JPS5911166B2 - Vacuum shield electrode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrode for a vacuum breaker in which the electrode is made of beryllium or a beryllium alloy.

Recently, beryllium or beryllium alloys have been used as electrode materials for vacuum circuit breakers in place of materials such as copper.

BeIJIJum has an atomic weight of 9.0122,
Its use is because it is extremely light compared to copper's atomic weight of 63.546, and therefore the metal particles generated by the arc diffuse much faster than the copper material, and therefore the insulation recovery across the gap after current cutoff is extremely good. This is the main reason.

It has been confirmed through experiments that the cutting ability of beryllium electrodes is approximately 2 to 2.5 times higher than that of copper electrodes having the same shape and structure.

For example, according to the test results of 24KV class, the diameter is 59m.
In the case of a copper plate electrode of m, the breaking limit current is about 12 to 13
It has been confirmed that a current of approximately 22 to 27 KA can be interrupted in the case of a aluminum electrode.

For the above reasons, beryllium or beryllium alloys are used as electrodes in vacuum circuit breakers.
On the other hand, aluminum has the disadvantage of being very fragile.

In general, electrodes for ultra-high voltages with large interelectrode distances and high cutoff and input speeds, such as interelectrode distances (gap)
60mm, 84KV with a breaking speed of about 3.5rn/sec
In electrodes for ultra-high voltages such as 1.5 or higher, it is customary to provide spiral or screw-shaped grooves 1, as shown in FIG. 1 or 2, for the purpose of improving the breaking capacity.

A plurality of grooves 1 are provided on the electrode 2, and an arc drive piece (pedal) 3 formed by the grooves 1 drives the arc column moving outward in the radial direction in the direction of its outer circumference.
This function prevents the arc column from stagnation, prevents local overheating of the electrode, and improves the breaking performance.

As mentioned above, beryllium is a fragile material, and
When a plurality of grooves 1, 1, . . . as described above are formed, the mechanical strength thereof is significantly reduced.

According to a strength experiment using a spiral shape, it has been demonstrated that the arc drive piece 3 breaks from the base after about 100 operation tests.

By the way, as shown in FIG. 3, when the disk-shaped electrode 2 without grooves is formed from aluminum alloy,
Although its mechanical strength increases, when a large current is interrupted, the arc locally stagnates at the tip of the disk, causing melting and loss of the electrode, resulting in a decrease in the interrupting capacity.

Therefore, although electrodes made of beryllium or beryllium alloys have better properties than copper, they have the disadvantage that they cannot be used effectively due to their brittleness.

This invention solves the above-mentioned conventional drawbacks,
The present invention aims to provide an electrode for a vacuum breaker that can increase the mechanical strength of the electrode made of beryllium or beryllium alloy, and can also increase the breaking capacity.

Hereinafter, embodiments of the present invention will be described in detail using the drawings from FIG. 4 onwards.

In FIG. 4, the reference numeral 5 indicates the electrode part of the vacuum breaker, and this electrode part 5 includes an arc electrode 6 formed into a disk shape and a reinforcing member for reinforcing the arc electrode 6. 7, a lead rod (electrode support member) 8, and the like.

The arc electrode 6 is made of beryllium or beryllium alloy, and the reinforcing member 7 is made of a metal having a higher conductivity than beryllium (40 to 45%), such as copper (conductivity 100%). It is configured and provided as follows.

The reinforcing member 1 is formed and provided, for example, as shown in FIG.

That is, what is indicated by 9 in the figure is the reinforcing member main body 10.
The central part 1 is provided in a cylindrical shape with a plurality of grooves provided in the cylindrical shape.
It is provided in a spiral shape extending radially outward from the outer circumferential portion of 1.

In the reinforcing member main body 10, a spiral pedal portion 12 formed in a spiral shape like the grooves 9 is formed between each groove.

A protrusion 13 that protrudes in the same direction as the center part 11 is provided at the outer peripheral end of each of the spiral pedal parts 12, and the reinforcing member main body 10
3 and the center portion 11 are brought into contact with the lower surface of the arc electrode 6, and are fixed to each other by suitable means such as brazing.

A circular recess 14 is provided in the axial center (center) of the lower surface of the reinforcing member main body 10, and the lead rod 8 is fitted and fixed in the recess 14.

Note that the axial center portion of the arc electrode 6, the axial center portion of the reinforcing member 7, and the axial center portion of the lead rod 8 are configured to be substantially coaxial.

In other words, the arc electrode 6 and the reinforcing member 7 are connected to the lead rod 8.
It is arranged concentrically with the

Although the reinforcing member 7 is made of copper, it is not limited to copper, and may be made of a metal or alloy that does not form an intermetallic compound with beryllium.

In addition, in the current path between the arc electrode 6 and the mechanical support portion (center portion 11, protruding portion 13) of the reinforcing member 1, a base IJ is provided.
A spacer (not shown) made of a metal that does not form an intermetallic compound with IJ may be interposed, or
The reinforcing member 7 side may be subjected to treatments such as plating or metal vapor deposition.

That is, for example, when copper is used for the reinforcing member 7, the reinforcing member 7 side between the arc electrode 6 and the mechanical support part of the reinforcing member 7 is plated with silver, nickel, etc. with a thickness of 10μ or more, or is diffused. It is desirable to perform a process such as vapor deposition to prevent the thickness from becoming too large, or to interpose a spacer such as silver or nickel between the arc electrode 6 and the mechanical support portion of the reinforcing member 7.

