JPH0528889A - Switch device - Google Patents

Abstract

PURPOSE:To provide a gas switch device of self-arc extinction type, which presents an excellent shutoff performance, when the shutoff current is small, without increasing the operating force at the time of shutting off and also without dropping the large current shutoff performance. CONSTITUTION:A vent 8 is provided in a bulkhead 9 between an arc chamber 6 and a pressure accumulating chamber 7, and in this hole 8 a gas flow controlling valve device is installed, which consists of a valve 11 to block the vent and a spring 12 to press the valve 11. When the shutoff current by the arc will not flow into the pressure accumulating chamber, so that the pressure in the arc chamber does not drop, and blowing to the arc when the shutoff current lies near zero, will be done satisfactorily. Thus an excellent shutoff performance is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is an SF with good arc extinguishing characteristics.
The present invention relates to a switch using an arc extinguishing fluid such as 6 gas, and particularly to an arc extinguishing chamber of a self-extinguishing type gas switch.

[0002]

2. Description of the Related Art FIG. 8 is a side sectional view showing a middle of a breaking operation of a switch similar to the conventional switch disclosed in Japanese Patent Publication No. 58-56935. In the figure, 1 is a movable contact, 2 is a fixed contact, 3 is an upper terminal, 4 is a cylinder, 5 is an insulating nozzle, 6 is an arc chamber, 7 is a pressure accumulating chamber, 8 is between the arc chamber 6 and the pressure accumulating chamber 7. Vent holes 10 provided in the partition wall 9 (fixed contact support) are arcs generated when the movable contact 1 is separated from the fixed contact 2.

Next, the operation will be described. When current is flowing from the upper terminal 3 to the fixed contact 2 and further to the movable contact 1 when the switch is closed, the movable contact 1 is driven in the direction of arrow A by a drive mechanism (not shown), When the movable contact 1 and the fixed contact 2 are separated, an arc 10 is generated between the both contacts. At this time, the gas temperature in the arc chamber 6 rises due to the arc energy, the gas pressure rises due to expansion and molecular decomposition, and flows into the pressure accumulating chamber 7 through the ventilation hole 8 and is stored therein. The arc current is commercial frequency (5
To varying 0 / 60H _Z), the current arc narrows accordance approaches zero, the temperature also drops, the gas pressure of the arc near to decrease. As a result, immediately before the current is cut off, the gas is blown from the pressure accumulating chamber 7 to the arc 10 to extinguish the arc. As described above, since only the movable contact 1 is operated and the arc extinguishing gas is blown to the arc by utilizing the energy of the arc itself, the breaking operation can be performed with a low operation force. However, when the breaking current value is small, the arc energy is small and the pressure increase in the pressure accumulating chamber 7 is small, the gas spraying on the arc 10 is weak, and the arc extinguishing performance is deteriorated.

[0004]

The conventional apparatus is constructed as described above, and since the arc extinguishing gas is blown to the arc 10 by utilizing the energy of the arc itself, the arc energy is small when the breaking current value is small. , Accumulator 7
However, there was a problem that the pressure rise was reduced, the gas spray was weakened against the arc, and the arc extinguishing performance was degraded.

The present invention has been made in order to solve the above-mentioned problems, and does not increase the operating force at the time of interruption and does not deteriorate the interruption performance when the interruption current value is large. An object is to obtain a switch having excellent breaking performance when the current value is small.

[0006]

A switch according to the present invention is provided with a valve device including a valve and a spring for pressing the valve from one side, in a ventilation hole of a partition wall between the arc chamber and the pressure accumulating chamber.

According to the second aspect of the present invention, the arc extinguishing fluid flows into the accumulator chamber from the arc chamber, but a check valve for blocking the opposite direction is provided together with the valve device.

In the invention according to claim 3, a valve device is constituted by a valve made of a good conductor and a spring made of a shape memory alloy, and the valve device is provided so as to form an electric path between the upper terminal and the fixed contact. Is.

[0009]

In the present invention, when the breaking current is small,
Since the pressure rise in the arc chamber due to the arc is small, the valve provided in the vent does not open, and therefore the gas in the arc chamber does not flow into the accumulator chamber, so the pressure in the arc chamber does not drop and the breaking current is near the zero point. The gas is sufficiently blown to the arc at, and therefore has excellent breaking performance.

