A self-excited arc blowing device and DC circuit breaker

Abstract

The present invention relates to the field of arc extinguishing devices, and in particular to a self-excited arc blowing device and a DC circuit breaker. The self-excited arc blowing device and the DC circuit breaker are used to solve the problem that the magnetic field generated by the iron core of the existing self-excited arc blowing device is limited, and it is difficult to achieve efficient arc extinguishing of the arc. The self-excited arc blowing device includes a moving contact and a static contact, and an arc runway is arranged on the upper part of the moving contact and the static contact, and the arc runway forms an arc blowing channel at the upper position of the fracture. An iron core with an external sleeve provided with an excitation coil is arranged on the outer side of the arc blowing channel, and the excitation coil is connected to the moving contact and the arc runway to generate a magnetic flux in the iron core when the moving and static contacts are separated and closed. A magnet is arranged on the outer side of the arc blowing channel to strengthen the magnetic field strength in the arc blowing channel. The magnetic field generated by the iron core is limited. After adding the magnet, the magnetic field strength in the arc blowing channel is increased, so that the Lorentz force on the arc in the magnetic field is increased, so that the arc is quickly transferred on the moving and static contacts to enter the arc runway, and the arc is efficiently extinguished.

Description

Technical Field

[0001] The invention relates to the field of arc extinguishing devices, and in particular to a self-excited arc blowing device and a DC circuit breaker. Background Art

[0002] DC circuit breakers are key equipment in DC power supply systems. Since the fault current rises quickly and has a large peak value when a short circuit occurs in a DC power supply system, a self-excited arc blowing device is usually installed in the DC circuit breaker to improve the breaking capacity of the DC circuit breaker.

[0003] The Chinese invention patent with the authorization announcement number CN111584321B discloses a magnetic blowout arc extinguishing device for a DC fast circuit breaker, the arc extinguishing device includes a moving contact and a stationary contact, both of which are provided with arc runways, the arc runways have a horizontal section extending horizontally and a vertical section extending vertically, the space between the vertical sections of the two arc runways constitutes an arc blowing space, and the arc blowing space corresponds to the top of the moving and stationary contacts where the arc is drawn, the outer side of the arc blowing channel is provided with an iron core with an external sleeve of an excitation spiral row, the excitation spiral row is connected to the arc runway to generate a magnetic flux in the iron core when the moving and stationary contacts are separated and combined, parallel T-shaped magnetizing irons are provided on the front and rear sides of the arc runway, and the T-shaped magnetizing irons are connected to the iron core through a magnetic conductive connecting plate. When the current is interrupted, the current will flow through the iron core and the excitation spiral row, and the magnetic field generated by the iron core and the excitation spiral row can generate an arc drawing force on the arc, so that the arc is elongated and cooled, and finally extinguished. Among them, the magnetic field generated by the iron core and the excitation spiral row is limited, and the arc extinguishing effect is also limited, making it difficult to achieve efficient arc extinguishing. Summary of the invention

[0004] The purpose of the present invention is to provide a self-excited arc blowing device to solve the problem that the magnetic field generated by the iron core of the arc blowing device in the prior art is limited, making it difficult to achieve efficient arc extinguishing of the arc. The purpose of the present invention is also to provide a DC circuit breaker to solve the problem that the magnetic field generated by the iron core of the arc blowing device of the prior art is limited, making it difficult to achieve efficient arc extinguishing of the arc.

[0005] In order to solve the above technical problems, a self-excited arc blowing device of the present invention includes moving and static contacts, and arc running tracks are arranged on the upper parts of the moving and static contacts, and the arc running tracks form an arc blowing channel above the fracture, and an iron core with an excitation coil on the outside is arranged on the outside of the arc blowing channel, and the excitation coil is connected to the moving contact and the arc running track so that the iron core generates magnetic flux when the moving and static contacts are opened and closed, and a magnet is arranged on the outside of the arc blowing channel for enhancing the magnetic field strength in the arc blowing channel.

[0006] Furthermore, the magnets are arranged in pairs, and the paired magnets are respectively arranged on both sides of the arc blowing channel, and the S poles of the magnets face inwards.

[0007] Furthermore, the magnet is coated with insulating material on the outside and is arranged close to the arc track through the insulating material.

[0008] Furthermore, a Z-shaped extension plate extending outward is provided on the arc track above the moving contact, the lower plane of the Z-shaped extension plate is used to be connected to the excitation coil, and the upper plane is used to support the corresponding insulating material. The static contact has a static contact extension portion extending outward, and the static contact extension portion is used to support the corresponding insulating material.

[0009] Furthermore, the insulating material is an insulating block that wraps the magnet, and the insulating block has a positioning fitting surface that is adapted to the shape of the outer side surface of the corresponding running arc track.

[0010] Furthermore, the heights of the magnets are consistent.

