JPS61126717A - Current limiting apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a slit-forming flow device that limits short-circuit current in a circuit breaker or the like by inserting a resistor into the circuit at the time of breaking.

[Conventional technology]

Conventionally, the most common method for limiting and interrupting short-circuit current is to use a power fuse. This power fuse is widely used for both low and high voltages, but cannot be used repeatedly.

Although no-fuse breakers (NFB) exist as devices that can be used repeatedly, their range of use is limited to low-pressure areas.

As a method that can be used repeatedly in a high pressure region, there is a method of commutation to a current limiting element, as shown in FIG. 4, which is used for DC cutoff and the like.

The principle is that when an overcurrent occurs while the commutation switch 101 and the disconnection switch 102 are closed in the energized state, the commutation switch 101 becomes open first, and the commutation switch 101 opens.
Since the current limiting element 103 is connected in parallel with 01, the current flows into the current limiting element, and the current is limited by the resistance (or the accelerator) of this current limiting element, and this current limiting action reduces the current to a small value. The purpose is to cut off the current with the disconnect switch 102 and open the circuit.

In this method, the smaller the fuse wire diameter in the power fuse, the better the current limiting characteristics. There is also a usage that solves the problem by distinguishing between the current-limiting section and the current-limiting section.

In this method, the following two methods have been conventionally used for the commutation section to the current limiting element 103.

+81 The commutation part is a fuse and the current limiting element is also a fuse.

A current-carrying fuse is set in the commutation switch 101 shown in Fig. 4, and a current-limiting fuse or current-limiting resistor is set in the current-limiting element 103, and the current-carrying fuse forcibly blows out the current-carrying element by explosion. (For example, JP-A-55-95
No. 241).

(b) The commutation part is a switching contact and the current limiting element is a current limiting resistor or fuse.

This utilizes a switching contact such as a circuit breaker in the commutation section (for example, Japanese Patent Laid-Open No. 55-21872).

[Problem that the invention seeks to solve]

However, in these conventional systems, the three functions of the commutation section, the current limiting element, and the disconnection section are each configured independently, resulting in a large number of parts and an increase in size.

The present invention solves the problems of conventional devices, enables repeated use at high voltage, and shares the switching contacts of the commutation section and disconnection section, thereby reducing the number of parts, downsizing, and simplifying scanning. The purpose of this invention is to obtain a slit commutation forming flow device.

[Means for solving problems]

In the present invention, both ends of a pair of resistive arc runner electrodes for arc shorting are connected to a fixed electrode and a movable electrode arranged oppositely, and the end portions of the resistive arc runner electrodes are connected on both sides of the arc path of the resistive arc runner electrodes. A pair of arc extinguishing plates are arranged such that the slit becomes narrower toward the discharge port side, and a U-shaped intermediate electrode that protrudes toward the slit is provided in the middle of the arc runner electrode. A commutation section is formed by short-circuiting the arc runner electrode and the intermediate bridge using a short-circuiting rod, and a portion that is not short-circuited by the short-circuiting rod is configured as a disconnection section.

〔Example〕

Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

Fig. 1 is a longitudinal sectional view showing the configuration of an embodiment of the present invention, Fig. 2 is a front sectional view taken from the -1 line in Fig. 1, and Fig. 3 is a view with one of the arc-extinguishing plates removed. It is a perspective view of a state.

In the figure, arc runner electrodes (hereinafter referred to as "runner electrodes") are placed above each of the fixed electrode 1 and the movable electrode 2.
3 and 4 are provided in parallel, and these runner electrodes 3,
A U-shaped intermediate runner electrode 3U is disposed in the middle of 4. A shorting rod 3B is connected between this intermediate runner electrode 3U and one of the runner electrodes (runner electrode 3 in FIGS. 1 and 2).

A commutation section is defined between the runner electrode 3 and the intermediate runner electrode 3U which are short-circuited by the short-circuiting rod 3B, and a disconnection section is defined between the runner electrode 4 and the intermediate runner electrode 3U which are not short-circuited by the short-circuiting rod 3B.