When an intermetallic compound is generated in the current path between the arc electrode 6 and the mechanical support part of the reinforcing member 7, the adhesive strength becomes weak and peeling becomes easy, but this can be prevented by the above structure. .

In the electrode section 5 having the above configuration, the arc generated when the current is cut off is generated on the center of the arc electrode 6 made of beryllium.

The arc on the center of the arc electrode 6 is directed outward in the radial direction due to the interaction between the diffusion force in vacuum, the self-electromagnetic force due to the arc current, and the electromagnetic force due to the external circuit, that is, in the direction indicated by arrow A in FIG. Move in the direction of the outer circumference shown.

The arc that has moved to approximately the middle of the arc electrode 6 in the radial direction is not affected by the magnetic field generated by the radially outward and radially inward currents that flow into the arc electrode 6 from the center portion 11 and the projection 13. As shown by arrows in FIG. 4, the spiral pedal portion 12 of the reinforcing member 7 is magnetically driven radially outward by the action of a radial magnetic field caused by substantially all the current flowing radially outward.

When the arc moves to the outer periphery of the arc electrode 6 due to the magnetic drive, most of the current flows through the spiral pedal section 12 of the reinforcing member 7; Due to this action, an electromagnetic force is generated in the outward radial direction, and also in the circumferential direction of the spiral shape.

Therefore, an electromagnetic force corresponding to the vector sum of the electromagnetic forces described above acts on the outer peripheral end of each spiral pedal part 12, and the electromagnetic force of this combined vector causes the outer peripheral end of the arc electrode 6 to The arc column of the arc that has been moved is driven once so as to be rotated in the circumferential direction.

That is, the arc generated when the current is cut off moves radially outward on the arc electrode 6 due to the interaction between the self-electromagnetic force generated by the arc current and the electromagnetic force generated by the external circuit, and the diffusion force in vacuum, and the arc The pedal part 12 is magnetically driven outward by a magnetic field generated by a radially outward current flowing through the pedal part 12, and is driven to rotate in the circumferential direction at its outer peripheral end.

Therefore, the arc column generated when the current is interrupted is effectively driven outward in the radial direction and in the circumferential direction, so that the arc column is efficiently cooled and the interrupting performance is greatly improved.

Furthermore, in this invention, the arc electrode 6 made of beryllium or its alloy, which is a fragile material, is supported by reinforcing members 7 at its center and outer periphery, so the mechanical strength is high. increase, be IJ
The mechanical strength of the arc electrode 6 made of IJium or its alloy can be compensated for.

Therefore, the arc electrode 6 made of beryllium can also be used for ultra-high voltage applications where the distance between electrodes is large and the breaking and closing speeds are large, such as 84KV class or higher voltages with a gap of 607n1rL and a breaking rate of about 3.5rn/sea. can be used safely.

Note that the shape of the groove 9 is not limited to the spiral shape, and may be provided in a screw shape, for example, as shown in FIG. It may be formed as a linear groove 9 in a tangential direction to the circumference of a circle (indicated by a dotted line).

Furthermore, a straight groove 9 may be formed by forming a straight groove 9 in a tangential direction from the center at a certain inclination angle.

In either configuration, the functions and effects of the present invention can be achieved.

Further, in the embodiment, the reinforcing member 7 and the lead rod 8
Although the case where the reinforcing member 7 and the lead rod 8 are formed separately is described, the invention is not limited to this, and the reinforcing member 7 and the lead rod 8 may be formed integrally, as shown in FIG. The outer circumferential portion may be covered with a bent portion 17 provided by bending the outer circumferential portion of the arc electrode 6.

By configuring in this way, the reinforcing member 7 can be protected from arcs and has the effect of being easy to manufacture.

Note that changes made to the structure of this invention without departing from the operation and effects of this invention also belong to this invention.

[Brief explanation of drawings]

1, 2, and 3 are explanatory diagrams of the prior art of the electrode according to the present invention, FIG. 4 is an explanatory diagram of the electrode according to the present invention, and FIG. 5 is a plan view of the main parts of the present invention. 6, 7 and 8 are explanatory diagrams of other embodiments of the essential parts of the present invention. 6... Electrode, 7... Reinforcement member, 8...
... Lead rod (electrode support member), 9 ... Groove, 11 ... Center part, 12 ... Pedal part, 13 ... Protrusion part .

Claims (1)

[Scope of Claims] 1. The electrode 6 is made of beryllium or beryllium alloy and formed into a disk shape, and a material having higher conductivity than the electrode 6 is disposed between the electrode 6 and an electrode support member 8 that supports the electrode 6. A reinforcing member 7 having a plurality of pedal parts 12 is interposed therebetween by an appropriate groove 9 formed radially outward from the vicinity of the center, and the electrode 6 and the center of the reinforcing member 7 and the electrode 6 are interposed therebetween. An electrode of a vacuum breaker characterized in that the electrodes are electrically connected to the outer peripheral end of each pedal part 12. 2. An electrode for a vacuum breaker according to claim 1, characterized in that the outer circumference of the reinforcing member 7 is covered with an electrode 6. 3. The electrode of a vacuum breaker according to claim 1, wherein the reinforcing member 7 and the electrode supporting member 8 are integrally formed. 4. The vacuum interrupter according to claim 1, wherein a metal that does not form an intermetallic compound with beryllium is fixed to the reinforcing member 7 at the conductive portion with the electrode 6 by appropriate means such as plating. Electrode of the device.