JPH0547275A - Vacuum valve - Google Patents

Abstract

PURPOSE:To improve the low-surge performance, and the large-current shielding performance by providing a contact comprising a first and a second composition ranges of different compositions, and a middle range disposed between them. CONSTITUTION:For a vacuum valve having contacts 13a, 13b composed of a high conductivity material and an arc-resistant material, the contacts 13a, 13b are each composed of a plural composition ranges of different compositions. That is, each is composed of a first composition range (I) 21, a second composition range (II) 23, and a middle range (M) 22 disposed at a middle position between the range (I) and the range (II). The range (I) 21 comprises Ag-Mo-based alloy, the range (II) 23 comprises Cu-Cr-based alloy having a large current shielding ability, and the range (M) 22 comprises alloy having an intermediate property of the range (I) 21 and the range (II) 23. A quantity of conductive components of the range (M) 22 is set to be within a range of (II)>(M)>(I) with relation to the quantity of conductive components in each range. A low- surge performance and a large-current shielding performance can thus be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum valve excellent in large current interruption performance and low surge performance.

[0002]

2. Description of the Related Art A vacuum switch has various excellent features such as small size, light weight, maintenance-free, and environmental friendliness as compared with other switches, so that its application range has been gradually expanded in recent years. The vacuum circuit breaker uses the arc diffusivity in a vacuum to interrupt a current in a high vacuum, and a vacuum valve will be described with reference to FIG.

The vacuum valve has a shut-off chamber 1 which is kept airtight in a vacuum, and the shut-off chamber 1 is formed of an insulating material in a substantially cylindrical shape, and sealing metal fittings 3a, 3 are provided at both ends thereof.
It is composed of metallic lids 4a and 4b provided via b. A pair of fixed electrodes 7 and movable electrodes 8 attached to opposite ends of the conductive rods 5 and 6 are disposed in the shutoff chamber 1. A bellows 9 is attached to the conductive rod 6 of the movable electrode 8 so that the movable electrode 8 moves in the axial direction while maintaining vacuum tightness in the blocking chamber 1. An arc shield 10 made of metal is provided above the bellows 9 to prevent the bellows 9 from being covered with arc vapor. Similarly, a metal arc shield 11 is provided so as to cover the fixed electrode 7 and the movable electrode 8 in the shutoff chamber 1, and prevents the insulating container 2 from being covered with arc vapor. The movable contact 13a is in contact with the fixed contact 13b during energization, and the current is interrupted by moving the conductive rod 6 downward and breaking the contact between the contacts 13a and 13b.

Next, the mutual fixing structure of the conductive rods 5 and 6 and the electrodes 7 and 8 and the electrodes 7 and 8 and the contacts 13a and 13b will be described.
This will be described with reference to FIG. 3 showing the details around the movable electrode 8 in FIG. The movable electrode 8 is fixed to the conductive rod 6 by brazing indicated by reference numeral 12 or caulking not shown, and the movable contact 13a is fixed at the movable electrode 8 by brazing indicated by reference numeral 14 or caulking not shown. The same applies to the method of fixing the fixed electrode 7 on the fixed side and the contact 13b.

[0005]

DISCLOSURE OF THE INVENTION Problems to be solved by the invention are as follows: (1) Low weldability (2)
They have high withstand voltage (3) excellent wear resistance (4) low contact resistance and stability. In addition to this, recent expectations for vacuum switchgear have further increased, and (5) low surge performance and (6) large current interruption performance are required, but these two requirements are contradictory.

