JPS6122524A - Vacuum bulb - 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 invention] The present invention relates to a vacuum valve.

[Magical background of invention and its problems]

A conventional vacuum valve using a vertical magnetic field effectively utilizes arc dispersion in a vacuum to interrupt current, and its general configuration is as shown in Fig. 3-42. A vacuum container is formed by an insulating container 1 formed into a substantially cylindrical shape and 72 flange 2 and 3 that seal both open ends of the insulating container 1.
A fixed electrode 6 and a mJ electrode 7 attached to opposite ends of the movable conductive rod 5 are arranged. The fixed electrode 6 consists of a live electrode 6a and a coil electrode 6b. The movable electrode 7 consists of a raw electrode 7a and a coil electrode 7b. The movable conductive rod 5 is driven in the axial direction by a drive device (not shown) while maintaining airtightness with respect to the 7 langes 3C.In order to maintain the airtightness, the movable conductive rods 5 and 7 are A bellows 8 is arranged between the flange 3 and the coil electrode 6b.

7bill: When four currents are transmitted, C2 generates a longitudinal magnetic field 10 parallel to the arc generated between the amphibious poles 6a and 7a. The coil A/electrodes 6b and 7b form a turn running in the circumferential direction in a plane perpendicular to the length of the movable side 4# dragon rod 5 to generate a vertical magnetic field 10. The longitudinal magnetic field 100 strength and distribution are:
・Varies depending on the shape of the coil electrode, the number of turns, and the distance between the two main gun poles. The shield 9 is provided so as to surround the electrodes 6.7 in order to prevent problems such as a decrease in the withstand voltage or damage to the vacuum valve due to the adhesion of C2 metal vapor to the insulating container 1 during current interruption.

ing.

In vacuum valves that apply a vertical magnetic field to prevent arc concentration and ensure high interrupting performance, a sufficiently strong magnetic field is applied between the piezo electrodes (i.e., in order to effectively act Therefore, as shown in Fig. 4, the magnetic field strength at the center between the main electrodes is lower than that at the second surface of the earth electrode, resulting in a magnetic field distribution that swells outward at the center between the two earth electrodes. This tendency becomes more pronounced as the ratio of the coil electrode diameter to the distance between the main electrodes becomes smaller.When the longitudinal magnetic field becomes weaker at the center between the electrodes, the diffusion of plasma particles that maintain the arc current increases, and the arc voltage increases. As the arc voltage increases, the energy input to the electrode increases, making it more likely that an anode spot will occur, leading to increased electrode wear, increased damage to the shield, and even failure to shut off.

As described above, the magnetic field distribution has a great effect on the lifespan and cut-off performance of the vacuum valve, so it is necessary to carefully consider the arrangement of the electrodes of other shapes. There are naturally many limits to making the magnetic field uniform, and as mentioned above, it is especially difficult to make the magnetic field distribution uniform when the ratio of the coil electrode diameter to the distance between the main electrodes is small.

[Purpose of the invention]

An object of the present invention is to provide a vertical magnetic field type vacuum valve with excellent shutoff performance, high reliability, and long life.

[Summary of the invention]

The present invention provides a cylindrical conductor around the electrode, and! The feature is that the distribution of the magnetic field generated between the poles is made uniform.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

Figure 1 shows an embodiment of the vacuum valve of the present invention.

The difference from the conventional vertical magnetic field type vacuum valve is that the shield 9 in FIG. 3 is replaced with a cylindrical conductor 11 (==).

For the cylindrical conductor IN=, a material having good conductivity such as copper or aluminum is used.

