JPH0447877Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a switch that extinguishes an arc generated between a movable contact and a fixed contact when a current is interrupted by spraying an arc extinguishing medium.

"Prior Art" Generally, in gas blowing switches or air blowing switches, an arc is generated between a movable contact and a fixed contact using an arc-extinguishing medium such as SF6 gas or air by a piston sliding inside a cylinder. The current is cut off by spraying it on the air. Conventionally,
This spraying of the arc-extinguishing medium is started at the same time as the movable contact is separated from the fixed contact.

``Problem that the invention aims to solve'' As mentioned above, when the movable contact is separated from the fixed contact and the current is suddenly cut off by spraying an insulating medium, the current is cut off at the first current zero point. In this case, there was a fear that harmful secondary phenomena such as generation of overvoltage would occur upon subsequent restriking.

Furthermore, since the arc-extinguishing medium is compressed between the piston and the cylinder before the current is cut off, extra operating energy is required, resulting in an increase in the size of the operating device.

``Means for solving the problem'' The present invention is to open the movable contact from the fixed contact to a position where it can be re-ignited or broken without restriking or breaking, while keeping the arc in a normal state, and then extinguishing the arc. This method solves the above-mentioned drawbacks of the conventional technology by blowing a medium onto the arc to make the current start and break. The arc-extinguishing medium is disposed at the discharge port through which the arc-extinguishing medium is discharged until just before the cylinder is opened, and at the arc-extinguishing medium blowing port formed in the cylinder, so that the arc-extinguishing medium will not close if the pressure of the arc-extinguishing medium is less than a certain pressure. and a control valve that opens when the pressure exceeds this certain pressure.

"Operation" Until the movable contact is separated from the fixed contact to a position where it can be re-ignited or disconnected, even if the piston slides inside the cylinder and compresses the arc-extinguishing medium, the arc-extinguishing The medium is discharged from the outlet and does not reach a constant pressure. Therefore, the control valve does not open, the arc extinguishing medium is not blown onto the arc generated between the movable contact and the fixed contact, and the current is not interrupted.

Thereafter, when the movable contact is separated from the fixed contact to a position where it can be re-ignited or disconnected, the discharge port is closed by the piston, and the arc-extinguishing medium becomes under a certain pressure within the cylinder. As a result, the control valve opens and
An arc-extinguishing medium is sprayed onto the arc generated between the movable contact and the fixed contact, and the current is quickly interrupted.

"Embodiment" Hereinafter, an embodiment of the present invention will be described in detail based on FIGS. 1 and 2. Note that FIG. 1 shows the switch in a closed state, and FIG. 2 shows the state in the middle of the switch's disconnection operation.

In these figures, an arc extinguishing medium 4 such as SF6 gas or air is sealed in a puffer chamber 3 which is made up of a cylinder 1 and a piston 2 that slides inside the cylinder 1. A fixed contact 6 is disposed near a blowing port 5 formed at one end of the cylinder 1. The movable contact 7, whose distal end moves toward and away from the fixed contact 6, has its proximal end fixed to a rotatably supported shaft 8.

Further, an operating shaft 9 for opening and closing the switch is rotatably supported, and an operating lever 10 is fixed thereto. One end of the operating rod 11 is connected to the operating lever 10 by a pin 12, and the other end is connected to the center of the movable contact 7 by a pin 13. One end of the piston rod 14 is connected to the operating lever 10 by a pin 15, and the other end is connected to the piston 2 by a pin 15.
6.

Furthermore, a discharge port 17 is formed within the cylinder 1 . This discharge port 17 is connected to the movable contact 7.
The arc extinguishing medium 4 is discharged by sliding the piston 2 to the right until it is separated from the fixed contact 6 to a position where it can be re-ignited or disconnected.

Further, a control valve 18 is disposed near the blowing port 5 of the cylinder 1, which is closed when the arc-extinguishing medium 4 is under a certain pressure, and is opened when the arc-extinguishing medium 4 is under this certain pressure.

Next, the operation of the above embodiment will be explained.

