JPS6214581Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a vacuum breaker, and more particularly to a vacuum breaker with an improved electrode structure.

As electrode structures for vacuum shield disconnectors, so-called magnetic drive type and vertical magnetic field type are known. The magnetic drive type has an electrode structure in which an arc drive electrode with a spiral pedal is placed around a contact electrode attached to an electrode rod, and the arc generated between the contact electrodes is connected to itself and an external circuit. The interaction of the magnetic fields causes the arc drive electrode to be driven along the pedal, thereby improving the cutting performance. In addition, as shown in FIG. 1, the vertical magnetic field type has a contact electrode 3 attached to the electrode rod 1 with a high resistance material 2 interposed therebetween, and the contact electrode 3 and the electrode rod 1 are connected to each other. It has an electrode structure that is electrically connected by a central ring-shaped coil electrode 4 with ends, and the arc generated between the contact electrodes 3 is caused by the longitudinal (axial direction) magnetic field generated by the coil electrode 4.
By uniformly dispersing it on the opposing surface of the contact electrode 3, the shearing performance is improved.

In the above-mentioned vertical magnetic field type, since the magnetic flux of the vertical magnetic field generated by the coil electrode 4 changes according to changes in the break current, many eddy currents occur in the contact electrode 3, especially in its center. However, this eddy current not only weakens the longitudinal magnetic field, but also causes a phase difference between the shearing current and the longitudinal magnetic field, resulting in a decrease in shearing performance. Additionally, in order to suppress the generation of eddy currents, electrodes may be made of a material with high electrical resistance such as tungsten alloy, but such electrodes may cause a temperature rise due to arcing during breakage, and The generation of thermoelectrons is promoted, resulting in a decrease in breaking performance.

This idea was devised in view of the problems of the prior art described above, and by forming the peripheral part of the contact electrode to be extremely small and increasing the heat transfer area, the temperature rise on the surface of the contact electrode can be suppressed. This is an attempt to solve the problems in the prior art described above by suppressing the eddy current and reducing the influence of the eddy current. Hereinafter, one embodiment of this invention will be described in detail using the drawings from FIG. 2 onwards.

FIG. 2 is a longitudinal cross-sectional view of the vacuum sheath breaker according to this invention. It is comprised of fixed and movable electrodes 6 and 7 having a magnetic field type electrode structure, and an operating device (not shown) for moving the movable electrode 7 toward and away from the fixed electrode 6. The vacuum container 5 includes two cylindrical insulating cylinders 8, 8 made of glass or ceramic, with ring-shaped sealing fittings 9, 9 implanted at both ends, and each insulating cylinder 8 is sealed at one end. Fastening fittings 9,
9, and the sealing fittings 9, 9 at the other end.
Both openings are closed by disk-shaped end plates 10, 10 joined to the same, and are evacuated to a high vacuum. A fixed electrode rod 1 is placed in the center of one end plate.
1 is penetrated and hermetically fixed,
The fixed electrode 6 is attached to the inner end of the fixed electrode rod 11 as described later. In addition, a movable electrode rod 12 that moves toward and away from the fixed electrode rod 11 is passed through the center of the other end plate 10 so as to be movable in the axial direction, and is airtightly attached via a bellows 13. The movable electrode 7, which is moved toward and away from the fixed electrode 6, is attached to the inner end of the movable electrode rod 12, as will be described later. The operating device is connected to the outer end of the movable electrode rod 12 as appropriate.

In FIG. 2, reference numeral 14 indicates a shaft shield for protecting the fixed electrode rod 11, reference numeral 15 indicates a bellows shield for protecting the bellows 13, and reference numeral 16 indicates a fixed electrode rod 11. ,
It is a substantially cylindrical main shield that surrounds the movable electrodes 6, 7, etc., and its outer periphery center is supported by sealing fittings 9, 9 at one end that join the insulating cylinders 8, 8, and is denoted by the reference numeral 17. 17 indicates each end plate 1
It is an annular auxiliary shield attached to the inside of 0.

At the inner end of the movable electrode rod 12, as shown in FIGS. 3 and 4, a contact electrode 18 and a coil electrode 1 are provided.
A movable electrode 7 having a so-called vertical magnetic field type electrode structure consisting of 9 is attached. That is, an electrode support member 21 made of pure copper or a copper alloy is joined to the inner end of the movable electrode rod 12 made of pure copper or a copper alloy with a high resistance member 20 such as stainless steel interposed therebetween. The electrode support member 21 is
The contact electrode 18 is attached as described later, and the electrode support member 21 and the movable electrode rod 12 are connected to an annular coil portion 19a with an end centered around the movable electrode rod 12, and a coil portion 19a with an end within a radius from both ends of the coil portion 19a. The coil electrode 19 is electrically connected to the coil electrode 19, which is made up of arm parts 19b, 19b, which extend parallel to each other in the directions, and whose ends are joined to the movable electrode rod 12 and the electrode support member 21, respectively.

The contact electrode 18 is bonded to the electrode support member 21 via a bonding portion 18a protruding from the center of the opposing back surface (lower surface in FIG. 4). The contact electrode 18 is made of copper-nickel alloy or copper-beryllium alloy, and has an electrical resistance of 1.5 to that of pure copper.
The contact portion 18b is approximately 5 times larger than the contact portion 18b, and is formed into a hat-shaped disk shape by a circular contact portion 18b provided at the center of the opposing surface and a sloped portion 18c provided around the contact portion 18b. The opposing surface and the opposing back surface of the contact portion 18b are provided with diametrical grooves 22, 2 passing through their centers.
At least two or more holes are provided in each case. Note that the bottom portions 22a, 2 of each groove 22, 23
3a, as shown in FIGS. 4 and 5, is formed in an arc shape centered on a predetermined point on the axis of the contact electrode 18, and its deepest point is at the contact portion 18b. It is said to be more than 1/2 the thickness.