In the above configuration, the materials of the runner electrode 3.4, the intermediate runner electrode 3U, and the shorting rod 3B are resistive, such as carbon having a specific resistance value ρ of too μΩ−1 or more.

The arc-extinguishing plate 6 is attached to sandwich the protrusions 3a, 4a of the runner electrodes from both sides, and one arc-extinguishing plate has a
As shown in Fig. 3, the runner electrode 3.4 and the shorting rod 3B
It has a groove that is slightly wider than these so that the intermediate runner electrode 3U can be accommodated therein.

The space formed by sandwiching both arc-extinguishing plates 6 is called a narrow gap, and this narrow gap is wide near the electrode (
The tips of the runner electrode 3.4 and the intermediate runner 'lt%3u are formed narrowly. The opening of this narrow slit serves as the discharge port 9.

With the above configuration, the fixed electrodes 1. Movable electrode 2
．． Runner electrode 3.4. By covering the intermediate runner electrode 3U and the arc extinguishing plate 6 with an insulating container 7, it is fixed @ 1
The space between the movable electrode 2 and the narrow gap space is formed as a pressurization chamber 10.

A fluid passage from this pressurization chamber 10 passes through a discharge port 9 to the atmosphere 1.
It is discharged during 1.

The movable electrode 2 and the runner electrode 4 on the movable side are electrically connected to the current collector 5 by a conductive current collector housing 5A, and also provide a sealing effect between the pressurization chamber IO and the atmosphere 11.

Next, the operation will be explained.

In a normal energized state, the fixed electrode 1 and the movable electrode 2 are in contact, as shown by the broken line in FIG. Moreover, the open state is shown by a solid line.

When an overcurrent occurs, the movable electrode 2 is opened by an external mechanism (not shown), and an arc is generated between the fixed electrode 1 and the movable electrode 2.

This arc is elongated with the opening operation of the movable electrode 2, becomes arcuate, and finally moves to the runner electrodes 3 and 4.

At this time, the current path is: external terminal - fixed electrode l - fixed side runner electrode 3 - runner electrode protrusion 3a - arc 8a
- Runner electrode protrusion 4a - Movable runner electrode 4 - Current collector housing 5A - Serves as an external terminal. The magnetic field generated by the current flowing through the runner electrode 3.4, which has a convex path, acts perpendicularly to the arc current, and according to Fleming's left-hand rule, the arc 8a will move upward in FIG. shall be.

This electromagnetic force causes the arc 8a to move through the gap space towards the narrower gap. From this arc occurrence, arc 8a
The arc heats up to 5,000 to 10,000 degrees Celsius while it runs through the slit space.
), the gas in the pressurization chamber 1O is heated and its pressure increases.

Similarly (when the arc 8a and the arc extinguishing plate 6 come into contact with each other, a part of the wall of the arc extinguishing plate 6 forming the arc extinguishing chamber is melted and vaporized. This vaporized and thermally dissociated molecules causes a pressure increase. will be contributed to.

The pressure increase during this period is made possible by forming a pressurization chamber lO that is sealed from the atmosphere, and since a pressurization chamber is not formed in a conventional air switch, no pressure increase can be expected.

This pressure increase, along with the electromagnetic force due to the magnetic field generated from the current path, also serves as a force that moves the arc 8a to the narrower gap in the upper part of FIG.

Next, the arc 8a moving upward in FIG.
becomes. In this embodiment, there is one commutation section formed by the intermediate runner electrode 3U and the shorting rod 3B, but a plurality of commutation sections may be provided.

Next, as the divided arcs 8b and 80 move toward the narrower side of the slit, when the diameter of the arc moves to a gap length larger than the slit gap length, the arc moves between the pressurization chamber lO and the discharge port 9. An occlusion occurs that closes the Due to the blockage caused by this arc, the pressurizing chamber 10 is completely sealed, and the pressure in the pressurizing chamber IO increases further. This pressure increase causes each segmented arc to enter a narrower slit.