To perform the cutting operation in the closed state of the switch shown in FIG. 1, an operation device (not shown) is used to
Rotate the operating shaft 9 counterclockwise. This operating shaft 9
As a result of the rotation, the movable contact 7 is rotated clockwise around the shaft 8 via the operating lever 10, and the tip of the movable contact 7 is separated from the fixed contact 6, and an arc is generated between them. do. At this time, the counterclockwise rotation of the operating lever 10 causes the piston 2 to slide to the right within the cylinder 1 via the piston rod 14. By sliding the piston 2 to the right, the arc-extinguishing medium 4 in the puffer chamber 3 is discharged to the discharge port 17.
Since the arc extinguishing medium 4 in the puffer chamber 3 does not increase in pressure and does not reach a constant pressure, the control valve 18 remains closed. Therefore, the arc extinguishing medium 4 is not sprayed onto the arc generated between the movable contact 7 and the fixed contact 6, and the arc continues in a straight line.

Furthermore, the operating lever 10 rotates counterclockwise,
Immediately before the movable contact 7 separates from the fixed contact 6 to a position where it can be re-ignited or disconnected, the piston 2 reaches a position where it closes the discharge port 17. This state is shown in FIG.

Note that even if the piston 2 slides to the right until the above process is reached, the arc-extinguishing medium 4 is discharged from the discharge port 17 as described above, so the pressure of the arc-extinguishing medium 4 does not increase and the It requires only a small amount of operating energy.

When the piston 2 further slides in the right direction inside the cylinder 1 from this state, the piston 2 moves to the discharge port 17.
Because it is located to the right of the
The arc-extinguishing medium 4 inside is not discharged from this discharge port 17, but the arc-extinguishing medium 4 is compressed. Then, the fixed contact 6
The arc-extinguishing medium 4 reaches a constant pressure when released from the arc-extinguishing medium 4 . As a result, the control valve 18 opens, the arc extinguishing medium 4 is sprayed onto the arc generated between the movable contact 7 and the fixed contact 6, and the arc is extinguished.
The current is then cut off.

In addition, when closing the switch, by rotating the operating lever 10 clockwise, the piston 2 slides to the left, and the movable contact 7 rotates counterclockwise about the shaft 8 to make a fixed contact. Since the operation is completely opposite to the above-mentioned shearing operation, the details thereof will be omitted.

"Effects of the Invention" According to the present invention, it is possible to achieve non-reignition and disconnection, so there is no generation of overvoltage, and it is possible to prevent damage to the insulator and shortening of its life due to this overvoltage. Furthermore, since the above-mentioned overvoltage does not occur, insulation of other equipment in the electric circuit connected to this switch can be reduced.

Furthermore, at the initial stage of the shearing operation, the arc-extinguishing medium in the puffer chamber is not compressed, so that only a small amount of operating energy is required and the operating device can be downsized.

[Brief explanation of the drawing]

1 and 2 are diagrams showing one embodiment of the present invention, with FIG. 1 showing the switch in a closed state, and FIG. 2 showing the switch in the middle of a disconnection operation. In the figure, 1 is a cylinder, 2 is a piston, and 4 is a cylinder.
5 is an arc-extinguishing medium, 5 is a blowing port, 6 is a fixed contact, 7 is a movable contact, 17 is a discharge port, and 18 is a control valve.

Claims (1)

[Scope of utility model registration request] In a switch that extinguishes an arc generated between a movable contact and a fixed contact by a piston sliding in a cylinder filled with an arc-extinguishing medium, the arc-extinguishing medium is sprayed onto an arc generated between a movable contact and a fixed contact. and a discharge port through which the arc extinguishing medium is discharged, and an arc extinguishing medium formed in the cylinder until the movable contact is separated from the fixed contact to a position where it can be re-ignited or disconnected. 1. A switch comprising: a control valve disposed in a blowing port; the control valve is closed when the pressure of the arc-extinguishing medium is less than a certain pressure; and is opened when the pressure of the arc-extinguishing medium is above the certain pressure.