First, the requirements for having a low surge performance will be described. When the current is cut off by an induction circuit such as a motor load, an excessive surge voltage may be generated, which may damage the insulation of the load device. The cause of this abnormal surge voltage is due to the current interruption phenomenon that occurs on the low current side during interruption in vacuum (the current is forcibly interrupted without waiting for the natural zero point of the AC current waveform). .. The abnormal surge voltage value is expressed by the product of the circuit surge impedance and the current cutoff value.To reduce the abnormal surge voltage, that is, to have low surge performance, the current cutoff value must be reduced. I won't. That is,
At the time of interruption, a large amount of ions and metal particles evaporate from the surfaces of the movable contact 13a and the fixed contact 13b due to the arc and float between the contacts, so that the arc must be easily connected. Therefore, the material used for the contacts 13a and 13b is required to have high vapor pressure, which is highly vaporizable, not only when a large current is cut off, but also when the switching current is small and the temperature rise of the contact is small. To be done. As a material satisfying such a low surge performance, an Ag-WC alloy containing Ag, which is a high vapor pressure material, is known. The contacts made of this alloy (1) The inclusion of WC facilitates the emission of ions from the contact surface. (2) The evaporation of metal particles from the contact surface due to the heating between the electrodes due to the collision of field emission electrons is promoted. (3) Carbide in the contact material is decomposed by the arc to generate a charged body, which has excellent low surge performance. In addition to this, as a material having this performance, a high vapor pressure material such as C
Cu-Cr alloys, Cu-Bi alloys and the like containing u are known.

On the other hand, the contacts 13a and 13b are required to be made of a material having a low vapor pressure in order to have a large current interruption performance which is the other contradictory requirement. When shutting off a large current, the surface temperature of the contacts 13a, 13b becomes extremely high, but even in such a case, the amount of evaporation from the contact surface due to the arc is small, and ions and metal particles are generated between both contacts. The barrier property will be impaired unless it floats almost. Therefore, in general, when the performance of either one is pursued, the performance of the other decreases.

As means for satisfying these two contradictory requirements, there is one in which the contact is made of two kinds of materials, a high vapor pressure material and a low vapor pressure material. When both contacts, which were in contact with each other during energization to separate the current, separate from each other, many ions and metal particles evaporate from the part made of the material with high vapor pressure and float between the contacts, and the arc guides them. It is connected to the high vapor pressure material comrades at both contacts.
After a lapse of time necessary to satisfy the low surge performance, the arc, which was connected to the high vapor pressure material at both contacts, is transferred to be connected to the low vapor pressure material at both contacts. This is the coil electrode shown in FIG.
44, a magnetic field H is generated using the spiral electrode 45 shown in FIG.
Can be performed by a method of changing the distribution of ions and metal particles floating between both contacts and forcibly moving the arc.

However, even in the low current circuit breaker, the physical properties of a high vapor pressure material having a low surge performance and the physical properties of a low vapor pressure material having a large current interruption function are very different in terms of vapor pressure property. Therefore, even if the distribution of ions and metal particles existing between both contacts is changed by the magnetic field, for example, the longitudinal magnetic field H, the arc is stagnant on the boundary between the part made of the high vapor pressure material and the part made of the low vapor pressure material. Does not migrate easily. Therefore, the low surge performance and the large current interruption performance cannot be satisfied at the same time by simply configuring the contact point by simply combining the high vapor pressure material and the low vapor pressure material. An object of the present invention is to provide a vacuum valve excellent in low surge performance and large current interruption performance.

[0010]

In order to achieve the above object, the vacuum valve of the present invention comprises a contact composed of first and second composition regions having different compositions and an intermediate region sandwiched therebetween. It is a thing.

That is, the vacuum valve of the present invention is a vacuum valve comprising a contact made of a highly conductive material and an arc resistant material, wherein the contact has a first composition region [I ], A second composition region [II], and an intermediate region [M] interposed between the first composition region [I] and the second composition region [II], and the first composition region [I] is low. consists surge of Ag-Mo ₂ C-based alloy,
The second composition region [II] is made of a Cu-Cr alloy having a large current blocking property, and the intermediate region [M] is composed of the first composition region [I] and the second
Composed of an alloy having intermediate properties in the composition region [II],
The amount of the conductive component of the above [M] was set in the range of [II]>[M]> [I] with respect to the amount of the conductive component in each region.

In a preferred embodiment of the present invention, the first
The composition region [I] contains 10 to 50% by weight of the highly conductive material A.
g, the balance of the arc-resistant material is Mo ₂ C, and the second composition region [II] contains Cu of 20 to 80 wt% as the highly conductive material.
The balance of the arc resistant material was made of Cr.

In another preferred embodiment of the present invention, in the intermediate region [M], the highly conductive material is at least one of Ag and Cu, and the arc resistant material is Cr or Mo _2.
It was made to consist of at least one of C.

