CN115483072A

CN115483072A - Contact system of low-voltage circuit breaker

Info

Publication number: CN115483072A
Application number: CN202110603170.9A
Authority: CN
Inventors: 徐琛君; 眭皓
Original assignee: Shanghai Renmin Electrical Apparatus Works Co Ltd
Current assignee: Shanghai Renmin Electrical Apparatus Works Co Ltd
Priority date: 2021-05-31
Filing date: 2021-05-31
Publication date: 2022-12-16

Abstract

The invention relates to a contact system of a low-voltage circuit breaker, which comprises a contact support (4) and a contact piece (9), wherein an arc striking piece (7) and a bracket (11) are arranged on the rear side of the contact piece (9), the arc striking piece (7) is arranged on the bracket (11), and the bracket (11) is arranged on the contact support (4). Compared with the prior art, the invention can effectively avoid the phenomenon that the arc contact on the contact sheet is burnt out too fast by the arc generated after short circuit or overload current fault breaking.

Description

Contact system of low-voltage circuit breaker

Technical Field

The invention relates to the technical field of circuit breakers, in particular to a contact system of a low-voltage circuit breaker.

Background

The circuit breaker is the most important distribution equipment in a low-voltage distribution system, along with the continuous improvement of the requirements of power supply and power transmission and distribution equipment in power engineering, the performance requirements for a circuit protection switch are higher and higher, and the miniaturization, high performance, modularization and high reliability are the main development directions of the air circuit breaker at the present stage. The contact system is an important component of the circuit breaker, when fault current occurs in a circuit and the current value exceeds the set protection range of the intelligent controller, the operating mechanism is driven to act, so that the contact system of the circuit breaker, namely a moving contact and a static contact, are rapidly disconnected, and at the moment, air medium is caused to discharge by the voltage between the moving contact and the static contact, so that high-temperature electric arcs are generated. Generally adopt the explosion chamber to carry out the arc extinguishing among the prior art, nevertheless because traditional circuit breaker electric arc exists can not be quick be introduced in the explosion chamber and by the explosion chamber extinguish, electric arc is in between the sound silver point for a long time, causes sound silver point to be burnt the defect that decreases fast, for solving this technical problem, prior art generally adopts and increases the striking plate, improves the striking ability.

Chinese patent CN205657035U is a molded case circuit breaker loop structure with an arc striking plate, which includes a wiring board, a movable contact plate, a static contact plate, an arc extinguishing chamber and an arc striking plate, wherein the wiring board includes an external wiring portion and an internal wiring portion, the internal wiring portion is connected with the movable contact plate through a conductor, the internal wiring portion is assembled with an installation end of the arc striking plate, an arc running end of the arc striking plate extends into the static contact plate and is located below a contact end of the movable contact plate, the arc extinguishing chamber is located above the arc running end of the arc striking plate, and the contact end of the movable contact plate can extend into the arc extinguishing chamber. The utility model discloses an increase the striking board, lengthen electric arc and extinguish in introducing the explosion chamber fast with electric arc, reach the purpose that improves the striking ability, reduce the probability that the movable contact plate is ablated, improve the life of circuit breaker. However, the arc striking plate designed by the patent is fixed and is arranged at the open distance position of the contact, the distance between the contact and the arc striking plate is continuously changed in the moving process of the contact, the distance is from large to small, and the magnetic field force of the arc striking plate borne by the arc on the contact is also increased from small.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a contact system of a low-voltage circuit breaker, which can effectively avoid the phenomenon that an arc generated after short circuit or overload current fault breaking burns an arc contact on a contact piece too fast.

The purpose of the invention can be realized by the following technical scheme: the contact system of the low-voltage circuit breaker comprises a contact support and a contact piece, wherein an arc striking piece and a support are arranged on the rear side of the contact piece, the arc striking piece is arranged on the support, and the support is arranged on the contact support.

Furthermore, an insulating gasket is arranged below the arc striking plate.

Furthermore, the arc striking piece comprises a first flat plate, a second flat plate and a middle bending plate for connecting the first flat plate and the second flat plate, wherein the first flat plate is fixedly connected with the support, and an included angle between the second flat plate and the middle bending plate is 30-60 degrees.

Further, the distance between the connecting inflection point of the second flat plate and the middle bending plate and the arc contact of the contact sheet is 3-5mm.

Furthermore, the insulating pad is L-shaped and is arranged below the bending plate.

