JPS6347219B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum interrupter, and more particularly to a so-called vertical magnetic field type vacuum interrupter that applies an axial magnetic field to an arc.

Vertical magnetic field type vacuum interrupters apply an axial magnetic field to the arc, thereby stably and uniformly distributing the arc on the electrode surface, improving the strength and cutting capacity. As shown in the figure, a pair of electrode rods 4 and 5 are placed in a vacuum container 3 in which both ends of an insulating cylinder 1 made of ceramic or glass are hermetically closed with end plates 2 made of metal and the inside is evacuated to a high vacuum. The contact electrodes 61 and 71 are introduced into the inner end of each electrode rod 4 and 5 so as to be able to approach and separate from each other relatively. The current flowing through the electrode rods 4 and 5, which are spaced apart from each other on the contact back surface side (electrode rod side) of the electrodes 61 and 71, is changed to a loop current centered around the respective electrode rods 4 and 5. An electrode 6 consisting of coil electrodes 62 and 72 that generate a magnetic field in the direction (vertical direction in FIG. 1);
It is composed of 7 connected in series.

In addition, in FIG. 1, 8 is a bellows, 9 is a main shield, and 10, 10 are auxiliary shields.

However, in the vacuum interrupter described above, when the contact electrodes 61 and 71 of each electrode 6 and 7 are made of a material such as Cu with high conductivity, the contact electrode 6 is
An eddy current flows through coil electrodes 62, 7
There is a problem in that the magnetic flux density of the axial magnetic field generated by 2 is reduced.

In order to deal with this problem, as shown in FIG. 2, a high resistance spacer (not shown) made of a material with low conductivity such as stainless steel is interposed and connected to the inner ends of the electrode rods 4 and 5. each contact electrode 61,
71, a plurality of radial slits 61a, 71
However, if the electrode diameter is about 100 m/m, the radial cut of each slit 61a, 71a needs to be deep, which reduces the mechanical strength of the electrode itself. decreases,
Moreover, the edges of the slits 61a, 71a cause a problem of lowering the withstand voltage, and the slits 61a, 71a are damaged due to the large number of shears caused by the large current, resulting in a decrease in the shearing performance.

Furthermore, in order to deal with the above-mentioned problems, it has been proposed that the contact electrodes 61, 71 are formed of a material with low conductivity without providing the slits 61a, 71a. but,%
Materials with electrical conductivity below 40%, such as beryllium,
Contact electrode 6 made of Cu-W alloy or Ag-W alloy
1, 71, the eddy current is considerably reduced and there is no need to provide a slit. radial arms 6
2a, 72a, and circular arc portions 62b, 72b curved in an arc shape from the ends of the respective arms 62a, 72a, and the ends of the respective circular arc portions 62b, 72b of the coil electrodes 62, 72 and contact electrodes. 61,
When connecting the vicinity of the outer periphery of the contact back surface of 71 via the axial connection conductor 11 (see Fig. 3),
As shown in FIG. 3, when the arc A is displaced from the contact portions 61b, 71b of the contact electrodes 61, 71 due to an external magnetic field etc., shunt currents I ₁ , I ₂ flow from each connecting conductor 11 to the arc A. , I ₃ , and I ₄ , and the distribution of the axial magnetic field is disturbed, resulting in a decrease in shearing performance. Furthermore, if the % conductivity of the contact electrodes 61, 71 is low, there are problems such as increased heat generation during energization.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a longitudinal magnetic field that suppresses the generation of eddy currents and increases magnetic flux density without reducing mechanical strength. The method is to provide a vacuum interrupter. below,
Embodiments of the present invention will be described in detail with reference to the drawings from FIG. 4 onwards. In the following explanation, the constituent members of the vacuum interrupter according to the present invention that have the same functions as the constituent members of the conventional vacuum interrupter described above are given the same reference numerals, and the explanation thereof will be omitted, and each electrode is similar to the constituent members of the conventional vacuum interrupter. Since this is a configuration, only one electrode will be explained, and the explanation of the other electrode will be omitted.

FIG. 4 is a longitudinal cross-sectional view of the electrode 7 of the vacuum interrupter according to the present invention, and the electrode 7 is made of beryllium,
% conductivity 40 like Cu-W alloy or Ag-W alloy
It is generally constructed by combining a cap-shaped disk-shaped contact electrode 71 made of a material with a low conductivity of less than 10%, and a 1/4 shunt type coil electrode 72 made of a material with a high conductivity such as Cu.

