.

〔effect〕

As described above, the present invention has the main contacts 7 and 9 facing each other so as to be separated from each other, and is electrically connected to each of the main contacts 7 and 9 as a pair, and is connected together with the main contacts 7 and 9 at the rated current. The auxiliary contacts 11 and 12 are opened after the main contacts 7 and 9 are opened, and one of the main contacts 7 and 9 and the auxiliary contacts 11 and 12 are electrically connected by a current limiting element. 13 in parallel, and when the large current flows and the main contact 7.9 opens, the electromagnetic force of the electromagnetic part Auxiliary contact 11
This prevents the phenomenon in which the auxiliary contacts 11 and 12 float up after the main contacts 7 and 9 open, thereby connecting the auxiliary contacts and the main contacts in parallel via the current limiting element. This method can solve the problems of this method.

Furthermore, the present invention includes a U-shaped braided wire 16 connecting between the auxiliary contact side movable contact plate 15 and the main contact side movable contact plate lO, and a U-shaped braided wire 16 that is fixed upright to both contact plates 10 and 15, respectively.
Moreover, since the wire is formed with the branch pieces 10a and 15a located on both sides of the cough wire, the U-shaped braided wire 16 acts to spread due to the electromagnetic repulsion force of the current, but the branch piece holders located on both sides It has the effect of preventing the spread.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a cross-sectional front view;
2 and 3 are operation diagrams, and FIG. 4 is a diagram of a different embodiment. 7.9...Main contact, 11.12...Auxiliary contact. 13... Current limiting element, 19... Arc extinguishing device, X... Electromagnetic part,
10a+15a...L-shaped piece, 10b, 15b...vertical piece. Patent applicant Matsushita Electric Works Co., Ltd. Patent attorney Toshikuro Takemoto (two idiots)? 1〉2Figure 16 t (33Figure 1F. 3226 Figure 4 6

Claims (1)

[Claims] (11) The main contacts face each other so as to be separated from each other, and are electrically connected to each main contact as a pair, and are connected together with the main contacts at the rated current, and are opened after the main contacts are opened. The auxiliary contact on the movable side is electrically connected to the main contact and the auxiliary contact in parallel via a current limiting element, and when the large current flows and the main contact opens, the auxiliary contact on the movable side In a circuit breaker equipped with an electromagnetic part that presses a movable auxiliary contact against a fixed auxiliary contact by an electromagnetic force exerted by a large current flowing through the contacts, the auxiliary contact side movable contact plate and the main contact side movable contact A circuit breaker characterized by having a U-shaped braided wire connected to the board, and branch pieces each fixed upright to both contact boards and located on both sides of the cough wire. vessel.