JPS6336919Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention relates to a vacuum valve for a breaker or breaker, and is particularly ideal for a vacuum breaker by providing a fixed contact rod with a larger cross-sectional area than a movable contact rod. This invention relates to a vacuum valve that is capable of producing a strong electric field.

(Prior art and its problems) Vacuum valves used for vacuum shields, disconnectors, etc. have a very large electric insulating force in a vacuum, and furthermore,
This device uses its remarkable arc-extinguishing effect to open, close, and cut off current in a vacuumed container, and its outer diameter has become significantly smaller due to recent technological advances. Therefore, by applying such a vacuum valve, there is a demand for a vacuum breaker and disconnector that is highly safe, compact, and inexpensive.

FIG. 1 shows an example of a vacuum valve used in a conventional vacuum shield and disconnector of this type. 1 is a vacuum valve,
2 is the valve insulating tube, 3 is its fixed side flange, 4
is the movable flange. Furthermore, 5 is an arc shield provided in an insulating cylinder, and a fixed contact rod 6 having a fixed contact 6A is arranged in this cylindrical arc shield 5 in a state fixed to the flange 3. A movable contact 7A attached to a movable contact bar 7 is disposed at a position opposite to the fixed contact 6A so as to be able to come into contact with and separate from the movable contact bar 7.

A bellows 8 is provided between the movable contact rod 7 and the movable flange 4, and the bellows 8 allows the movable contact rod 7 to be opened and closed in a vacuum isolated from the outside air. Furthermore, 9 is a protective cap that electrically and mechanically protects the bellows 8.

On the other hand, an electric field balance cap 10 is provided on the side of the fixed contact rod 6, and by providing such a balance cap 10, a structural balance can be maintained with respect to the insulating tube 2 and the arc shield 5. This makes it possible to match both electric fields symmetrically and maintain ideal blistering performance and withstand voltage performance. Note that 6B and 7B are terminals of the fixed contact bar 6 and the movable contact bar 7, respectively, and the terminal 7B on the movable side is connected to an external connection terminal via a flexible conductor (not shown), and further to the terminal 6.
B is connected to the external connection terminal on the fixed side.

However, in this type of vacuum valve 1, the fixed contact 6A and the movable contact 7 of the vacuum valve 1 are
Although heat is generated due to the large contact resistance between the vacuum valve 1 and A, there is no cooling effect due to air convection due to the high vacuum inside the vacuum valve 1. It is conducted via the fixed contact rod 6 and the movable contact rod 7 to terminals 6B and 7B outside the valve, where cooling takes place.

Therefore, in the conventional case, these terminals 6
In order to prevent the conductive members and connecting parts placed near B and 7B from becoming hotter than the allowable value, cooling fins may be attached to these parts, or the members themselves may be made larger to cool them down. I was trying to make it more effective.

In particular, the movable contact 7A side connects an external terminal to the movable contact rod 7 via a flexible conductor (not shown),
Since electrical connections are made, the flexible body itself and its connections have a high resistance value, which generates heat, so in order to improve the cooling effect, the dimensions must be further increased, and the weight of the movable body side must be increased. This is causing an increase.

For this reason, the operating force required to perform the closing/shrinking operation increases, a large operating device is required, the vacuum sheath disconnector itself becomes large, and the cost of the sheath disconnector in general increases.

(Purpose of the invention) The purpose of the invention is to eliminate the above-mentioned drawbacks and to form the components of the vacuum valve into a shape that provides an ideal electric field, thereby preventing the temperature rise of the moving parts and increasing the weight. An object of the present invention is to provide a small and inexpensive vacuum valve for a vacuum shield or disconnector that can suppress the occurrence of damage.

(Key points of the invention) In other words, the invention consists of a movable contact bar equipped with a protective cap to protect the bellows for vacuum maintenance, and a protective cap on the fixed contact side from a position symmetrical to the external terminal of the fixed contact. The above object is achieved by having a fixed contact rod with a large diameter part having the same diameter as the protective cap between the fixed contact rods and having a larger cross-sectional area than the movable contact rod. can do.

(Embodiments of the invention) The invention will be described below with reference to the drawings.

FIG. 2 shows an embodiment of the present invention. In the vacuum valve 11 of this example, a large diameter portion 16 is formed between the position of the fixed contact bar 6 corresponding to the mounting position of the electric field balance cap 10 shown in FIG. 1 and the terminal 6B thereof.

That is, in the example of Fig. 1, balance cap 1
0 was only attached and did not function as a current-carrying part, but in this example, the diameter of the large diameter part 16 of the fixed contact rod 6 is made the same as the diameter of the protective cap 9,
Moreover, by making it a current-carrying part, contacts 6A and 7A
Most of the heat generated between the two is conducted to the large diameter portion 16 having a large heat capacity, and the amount of heat transferred to the external terminal 7B side of the movable contact bar 7 is suppressed.

Therefore, the structure on the side of the movable contact rod 7 does not need to be large-sized and can be made small, and the vacuum valve 11 itself can be made small and lightweight.

(Effects of the invention) As explained above, according to the invention, the diameter of the fixed contact rod is symmetrically increased from the middle in correspondence with the diameter of the protective cap provided on the movable contact rod. Since the part up to the external terminal is a large diameter part, not only can an ideal electric field be obtained, but most of the heat generated at the contact part is conducted to the fixed part side, which has a large heat capacity, and tends to become high temperature. Heat conduction to the movable part side is suppressed, there is no need to increase the size of the members on the movable side part, and the vacuum valve itself can be made smaller, making it an inexpensive vacuum shield and disconnector. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing an example of the structure of a conventional vacuum valve for a shingle breaker, and FIG. 2 is a partial sectional view showing an example of the structure of a vacuum valve for a shingle breaker according to the present invention. 1... Vacuum valve, 2... Insulating cylinder, 3... Fixed side flange, 4... Movable side flange, 5... Arc shield, 6... Fixed contact rod, 6A... Fixed contact, 6B... External terminal, 7...Movable contact bar, 7A...Movable contact, 7B...External terminal, 8
... Bellows, 9 ... Protection cap, 10 ... Electric field balance cap, 11 ... Vacuum valve, 16
...Large diameter section.

Claims (1)

[Scope of utility model registration request] A movable contact bar is provided with a protective cap to protect the bellows for vacuum maintenance, and the distance from the position opposite to the protective cap on the fixed contact side to the external terminal of the fixed contact is equal to the protective cap. 1. A vacuum valve for a shingle breaker, characterized in that it has a fixed contact rod having a large diameter portion, and the large diameter portion provides an electric field balance with the protective cap.