That is, as shown in FIGS. 4 and 5, the inner end of the electrode rod 5 is provided with a disk-shaped mounting base 72c having an appropriately larger diameter than the outer diameter of the electrode rod 5, and an outer circumference of the mounting base 72c. A coil electrode 72 consisting of four arms 72a extending radially outward from the base and a circular arc portion 72b curved in an arc shape from the end of each arm 72a is attached to one surface of the mounting base 72c (FIG. 4). The coil electrode 7 is fitted through a circular recess 12 provided on the lower surface of the
A hole 13 into which the connecting conductor 11 is inserted is provided at the end of each of the two arcuate portions 72b so as to pass through the hole 13 in the axial direction. The coil electrode 72 includes a ring-shaped attachment part 14a that is fitted and brazed to the outer periphery of the electrode rod 5 near the inner end thereof, and a ring-shaped attachment part 14a that extends radially outward from the outer periphery of the attachment part 14a. It is supported by a reinforcing support member 14 (see FIG. 6) comprising a plurality of (eight in this embodiment) support arms 14b.

The reinforcing support member 14 is made of a material with relatively high mechanical strength and low conductivity, such as stainless steel, and the number of support arms 14b is at least the same as the number of arms 72a of the coil electrode 72. , and the end of the support arm 14b is brazed to the end of the arc portion 72b.

In the circular recess 15 provided on the other surface of the mounting base 72c of the coil electrode 72, there is a high resistance spacer 16 made of a material having a short cylindrical shape with flanges at both ends and having a low % conductivity such as stainless steel.
are fitted through a flange at one end and brazed. As shown in FIGS. 4 and 7, the flange at the other end of the high-resistance spacer 16 has a ring circle having a diameter larger than that of the flange and having a through hole with the same diameter as the inner diameter of the high-resistance spacer 16. A plate-shaped mounting base 17a and a mounting base 17
4 extending radially outward from the outer periphery of a
Book arms 17b, and arcuate portions 17c curved from the end of each arm 17b toward the end of one of the adjacent arms 17b.
An adapter 17 consisting of
The current flowing through the coil electrode 72
The mounting base 17a is fitted and brazed through a circular recess 18 provided on one surface of the mounting base 17a so that the current flows in the same direction as the current flowing through the mounting base 17a. The adapter 17 is made of a relatively high conductivity material such as Cu, and its mounting base 17a is connected to the arm 17.
b and the circular arc portion 17c in FIG. 4, it projects slightly upward. In addition, in the recessed portion 19 provided at the end of each arcuate portion 17c of the adapter 17, in order to electrically connect the adapter and the coil electrode 72,
One end of the axial connection conductor 11 is inserted into the hole 13 of the circular arc portion 72b of the coil electrode 72, and the other end of the axial connection conductor 11 is fitted.

The adapter 17 includes the contact electrode 71 formed in the shape of a cap-shaped disk having approximately the same diameter as the coil electrode 72.
are fitted and brazed together through a circular recess 20 provided at the center of the contact back surface, and the contact back surface is brazed in contact with each arm 17b and arcuate portion 17c of the adapter 17.

The current flowing through each adapter 17 is
flows as a circular current, and flows through the arm 17b, the mounting base 17a, and the contact electrode 71 to the other electrode 61, but this adapter 17 is joined to the back side of the contact electrode 71 by brazing or the like. Therefore, even if the contact electrode 71 is made of a material with low conductivity, when the current actually flows through the arm 17b, the current also flows through the contact electrode 17 to the end face side of the adjacent circular arc portion 17c. This current is related to the distance between the end of the arc portion 17c and the adjacent arm 17b, and as the distance becomes shorter, a larger current flows, reducing the magnetic flux produced by the coil and causing a phase lag, which cannot be ignored.

Therefore, we measured the magnetic flux density B (Gauss/KA) and the phase delay θ (degrees) of the longitudinal magnetic field at the center position of the contact electrode when the length of the arcuate portion 17c of the adapter 17 was changed, and obtained the measurement results shown in Fig. 8. Ta.

Note that l/L in FIG. 8 is the arc length at radius r between arms 17b arranged at equal angle θ ₁ (360°/number of arms) as shown in FIG. Angle θ ₂ of the end of the circular arc portion 17c from the center of the arm of
The figure shows the ratio l/L (%) of l to L, where l is the arc length at the radius r.

In reality, we used a pair of contact electrodes made of a low-conductivity material with an outer diameter of 100 m/m, a 1/2 shunt type coil electrode, and an adapter. It was measured.