Further, the arc striking piece is in a shape with a wide lower part and a narrow upper part, namely the width of the second flat plate is smaller than that of the first flat plate.

Furthermore, the contact piece is arranged on the contact support, and side plates are arranged on two sides of the contact support.

Furthermore, the contact support is provided with a groove, and the bracket is arranged in the groove and connected with the left side plate and the right side plate.

Furthermore, the bracket is connected with the side plate through a screw.

Furthermore, the arc striking piece is made of ferromagnetic materials and used for guiding the electric arc to rapidly flow to the arc striking piece when the electric arc is generated during disjunction, so that the arc contact is protected from being eroded by the electric arc.

Compared with the prior art, the invention has the following advantages:

1. in order to avoid that an arc generated after short circuit or overload current fault breaking burns an arc contact on a contact piece too fast, an arc striking piece is added in the prior art, but the arc striking piece is generally arranged at the position of the open distance of the contact, the distance between the arc striking piece and the arc is larger at the moment when the arc is generated on the contact, and the force of a received magnetic field is smaller.

2. The invention arranges an insulating liner at the rear side of the middle part of the arc striking piece, the insulating liner is in an L shape, two surfaces of the insulating liner are respectively attached to the two bending plates of the arc striking piece and face the contact piece, the liner is closely attached to the surface of the middle bending plate in an insulating way, the surface of the insulating liner is subjected to insulating treatment, so that electric arc is not easy to flow onto the middle bending plate and flow onto the second flat plate when the arc is broken, and the electric arc can be quickly attracted upwards and flows into an arc extinguishing chamber.

3. The arc striking sheet is in a shape with wide bottom and narrow top, so that electric arcs are always deflected to one side when the arc striking sheet is broken, the electric arcs can be concentrated towards the middle by the aid of the shape with wide bottom and narrow top, only one side of the arc extinguishing chamber can be prevented from playing an arc extinguishing role after the electric arcs enter the arc extinguishing chamber, and the whole arc extinguishing chamber can be fully utilized.

4. The lower part of one end of the arc striking piece is provided with the bracket, the contact support is provided with the corresponding groove, the bracket is inserted into the groove during installation, and the bracket is limited and fixed through the side plates at two sides, so that the whole arc striking piece assembly is firmly fixed on the contact support, and the arc striking piece assembly cannot shake or fall off in the use process.

Drawings

FIG. 1 is a schematic structural view of a contact system of the present invention;

figure 2 is a schematic diagram of the contact support structure of the contact system of the present invention;

FIG. 3 is a schematic structural view of the arc runner assembly of the present invention;

FIG. 4 is a side view of the arc ignition blade assembly of the present invention;

FIG. 5 is a schematic view of a contact sheet;

the labels in the figure are: the contact structure comprises a busbar 1, a support 2, a side plate 3, a contact support 4, a connecting rod 5, a liner 6, an arc striking sheet 7, a first flat plate 71, a second flat plate 72, a middle bending plate 73, an insulating liner 8, a contact sheet 9, a cover 10 and a support 11.

Detailed Description

The contact system of the low-voltage circuit breaker according to the invention will be described in more detail below with reference to the schematic drawings, in which preferred embodiments of the invention are shown, it being understood that a person skilled in the art may modify the invention described herein while still achieving the advantageous effects of the invention. Accordingly, the following description should be construed as broadly as possible to those skilled in the art and not as limiting the invention.

As shown in fig. 5, the contact system includes a contact piece 9 and silver dots 902 disposed on the contact piece 9, after a short circuit or overcurrent fault is broken, the arc contacts 901 on the contact piece 9 may be burned down significantly, when the arc contacts 901 are burned down to a certain extent and then encounter a short circuit or overcurrent, because there is no protection of the arc contacts, the arc generated during breaking may directly burn down the silver dots 902 on the contact piece 9, and the burning down of the silver dots 902 may directly cause various performance degradation (mechanical life, electrical life, and temperature rise in use) of the circuit breaker, and may cause the burning down of the entire circuit breaker more seriously, resulting in the burning down of the entire circuit.