[0011] Furthermore, the magnet is a permanent magnet.

[0012] Furthermore, the excitation coil is a copper foil coil.

[0013] Furthermore, magnetizing irons are arranged on the front and rear sides of the arc track, the two magnetizing irons are connected to the iron core, and the space between the two magnetizing irons corresponds to the setting of the arc track.

[0014] The present invention proposes an improved technical solution, in which a magnet is arranged on the outside of the arc blowing channel to strengthen the magnetic field strength in the arc blowing channel. When the moving and static contacts are opened and closed, the magnetic field provided by the magnet can make the arc quickly transfer on the moving and static contacts and enter the arc running track. The magnetic field generated by the iron core is limited. After adding the magnet, the magnetic field strength in the arc blowing channel is increased, so that the Lorentz force on the arc in the magnetic field is increased, so that the arc is quickly transferred on the moving and static contacts to enter the arc running track, and the arc is efficiently extinguished.

[0015] Another aspect of the present invention provides a DC circuit breaker, which includes a self-excited arc blowing device, which includes a moving contact and a static contact, and an arc runway is provided on the upper part of the moving contact and the static contact, and the arc runway forms an arc blowing channel above the fracture, and an iron core with an excitation coil on the outside is provided on the outside of the arc blowing channel, and the excitation coil is connected to the moving contact and the arc runway so that the iron core generates a magnetic flux when the moving and static contacts are opened and closed, and a magnet is provided on the outside of the arc blowing channel for enhancing the magnetic field strength in the arc blowing channel.

[0016] Furthermore, the magnets are arranged in pairs, and the paired magnets are respectively arranged on both sides of the arc blowing channel, and the S poles of the magnets face inwards.

[0017] Furthermore, the magnet is coated with insulating material on the outside and is arranged close to the arc track through the insulating material.

[0018] Furthermore, a Z-shaped extension plate extending outward is provided on the arc track above the moving contact, the lower plane of the Z-shaped extension plate is used to be connected to the excitation coil, and the upper plane is used to support the corresponding insulating material. The static contact has a static contact extension portion extending outward, and the static contact extension portion is used to support the corresponding insulating material.

[0019] Furthermore, the insulating material is an insulating block that wraps the magnet, and the insulating block has a positioning fitting surface that is adapted to the shape of the outer side surface of the corresponding running arc track.

[0020] Furthermore, the heights of the magnets are consistent.

[0021] Furthermore, the magnet is a permanent magnet.

[0022] Furthermore, the excitation coil is a copper foil coil.

[0023] Furthermore, magnetizing irons are arranged on the front and rear sides of the arc track, the two magnetizing irons are connected to the iron core, and the space between the two magnetizing irons corresponds to the setting of the arc track.

[0024] The present invention proposes an improved technical solution, in which a magnet is arranged on the outside of the arc blowing channel to strengthen the magnetic field strength in the arc blowing channel. When the moving and static contacts are opened and closed, the magnetic field provided by the magnet can make the arc quickly transfer on the moving and static contacts and enter the arc running track. The magnetic field generated by the iron core is limited. After adding the magnet, the magnetic field strength in the arc blowing channel is increased, so that the Lorentz force on the arc in the magnetic field is increased, so that the arc is quickly transferred on the moving and static contacts to enter the arc running track, and the arc is efficiently extinguished. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a three-dimensional structural schematic diagram of a self-excited arc blowing device of the present invention; Figure 2 It is a structural schematic diagram of a partial structure of a self-excited arc blowing device of the present invention; Figure 3 for Figure 2 A local enlarged schematic diagram.

[0026] In the figure: 1. Iron core; 2. Copper foil coil; 3. Arc track; 4. Moving contact; 5. Static contact; 6. Permanent magnet; 7. Connecting busbar; 8. Magnetizing iron; 9. Connecting plate; 10. Insulating block. DETAILED DESCRIPTION

[0027] The present invention proposes an improved technical solution to the problems existing in the prior art. The core concept of the present invention is: a magnet is arranged on the outside of the arc blowing channel to strengthen the magnetic field strength in the arc blowing channel. When the moving and static contacts are opened and closed, the magnetic field provided by the magnet can make the arc quickly transfer on the moving and static contacts and enter the arc running track. The magnetic field generated by the iron core is limited. After adding the magnet, the magnetic field strength in the arc blowing channel is increased, so that the Lorentz force on the arc in the magnetic field is increased, so that the arc is quickly transferred on the moving and static contacts to enter the arc running track, and the arc is efficiently extinguished.