In another preferred embodiment of the present invention, the first
The highly conductive material in the composition region [I] consists of Ag and Cu, the content of the highly conductive material is in the range of 10 to 50% by weight, and the amount of Cu is within 40% with respect to the amount of Ag. did.

In another preferred embodiment of the present invention, the arc resistance component Cr + Mo ₂ C in the intermediate region [M] is
From the one side in contact with the first composition region [I] to the other side in contact with the second composition region [II], the ratio of Cr to Mo ₂ C is from the arc-resistant component amount of the first composition region [I]. The amount of the arc resistant component in the second composition region [II] is changed stepwise or continuously.

In another preferred aspect of the present invention, the first
Each of the composition region [I], the second composition region [II] and the intermediate region [M] is [II] in the radial direction from the center of the contact.
They are arranged in the order of [M] [I] or in the order of [I] [M] [II].

[0017]

The contact used in the vacuum valve of the present invention has a first composition region [I] and a second composition region [I] having different compositions.
I] and an intermediate region [M] interposed at an intermediate position between [I] and [II], and the first composition region [I] is an Ag-Mo ₂ C-based alloy excellent in low surge property, 2 composition area [I
I] is composed of a Cu-Cr alloy excellent in blocking large currents, and the intermediate region [M] is composed of an alloy having intermediate properties between [I] and [II]. Is in the range of [II]>[M]> [I] with respect to the amount of the conductive component in each region. Therefore, in the case of a circular contact, for example, the amount of conductive components that have an important influence on the low surge property is [I] [M] [II] in the radial direction or [II] [M] [I]. It is changing in order. When using a contact with such a structure as a vacuum valve to cut off the current, when the two contacts that were in contact with each other during energization are separated, the material with the least amount of conductivity in the area that constitutes the contact is selected. A large number of ions are emitted from the first composition region [I] or metal particles are evaporated from the first composition region [I] to float between the alloy regions of both contacts, and an arc is introduced between them to connect them. After that, when the distribution of ions and metal particles existing between both contacts is changed by the action of the magnetic field, the first composition region [I]
The arc goes from the center to the intermediate region [M]. That is, since the amount of the highly conductive component gradually increases from the first composition region [I] through the intermediate region [M] to the second composition region [II], the arc can be easily maintained without stagnating. Transition. In this way, the arc is forcibly moved toward the second composition region [II] by controlling the magnetic field. Then, after the time required for satisfying the low surge performance, that is, because the arc is connected between both contacts, the second composition region [II] without Ag is moved,
At this moment, the arc will be disconnected.

The first composition region [I] is made of a low surge Ag—Mo ₂ C alloy. This Ag-Mo ₂ C
The system alloy is an alloy having an excellent low surge function as described above.

[0019] because Ag-Mo ₂ C-based alloy in the present invention, Ag as a conductive material, or as main component and a part of the Ag composed those substituted with Cu, the Mo ₂ C as arc-proof component It means an alloy. Then, the highly conductive material is 10 to 50% by weight of Ag, and the remaining arc resistant component is M.
It is preferably composed of o ₂ C. When the amount of the conductive component in the first composition region [I] is less than 10% by weight, the breaking current value is not sufficiently low, and the fluctuation is large, and the breaking tendency tends to deteriorate with the passage of the switching circuit. on the other hand
If it exceeds 50% by weight, the breaking current value becomes high, which is not preferable.

The highly conductive material in the first composition region [I] is not limited to Ag, and even if it is made of Ag and Cu, the content of the highly conductive material is 10 to 50% by weight. And the amount of Cu is within 40% of the amount of Ag, the amount of conductive component in the intermediate region [M] is [II]>[M]>
As long as it is in the range of [I], the arc spreads over the entire electrode surface and exhibits favorable interruption characteristics.

