CN107342197B

CN107342197B - Arc extinguishing device of sliding plate type circuit breaker

Info

Publication number: CN107342197B
Application number: CN201710727648.2A
Authority: CN
Inventors: 张珂; 张信明
Original assignee: Hebei Bao Kay Electric Co ltd
Current assignee: Hebei Bao Kay Electric Co ltd
Priority date: 2017-08-23
Filing date: 2017-08-23
Publication date: 2020-06-09
Anticipated expiration: 2037-08-23
Also published as: CN107342197A

Abstract

An arc extinguishing device of a sliding plate type circuit breaker belongs to the technical field of emergency protection devices and is used for improving the capacity of breaking short-circuit current of the circuit breaker; the insulating shielding plate and the armature are positioned on the other side of the static contact, and the insulating shielding plate is fixed on the armature and corresponds to a gap between a moving contact and the static contact of the circuit breaker; one end of the sliding rod is fixedly connected with the magnetic yoke, and the other end of the sliding rod penetrates through the pressure spring and the armature in sequence and then is screwed into the anti-falling nut. The insulating shielding plate can be quickly inserted into a gap between a moving contact and a static contact of the breaker when the breaker breaks short-circuit current, so that an electric arc between the moving contact and the static contact is extinguished, the amplification time of electric arc energy is shortened, short arcing or no arcing of the breaker is realized, and the capacity of the breaker for breaking short-circuit current is greatly improved.

Description

Arc extinguishing device of sliding plate type circuit breaker

Technical Field

The invention relates to a device capable of effectively preventing a large electric arc from being generated between a moving contact and a static contact of a breaker when the breaker breaks short-circuit current, and belongs to the technical field of switches.

Background

Plastic case circuit breakers (MCCB) and conventional circuit breakers (ACB) are important electrical components in industrial and civil low-voltage distribution equipment, and are often used as branch switches or main switches of low-voltage distribution systems. At present, both MCCB and ACB at home and abroad adopt an arc extinguishing chamber technology to cool and extinguish a high-temperature and high-voltage electric arc generated when short-circuit current is cut off, and the arc extinguishing principle of the technology is as follows: when the short-circuit current is cut off, after the electric arc is generated between the moving contact and the static contact and is stretched to a certain length and the energy is correspondingly amplified, the high-energy electric arc is driven to enter the arc extinguish chamber by adopting magnetic field electrodynamic force or other modes, so that the high-energy electric arc is extinguished under the cooling action of the metal grid sheet in the arc extinguish chamber. The arc extinguishing effect of the method is influenced by factors such as arc extinguishing chamber materials, contact opening speed, contact opening distance, contact materials and the like, and particularly for the MCCB with a single-breakpoint structure, the capability of breaking short-circuit current is poor and generally does not exceed the AC 400V, ACB: 50-80 kA, MCCB: 30-50 kA, if the performance parameter is increased, the manufacturing cost is greatly increased. And the direct current short-circuit current is not easy to break because of no zero-crossing process.

With the construction and development of power grids and the improvement of the reliability requirements of people on the power grids, a new arc extinguishing scheme is objectively needed to greatly improve the capacity of a breaker for breaking short-circuit current and realize the generalization of alternating current and direct current arc extinguishing devices.

Disclosure of Invention

The invention aims to provide an arc extinguishing device of a sliding plate type circuit breaker, aiming at overcoming the defects of the prior art, so as to improve the capacity of the circuit breaker for breaking short-circuit current.

The problems of the invention are solved by the following technical scheme:

an arc extinguishing device of a sliding plate type circuit breaker comprises an insulating shielding plate, an armature, a magnetic yoke, a sliding rod and a pressure spring, wherein the magnetic yoke is fixed on one side of a fixed contact of the circuit breaker and is lower than a contact surface of the fixed contact and a movable contact; the insulating shielding plate and the armature are positioned on the other side of the static contact, and the insulating shielding plate is fixed on the armature and corresponds to a gap between a moving contact and the static contact of the circuit breaker; one end of the sliding rod is fixedly connected with the magnetic yoke, and the other end of the sliding rod penetrates through the pressure spring and the armature in sequence and then is screwed into the anti-falling nut.