[0028] According to the above invention concept, a self-excited arc blowing device of the present invention comprises: Figure 2 The moving contact 4 and the stationary contact 5 shown in the figure are both provided with an arc track 3 on the upper part of the moving contact 4 and the stationary contact 5. The arc track 3 of this embodiment has a horizontal section extending horizontally and a vertical section extending vertically. The vertical sections of the two arc tracks 3 are arranged to be inclined downward to form a flared arc blowing channel, and the arc blowing channel corresponds to the upper part of the fracture of the moving and stationary contacts. An iron core 1 with an external sheath of an excitation coil is arranged on the upper part of the moving contact 4 and on the outer side of the arc blowing channel. The excitation coil is connected to the moving contact 4 and the arc track 3 so that the iron core 1 can generate magnetic flux when the moving and stationary contacts are opened and closed. The moving contact 4 of this embodiment is installed on the left side, and the static contact 4 is installed on the right side. The static contact 4 on the right side is connected to the corresponding arc track 3. The excitation coil is installed on the side of the arc track 3 on the left side. The excitation coil is connected to the moving contact through the connecting busbar 7. When the circuit breaker is opened, the moving contact 3, the arc track 3, the excitation coil, the iron core 1, and the connecting busbar 7 form an excitation circuit. The magnetic field strength is evenly diffused outward from the iron core 1. The magnetic field generated by the iron core 1 can generate an arc-drawing force on the arc, so that the arc is elongated and cooled. A magnet is provided on the outside of the arc blowing channel to enhance the magnetic field strength in the arc blowing channel. The magnetic field generated by the magnet can generate a spiral upward Lorentz force on the arc, so that the arc quickly enters the arc track 3 from the moving and static contacts. The magnetic field generated by the iron core 1 is limited. After adding the magnet, the magnetic field strength in the arc blowing channel is increased, so that the Lorentz force on the arc in the magnetic field is increased, so that the arc is quickly transferred on the moving and static contacts to enter the arc runway 3, achieving efficient arc extinguishing and improving the arc extinguishing efficiency of the self-excited arc extinguishing device.

[0029] In this embodiment, if Figure 2 , Figure 3As shown, the magnets are arranged in pairs, and the paired magnets are respectively arranged on both sides of the arc blowing channel, and the S poles of the magnets face inward. The paired magnets with the S poles facing inward can generate magnetic fields on both sides of the arc blowing channel, and the arc is subjected to the spiral upward Lorentz magnetic force, so that the time the arc stays on the contact can be further shortened, thereby improving the arc extinguishing efficiency of the self-excited arc extinguishing device. In addition, in other embodiments, the magnet can also be arranged on only one side of the arc blowing channel, and it is only necessary to ensure that the magnetic field generated by the magnet can quickly transfer the arc from the moving and static contacts to enter the arc running track.

[0030] In this embodiment, the magnet is coated with insulating material on the outside and is arranged close to the arc track 3 through the insulating material. The magnet is arranged close to the arc track 3 so that the magnetic field generated by the magnet can better guide the arc to the arc track, thereby improving the arc extinguishing efficiency. The insulating material coated on the outside of the magnet ensures that the magnetic fields between the two magnets will not affect each other, and at the same time, it will not affect the excitation circuit when it contacts the arc track 3. In addition, in other embodiments, the magnet can also be installed at a position slightly away from the outside of the arc blowing channel, as long as it is ensured that the magnetic field it generates can transfer the arc on the moving and static contacts and enter the arc track.

[0031] In this embodiment, the arc track 3 on the upper part of the moving contact 4 is provided with a Z-shaped extension plate extending outward, the lower plane of the Z-shaped extension plate is used to connect with the excitation coil, and the upper plane is used to support the corresponding insulating material, and the static contact 5 has a static contact extension extending outward, and the static contact extension is used to support the corresponding insulating material. The supporting structure of the magnet in this embodiment is a simple deformation of the original material. The Z-shaped connecting plate of the arc track is used on one side of the moving contact 4 to simultaneously achieve its connection with the arc track 3 and the excitation coil and support for the magnet; the static contact extension provided on one side of the static contact 5 cleverly realizes the support for the magnet, and the structure is simple.

[0032] In this embodiment, the insulating material is an insulating block 10 that wraps the magnet, and the insulating block 10 has a positioning fitting surface that matches the shape of the outer side surface of the corresponding arc track 3. The vertical section of the arc track 3 of this embodiment is tilted downward, and the insulating block 10 has an inclined surface that matches the shape of the arc track. When the insulating block 10 on one side of the moving contact 4 is installed on the arc track 3, its inner side surface has an inclined surface and a plane that match the shape of the arc track; when the insulating block 10 on one side of the static contact 5 is installed on the arc track 3, its inner side surface has an inclined surface and a plane that match the contours of the arc track 3 and the static contact 5, so that the positioning of the insulating block 10 and the magnet can be quickly achieved. During installation, the position of the magnet in the insulating block 10 can be set in advance. During installation, it is only necessary to place the insulating block 10 in the arc track 3, and the positioning fitting surface of the insulating block 10 will position the insulating block 10 at the corresponding position, thereby determining the position of the magnet in the entire device. In addition, in other embodiments, the insulating block may also be in other shapes, such as a cubic structure, as long as the magnets therein can be installed on both sides of the running arc track.