In the second aspect of the invention, when the breaking current is large, the pressure in the arc chamber due to the arc increases greatly, so the valve provided in the vent hole opens and the gas in the arc chamber flows into the accumulator chamber and shuts off. Gas is sufficiently blown from the pressure accumulating chamber to the arc through the check valve in the vicinity of the zero point of the current, so that the large current interruption performance does not deteriorate.

According to the third aspect of the invention, when the breaking current is large, the temperature of the shape memory alloy spring having a high electric resistance rises due to Joule heat, and when it reaches a predetermined temperature, the valve is opened and the arc chamber is opened. Gas flows into the accumulator. At this time, the shape memory alloy spring keeps the valve open until its temperature drops, so that the arc is sufficiently blown from the accumulator through the valve near the zero point of the breaking current, and the large current breaking performance deteriorates. do not do.

[0012]

【Example】

Example 1. 1 to 3 are sectional views showing a contact opening process of a switch according to an embodiment of the present invention. The same or corresponding parts as in FIG. Reference numeral 11 is a valve provided in the vent hole 8, 12 is a compression spring provided so as to press the valve 11 to keep the vent hole 8 closed in the initial state, and 13 is a spring support. In such a switch, when the pressure in the arc chamber 6 that is boosted by the arc is high, for example, when a large current of several tens kA is cut off, the valve 11 is pushed up against the spring force of the compression spring 12. Since the vent hole 8 is opened and the high temperature / high pressure gas in the arc chamber 6 flows into the pressure accumulating chamber 7, the pressure accumulating chamber 7 is pressurized.
This state is shown in FIG. In the vicinity of the zero current point, conversely, gas is sprayed from the pressure accumulating chamber 7 to the arc 10 via the arc chamber 6. At this time, the valve 11 tries to be in a closed state, but since the response speed of the valve is slow, the gas is not extinguished from the pressure accumulating chamber 7 against the arc, and the arc is extinguished to complete the cutoff. This state is shown in FIG. On the other hand, when the pressure rise in the arc chamber 6 is low, such as when a small current of several kA is cut off, the force of opening the valve 11 by the pressure of the arc chamber closes the valve 11 by the spring force of the compression spring 12. Therefore, the vent hole 8 is kept closed, and the gas flow from the arc chamber 6 to the accumulator chamber 7 is eliminated. Therefore, the pressure in the arc chamber is maintained without lowering, gas is sufficiently blown from the arc chamber 6 to the arc in the vicinity of the zero current point, and the breaking performance is improved.

Example 2. Although the vent hole 8 and the valve 11 are installed outside the fixed contact 2 in the above-mentioned embodiment, the valve 11 can be replaced by the one shown in FIG.
Even if it is installed inside the fixed contactor 2 as described above, the same effect can be obtained.

Further, in the above embodiment, the compression spring is used as the spring 12 for controlling the valve 11, but the same effect can be exhibited by controlling the valve 11 by using the tension spring.

Example 3. FIG. 5 is a side cross-sectional view showing a state immediately before completion of interruption of a switch according to still another embodiment. In FIG. 5, the arc extinguishing gas 14 flows from the pressure accumulating chamber 7 into the arc chamber 6, It is a check valve that does not flow in the opposite direction. In this case, when the arc extinguishing gas flows from the arc chamber 6 into the pressure accumulating chamber 7 when the large current is shut off and the pressure in the pressure accumulating chamber 7 becomes higher than the pressure in the arc chamber 6, even if the valve 11 is in the closed state, the pressure accumulating pressure is increased. Even if the blowing of the arc-extinguishing gas from the chamber 7 to the arc 10 is reduced, the check valve 14 operates to open the state, and the arc-extinguishing gas is blown from the pressure accumulating chamber 7 to the arc 10. Can be obtained.