According to the arc extinguishing device of the sliding plate type circuit breaker, the sliding rod and the pressure spring are arranged in two numbers and are symmetrically arranged on two sides of the fixed contact of the circuit breaker.

According to the arc extinguishing device of the sliding plate type circuit breaker, the insulating shielding plate is in the shape of an inverted dustpan, the front end of the insulating shielding plate corresponds to a gap between a moving contact and a static contact of the circuit breaker, and the back plate penetrates through the sliding rod and is fixedly connected with the armature.

The insulating shielding plate can be quickly inserted into a gap between a moving contact and a static contact of the breaker when the breaker breaks short-circuit current, so that an electric arc between the moving contact and the static contact is extinguished, the amplification time of electric arc energy is shortened, short arcing or no arcing of the breaker is realized, and the capacity of the breaker for breaking short-circuit current is greatly improved.

Drawings

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

fig. 2 is an initial position of the short circuit instantaneous trip and the action mechanism;

FIG. 3 is a short circuit instantaneous trip and the operating mechanism operating position;

fig. 4 is a schematic structural view of the armature (the structure of the yoke is the same as that);

FIG. 5 is a top view of FIG. 4;

fig. 6 is a schematic view of a static contact structure; (ii) a

FIG. 7 is a left top view of FIG. 6;

FIG. 8 is a schematic view of the structure of the dielectric shield;

fig. 9 is a left side view of fig. 8.

The list of labels in the figure is: 1. static contact; 2. a moving contact; 3. a magnetic yoke; 4. an insulating shield plate; 5. an armature; 6. a pressure spring; 7. a slide bar; 8. a pin shaft; 9. short-circuit instantaneous release and actuating mechanism.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The invention provides a special insulation shielding arc-extinguishing structure aiming at the defects of the prior art, which can utilize electromagnetic driving force to force an insulation shielding plate arranged at the side part of a static contact to be rapidly inserted between a movable contact and a static contact to play a role of rapidly extinguishing arc at the arc stagnation stage when a short circuit instantaneous release and an action mechanism are instantaneously operated at the moment of occurrence of fault short circuit current and the movable contact and the static contact are not completely opened. The invention is applied to MCCB and ACB, can greatly improve the capacity of breaking short-circuit current and realize the generalization of AC and DC arc extinguishing devices.

The invention can be used for various types of circuit breakers, such as universal circuit breakers and other products. If the circuit breaker is of a repulsion structure, the metal strip of the static contact at least comprises a straight section parallel to the moving contact, the direction of current in the straight section is opposite to that of current in the moving contact, and the length of the straight section is more than or equal to the length required by repulsion generated when short-circuit current flows in the moving contact and the static contact to repel each other.

The insulation shielding plate 4 is made of high-strength and high-temperature-resistant engineering plastic materials. The number of times (3 times at most) of effectively breaking the short-circuit current specified by the product standard can be ensured.

Referring to fig. 1 to 9, the present invention adopts a slide bar type structure, and mainly includes a magnetic yoke 3, an insulating shielding plate 4, an armature 5, a pressure spring 6, and a slide bar 7, which are disposed in a circuit breaker housing.