[0033] In this embodiment, the heights of the magnets are consistent. In this way, the magnetic fields generated by the magnets on both sides are symmetrically distributed, increasing the magnetic field strength at the arc. In addition, in other embodiments, the heights of the magnets may not be consistent, as long as the magnetic fields generated by the magnets on both sides can cause the arc to be subjected to the spiral upward Lorentz force.

[0034] In this embodiment, the magnet is a permanent magnet 6. Two transversely arranged permanent magnets 6 can generate a stronger magnetic field, thereby more effectively guiding the arc to move along the predetermined arc track 3. This enhanced guiding effect helps to speed up the arc extinguishing speed and improve the arc extinguishing efficiency. In addition, in other embodiments, the magnet can also be a soft magnet.

[0035] In this embodiment, the excitation coil is a copper foil coil 1. The copper foil coil 1 has a high conductivity, can quickly transmit current, and can more effectively generate a magnetic field, thereby enhancing the arc extinguishing effect on the arc. At the same time, the resistance of the copper foil coil 1 is relatively small, which reduces the energy loss caused by resistance heating and improves the overall efficiency of the device. In addition, in other embodiments, the excitation coil may also be an alloy coil or other metal coil (such as copper, silver, aluminum coil).

[0036] In this embodiment, the front and rear sides of the running arc 3 are provided with Figure 1The magnetizing iron 8 shown is connected to the iron core 1, and the space between the two magnetizing irons 8 corresponds to the arc track 3. The upper part of the arc track 3 of this embodiment is arranged horizontally, and the magnetizing iron 8 is arranged in a T-shape, and the two T-shaped magnetizing irons 8 are bolted or welded to the iron core 1 through a connecting plate 9. The existence of the magnetizing iron 8 can concentrate the magnetic field generated by the iron core 1 to the arc track 3 area, so that the arc moves quickly on the arc track 3. The magnetic field generated by the magnet can also be increased to increase the Lorentz force on the arc, thereby improving the arc blowing effect of the arc blowing device.

[0037] Another aspect of the present invention further provides a DC circuit breaker, which includes a self-excited arc blowing device. Since the self-excited arc blowing device is the same as the embodiment of the self-excited arc blowing device described above, it will not be described in detail here.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

Claims

1. A self-excited arc blowing device, comprising a moving contact and a stationary contact, wherein an arc runway is provided on the upper part of the moving contact and the stationary contact, and the arc runway forms an arc blowing channel at the upper part of the fracture, and an iron core with an excitation coil externally provided is provided on the outer side of the arc blowing channel, and the excitation coil is connected to the moving contact and the arc runway so that the iron core generates a magnetic flux when the moving and stationary contacts are opened and closed, characterized in that: A magnet is arranged on the outer side of the arc blowing channel for strengthening the magnetic field strength in the arc blowing channel.

2. The self-excited arc blowing device according to claim 1, characterized in that: The magnets are arranged in pairs, and the paired magnets are respectively arranged on both sides of the arc blowing channel, and the S poles of the magnets face inwards.

3. The self-excited arc blowing device according to claim 2 is characterized in that: The magnet is coated with insulating material on the outside and is arranged close to the arc track through the insulating material.

4. The self-excited arc blowing device according to claim 3 is characterized in that: The arc track above the moving contact is provided with a Z-shaped extension plate extending outward, the lower plane of the Z-shaped extension plate is used to connect with the excitation coil, and the upper plane is used to support the corresponding insulating material. The static contact has a static contact extension part extending outward, and the static contact extension part is used to support the corresponding insulating material.

5. The self-excited arc blowing device according to claim 4, characterized in that: The insulating material is an insulating block that wraps the magnet, and the insulating block has a positioning fitting surface that is adapted to the shape of the outer side surface of the corresponding running arc track.

6. The self-excited arc blowing device according to any one of claims 2 to 5, characterized in that: The heights of the magnets are consistent.

7. The self-excited arc blowing device according to any one of claims 1 to 5, characterized in that: The magnet is a permanent magnet.

8. The self-excited arc blowing device according to any one of claims 1 to 5, characterized in that: The excitation coil is a copper foil coil.

9. The self-excited arc blowing device according to any one of claims 1 to 5, characterized in that: The front and rear sides of the arc track are provided with magnetizing irons, the two magnetizing irons are connected to the iron core, and the space between the two magnetizing irons corresponds to the setting of the arc track.

10. A DC circuit breaker, comprising a self-excited arc blowing device, characterized in that: The self-excited arc blowing device comprises the self-excited arc blowing device according to any one of claims 1-9.

Images