JPS5849976B2 - Vacuum cutter - Google Patents

Description

[Detailed description of the invention] The present invention relates to a vacuum breaker.

In general, a vacuum breaker is constructed of a pair of electrodes arranged in a vacuum container so as to be able to be brought into contact and separated from each other through electrode rods, respectively, and current is turned on or cut off by bringing one electrode into contact with or separating from the other.

However, when breaking, an arc is generated between the electrodes, and if the breaking current is large, this arc receives electromagnetic force in the direction of the electrode's outer circumference due to the interaction between the magnetic field generated by the arc itself and the magnetic field created by the external circuit, and the arc It leans toward the outer periphery and locally heats that area, generating a large amount of metal vapor.

For this reason, metal vapor remains between the electrodes after the current reaches zero, delaying insulation recovery and reducing the breaking ability.

Conventionally, as a countermeasure against this problem, applying an axial magnetic field to the arc has been carried out.

An example is shown in FIG.

In the figure, 1 is an insulating cylinder, 2 and 3 are end plates attached to both ends of the insulating cylinder 1, and these constitute a vacuum container.

Reference numeral 4 indicates a fixed electrode rod inserted into the end plate 2, 5 a movable electrode rod inserted through the end plate 3 and attached to the end plate 3 via a bellows 6, and 7.8 the electrode rods 4 and 5, respectively. The movable electrode 8 is a coil electrode 9 having a base 9a attached to the tip of the movable electrode rod 5 and a coil portion 9b extending in a coil shape from the base 9a.
And a high resistance spacer 1 made of stainless steel or the like is attached to the base 9a.
0 and the coil portion 9b.
The fixed electrode 7 is similarly composed of a coil electrode 13, a spacer 14, a contact electrode 15, and a connection conductor 16.

In this vacuum breaker, the breaking current at the time of breaking is, for example, movable electrode rod 5 - coil electrode 9 - connecting conductor 12 - contact electrode 1
1-Arc-contact electrode 15-Connecting conductor 16-Coil electrode 13-Fixed electrode rod 4 flow, each coil electrode 9,1
3 generates an axial magnetic field.

Therefore, the electrons and metal ions carrying the arc current are captured by this magnetic field, preventing arc concentration, and each contact electrode i1. Since IS is not locally heated, it does not generate a large amount of metal vapor, and the insulation recovery after the current zero point is quick and the breaking ability is improved.

However, in the vacuum breaker described above, eddy currents are generated in each contact electrode 11.15 and each electrode bar 4, 5 due to the axial magnetic field, and the eddy current is in the opposite direction to the axial magnetic field generated by each coil electrode 9.13. As a result, the axial magnetic field acting on the arc at the time of interruption is weakened and the phase of the axial magnetic field is out of phase with respect to the interruption current.

For this reason, even after the arc is extinguished at the zero current point, a magnetic field remains, and the charged particles between the electrodes 7.8 are trapped in this magnetic field and prevented from spreading, delaying insulation recovery and reducing the breaking ability.

Therefore, in the past, each contact electrode 11.15 and each electrode rod 4,5
eddy currents were suppressed by providing multiple slits radially, but in this case, the relationship between the number of slits and the phase delay of the magnetic field is as follows: the phase delay when no slits are provided is 100 f.
b, as shown in FIG. 2, and each contact electrode 11
, 15 and the radius of each electrode rod 4, 5, the relationship between the length of the slit and the phase delay of the magnetic field is as shown in FIG. 3, assuming that the phase delay when no slit is provided is 100%.

Therefore, a sufficient effect cannot be obtained unless four or more slits are provided and the length is 50% or more of the radius.

For this reason, the processing for forming the slits is troublesome, and the mechanical strength of the contact electrodes 11.15 and the electrode rods 4.5 is reduced.

The present invention eliminates the above-mentioned drawbacks and provides a vacuum breaker that does not reduce the mechanical strength of contact electrodes and electrode rods, is relatively easy to process, and can suppress residual magnetic fields and improve breaking ability. The purpose is to provide.

The present applicant has conducted various studies to achieve the above object.

The results are described below. 1. As shown in Figure 4B, there is a disc-shaped member 17 having a diameter Dl and a hole 17a having a diameter D2 in the center.

A single slit 18 with a diameter D1 and a hole 18a with a diameter D2 provided in the center and reaching from the outer periphery with a hole 18at.
An axial magnetic field based on a current was applied to each disc-shaped member 17, 18, and the residual magnetic flux was measured after the current was reduced to zero.