The magnetic yoke 3 is fixed on a static contact 1 of the circuit breaker, the two slide bars 7 are fixed on the magnetic yoke 3 through screws, the two pressure springs 6 are respectively arranged on the two slide bars 7, the armature 5 and the insulation shielding plate 4 are fixed into a whole through screws and then are arranged on the two slide bars 7, the end parts of the two slide bars 7 are provided with anti-falling nuts for limiting the combination of the armature 5 and the insulation shielding plate 4 and preventing the two from falling off from the slide bars 7, and the combination of the armature 5 and the insulation shielding plate 4 can overcome the elasticity of the pressure springs 6 and slide to one side of the static contact 1 and the magnetic yoke 3 under the action of external force. When a fault short-circuit current occurs in a circuit, because a strong electromagnetic field is generated around the static contact 1, the magnetic yoke 3 attracts the armature 5 after being magnetized, the combination body of the armature 5 and the insulation shielding plate 4 overcomes the elastic force of the pressure spring 6 and slides towards one side of the static contact 1 and the magnetic yoke 3 rapidly, at the moment of action of the short-circuit instant release and the action mechanism 9, the moving contact 2 rotates clockwise by the pin shaft 8 and is opened, meanwhile, the insulation shielding plate 4 is rapidly inserted between the moving contact 2 and the static contact 1 to play a role of rapid insulation shielding arc extinguishing, then, the moving contact 2 rotates clockwise by taking the pin shaft 8 as an axis, and the moving contact and the static contact are completely. After the short-circuit current disappears, the attraction force borne by the armature 5 disappears, the combination body of the armature 5 and the insulating shielding plate 4 returns to the original position under the action of the elastic force of the pressure spring 6, and the circuit breaker completes the whole process of breaking the short-circuit current.

The insulating shielding plate 4 is used as an auxiliary arc extinguishing mechanism for extinguishing arc when the moving contact and the static contact are not completely opened, and the arc extinguishing chamber has a good residual arc extinguishing effect after the moving contact and the static contact are completely opened.

Due to the technical scheme adopted by the arc extinguishing device of the MCCB or the ACB, the following technical progress can be obtained:

1, the capacity of breaking short-circuit current of a product can be greatly improved;

2. the purpose of alternating current and direct current is achieved;

3. when the fault short-circuit current is cut off, the further expansion of the arc energy can be limited, so that short arcing or no arcing of the product can be realized.

Claims

1. An arc extinguishing device of a sliding plate type circuit breaker is characterized by comprising an insulating shielding plate (4), an armature (5), a magnetic yoke (3), a sliding rod (7) and a pressure spring (6), wherein the magnetic yoke (3) is fixed on a fixed contact (1) of the circuit breaker and is lower than a contact surface between the fixed contact (1) and a moving contact (2); the insulation shielding plate (4) and the armature (5) are positioned on the other side of the static contact (1), and the insulation shielding plate (4) is fixed on the armature (5) and corresponds to a gap between the moving contact (2) and the static contact (1) of the circuit breaker; the insulating shielding plate (4) is used as an auxiliary arc extinguishing mechanism to extinguish arcs when the moving contact and the static contact are not completely opened; one end of the sliding rod (7) is fixedly connected with the magnetic yoke (3), and the other end of the sliding rod penetrates through the pressure spring (6) and the armature (5) in sequence and then is screwed into the anti-falling nut.

2. The arc extinguishing device of the sliding plate type circuit breaker according to claim 1, wherein the metal strip of the static contact at least comprises a straight section parallel to the moving contact, the current in the straight section is opposite to the current in the moving contact in direction, and the length of the straight section is greater than or equal to the length required for generating repulsion force for repelling the moving contact and the static contact when short-circuit current flows through the moving contact and the static contact.

3. The arc extinguishing device of the sliding plate type circuit breaker according to claim 2, characterized in that the sliding rod (7) and the compression spring (6) are arranged in two, and are symmetrically arranged on two sides of the fixed contact (1) of the circuit breaker.

4. The arc extinguishing device of the sliding plate type circuit breaker according to claim 3, characterized in that the insulating shielding plate (4) is in the shape of an upside-down dustpan, the front end of the insulating shielding plate corresponds to the gap between the moving contact (2) and the static contact (1) of the circuit breaker, and the back plate penetrates the sliding rod (7) and is fixedly connected with the armature (5).