Circuit breaker automatic current limiting structure and circuit breaker

Abstract

The utility model relates to the technical field of circuit breakers, and discloses an automatic current-limiting structure of a circuit breaker and the circuit breaker, the automatic current-limiting structure of the circuit breaker comprises a moving contact and a conducting bar, a contact surface between the moving contact and the conducting bar is provided with a protruding current-limiting resistor and a notch, when the circuit breaker is in a closed state, the moving contact is directly connected with the conducting bar, and the notch is arranged between the moving contact and the conducting bar. When the circuit breaker is in an opening state, the moving contact acts, and the current-limiting resistor is separated from the notch and is located between the moving contact and the conducting bar, so that the moving contact is connected with the conducting bar through the current-limiting resistor, and the moving contact is disconnected from the conducting bar directly and enters a high-impedance state. By arranging the current-limiting resistor and the conducting bar, the current-limiting resistor can be switched between a contact state and a non-contact state with the conducting bar, when the contact of the circuit breaker is opened to a certain distance, the current-limiting resistor is serially connected into a loop through the action of the moving contact, and the loop of the circuit breaker is switched to a high-impedance state, so that the current-limiting capability and the breaking capability of the circuit breaker can be effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit breakers, in particular to an automatic current limiting structure of a circuit breaker and a circuit breaker. Background Art

[0002] A circuit breaker is a distribution component used in circuits. It can be used to cut off and connect load circuits. When overload and short-circuit currents occur in the circuit, it can cut off the circuit in time, thereby protecting the circuit and the load.

[0003] In recent years, with the rapid development and application of the new energy industry, in order to adapt to the ever-increasing new demands of the new energy system, the operating voltage of the circuit breaker is constantly increasing, and higher requirements are also placed on the reliable breaking performance of the circuit breaker.

[0004] Circuit breakers usually adopt methods such as increasing the number and area of arc extinguishing grids and increasing the contact spacing to improve the breaking capacity. However, due to the limitations of circuit breaker volume and breakpoint structure, the effect of improving the breaking capacity is limited.

[0005] In the prior art, a few circuit breakers are designed to insert a current-limiting resistor made of high-resistance material in series in the circuit to play a current-limiting role. After the circuit breaker is closed, the current-limiting resistor continues to be energized. However, due to the large resistance of the current-limiting resistor, the power consumption of the circuit is increased. At the same time, due to the limitations of temperature rise requirements, this solution can only be applied to circuit breakers of 32A and below. In response to the above problems, this application is proposed. Utility Model Content

[0006] The purpose of the utility model is to provide a circuit breaker automatic current limiting structure and a circuit breaker. In the closed state, the circuit breaker circuit is low-impedance. When the circuit breaker contacts are opened (or the moving contacts are repelled by the short-circuit current) to a certain distance, the conductor of the circuit breaker conductive circuit can be automatically converted, and a current-limiting resistor is connected in series. The circuit breaker circuit switches to a high-impedance state. The increase in impedance limits the rise of the short-circuit current, reduces the energy of the arc, and effectively improves the current limiting capability and breaking capacity of the circuit breaker.

[0007] The utility model is realized through the following technical solutions.

[0008] The utility model discloses an automatic current limiting structure for a circuit breaker, comprising a moving contact and a conductive bar. A protruding current limiting resistor and a notch are provided at the contact surface between the moving contact and the conductive bar. When the circuit breaker is in a closed state, the moving contact is directly connected to the conductive bar, and the current limiting resistor is located in the notch. When the circuit breaker is in an open state, the moving contact is actuated, and the current limiting resistor is disengaged from the notch and located between the moving contact and the conductive bar, so that the moving contact is connected to the conductive bar via the current limiting resistor, and the moving contact is disconnected from the direct connection with the conductive bar, entering a high-impedance state.

[0009] According to an embodiment of the present invention, the conductive bar is provided with two groups of conductive arms arranged opposite to each other, and the movable contact is arranged between the two groups of conductive arms, so that the movable contact has two contact surfaces with the conductive bar.

[0010] According to an embodiment of the present invention, the current-limiting resistor is provided on the moving contact, and the notch is provided on the conductive bar.

[0011] According to an embodiment of the present invention, the thickness of the current-limiting resistor is smaller than the depth of the notch, and the current-limiting resistor does not directly contact the inner wall of the notch when located in the notch.

