JPS5981820A - 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 for reducing the
This 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.

[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, US Patent Specification No. 381.
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.

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 a Japanese Utility Model Publication No. 5 (I-36037), in which the generated arc first transfers to the induction arc plate through a space, and then the arc and the induction arc plate pass through the coil. A large current flows through the plate, and magnetic drive is performed by magnetomotive flux.The disadvantage of this third conventional example is that it takes time for the arc to transfer to the induction arc plate, and according to experiments, it takes 2 to 3 m5ecj. I read it.

[Purpose of the invention]

The present invention has been made in view of the above points, that is, it uses a coil that can set the magnetic drive of the arc to be strong depending on the number of turns, suppresses heat generation of the coil as much as possible, and instantaneously generates magnetic flux. The purpose is to act on

[Disclosure of the invention]

(Example) The following description will be based on the drawings showing the present invention as an example. l is a breaker body, a synthetic resin container stand 2 and an upper lid 3.
I'm talking about it. Reference numeral 4 denotes an exhaust hole formed at one end of the main body 1; 5, a power supply side terminal fitting provided at one end of the instrument stand 2; and 6, a base end 6a is connected to the power supply side terminal fitting 5, and the instrument stand 2 is connected to the power supply side 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 free end 6a is formed into a folded U-shape. 8
An insulator inserted into the folded portion prevents the free end 6a from drooping. 9 is the other main contact which becomes the movable contact,
It is fixed to the movable contact plate ■0 connected to the load side terminal fitting. Therefore, the free & 1M 6 of the fixed contact plate 6
The reason why b is folded back into a U-shape is that the current direction 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, which increases the opening speed of the movable contact plate 10. ” This is to make people feel like “Ni.” 11 is an auxiliary contact electrically connected to the main contact 7 on the fixed contact side, and 12 is the main contact 9 on the movable contact side.
An auxiliary contact electrically connected to the First, the electrical connection between the main contact 7 and the auxiliary contact 11 on the fixed contact side is made via the coil 13. Immediately, one end 13 of the coil 13
a to the free end 6a of the fixed contact plate 6, and the other end 13
b is connected to the relay terminal plate 14, and the auxiliary contact 11 is fixed to this relay terminal plate 14. Furthermore, the tip of this relay terminal plate 14 is close to the protrusion 6c protruding from one end 13b of the terminal plate 6 of the main contact 7 on the parallel connection side, and when the main contact 7.9 is opened, the arc generated and the protrusion 6c, and serves as a guide for the arc to facilitate its transition. The direction of this protrusion 6c is the main contact 7.9 and the auxiliary contact jl, 1
2 and the direction away from it. The main contact 9 and the auxiliary contact 12 on the movable contact side are connected by an auxiliary movable contact plate 15 and a braided wire 1.
6. That is, a support piece 10a is provided at the free end of the movable contact plate 10, and the auxiliary movable contact plate 15 is attached to the shaft 17.
is centrally supported. The braided wire 16 is present to improve the electrical connection of this pivot, and the auxiliary contact 12 is fixed to the auxiliary movable contact plate 15. This auxiliary movable contact plate 15 is always connected to the auxiliary contact 11 on the fixed contact side by a tension spring 18 suspended between the auxiliary movable contact plate 15 and the movable contact plate 10.
are being oppressed to join the Therefore, the main contact 7.9
Even if the gap is opened, the spring 18 acts so that the co-auxiliary movable contact plate 15 hangs down to some extent, and the contact is opened. That is, since an arc is generated on the side of the auxiliary contacts 11' and 12, the contacts 11 and 12 are made of a high melting point metal such as tungsten or an alloy thereof to reduce the generation of metal vapor and have a low vapor density. This improves the cutoff conditions. (2) 9 is an arc extinguishing device located on the arc extinguishing hole 4 side, and in the drawing of the embodiment, it is made up of a plurality of glyphs 1°20 stacked at regular intervals, and the lowermost grid 20 and the It is connected to the relay terminal board 14. Of course, the arc extinguishing device is not limited to this, and other means may be used. 21 an insulating frame for fixing the grid 20;
2 is a winding frame and yoke of the coil 13.

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

In this state: Since the first coil 13 is inserted, the resistance is higher on the side of the auxiliary contacts 11 and 12, the current flows on the side of the main contacts 7 and 9, 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 10 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 are still connected at No. 18.
, 1.2 are connected 7. Therefore, the large current flows through the fixed contact plate 6 - coil 13 - relay terminal plate 14 - auxiliary contact 11.12 - auxiliary movable contact plate 15 - braided wire 16 - as shown by the arrow in the figure.
A strong magnetomotive flux is generated in the coil 13, 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. 3, the arc current flows through the arc extinguishing device and is quickly extinguished.

In such a case, in the initial state shown in FIG. 2 where the resistance of the auxiliary contact side is high due to the large current, the arc generated between the main contacts 7 and 9 will first be released from the protrusion 6c of the fixed side terminal plate 6 as the contact is opened. The arc shifts to the parallel connected auxiliary contact 11.
This prevents the main contacts 7 and 9 from being damaged by arcing.

〔effect〕

As described above, the present invention has the main contacts 7.9 facing away from each other, electrically connected to each of the main contacts 7, 9 as a pair, and connected together with the main contacts 7, 9 at the time of 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 in parallel. At the same time, when the large current flows and the main contacts 7 and 9 open,
Auxiliary contact 11 which opened with a delay due to the magnetic flux flowing through it.
12 is magnetically driven toward the arc extinguishing device 19 side, the magnetic drive of the arc can be set to be powerful by changing the number of turns of the coil 13, and when the rated current is flowing through the coil 13, The coils 13 are connected in parallel to the main contacts, so the heat generated by the current is minimal, and when operating with a large current, the coils 13 are connected in series, and the generated magnetic flux acts strongly and operates instantaneously.

Furthermore, the present invention provides the terminal plate 6 of the main contact 7 of the auxiliary contacts 11 connected in parallel in a direction away from the main contacts 7, 9 and the auxiliary contacts LL, 12, and closer to the terminal plate 14 of the auxiliary contact 11. Since the protrusion 6c is provided, no arc is originally generated between the main contacts 7 and 9, but if the resistance of the auxiliary contacts including the coil 13 is extremely high, some arc will occur.
The arc is quickly transferred to the arc extinguishing device 19 via the terminal plate 14 by the protrusion 6c to protect the main contact, and thereby the circuit breaker which adopts the structure of the main contact and the auxiliary contact as in the present invention. It has the effect of preventing unexpected situations.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a cross-sectional front view;
20 to 3 are operational diagrams. 6...Terminal board, 6C...Protrusion, 7,9...Main contact, 11
．． 12.. Auxiliary contact, 13.. Coil, 14.. Slope, 19.. Arc extinguishing device. Patent applicant Matsushita Electric Works Co., Ltd. Representative patent attorney Toshikuro Takemoto (and 2 others)

Claims (1)

[Claims] (1) The main contacts face each other so as to be separated from each other, and are electrically connected to each of the main contacts as a pair, and are connected together with the main contacts at the rated current, and after the main contacts are opened, the The auxiliary contact to be opened is electrically connected to one side of the main contact and the auxiliary contact in parallel, and when the large current flows and the main contact opens, there is a delay due to the magnetic flux flowing through the main contact. In a circuit breaker that magnetically drives the arc of the auxiliary contact opened by the arc extinguishing device, a terminal plate of the main contact on the side of the parallel connected auxiliary contacts is connected in a direction away from the main contact and the auxiliary contact. A circuit breaker characterized by having a protrusion adjacent to the terminal plate of the auxiliary contact.