The above-mentioned second composition region [II] is made of a Cu-Cr type alloy having a large current interrupting property. This Cu-Cr alloy is an alloy having excellent large current interruption characteristics as described above. Here, it is preferable that the highly conductive material is 20 to 80% by weight of Cu, and the balance of the arc resistant material is Cr. The amount of the conductive component in the second composition region [II] is 20% by weight.
When it is less than the above range, the arc is not easily transferred from the intermediate region [M] to the second composition region [II]. On the other hand, if it exceeds 80% by weight,
The arc increases the consumption of the second composition region [II].

The intermediate region [M] is located at an intermediate position between the first composition region [I] and the second composition region [II], and the first composition region [I] and the second composition region [I]. It is composed of an alloy having an intermediate property of [II].

With this structure, the first
The arc is smoothly transferred from the composition region [I] through the intermediate region [M] to the second composition region [II]. As the constituent material of the intermediate region [M], the highly conductive material is at least one of Ag and Cu,
It is preferable that the arc resistant material is made of at least one of Cr and Mo ₂ C.

Therefore, as the constituent material of the intermediate region [M], specifically, Ag--Mo ₂ C, Cu--Mo ₂ C, Ag +
_{Cu-Mo 2 C, Ag-} Cr, Cu-Cr, Ag + Cu
_{-Cr, Ag + Cu-Mo 2} C + Cr, Ag-Mo 2 C
There are + Cr and Cu-Mo ₂ C + Cr combinations, be of any thereof, conductive component amount [I
As long as it is in the range of I]>[M]> [I], it shows a preferable breaking performance.

When Mo ₂ C + Cr is used as the arc resistant material in the above-mentioned intermediate region [M], Cr is applied from one side in contact with the first composition region [I] to the other side in contact with the second composition region [II]. by forming the ratio of Mo ₂ C as stepwise or continuously changes from arc-proof component content of the first compositional region [I] to arc-proof component content of the second composition region (II) This is preferable because the arc smoothly transitions from [I] → [M] → [II].

[0026]

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

According to one embodiment of the present invention, the contact is made from Ag--Mo ₂ C as the first composition region [I], Cu-Cr as the second composition region [II], and an intermediate region [M] between them. This case will be described with reference to FIG. 1 in which the contacts are viewed from above. It differs from the conventional contact shown in FIG. 4 in that an intermediate region [M] is arranged between [I] and [II].

Next, the results of test evaluation of the low surge property and large current interruption property of the contact according to the present invention will be described. In order to compare and contrast the low surge performance and large current interruption performance of each contact, the contact pressure when both contacts were in contact, the contact opening speed when separating from this condition, and the degree of vacuum were the same conditions.

The superiority or inferiority of the low surge property can be evaluated by the magnitude of the current interruption value required for the arc to be connected between the separated contacts. The smaller this value, the better the low surge property. Becomes 44A AC via LC circuit
When an electric current was applied, the voltage drop of the coaxial shaft inserted in series with the vacuum circuit breaker was measured with an oscilloscope to calculate the current interruption value.

The superiority or inferiority of the large current interruption property can be evaluated by the magnitude of the current when the interruption is successful, that is, the maximum value of the current. The larger this value, the better the large current interruption property. After cleaning the contact surface by baking, voltage aging, etc. to make the conditions constant, 7.
The maximum value of the current at the interruption limit was measured while increasing the current by 1 KA at 2 KV and 50 Hz, and the magnification against a predetermined standard value was calculated as the interruption magnification. Example 1 and Comparative Examples 1 to 2 The effects of the contact according to the present invention will be described with reference to Tables 1 and 2 showing the surge current value and the breaking ratio for each contact described above.

In each of Example 1 and Comparative Examples 1 and 2, 33Ag-Mo ₂ C, which is a low breaking material, is used as (21) in FIG.
That is, in the first composition region [I], 50
Cu-Cr was used for the second composition region [II], that is, (23) in FIG. On the other hand, in the intermediate region [M] existing between [I] and [II], that is, (22) in FIG. 1, the amount of the conductive component Ag is 15 wt% (Comparative Example-1) and 42 wt% (implementation). Example-1) and 75 wt% (Comparative Example-2) were evaluated, and when the amount of Ag of [M] was an intermediate amount between the conductive materials of [I] and [II], it became [I]. The ignited arc is [I
I) and the effective use of the electrode area,
It showed excellent blocking performance (Example-1).