[0012] According to an embodiment of the present invention, the outer edges of the current limiting resistor and the notch are both provided with inclined surfaces.

[0013] According to an embodiment of the present invention, the movable contact is connected to the shaft, and when the movable contact moves, it moves around the shaft and generates relative rotation with the conductive bar.

[0014] According to an embodiment of the present invention, a groove for installing a current-limiting resistor is provided on the moving contact.

[0015] According to an embodiment of the present invention, the current-limiting resistors are provided in several groups, and the number of the notches is the same as the number of the current-limiting resistors.

[0016] According to an embodiment of the present invention, the current-limiting resistor is a cylindrical protrusion or a square protrusion, and the notch is a blind hole or a through hole.

[0017] A circuit breaker is provided with the above-mentioned automatic current limiting structure for the circuit breaker.

[0018] Beneficial effects of the utility model:

[0019] By setting a current-limiting resistor and a conductive bar, the current-limiting resistor can be switched between contacting and non-contacting the conductive bar, realizing whether the current-limiting resistor is added to the circuit. This switching action is achieved by the movement of the moving contact. In the closed state, the current-limiting resistor is not in contact with the conductive bar, and the moving contact is in direct contact with the conductive bar. At this time, the circuit breaker circuit has a low impedance. When the circuit breaker contacts are opened to a certain distance, the movement of the moving contact causes the current-limiting resistor to be connected in series with the circuit, and the circuit breaker circuit switches to a high-impedance state. The increase in impedance limits the rise of short-circuit current, greatly reducing the energy of the arc, and effectively improving the current limiting and breaking capacity of the circuit breaker. The utility model can be effectively applied to circuit breakers of various specifications. The connection and removal of the current-limiting resistor are closely coordinated with the movement of the moving contact, resulting in a simple, reliable structure and high stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 It is the overall structural diagram of the automatic current limiting structure of the circuit breaker;

[0023] Figure 2 This is a schematic diagram of the structure of the automatic current limiting structure of the circuit breaker after the drive frame is hidden;

[0024] Figure 3 Schematic diagram of the explosion structure at the moving contact and conductive bar;

[0025] Figure 4 It is a structural diagram of the moving contact;

[0026] Figure 5 It is the structural diagram of the drive frame;

[0027] Figure 6 Schematic diagram of the structure of the conductive bar;

[0028] Figure 7 This is a circuit diagram of the circuit breaker in the closed state;

[0029] Figure 8 This is a circuit diagram of the circuit breaker in the open state;

[0030] Figure 9 This is a schematic diagram of a circuit breaker;

[0031] Figure 10 Schematic diagram of the structure of the moving contact and the conductive bar in Example 2;

[0032] Figure 11 Schematic diagram of the explosion structure at the moving contact and conductive bar in Example 2. DETAILED DESCRIPTION

[0033] The following combination Figures 1-11 The utility model is described in detail.

[0034] Example 1:

[0035] The utility model discloses an automatic current limiting structure for a circuit breaker, comprising a moving contact 101, a current limiting resistor 107 and a conductive bar 103. When the circuit breaker is in the closed state, Figure 7, the moving contact 101 is directly connected to the conductive bar 103, when the circuit breaker is in the open state, such as Figure 8 The moving contact 101 and the conductive bar 103 are connected via a current-limiting resistor 107 .

[0036] The switching effect of the current limiting resistor 107 in the circuit can be achieved through the circuit or through structural action. In this embodiment, it is achieved through structural action.

[0037] Optionally, the current-limiting resistor 107 may be provided on the conductive bar 103 or on the moving contact 101 .

[0038] In this embodiment, Figure 3-Figure 4 The current limiting resistor 107 is connected to the moving contact 101 and protrudes to form a boss. A number of grooves for installing the current limiting resistor 107 are provided on the contact surfaces 110 on both sides of the moving contact 101. The current limiting resistor 107 is connected to the moving contact by welding, riveting or other connection methods. Specifically, the current limiting resistor 107 is arranged in a ring at the contact surface 110 of the moving contact 101. In this embodiment, three current limiting resistors 107 are provided at each contact surface 110. Figure 6 The conductive bar 103 is provided with two sets of conductive arms 108 arranged opposite to each other, and the moving contact 101 is arranged between the two sets of conductive arms 108 .