Example 4. FIG. 6 and FIG. 7 are a side sectional view showing a middle of the breaking operation of a switch according to still another embodiment and a side sectional view showing a state after completion of the breaking. In these figures, 11 is a valve having a good conductor, 15 is a control spring made of a shape memory alloy, and 16 is an expandable and contractible lead wire connecting the fixed contact support 9 and the valve 11. In such a switch, current flows from the upper terminal 3 to the fixed contact 2 through the control spring 15, the lead wire 16, the valve 11 of good conductor and the fixed contact support 9. In the case of large current interruption, the material of the control spring 15 has a high electric resistance, so that the temperature rises due to Joule heat, and when the control spring 15 reaches a predetermined temperature, the valve 11 operates to open. . This state is shown in FIG. When the high temperature / high pressure gas in the arc chamber 6 flows into the pressure accumulating chamber 7, the pressure accumulating chamber 7 is boosted, and gas is blown from the pressure accumulating chamber 7 through the arc chamber 6 to the arc 10 in the vicinity of the zero current point to extinguish the gas. To the arc. Here, since the time taken to increase the pressure in the pressure accumulating chamber 7 to the vicinity of the current zero point is usually short (several ms to several tens of ms), the temperature of the heated control spring 15 hardly decreases and reaches the vicinity of the current zero point. In order to reliably keep the valve 11 in the open state, gas is sufficiently sprayed from the pressure accumulating chamber 7 to the arc 10, and stable shutoff performance is obtained. After the current to the vicinity of the current zero point is cut off,
When the control spring 15 is naturally cooled to a temperature below a predetermined temperature,
Since the valve 11 returns to the initial shape, the valve 11 is closed. This state is shown in FIG. On the other hand, in the case of the small current interruption, the temperature rise of the control spring 15 due to Joule heat is small and the predetermined operating temperature is not reached, so the valve 11 does not operate and the closed state is maintained. Therefore, as described above, the pressure in the arc chamber is maintained without decreasing, and the arc chamber 6 near the zero current point is maintained.
Since the gas is sufficiently blown from the arc to the arc, excellent breaking performance can be obtained.

The control spring 15 can be formed in a coil shape, a plate shape, a bar shape, or the like.

[0018]

As described above, according to the present invention, when the breaking current is small, the vent hole is not increased without increasing the operating force at the breaking time and without lowering the breaking performance when the breaking current value is large. Since the valve installed in the is closed and the gas in the arc chamber, which has been boosted by the arc, does not flow into the accumulator chamber, the pressure in the arc chamber does not drop, and gas is sufficiently blown to the arc near the zero point of the breaking current. Therefore, there is an effect that a switch having excellent breaking performance can be obtained.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an open state of a switch according to a first embodiment of the present invention.

FIG. 2 is a side sectional view showing the middle of the breaking operation of the switch according to the first embodiment of the present invention.

FIG. 3 is a side sectional view showing a state after completion of the breaking operation of the switch according to the first embodiment of the present invention.

FIG. 4 is a side sectional view showing a state after completion of the breaking operation of the switch according to the second embodiment of the present invention.

FIG. 5 is a side sectional view showing a state immediately before the completion of the breaking operation of the switch according to the third embodiment of the present invention.

FIG. 6 is a side sectional view showing the middle of the breaking operation of the switch according to the fourth embodiment of the present invention.

FIG. 7 is a side sectional view showing a state after completion of the breaking operation of the switch according to the fourth embodiment of the present invention.

FIG. 8 is a side sectional view showing a state after completion of a breaking operation of a conventional switch.

[Explanation of symbols]

1 Movable contact 2 Fixed contact 3 Upper terminal 4 cylinders 5 Insulation nozzle 6 arc chamber 7 Accumulation chamber 8 ventilation holes 9 Partition (fixed contact support) 10 arc 11 valves 12 Compression spring 14 Check valve 15 Control spring 16 lead wires

Claims (3)

[Claims] 1. A pair of separable contacts arranged in an arc-extinguishing fluid, an arc chamber surrounding an arc generated when the contacts are separated, and a communication with the arc chamber via a vent hole. Then, while introducing a high-pressure arc-extinguishing fluid in the arc chamber generated at the time of arc generation from the vent hole to temporarily store it, and at the time of arc extinguishing, a pressure accumulating chamber that blows the stored arc-extinguishing fluid to the arc. A switch having a gas flow control valve device comprising a valve and a spring for pressing the valve from one side in a vent hole between the arc chamber and the accumulator chamber. 2. A check valve is provided so that the arc extinguishing fluid flows into the arc chamber from the pressure accumulating chamber but does not flow in the opposite direction. Switch. 3. The switch according to claim 1, wherein the spring of the valve device is made of a shape memory alloy.