Note that the diameter D2 of the holes 17a and 18a was variously changed.

As a result, the characteristics shown in FIG. 4C were obtained.

That is, in the case of the disc-shaped member 17, D2 as shown in line A
Even if you increase the amplitude, the phase delay of the magnetic field will not decrease at all, but
In the case of the disk-shaped member 18, it has been found that as D2 increases, the phase delay of the magnetic field decreases rapidly, as shown by the line.

This is because in the case of the disk-shaped member 17, the eddy current flows circumferentially as shown by the human arrow in Figure 4, and a large magnetic field is generated by the eddy current, whereas in the case of the disk-shaped member 18, In this case, due to the presence of Surin N8b, the eddy current flows back and forth in a circumferential manner as shown by the arrow in Figure 4B, and the magnetic field generated by this cancels out, and the magnetic field due to the eddy current becomes smaller. be.

Therefore, instead of providing four or more slits with a diameter of 50 or more as in the conventional case, by providing a hole 18a with a diameter of 20 to 30 and one slit 18b, the phase delay of the axial magnetic field can be sufficiently delayed. It turns out that it can be made smaller.

In addition, as shown in the fourth diagram, there is a hole 19a and two sulins) 1
In the case of the disk-shaped member 19 having the slits 9b, the eddy current flows as shown in the figure, so that the same effect as in the case of the disk-shaped member 18 is produced, and the same is true when three or more slits are provided.

Also, in the case of a disc-shaped member 20 provided with a hole 20a and a single slit 20b cut from the outer periphery at a point 1 slightly in front of the hole 20a, as shown in FIG. Since no current flows through the remaining portion 20c, the same effect as in the case of the disk-shaped member 18 is obtained.

Moreover, FIG. 4G shows the distribution characteristics of the phase delay of the axial magnetic field in the member, and the C line shows the disc-shaped member 18 (
7) D2/DlX 100 = 40% (D case is shown, the second line shows four slits 21a (length t2/11×1oo=70%) with radius t1 as shown in FIG. 4F. The case of a disc-shaped member 21 is shown.

Also, the line (e) is D2/ of the disc-shaped member 17 shown in FIG.
The case where D x 100 = 70 coefficients is shown.

As is clear from the figure, in the case of the disk-shaped members 18 and 21, the overall phase delay is significantly reduced compared to the case of the disk-shaped member 17, and especially in the case of the disk-shaped member 18, the phase delay in the central part is An advancing part occurs.

Therefore, this phase lead portion helps improve the phase delay of the axial magnetic field between the electrodes.

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

In FIG. 5, 22 is an electrode rod having a hole 22a with a diameter of about 30% of the diameter in the center and a single sulin (22b) at the end reaching the hole 22a from the outer periphery, and 33 is an electrode rod that fits into the hole 22a. 24 is a coil electrode having a base 24a attached to the tip of the electrode rod 22 and a coil portion 24b extending in a coil shape from the base 24a. A single slit 2 is provided around a hole 24c having a diameter of about 40% and extends from the outer periphery with a groove in the hole 24c.
4d is provided.

25 is a cylindrical high-resistance spacer made of stainless steel or the like, and 25a is an air hole.

26 is a connecting conductor erected at the tip of the coil portion 24b;
Reference numeral 7 denotes a copper adapter attached to the end of the high-resistance spacer 25 and attached to the end of the connection conductor 26 via a protruding connection part 27a. A hole 27b is provided, and a slit 27c reaching the hole 27b from the outer periphery is provided.

28 is a contact electrode made of aluminum, and 29 is a highly conductive spacer made of silver provided between the adapter 27 and the contact electrode 28. The highly conductive spacer 29 has a diameter of about 40% of the diameter at the center. A hole 29a is provided, and a slit 29b reaching the hole 29a from the outer periphery is provided.

The contact electrode 28 made of beryllium has a lower conductivity than metals such as copper or silver thread, so eddy currents hardly flow therethrough and the residual magnetic field is small.

■Because the secondary electron emission coefficient is small, neutral particles of metal vapor are difficult to ionize, arc concentration is difficult to occur, and less metal vapor is generated.

■Because the specific heat is large, the temperature rise due to arcing is small, and less metal vapor is generated.

■Because it has a small atomic weight, it is light, and the particles generated when it is shut off diffuse quickly.