[0039] The conductive arm 108 is a part of the conductive bar 103. The conductive arm 108 is provided with a notch 109. The notch 109 is used to accommodate the current limiting resistor 107. The notch 109 is a square groove. The current limiting resistor 107 is in a square shape. Preferably, the thickness of the current limiting resistor 107 is less than the depth of the notch 109. When the current limiting resistor 107 is located in the notch 109, it does not directly contact the conductive bar 103. When the circuit breaker is in the closed state, the current limiting resistor 107 is located in the notch 109, and the moving contact 101 is in contact with the conductive bar. When the circuit breaker is in the open state, the movable contact 101 moves and generates relative displacement between the conductive bar 103. The current-limiting resistor 107 is released from the notch 109 and positioned between the movable contact 101 and the conductive bar 103. The conductive bar 103 undergoes a certain elastic deformation, causing the movable contact 101 and the conductive bar 103 to break away from direct contact. Instead, they are connected through the current-limiting resistor 107. The current-limiting resistor 107 is automatically connected in series between the movable contact and the conductive bar, forming a new current loop. Due to the high resistance of the current-limiting resistor 107, the circuit now has a current-limiting function.

[0040] It is understandable that, in other solutions, only one group of conductive arms 108 may be provided to contact one side of the moving contact 101 , and the minimum number of current-limiting resistors 107 may be one.

[0041] The current limiting resistor 107 is preferably made of a high-impedance resistive material such as an iron-nickel alloy.

[0042] In this embodiment, the movable contact 101 is in a rotating motion. Figure 2 、 Figure 3 A shaft 104 is provided on the conductive bar 103 , the movable contact 101 is connected to the shaft 104 , and the current limiting resistor 107 and the notch 109 are both provided around the shaft 104 .

[0043] It should be noted that the relative movement between the movable contact 101 and the conductive bar is not limited to rotational movement, as long as the current-limiting resistor 107 can be separated from the notch 109 and contact the conductive bar.

[0044] Preferably, the outer edges of the current limiting resistor 107 and the notch 109 are both provided with inclined surfaces, so that the current limiting resistor 107 can be more smoothly removed from the notch 109. Optionally, the edge of the current limiting resistor 107 can also be provided as a curved surface.

[0045] In order to ensure that the conductive arm 108 maintains stable contact with the moving contact 101 when the circuit breaker is in the closed state, Figure 2 An elastic member 106 is provided on the outside of the conductive arm 108. The elastic member 106 is generally a spring. The elastic member 106 contacts the conductive arm 108. When the circuit breaker is closed, the elastic member 106 squeezes the conductive arm 108 to make the conductive bar contact with the moving contact 101. A washer 105 is provided on the outside of the elastic member 106. The shaft 104 passes through the washer 105. The spring is sleeved outside the shaft 104, and the washer 105 contacts the outer driving frame 102.

[0046] When the circuit breaker is closed, the conductive arms 108 of the conductive bar 103 have the same number of notches 109 as current-limiting resistors 107, and the depth of the notches 109 is greater than the height of the protrusions of the current-limiting resistors 107. At this point, the current-limiting resistors 107 are perfectly positioned within the notches and do not contact the bar. Under the pressure of the spring, the conductive arms 108 of the conductive bar are in direct contact with the moving contact 101. Current flows directly from the moving contact to the conductive bar, bypassing the current-limiting resistors 107. The current conduction path is: stationary contact → moving contact → conductive bar. Therefore, in the closed state, the current path exhibits low impedance, meeting the circuit breaker's power consumption and temperature rise requirements.

[0047] When the circuit breaker begins opening from the closed state, the moving contact is rapidly lifted, causing it to rotate about axis 104. Current-limiting resistors 107 rotate simultaneously with moving contact 101, while the conductive bar remains fixed. Therefore, after moving contact 101 rotates to a certain angle, the current-limiting resistors 107 on either side disengage from the notches 109 in conductive bar 103, squeezing the conductive bar's conductive arms 108 slightly to the sides. At this point, conductive bar 103 separates from moving contact 101, and current-limiting resistors 107 automatically connect between moving contact 101 and conductive bar 103, forming a new current loop. Due to the high resistance of current-limiting resistors 107, the circuit now functions as a current limiter.