As shown in FIGS. 4 and 5, the slope portion 18c of the contact electrode 18 is formed to have an outer diameter approximately the same as that of the coil electrode 19, and the opposite back surface thereof has a contact portion 18b. The pleated protrusions 24, 24, . . . are formed in a direction perpendicular to the contact surface.
A large number of folded protrusions 24, 2 are provided.
4, . . . are arranged radially around the movable electrode rod 12. The length and thickness of this protrusion 24 are set appropriately. Grooves 24a, 24a, . . . formed between each protrusion 24
The thickness between the bottom portion (bottom surface) of the contact portion 18b and the surface of the contact portion 18b is extremely thin. A reinforcing member 25 having protrusions 25a corresponding to each groove 24a is fitted into the grooves 24a, 24a, . . . . The reinforcing member 25 is intended to improve the mechanical strength when inserting and cutting the contact electrode 18, which has low mechanical strength, and to suppress the temperature rise of the contact electrode 18 during the cutting operation. It is made of a material like stainless steel that has an electrical resistance several tens of times higher than that of pure copper (1.7μΩ・cm) and has high mechanical strength. The thickness between the bottom of the groove 24a between the protrusions 24 and the surface of the contact portion 18b is desirably 1/3 or less of the thickness at the contact portion 18b.

The configuration of the movable electrode 7 attached to the movable electrode rod 12 has been described above, but since the configuration of the fixed electrode 6 attached to the fixed electrode rod 11 is also almost the same as that of the movable electrode 7, the movable electrode 7 in the fixed electrode 6 Components that have the same functions as those shown in FIG.

According to the above configuration, the electrical resistance of the eddy current circuit in the central portion of the contact electrode 18 is increased, and the generation of eddy current is significantly suppressed, thereby improving the shearing performance. In addition, the temperature rise of the contact electrode 18 due to the arc during breakage is caused by the reinforcing member 2 having a large heat capacity.
5, the mechanical strength of the contact electrode 18 during closing and cutting operations is compensated for by the reinforcing member 25, without causing a decline in the shearing performance due to thermionic generation. can become.

In particular, in this invention, a large number of pleated protrusions 24, 24, . Since it is configured to be in contact with the protruding portion 25a of the reinforcing member 25 having a large diameter, the temperature rise at the outer circumferential portion of the contact electrode 18 due to arcing in particular during breakage is prevented, and the influence of eddy current is minimized. It is possible to improve the cutting performance. Moreover, the protrusion 24 between the grooves 24a
By forming the contact portion 18b thinly, and
By connecting the protrusion 24a and the protrusion 24a, a configuration with better heat dissipation effect can be obtained.

Incidentally, FIG. 7 shows the test results of a vacuum shield breaker having an electrode with an improved structure according to this invention.
In other words, the difference between the 100% of the thickness of the peripheral part of the contact electrode relative to the thickness of the central part and the phase lag of the longitudinal magnetic field with respect to the shearing current is the ratio of the thickness of the peripheral part to the thickness of the central part. If the ratio is plotted on the horizontal axis and the phase lag is plotted on the vertical axis, it can be seen that as the ratio of the thickness of the peripheral portion to the thickness of the central portion increases, the phase lag decreases.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of the electrode structure of a conventional vacuum breaker, Fig. 2 is a vertical cross-sectional view of the vacuum breaker according to this invention, and Fig. 3 is a main feature of this invention. FIG. 4 is a sectional view taken along the - line in FIG. 3, FIG. 5 is a partially cutaway perspective view of the main part of this invention, and FIG. A cross-sectional view along the line, FIG. 7, is an explanatory diagram of the test results of the vacuum shield breaker according to this invention. 5... Vacuum container, 11... Fixed electrode rod, 12...
...Movable electrode rod, 18...Contact electrode, 18b...Contact part, 18c...Slope part, 19...Coil electrode,
20... High resistance member, 24... Projection, 24a...
...Groove, 25...Reinforcement member.

Claims (1)

[Scope of utility model registration request] Fixed and movable electrode rods 11 and 12 are arranged in the vacuum container 5 so as to be able to approach and separate from each other, and the fixed and movable electrode rods 1
Contact electrodes 18 that can be freely connected to and separated from each other at the inner ends of 1 and 12
The fixed and movable electrode rods 11 and 12 and the respective contact electrodes 18 are connected by an annular coil electrode 19 with an end centered around each electrode rod 11 and 12. In the vacuum shield and disconnector, each of the contact electrodes 18 is formed into a cap-shaped disk shape by a circular contact portion 18b provided at the center of the opposing surface and a slope portion 18c integrally provided around the circular contact portion 18b, and the slope portion A large number of axially pleated protrusions 24 are formed radially around the movable electrode rod 12 on the opposite back side of the portion 18c, and the bottom of the groove 24a between the protrusions 24 and the surface of the contact portion 18b are formed. The thickness between the grooves 24a is thin, and a reinforcing member 25 having a large electrical resistance and high mechanical strength is fitted into the groove 24a and has a protrusion 25a corresponding to the groove 24a. Vacuum cutter.