As is well known (= in materials with high conductivity, the alternating current electromagnetic field is localized to the surface of the conductor and there is no one inside, that is, the skin effect becomes noticeable.The electromagnetic field is 1/e of the surface intensity. (=Thickness δ is δ=(2/μσω)
It is given by 2. Here, μ is magnetic permeability, σ is electrical conductivity, and ω is the angular frequency of the electromagnetic field. For example, in the case of Cu material, 50
δ for a vertical magnetic field of Hz is 93.5 mm (==.Actually, the thickness of the conductor is set to 30% or more of δ in order to have a safety effect on the conductor wall against the fluctuation of the arc plasma. In particular, the expansion of the electromagnetic field can be suppressed and the arc plasma in the vertical magnetic field can be stabilized, so the breaking performance is improved. If nothing is inserted into this groove, or a high-resistance material is inserted, the circumferential turn Ktti in the plane perpendicular to the longitudinal magnetic field is prevented from being averted inside the conductor, and the longitudinal magnetic field is It is necessary to prevent this from being canceled out.The inner diameter of the cylindrical conductor 11 is
Main electrodes 6a, 7a outer diameter 4: The closer they are, the greater the effect of uniformizing the magnetic field.

For the reasons stated above, the vertical magnetic field distribution between the earth electrodes is uniform as shown in Figure 1 (Figure 1). Loss is reduced and arc voltage is suppressed to a low level, which improves electric mL interrupting performance and reduces the energy injected into the electrode, reducing electrode wear.In addition, the shield and magnetic field lines do not intersect as in conventional vacuum valves. The damage to the conductor caused by the arc plasma is small.

In order to prevent the cylindrical conductor 11 from canceling the vertical magnetic field, a part of the cylindrical conductor 11 is provided with a thread, and a groove (= means that nothing is inserted or a gas resistor (an insulator may be used) must be inserted. As mentioned earlier, it is also possible to use stainless steel bellows, for example, in the circumferential direction as a high-resistance material.In this way, the cylindrical body is integrated compared to the case where grooves are provided. Compared to the case where an insulator is used as the four resistors, there is an advantage that a large amount of gas is not generated when the arc plasma collides.

There is also a configuration in which the cylindrical conductor is divided into a plurality of parts and each part is supported instead of forming a groove in the cylindrical conductor.

Furthermore, in Figure 1, the conductor is placed inside a vacuum container, but
It goes without saying that this may be placed outside the insulating container 1.

In the example shown in Fig. 2, the cylindrical conductor 11 is used as part of a vacuum vessel. Yes, this allows the outer diameter of the vacuum valve to be reduced.

The effect of uniformizing the magnetic field by the cylindrical conductor 11 is the distance force between the main electrode outer periphery and the cylindrical conductor; There is a risk that an arc current may flow. Since the cylindrical conductor is generally made of a material different from the electrode material, the current interrupting ability may be reduced.

Therefore, by providing an insulator on the inner surface of the cylindrical conductor, it is possible to prevent current from flowing through the cylindrical conductor, and at the same time, by bringing the cylindrical conductor closer to the live electrode, the effect of uniformizing the magnetic field can be greatly increased.

〔Effect of the invention〕

According to the present invention, by providing a cylindrical conductor around an electrode, it is possible to provide a vacuum valve with excellent reliability and long life.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing one embodiment of the vacuum nozzle according to the present invention, FIG. 2 is a longitudinal sectional view showing another embodiment of the vacuum nozzle according to the present invention, and FIG. Fig. 4, a vertical cross-sectional view of a conventional vacuum valve, is an explanatory diagram showing the distribution of the vertical magnetic field generated between the subject poles. 11...Cylindrical conductor (7317) Agent Patent attorney Rule Chika jl!
Yu (#deka) 1 person) Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A vacuum comprising a vacuum container, a pair of electrodes arranged in the vacuum container so as to be openable and closable, and a coil electrode arranged on the back side of the electrodes to generate a magnetic field parallel to the arc generated between the electrodes when current is interrupted. In the valve, a cylindrical conductor arranged around the electrode is attached to the vacuum container,
A vacuum valve characterized in that the cylindrical conductor has one or more grooves in the axial direction, and the grooves are made of a high-resistance material.