[0048] Example 2: The difference from Example 1 is that Figure 10 、 Figure 11 In this embodiment, the current limiting resistor 107 is cylindrical and can be connected to the moving contact 101 by welding or riveting. In other embodiments, the current limiting resistor 107 can also be spherical. In addition to the above-mentioned fixed installation method, rolling installation can also be used. The notch 109 is set as a through hole, which can be set as an elliptical through hole or a waist-shaped through hole.

[0049] Example 3: Different from Example 1 or 2, in this embodiment, the moving contact 101 and the conductive bar 103 are not connected by an axis, that is, the movement relationship between the moving contact 101 and the conductive bar 103 is not relative rotation. A relative displacement in the vertical direction or horizontal direction (such as the moving contact 101 moving horizontally or vertically between the long contact surfaces of the conductive bar 103) can be used to achieve the current limiting resistor 107 entering or exiting the slot 109.

[0050] Embodiment 4: Different from Embodiment 1, in this embodiment, the current-limiting resistor is provided on the conductive bar, and the notch is provided on the moving contact 101 .

[0051] A circuit breaker, such as Figure 9 The circuit breaker is provided with the automatic current limiting structure 10 of the circuit breaker in any of the above embodiments. Generally, the circuit breaker also includes a tripping system 30, a housing 40, an operating system 50 and an arc extinguishing system 60. When the circuit breaker is in the closed state, the operating system drives the driving frame 102 to make the moving contact 101 contact with the static contact 20.

[0052] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand and implement the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications based on the spirit of the present invention are intended to fall within the scope of protection of the present invention.

Claims

1. A circuit breaker automatic current limiting structure, characterized by: The invention comprises a movable contact (101) and a conductive bar (103); a protruding current-limiting resistor (107) and a notch (109) are provided at the contact surface between the movable contact (101) and the conductive bar (103); when the circuit breaker is in a closed state, the movable contact (101) is directly connected to the conductive bar (103), and the current-limiting resistor (107) is located in the notch (109); when the circuit breaker is in an open state, the movable contact (101) is actuated, and the current-limiting resistor (107) is disengaged from the notch (109) and located between the movable contact (101) and the conductive bar (103), so that the movable contact (101) is connected to the conductive bar (103) via the current-limiting resistor (107); the movable contact (101) is disconnected from the direct connection with the conductive bar (103), and enters a high-impedance state.

2. The circuit breaker automatic current limiting structure according to claim 1, characterized in that: The conductive bar (103) is provided with two groups of conductive arms (108) arranged opposite to each other, and the movable contact (101) is arranged between the two groups of conductive arms (108), so that the movable contact (101) and the conductive bar (103) have two contact surfaces.

3. The automatic current limiting structure of a circuit breaker according to claim 1, characterized in that: The current-limiting resistor (107) is provided on the moving contact (101), and the notch (109) is provided on the conductive bar (103).

4. The circuit breaker automatic current limiting structure according to any one of claims 1 to 3, characterized in that: The thickness of the current-limiting resistor (107) is smaller than the depth of the notch (109), and when the current-limiting resistor (107) is located in the notch (109), it does not directly contact the inner wall of the notch (109).

5. The circuit breaker automatic current limiting structure according to claim 4, characterized in that: The outer edges of the current-limiting resistor (107) and the notch (109) are both provided with inclined surfaces.

6. The circuit breaker automatic current limiting structure according to claim 5, characterized in that: The moving contact (101) is connected to the shaft (104), and when the moving contact (101) moves, it moves around the shaft and generates relative rotation with the conductive bar (103).

7. The automatic current limiting structure of a circuit breaker according to claim 3, characterized in that: The moving contact (101) is provided with a groove for installing a current-limiting resistor (107).

8. The circuit breaker automatic current limiting structure according to any one of claims 1 to 3, characterized in that: The current-limiting resistors (107) are provided in several groups, and the number of the notches (109) is the same as the number of the current-limiting resistors (107).

9. The circuit breaker automatic current limiting structure according to claim 8, characterized in that: The current-limiting resistor (107) is a cylindrical protrusion or a square protrusion, and the notch (109) is a blind hole or a through hole.

10. A circuit breaker, characterized in that: The circuit breaker is provided with the circuit breaker automatic current limiting structure according to any one of claims 1 to 9.

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