It has the following advantages and can improve the cutting ability.

In addition, the adapter 27 is designed to prevent the contact electrode 28 from being distributed evenly due to current flowing around the contact electrode 28 when the contact electrode 28 is directly connected to the connecting conductor 26, and to prevent the arc from being distributed uniformly when the contact electrode 28 is cut off. This is provided to prevent the contact electrode part 28 from tilting if connected to both the spacer 25 and the connecting conductor 26, and to prevent the machining of the hard and brittle aluminum from becoming troublesome.

Furthermore, the silver highly conductive spacer 29 is connected to the copper adapter 27.
This is provided to prevent the formation of an intermetallic compound (Be3Cu) when the contact electrode 28 of Be3Cu is brazed and the strength is extremely reduced.

The axial length of the electrode rod 22b is 1° from the lower surface of the central part of the base 24a of the coil electrode 24 to the coil portion 2.
The length at the lower end 1 of 4b is L□, L1≦t2≦2t1
is desirable.

(If t2 is smaller than M, the eddy current suppressing effect will not be sufficient, and if it is larger than 2./, 1, the eddy current suppressing effect will not improve and the mechanical strength will become weak.

) Note that 30°3 is a reinforcing material made of a high resistance material such as stainless steel.

In Keiki's vacuum breaker, current flows from the electrode rod 22 to the coil electrode 24, and then to the connecting conductor 26, adapter 27, and so on. It flows to the contact electrode 28 via the highly conductive spacer 29 .

Therefore, the coil portion 24b generates an axial magnetic field.

However, the electrode rod 22, the base 24a of the coil electrode, the adapter 27, and the highly conductive spacer 29 have holes 22a and 2, respectively.
4c, 27b.

29a and slits 22b, 24d, and 27c.

29b makes it difficult for eddy current to flow,
The edges of these parts are the mouth lines in Figure 4 C (when viewed as a whole)
The phase delay of the axial magnetic field with respect to the cutoff current decreases as shown by the C line in FIG. 4G (when viewed in terms of distribution).

Particularly, a phase advance also occurs in the central part of these members as shown by the C line in FIG. The phase delay is significantly reduced and the blocking ability is improved, as in the case of a wire.

Incidentally, the T line in FIG. 5F shows that four slits with a radius of 70 fb are provided in the adapter 27 and the highly conductive spacer 29 (no holes are provided), and four slits with a radius of 50 fb are provided in the electrode rod 22. (No holes are provided).
Only the slits 22b, 24d, 27c, 2 are provided.
The case where 9b is not provided is shown.

As a result of the cutoff test, the cutoff ability was improved by 1.3 to 1.5 times in the case shown by the T line compared to the case shown by the G line, and by 1.8 to 2.2 times in the case of the present example.

FIG. 6 shows a second embodiment of the present invention, in which 32 is an electrode rod;
Reference numeral 33 has a base 33a attached to the tip of the electrode rod 32, and a coil portion 33b extending in a coil shape from the base 33a.
The base 33a has a hole 33c in the center.
and a slit 3 reaching the hole 33c from the outer periphery.
Provide 3d.

34 is a cylindrical high-resistance spacer made of a high-resistance material such as stainless steel, and is attached to the upper part of the base 33a.

35 is a base portion 33a inside the high-resistance spacer 34.
The first connecting conductor 35 is provided with four slits 35a having a length of 50 or more times the radius from the outer periphery toward the center.

Reference numeral 36 denotes a first highly conductive spacer made of silver attached to the upper end of the first connection conductor 35, and is provided with four lines 35a having a length of 50 or more times the radius from the outer periphery toward the center.

The contact portion of the contact electrode made of beryllium is attached to the top of the highly conductive spacer 36 of 37Hil.

Further, 38 is a second connection conductor erected at the tip of the coil portion 33b, 39 is an adapter made of copper attached to the high resistance spacer 34 and the end of the second connection conductor 38,
The adapter 39 is provided with a hole 39a in the center and a sling 39b that reaches from the outer periphery at the hole 39a1.

A second highly conductive spacer 40 is attached to the top of the adapter 39 and has a hole 40a in the center and a hole 40b extending from the outer periphery through a hole 40a1.

Reference numeral 41 denotes an arc diffusion part of a contact electrode provided on the upper part of the second highly conductive spacer 40, which is made of aluminum and has a hole 41a in the center, and a contact electrode located inside this hole 41a. There is a gap between the part 37 and the part 37.

