JPH0325822A - Vacuum switch - Google Patents

Abstract

PURPOSE:To obtain a vacuum switch which is capable of conducting a highly sensitive and highly reliable switching action, by dividing movable side electrodes and fixed side electrodes into the one for switching on/off a super electric current and the one for switching on/off non load/load electric currents, and conducting a series arrangement one set by one set. CONSTITUTION:Movable side electrodes 3a, 3b and fixed side electrodes 4a, 4b are respectively divided into the one for switching on/off a super electric current and the one for switching on/off non load/load electric current, and a series arrangement is conducted one set by one set. In the case of a short circuit accident having occurred and an excessive electric current having run at an electric passage, the movable side electrode 3a at a super electric current switching on/off switch portion 8 is opened so that it may be separated from the fixed side electrode 4a. In this instance, opening is done at a high speed, but its frequency is few, so as for bellows 7a, those which are small diametered, has few heaps and are generally inexpensive, can be used. Meanwhile, at the time of switching on/off the electric current at the time of non load or load, the movable side electrode 3b at an ordinary switching on/off switch 9 conducts action os that it may come into contact with the fixed side electrode 4b or be separated from it. For these actions of separation/coming into contact, respective electrodes 3b, 4b which conduct action at a high frequency between opening/closing gaps, are used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vacuum switch having two sets of current switching parts in one current path.

[Conventional technology]

FIG. 3 is a sectional view showing a conventional vacuum switch disclosed in, for example, Japanese Patent Publication No. 54-129481. 3 is the movable side electrode, 4 is the fixed side electrode,
Reference numeral 5 denotes a movable electrode rod, 6 a fixed electrode rod, and 7 a bellows for supporting the movable electrode rod 5 within the insulating tube 1, which is made of a bellows-shaped thin stainless steel material.

FIG. 4 is a cross-sectional view showing a conventional vacuum switch disclosed in, for example, Japanese Utility Model Publication No. 50-9562.
2 are placed opposite to each other on both sides of the fixed side electrode 4 placed in the middle part.
Therefore, there are two movable electrode rods 5 and two bellows supporting them.

Next, the operation will be explained.

In both of the above two vacuum switches, both large current and load current are interrupted using the same movable electrode 3 and fixed electrode 4. In particular, when interrupting large current, Since the temperature of each electrode 3.4 rises rapidly and its surface becomes molten, the withstand voltage characteristics of each electrode 3.4 are extremely reduced. On the other hand, in order for the interruption to be successful, it is necessary to withstand the recovery voltage between the electrodes that is applied after the current zero point, and the gap between the electrodes must be rapidly increased to a predetermined value in a short period of time from when the contacts are opened until the current zero point is reached. It is necessary to open up to

Furthermore, the number of times that a large current such as a short-circuit current can be interrupted may be about several dozen times, whereas the switching of no-load and load currents requires frequent switching of tens of thousands of times. Therefore, in order to smoothly follow high-speed operation, the bellows 7 must also be highly sensitive and durable.

[Problem to be solved by the invention]

Conventional vacuum switches are configured as described above, so
As the movable electrode is opened and closed at high speed with respect to the fixed electrode 4, the movement of the bellows T must also be highly sensitive and durable, making the structure complex and large, and extremely difficult to operate. There were issues such as being expensive.

This invention was developed in order to solve the above-mentioned problems.The fixed side electrode and the movable side electrode are separately provided for large current switching and for no-load/load current switching, thereby reducing the cost. The purpose of the present invention is to obtain a vacuum switch that can perform high-frequency switching of large currents and high-frequency switching of normal load currents.

[Means to solve the problem]

The vacuum switch according to the present invention has movable side electrodes and fixed side electrodes arranged in series, one for large current switching and one for no-load/load current switching.

[For production]

In the vacuum switch according to the present invention, there are two sets of movable side electrodes and fixed side electrodes, one set is operated for switching large currents with low switching frequency, and the other set is operated for switching no-load current or load current. Operates frequently between small opening and closing gaps.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 8 is a large current switching section that operates only when switching large currents, 9 is a normal switching section that operates only when switching no-load current and load current, 3a, 3b
are movable side electrodes, 4a and 4b are fixed side electrodes, 5a and 5b are movable side electrode rods, 5a and 5b are fixed side electrode rods, 7a and 7
b is a bellows. Other components that are the same as those shown in FIG. 3 are designated by the same reference numerals, and redundant explanation thereof will be omitted.