On the other hand, the amount of Ag of [M] is 15 wt%
In the case of, that is, when the amount of Ag (conductive material) of [I] is smaller (Comparative Example-1), the arc tends to stick at the boundary between [I] and [M], and the electrode surface It could not be used effectively and the blocking characteristics were not sufficient (Comparative Example-
1).

On the other hand, when the amount of Ag of [M] is 75 wt%,
That is, when the amount of the conductive material Cu of [II] is larger (Comparative Example-2), the arc tends to stick to the boundary between [M] and [II], and the breaking performance of [II] is excellent. 50C of area
The ability of u-Cr could not be fully exhibited, and the blocking characteristics were not sufficient (Comparative Example-2). From the above, the amount of the highly conductive material in the intermediate region [M] needs to be in the range of [II]>[M]> [I]. Example 2, Comparative Examples 3-4

In the above-mentioned case, Ag-Mo ₂ C using Ag as a conductive component in the intermediate region [M] is described, but the same tendency is obtained in Cu-Mo ₂ C using Cu as a conductive component. It was

That is, when the amount of Cu in [M] is an intermediate amount between the conductive components of [I] and [II], the arc ignited by [I] spreads rapidly to [II], As a result of effectively utilizing the electrode surface, excellent blocking performance was exhibited (Example-2).

On the other hand, the amount of Cu in [M] is 20 wt%
In the case of, that is, when it is less than the amount of Ag (conductive material) of [I] (Comparative Example-3), the arc tends to stagnate at the boundary between [I] and [M]. The blocking property was not sufficient due to electrode damage (Comparative Example-3).

On the other hand, when the amount of Cu in [M] is 70 wt%,
That is, when the amount of Cu (conductive component) of [II] is larger than that (Comparative Example-4), the arc tends to stick to the boundary between [M] and [II], resulting in excellent breaking performance [II]. ] Area
The ability of 50Cu-Cr could not be fully exerted, and favorable blocking characteristics could not be obtained (Comparative Example-
4). From the above, the amount of highly conductive material in the intermediate region [M] is
[II]> as in the case of Ag described in Example-1 above
It is desirable that it is in the range of [M]> [I]. Examples 3 to 7

The contacts used in [M] are the same as those used in the first embodiment.
Not only Ag—Mo ₂ C and Cu—Mo ₂ C as shown in ₂ but also Ag—Cr and Cu—Cr (Examples 3 to 4), the amount of the conductive component is [II]> as described above. [M]> [I]
, The favorable blocking performance was obtained.

Similarly, the same effect was obtained when the conductive component of the contact used for [M] was Ag + Cu (Examples 5 to 7).
Similar effects were obtained even when the arc resistance component was C + Cr (Example-7). Example-8

In Examples 1 to 7 and Comparative Examples 1 to 4, the first composition region [I] is an example of Ag-Mo ₂ C alloy, but the conductive component is not limited to Ag + Cu. However, when the total amount is 29 wt%, preferable blocking characteristics are exhibited when the amount of the conductive component in the intermediate region [M] is within the range of [II]>[M]> [I] (Example- 8). In this case, the arc spreads well over the entire electrode surface, as in the above-described embodiment. Examples 9-10, 7-8

As described above, the amount of the conductive component in the alloy is [II] as a condition for sufficiently exhibiting the blocking characteristics of the material of the second composition region [II] due to the presence of the intermediate region [M].
It has been found that it is necessary to satisfy>[M]> [I].

On the other hand, when the amount of the conductive component in the first composition region [I] is 4 wt% Ag, the breaking current value is not sufficiently low (improved) and the variation is large (Comparative Example-7). ), At least 10 wt% Ag (Example-9), and also when the amount of the conductive component in [I] is 75 wt% Ag, the dicing current value is high, which is not preferable (Comparative Example). -8).

