JPS5828122A - Vacuum 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 This invention relates to a true breaker 4 in which a coil for generating an axial magnetic field perpendicular to the electrostatic surface is disposed.

Generally, a straight-on breaker has a rose-shaped structure as shown in Figure 1.

Both ends of a cylindrical insulating cylinder 1 made of glass or ceramic are tightly closed by a disc-shaped metal end plate 2 to form a vacuum leak 3, and a vacuum chamber 3 is formed inside the vacuum vessel 3.
A pair of electrodes 4 are introduced from the center portions of both metal end plates 2 so as to be able to approach and separate from each other via a pair of electrode rods 5, so that they can come into contact with each other and move away from each other (sides 1 can be moved freely).

However, the arc that occurs when a typical vacuum breaker breaks is extremely unstable due to the interaction between its own magnetic field and the magnetic field of the external circuit.

As it moves along the electrode surface, it is unevenly distributed around the electrode surface.

The electrode is locally heated and a large amount of metal vapor is emitted, resulting in a decrease in interrupting capacity.

In order to deal with this problem, as shown in FIG. 2, a current flowing through the electrode rod 5 is transformed into a loop current with the electrode rod 5 as the center of the current, and an axis perpendicular to the electrode surface is installed on the back of the electrode 4. direction(
A coil 6 that generates a magnetic field (in the vertical direction in FIG. 2) is provided, and the axial magnetic field generated by the coil 6 uniformly diffuses the arc over the electrode surface to increase the breaking capacity. A so-called vertical magnetic field electrode vacuum breaker is known.

However, in a vacuum breaker with vertical magnetic field electrodes, the axial magnetic field generated by the coil 6 intersects with the electrode II5 made of normal steel, causing eddy currents in the electrodes 4!115, and the magnetic field generated by this eddy current acts to reduce the axial magnetic field, resulting in a corresponding reduction in the breaking capacity.

The present invention has been made in view of the above-mentioned problems.

The purpose of this is to reduce the eddy current generated in the electrode rod by improving the shape etc. of the electrode rod, thereby reducing the loss of the axial magnetic field generated by the coil.
Another object of the present invention is to provide a vacuum breaker with vertical magnetic field electrodes that can effectively increase the breaking capacity.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings from FIG. 3 onwards. In the following description, structural members that have the same functions as those described above are designated by the reference numerals 1 and 4i, and overlapping descriptions will be omitted.

FIG. 3 is a sectional view of the main parts of the vacuum breaker according to the present invention,
A small diameter portion 51 is formed over a predetermined length at the inner end portions of a pair of electrode rods 5 made of steel that are introduced into a vacuum volume N (not shown in the figure '4i) so as to be able to approach and separate from each other. ing. The small diameter portion 5a is for reducing the cross-over of the axial magnetic field generated by the coil 6 to reduce the generation of eddy current on the electrode rod 54. The outer diameter d of the portion corresponding to the length L of the outer diameter of the electrode 4 from the inner end (upper end in figure #3) of ζ or more is 30 rm or less, and this small diameter portion 5a is mechanically A reinforcing pipe 1 made of stainless steel is fitted by brazing or the like in order to increase the strength and enable high-voltage current to be turned on and off.

Note that the small diameter portion 5a is formed when the outer diameter of the electrode rod 5 exceeds 30 m/m, and of course is not formed when the outer diameter of the electrode rod 5 is 30 m/m or less over the entire length. It is. Further, the reinforcing vibrator 7 has a circumferential surface and a small diameter portion 5.
Even if the outer peripheral surface of a is in close contact, there is 7I between both surfaces! There is no problem even if there are gaps.

Here, the range of change in the outer diameter of the electrode rod 5 and change in external temperature (
In other words, the rate at which eddy current is generated due to a change in the length of the electrode II5, or in other words, the effect that the axial magnetic field generated from the coil 6 is affected by a change in the shape of the electrode II5.

The experimental results are as shown in FIG. That is, the fourth
In the figure, the horizontal axis represents the outer diameter of the electrode @S, and the vertical axis represents the magnetic flux density at the center of the electrode surface with the case where there is no electrode rod 5 as 100%. The outer diameter changes uniformly over the entire length.

Curve B is a curve in which the range of change in the outer diameter of the electrode rod 5 is greater than ζ of the W armature, curve C is a curve in which the range of change in the outer diameter of the electrode bar 5 is greater than ζ of the electrode, and curve dp is The range of change in the outer diameter of the electrodes I1I5 is shown to be greater than or equal to the electrode diameter. Therefore, the outer diameter of the area corresponding to a length of 14 or more of the electrode diameter at the inner end of the electrode rod 5 is 30
It can be seen that by setting rrvm to 1, the influence of eddy current can be reduced to 4011 or less.

As described above, the present invention provides a pair of electrodes in a vacuum container so as to be able to move toward and away from each other via a pair of electrode rods that are introduced into a vacuum container so as to be able to approach and move away from each other, and to generate an axial magnetic field at the back of each electrode. A vacuum cutoff 5+ formed by arranging a coil,
The outer diameter of the part corresponding to the length from the middle part of each coil of each front electrode to the outer diameter of the electrode is 30Vm.
Since it is as follows, the linkage of the axial magnetic field to the 'polar key' is reduced, so that the generation of eddy current can be significantly reduced. Therefore, the axial magnetic field can be effectively applied to the electrode surface, and the breaking capacity of the vacuum breaker of the vertical magnetic field electrode can be effectively increased.

[Brief explanation of drawings]

Figure 1 is a schematic fl152 diagram of a general true 9 circuit breaker. Fig. 2 is a schematic explanatory diagram of a vertical magnetic field electrode, Fig. 3 is a sectional view of a main part of a vacuum breaker according to the present invention, and Fig. 84 is a diagram illustrating the change in shape of the electrode rod according to the present invention. It is an explanatory diagram showing the experimental results of influence. 3... Vacuum container, 4... Electrode, 6... Electrode rod, 5
h...Small diameter part, 6...Coil. Figure 1 Figure 2 Figure 4 Figure 3 Outer diameter Figure 3

Claims (1)

[Claims] A pair of electrodes are introduced into the vacuum volume 4 so as to be able to approach and separate from each other via a pair of electrode rods, and
In a vacuum breaker in which a coil for generating an axial magnetic field is disposed on the back of each electrode, a portion of the electrode rod extending from the middle of each coil to a length corresponding to the outer diameter of the electrode or more. A vacuum breaker characterized in that the diameter is 30 m/m or less.