In addition, the resistive runner electrode 4.5 and a part of the intermediate runner electrode 3U are inserted into the circuit in the current path, so the breaking current is limited as the arc moves, the diameter of the arc is reduced, and the arc Zero or more current paths, which are increasingly likely to be inserted into narrow gaps, are indicated by arrows in FIG.

At this time, the commutation section 7-8b is short-circuited by the remaining runner electrodes 3 shown by broken lines in FIG. 3 other than the current path, the intermediate runner electrode 3U, and the short-circuiting rod 3B. Let the arc resistance of the arc 8b be r, and the resistance of the resistive electrode short-circuiting the arc 8b be ``,
Then, arc 8b under commutation conditions such that ``,>r,
disappears.

In the present invention, the arc 8b migrates through the gap towards the narrower gap, thereby increasing the arc resistance.

As the resistance r increases, the resistance r indicated by the broken line in FIG. 3 decreases, making it easier to realize the commutation condition r>r.

Another factor that enables this commutation condition to be achieved quickly is that the arc's slit insertion effect is promoted by the pressure increase in the pressure boosting chamber 10.

Next, when the arc 8b disappears, the breaking current is commutated to the runner electrode 3, the shorting rod 3B, and a part of the intermediate runner electrode 3U, a resistor is inserted into the circuit, and the breaking arc 8C causes the pressure in the boosting chamber 10 to increase. The arc 8C is inserted into a narrower gap and is interrupted at the zero point of the interrupting current, extinguishing the arc 8C. The extinction of the arc 8C serves as a disconnection section as long as the movable electrode 2 is in the open state.

〔Effect of the invention〕

As described above, the present invention provides the following effects.

■With only one pair of switching electrodes, a commutation section and a disconnection section are created by high-speed transition of the arc and its separation.Furthermore, the commutation section is made of a resistive arc runner electrode and an intermediate runner electrode, making commutation easy as the arc transitions. Therefore, the runner electrode can be made thinner to increase the resistance value of the runner electrode.

■Since the pressurizing chamber is shaped so that the arc moves into a narrower slit, the number of parts and size can be reduced, and the current limiting effect of the current limiting device can be significantly enhanced.

■Unlike conventional fuses, it can be used repeatedly.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional perspective view of this embodiment, and FIG. 4 is a circuit diagram showing the configuration of a conventional device. 1: Fixed electrode 2: Movable electrode 3: Runner electrode 3a: Projection part 3U: Intermediate runner electrode 4: Runner electrode 5: Current collector SA: z Electronic housing 6: Arc extinguishing plate 7: Insulating container 81-8C: Arc 9 :Discharge port 1O: Pressurization chamber 11: Atmosphere

Claims (1)

[Claims] 1. A current limiting device in which a pair of contacts are disposed, and an arc generated when these contacts are opened is transferred along a resistive arc runner electrode to limit the interrupting current, Both ends of a pair of resistive arc short circuiting arc runner electrodes are connected to a fixed electrode and a movable electrode arranged oppositely, and on both sides of the arc path of the resistive arc runner electrodes,
A pair of arc-extinguishing plates are arranged in such a manner that the slit becomes narrower toward the discharge port side of the end, and a U-shaped intermediate electrode is provided in the middle of the arc runner electrode that protrudes toward the slit, A current limiting device characterized in that one of the arc runner electrodes and the intermediate electrode are short-circuited by a short-circuiting rod to form a commutation section, and a portion not short-circuited by the short-circuiting rod is configured as a disconnection section. 2. The slit formed by the arc-extinguishing plate located farthest from the electrode contact was left as the discharge port, and the other components, such as the contact, arc-extinguishing plate, and arc runner electrode, were sealed in an insulating container. A current limiting device according to claim 1.