In FIG. 8, the horizontal axis shows the l/L%, the left side of the vertical axis shows the magnetic flux density B (Gauss/KA), and the right side shows the phase delay θ (degrees) of the vertical magnetic field.

The A curve represents the magnetic flux density at the center position, and the B curve represents the phase delay.

From the curve diagram in Figure 8, the l/L ratio (%) is 75%.
When it exceeds , the magnetic velocity density at the center position suddenly decreases, and the phase delay angle also increases rapidly. This seems to be due to the fact that the current in the arm 17b passes through the contact electrode to the end of the adjacent circular arc portion of the I section, and the current is shunted, and this shunted current has an adverse effect. 75%
It can be seen that when the ratio is less than 1, the current is prevented from branching through the contact electrode 71 between the end of the arcuate portion 17c of the adapter 17 and the adjacent arm 17b, resulting in good results.

In the above-described embodiment, the coil electrode 72 and the adapter 17 are of the 1/4 shunt type; however, the present invention is not limited to this.
A 2-branch type or a 1/3-branch type may also be used.

As described above, the present invention introduces a pair of electrode rods into a vacuum container so that they can approach and separate from each other, and a contact portion is formed at the center of one surface at the inner end of each electrode rod using a material with low conductivity. and a circular mounting base on the other side, a plurality of arms extending in the radial direction from the mounting base, and a circular arc curved from the end of each arm toward the end of the adjacent arm, and between the two. 3/4 of the arc of
A plurality of contact electrodes each having a circular arc portion having a length as follows are arranged in series with a high-resistance spacer interposed therebetween, and extending radially from the outer peripheral surface near the inner end of each electrode rod. A coil electrode consisting of an arm and a circular arc portion curved into an arc shape from the end of each arm is attached, and the end of each circular arc portion of the coil electrode and the end of the circular arc portion of the adapter are connected to an axial magnetic field. Since the contact electrode is connected via an axial connection conductor to generate heat, the mechanical strength of the contact electrode does not decrease, and the current conduction path within the contact electrode is shortened, reducing heat generation. can do. In addition, the adapter functions as a coil in conjunction with the coil electrode, and the current is not shunted between the arm of the adapter and the arc portion via the contact electrode, so the magnetic flux density can be further improved. It has the effect of

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a conventional vacuum interrupter, FIG. 2 is a perspective view of its electrodes, FIG. 3 is an explanatory diagram of the operation of the conventional electrodes, and FIG. 4 is a longitudinal cross-sectional view of the electrodes of the vacuum interrupter according to the present invention. 5, 6, and 7 are plan views of the main parts, and FIG. 8 is an explanatory diagram showing the state of magnetic flux density and phase delay when the length of the arc portion of the adapter is changed. It is. 3... Vacuum container, 4, 5... Electrode rod, 6, 7... Electrode, 11... Connection conductor, 16... High resistance spacer, 1
7...Adapter, 17a...Mounting base, 17b...
Arm, 17c... Arc part, 61, 71... Contact electrode, 6
2, 72...Coil electrode, 72a...Arm, 72b...Circular arc portion.

Claims (1)

[Claims] 1 A pair of electrodes are disposed facing each other in a vacuum container through electrode rods so as to be able to come into contact with and separate from the electrodes, and a contact electrode that is in contact with the opposing electrode is supported by the electrode rod through a high resistance spacer, and an opposite contact of the contact electrode is supported by the electrode rod through a high resistance spacer. A vacuum shield disconnector is provided with a coil electrode connected to the electrode rod and the contact electrode on the side and generating an axial magnetic field by converting the current flowing through the electrode rod into a loop current centered on the electrode rod. a mounting base for attaching the electrode to the inner end of the electrode rod; a plurality of arms provided on the mounting base and extending in the radial direction; The contact electrode is formed of a material with high conductivity and has a circular arc portion extending close to the arm of the coil electrode. An adapter is formed by brazing an adapter made of a highly conductive material having a circular arc portion curved in an arc shape in the circumferential direction opposite to that of the coil electrode with approximately the same radius as the end portion of the coil electrode. While electrically connecting the end of the arc part of with the connecting fitting,
The arc length at the radius r of the angle θ ₁ between adjacent arms of the adapter is L, and the arc length at the radius r of the angle θ ₂ between the arm center line of the arms and the end of the arc portion is l. A vacuum interrupter characterized in that the length of part L is 75% or less of L.