Next, the operation will be explained. First, when a short-circuit accident occurs and an excessive current flows in the current path, a trip signal from the overcurrent detection device causes the movable side electrode 3a of the large current switching section 8 to be connected to the fixed side electrode 4a. Open the poles so that they are separated. In this case, the opening is performed at high speed, but the number of openings is as small as several tens of times, so a common and inexpensive bellows 7a with a small diameter and a small number of ridges can be used.

Furthermore, since there is little wear on the various mechanisms, inexpensive bearings can be used. Furthermore, this large current switching section 8 is capable of interrupting large currents.Although it requires electrode material and structure, the interruption frequency is low, so there is less electrode wear.
g <, magnetic field. It is also possible to use a configuration in which the coil electrodes 10 and 11 that are generated are arranged on the back surfaces of the movable side electrode 3a and the fixed side electrode 4a, which are the main electrodes.

On the other hand, when the current is switched on and off when there is no load or when there is a load, the movable electrode 3b of the normal switching switch section 9 moves into and out of contact with the fixed electrode 4b. In this contact/separation operation, the temperature rise of each electrode 3b, 4b is small, so the withstand voltage of the electrode is high, and the gap between the electrodes up to the current zero point can be small. Therefore, the opening speed can be slowed down, and the bellows 7 used here
Even though the opening and closing frequency is high, the gap between the electrodes is only 1K, so a normal one with a small diameter and a small number of ridges can be used. Furthermore, with regard to other mechanisms, fatigue and wear of materials can be suppressed, and even if special materials and configurations are required, overall costs can be reduced.

By the way, it is known that the normal opening/closing switch section 9 has an excessively good current extinguishing performance and therefore causes a current cutting phenomenon when opening/closing a small delayed current. To deal with this,
Low-cut electrode materials containing large amounts of low-melting-point metals have been developed, but on the other hand, they are not suitable for large current interruption or high voltage applications, and when used for loads with low insulation performance, they require high cutting current. A normal opening/closing switch section 9 having an electrode material is used, and a surge absorber or the like is used to suppress the current cutting phenomenon.

However, surge absorbers are large and expensive.

Moreover, when regularly checking the switch section 9 for normal opening/closing,
The quality of the vacuum is determined by applying high voltage, but there are inconveniences such as accidentally destroying the device if you forget to remove it. Therefore, if a low-cut material is used as the electrode material for the vacuum switch tube, there is no need to interrupt large currents, and
Since there is no drop in withstand voltage that occurs after interrupting a large current, it is possible to interrupt a large current with a low surge.

Further, FIG. 2 shows another embodiment of the present invention.

This differs from the one shown in FIG. The operation and electrical characteristics are also similar to those of the above embodiment. According to this embodiment, the fixed side electrode rods sa and sb can be omitted, the overall structure can be made smaller, and the bellows 78#7 with substantially the same structure can be used.
You can also use b.

〔Effect of the invention〕

As described above, according to the present invention, the movable side electrode and the fixed side electrode are divided into large current switching and no-load/load current switching, respectively, and are arranged in series in l groups, so that the switching frequency can be increased. Movable side electrode for high current switching with low switching frequency, and no-load electrode for high switching frequency but small switching gap.
An ordinary small bellows can be used for both of the movable electrodes for switching the load current, and the entire mechanism including the bellows can be made smaller and lower in cost, while achieving high sensitivity and reliability. This has the effect of providing a vacuum switch that can perform opening and closing operations.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a vacuum switch according to an embodiment of the present invention, FIG. 2 is a sectional view of a vacuum switch showing another embodiment of the invention, and FIG. 3 is a sectional view showing a conventional vacuum switch. 4 is a sectional view of a vacuum switch showing another conventional example. 1 is an insulating cylinder, 2 is a shield, 3a #3b is a movable side electrode,
4a and 4b are fixed side electrodes, 5a and 5b are movable side electrode bars, 6a and 5b are fixed side electrode bars, and 7a and 7b are bellows. In the figures, the same symbols indicate the same or equivalent parts. Figure 1 6h

Claims (1)

[Claims] An insulating cylinder whose interior is kept at a high degree of vacuum and has a shield inside, a movable side electrode and a fixed side electrode provided in this insulated cylinder, and a movable side electrode rod to which the movable side electrode is attached is supported. A vacuum switch equipped with a bellows, characterized in that the movable side electrode and the fixed side electrode are arranged in series, one set for large current switching and one for no-load/load current switching.