From these, in the vacuum valve of the present invention, the first
The amount of the conductive component in the composition region [I] is preferably 10 to 50 wt%. In particular there is a tendency of 4Ag-Mo ₂ C (Comparative Example -7) the chopping of deterioration with the lapse of opening and closing times (chopping current is increased). Examples 11-13, Comparative Examples 9-10

Cu-Cr used in the second composition region [II]
When the amount of the conductive component in the alloy is 10 wt% Cu, the arc does not show a sufficient transition to [M] or [II], and in the case of 95 wt% Cu, the arc causes [II] Exhaustion is large. Therefore, it is preferable that the amount of the conductive component in the second composition region [II] is in the range of 20 to 80 wt%.

As shown above, it is essential that the amount of the conductive component of [M] is within the range of [II]>[M]> [I]. May be a multi-component instead of a single component, and particularly may change continuously or stepwise from [II] to [I].

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

As described above, according to the present invention, the contacts of the vacuum valve of the present invention, organic and Ag-Mo ₂ C based alloy region having a low surge performance, and a Cu-Cr-based alloy region having a high current interruption performance However, it is composed of an alloy having properties intermediate between these alloy regions between the respective alloy regions, and the amount of conductive components thereof is Cu—Cr alloy region> intermediate region> Ag—Mo ₂
Since it has a boundary region within the range of the C-based alloy region, Ag
-Mo ₂ C alloy region to Cu-Cr alloy region is controlled by a magnetic field to easily perform forced arc transfer without stagnation, and a vacuum excellent in low surge performance and large current interruption performance. You can get a valve.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a contact of a vacuum valve of the present invention.

FIG. 2 is a diagram showing a vacuum valve.

FIG. 3 is an enlarged view of a movable electrode portion in FIG.

FIG. 4 is a view showing a contact of a conventional vacuum valve.

FIG. 5 is a view showing a coil electrode used in a vacuum valve.

FIG. 6 is a view showing a spiral electrode used in a vacuum valve.

[Explanation of symbols]

13a, 13b ... Contact, 21 ... First composition region, 22 ... Intermediate region, 23 ... Second composition region.

Claims (6)

[Claims] 1. A vacuum valve in which a contact of a pair of electrodes arranged to face each other in a vacuum container so as to come into contact with and separate from each other is made of a highly conductive material and an arc resistant material, wherein the contact has a first composition different from each other. The first composition is composed of a region [I], a second composition region [II], and an intermediate region [M] interposed between the first composition region [I] and the second composition region [II]. The region [I] is made of a low surge Ag—Mo ₂ C-based alloy, and the second composition region [II] is a large current interrupting C.
It is made of a u-Cr alloy, the intermediate region [M] is made of an alloy having intermediate properties between the first composition region [I] and the second composition region [II], and the conductivity of the [M]. A vacuum valve, wherein the amount of the component is in the range of [II]>[M]> [I] with respect to the amount of the conductive component in the first composition region and the second composition region. 2. The contact comprises the first composition region [I] made of a highly conductive material of 10 to 50% by weight of Ag, and the balance made of an arc resistant material Mo ₂ C, and the second composition region [II]. ] The vacuum valve according to claim 1, wherein the highly conductive material comprises 20 to 80% by weight of Cu, and the balance comprises the arc resistant material Cr. 3. The contact has a highly conductive material in at least one of Ag and Cu in the intermediate region [M],
Claim 1 or 2 vacuum valve according arc-proof material is characterized in that it consists of at least one of Cr or Mo ₂ C. 4. The high-conductivity material of the first composition region [I] of the contact comprises Ag and Cu, and the content of the high-conductivity material of the contact is in the range of 10 to 50% by weight and Cu. The vacuum valve according to claim 1 or 3, wherein the amount is within 40% with respect to the amount of Ag. 5. The contact is such that the arc-resistant component Cr + Mo ₂ C in the intermediate region [M] changes from the side in contact with the first composition region [I] to the other side in contact with the second composition region [II]. The ratio of Cr to Mo ₂ C from the arc-resistant component amount of the first composition region [I] to the second composition region [I
The vacuum valve according to any one of claims 1 to 4, wherein the arc resistant component amount of I] is changed stepwise and continuously. 6. The contact comprises the first composition region [I],
Each region of the second composition region [II] and the intermediate region [M] is [II] [M] in the radial direction from the center of the contact.
6. The vacuum valve according to claim 1, wherein the vacuum valves are arranged in the order [I] or [I] [M] [II].