In order to solve the above problems, the present invention adds an arc striking plate assembly on the basis of a contact system of a conventional low voltage circuit breaker, which comprises a bus bar 1, a bracket 2, a side plate 3, a contact support 4, a connecting rod 5, a liner 6, a contact piece 9 and a cover 10, as shown in fig. 1. The arc striking piece assembly is additionally arranged on the basis, and comprises an arc striking piece 7, an insulating liner 8 and a support 11. The arc striking plate 7 is arranged on a bracket 11, and the bracket 11 is arranged on the contact support 4. An insulating gasket 8 is arranged below the arc striking plate 7.

As shown in fig. 2-3, the arc striking plate 7 includes a first flat plate 71, a second flat plate 72, and a middle bending plate 73 connecting the first flat plate 71 and the second flat plate 72, wherein the first flat plate 71 is fixedly connected to the bracket 11, and an included angle between the second flat plate 72 and the middle bending plate 73 is 30-60 degrees. The distance between the connecting inflection point of the second flat plate 72 and the middle bending plate 73 and the arc contact 901 of the contact piece 9 is 3-5mm.

The insulating pad 8 is L-shaped and is arranged below the bending plate 73. The arc ignition sheet 7 is in a shape with a wide lower part and a narrow upper part, namely the width of the second flat plate 72 is smaller than that of the first flat plate 71.

The contact piece 9 is arranged on the contact support 4, and the two sides of the contact support 4 are also provided with side plates 3. The contact support 4 is provided with a groove 401, and the bracket 11 is installed in the groove 401 and connected with the left and right side plates 3 through screws. As shown in fig. 2.

The arc striking piece 7 is made of ferromagnetic material and is used for guiding the arc to rapidly flow to the arc striking piece 7 when the arc is generated during breaking, so that the arc contact 901 is protected from being eroded by the arc.

Comparative example

And a moving contact system of the arc striking plate is not installed. The rest is the same as example 1.

Comparing the inventive structure with the comparative example, the performance is as follows: (the product is DC1500V product, but the invention is also suitable for other AC breakers and other products below 1500V)

It should be noted that the use of the ordinal adjectives "first", "second", etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and "left", "right", etc., indicate only one possible occurrence in an embodiment, and are not intended to imply that the objects so described must be in a given sequence or orientation, either temporally, spatially, in ranking, or in any other manner.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any way. It will be understood by those skilled in the art that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The contact system of the low-voltage circuit breaker comprises a contact support (4) and a contact piece (9), and is characterized in that an arc striking piece (7) and a support (11) are arranged on the rear side of the contact piece (9), the arc striking piece (7) is arranged on the support (11), and the support (11) is installed on the contact support (4).

2. Contact system for a low-voltage circuit breaker according to claim 1, characterized in that an insulating gasket (8) is provided under said striking plate (7).

3. Contact system of a low-voltage circuit breaker according to claim 1 or 2, characterized in that the arc striking plate (7) comprises a first flat plate (71), a second flat plate (72), and a middle bending plate (73) connecting the first flat plate (71) and the second flat plate (72), wherein the first flat plate (71) is fixedly connected with the support (11), and the angle between the second flat plate (72) and the middle bending plate (73) is 30-60 degrees.

4. A contact system of a low-voltage circuit breaker according to claim 3, characterized in that the distance between the arc contact (901) of the contact piece (9) and the connecting inflection point of the second flat plate (72) and the intermediate bending plate (73) is 3-5mm.

5. Contact system for low-voltage circuit breakers according to claim 3, characterized in that said insulating gasket (8) is L-shaped and is arranged below the bending plate (73).

6. Contact system for a low-voltage circuit breaker according to claim 3, characterized in that said arc runner (7) is shaped so as to be wider at the bottom and narrower at the top, i.e. the width of the second plate (72) is smaller than the width of the first plate (71).

7. Contact system for a low-voltage circuit breaker according to claim 1, characterized in that said contact plate (9) is arranged on a contact support (4), and that side plates (3) are arranged on both sides of the contact support (4).

8. Contact system for a low-voltage circuit breaker according to claim 7, characterized in that said contact support (4) is provided with a slot (401), said holder (11) being mounted in said slot (401) and being connected to said left and right side plates (3).

9. Contact system for a low-voltage circuit breaker according to claim 8, characterized in that said support (11) is screwed to said side plate (3).

10. Contact system for a low-voltage circuit breaker according to claim 1, characterized in that said arc runner (7) is made of ferromagnetic material and is adapted to guide the arc to flow rapidly towards the arc runner (7) when the arc is generated during breaking, so as to protect the arcing contacts (901) from erosion by the arc.