Further, 42 is a reinforcing material made of high resistance material such as stainless steel.

In this vacuum breaker, during normal energization, the current flows through the electrode rod 3.
2 flows from the base 33a, the first connecting conductor 35°, through the first highly conductive spacer 36 to the contact portion 37, and further flows to the counter electrode.

Further, when the arc is cut off, the arc that first occurs in the contact portion 37 moves to the shear arc diffusion portion 41 due to its diffusion force.

Therefore, the cutoff current flows from the electrode rod 32 to the coil electrode 33.
．． Second connection conductor 38. The arc diffuser 41 flows through the adapter 39 and the second highly conductive spacer 40 .

The coil electrode 33 generates an axial magnetic field.

Therefore. Since no current flows through the coil electrode 33 and the like except when the circuit is cut off, heat generation due to resistance loss is reduced, and disadvantages due to temperature rise can be suppressed.

In this example as well, the base 33a1, the adapter 39, and the second highly conductive spacer 40 have holes 33c and 39a, respectively.

40a and a slit 33d.

39b and 40b make it difficult for eddy current to flow, and the phase delay of the axial magnetic field is significantly reduced.

In addition, since the first connecting conductor 35 and the first highly conductive spacer 36 (ri) do not require much mechanical strength, eddy currents are suppressed by providing slits 35a and 36a, respectively. Reduces phase delay.

In each of the above embodiments, one slit is provided in the electrode rod, the base of the coil electrode, the adapter, the highly conductive spacer, etc., but a plurality of slits may be provided.

Also, the slit does not have to be reached by a trench. As described above, in the present invention, an axial hole and a radial slit are formed in at least one current-carrying member of the electrode rod and the members constituting the electrode, excluding the contact electrode and the coil portion of the coil electrode. This makes it difficult for eddy currents to flow through this current-carrying member, thereby reducing the phase delay of the magnetic field.

Moreover, a phase advance of the magnetic field also occurs in the center of the current-carrying member, and this phase advance acts to cancel the phase delay of the magnetic field of the contact electrode, so that the phase delay of the magnetic field in the entire electrode is reduced, and the breaking ability is improved.

Furthermore, the length of the slits described above is shorter than in the past, and the number of slits can be reduced, making processing easier and improving mechanical strength.

[Brief explanation of drawings]

1A and 1B are respectively a longitudinal sectional front view and a perspective view of a coil electrode of a conventional vacuum breaker; FIGS. 2 and 3 are characteristic diagrams of magnetic field phase lag in other conventional vacuum breaker, respectively; FIG. 4 A, B, and D-F are plan views of disc-shaped members as research samples, respectively. Figures 4C and G are characteristic diagrams of the phase delay of the magnetic field in each disc-shaped member, respectively. A longitudinal sectional front view of the electrode portion of the vacuum breaker in the first embodiment of the present invention, respectively;
The plan view of the electrode rod, the plan view of the coil electrode, the plan view of the adapter, the plan view of the highly conductive spacer, the phase delay characteristic diagram of the magnetic field, and FIGS. FIG. 2 is a longitudinal sectional front view of an electrode portion of a circuit breaker, a top view of a coil electrode, a top view of a first connecting conductor, and a top view of a first highly conductive spacer. 1... Insulating cylinder, 2, 3... End plate, 6.
...Bellows, 22.32...Electrode rod,
22a...hole, 22b...slit,
24.33... Coil electrode, 24a. 33a...Base, 24b, 33b...
Coil part, 24c, 33c... Hole, 24d, 3
3d...Slit, 26.38...Connection conductor, 27.39...Adapter, 27 b
, 39 a-" hole, 27 c, 39b...
・Slit, 28...Contact electrode, 29.40・
...Highly conductive spacer, 29a, 40a...
...hole, 29b, 40b...slit, 37
. . . Contact portion of the contact electrode, 41 . . . Arc diffusion portion of the contact electrode.

Claims (1)

[Claims] 1. In a vacuum breaker in which a pair of electrodes are arranged facing each other so as to be able to come into contact with and separate from each other through electrode rods in a vacuum container, the electrodes are provided with a coil electrode that generates an axial magnetic field, and the electrode rods and electrodes are constructed and At least one current-carrying member 1, excluding the contact electrode and the coil portion of the coil electrode, which contacts the counter electrode, is provided with an axial hole and at least one radial slit. vacuum breaker.