Contact system of a low-voltage circuit breaker

Abstract

A contact system of a low-voltage circuit breaker, which comprises a static contact (1) and a moving contact (2). The static contact (1) includes a wiring terminal (101), an inner arm (102) and outer arms (103, 104). At least two outer arms (103, 104) are connected in parallel, one end of which is connected to the wiring terminal (101), and the other end is connected to the non-contact end (102a) of the inner arm (102). The contact end (102b) of the inner arm (102) is located between the wiring terminal and the non-contact end (102a) of the inner arm (102). It is characterized in that: a disconnection part (103a, 104a) is provided on at least one outer arm (103, 104), and an auxiliary moving contact (105, 106) is correspondingly arranged for the disconnection part (103a, 104a). One end of the auxiliary moving contact (105, 106) is connected to the disconnection part (103a, 104a) when the circuit breaker is switched on. The auxiliary moving contact (105, 106) can be separated from the disconnection part (103a, 104a) when being driven by the moving contact (2) when the circuit breaker is switched off. This contact system does not need to change the structure of the moving contact of the circuit breaker, and only needs to improve the static contact to effectively and reliably increase the breaking capacity of the circuit breaker.

Description

Technical Field

[0001] The present invention belongs to the technical field of circuit breakers, and specifically relates to a contact system of a low-voltage circuit breaker. Background Art

[0002] With the development of new energy industries such as photovoltaic, the requirements for the breaking capacity of low-voltage circuit breakers are also getting higher and higher. Low-voltage circuit breakers need to have a high breaking capacity under high voltages, and DC low-voltage circuit breakers need to reliably interrupt the critical current. Since it is difficult to increase the internal space of low-voltage circuit breakers, it is more difficult to further improve the breaking capacity of low-voltage circuit breakers by traditional means such as increasing the opening distance and heightening the arc extinguishing chamber.

[0003] Chinese Patent CN103077856B discloses an asymmetric double - contact circuit breaker, which includes a first moving contact, a static contact, a contact spring, a moving - contact bracket, an upper connecting rod, a lower connecting rod, a tripping latch, a locking latch and a mechanism bracket. The two ends of the first moving contact are respectively provided with a first contact and a second contact. The first moving contact is elastically connected to the moving - contact bracket through the contact spring. The moving - contact bracket has a pivot shaft shared with the first moving contact. The static contact is fixedly installed on the double - contact circuit breaker. The static contact is provided with a static - contact contact. One end of the upper connecting rod is pivotally connected to the tripping latch, and the other end of the upper connecting rod is pivotally connected to one end of the lower connecting rod. The other end of the lower connecting rod is pivotally connected to the moving - contact bracket. The tripping latch and the locking latch are pivotally installed on the mechanism bracket. The double - contact circuit breaker further includes a second moving contact and an opening drive rod. The second moving contact is pivotally arranged in the double - contact circuit breaker. One end of the second moving contact is provided with a second - moving - contact contact, and the other end of the second moving contact is connected to a terminal. The first and second contacts achieve the connection and disconnection of the current through the contact and separation from the static - contact contact and the second - moving - contact contact. The opening drive rod is pivotally arranged in the double - contact circuit breaker and is configured to rotate clockwise under the drive of the moving - contact bracket during the opening process of the double - contact circuit breaker, thereby driving the second moving contact to rotate counterclockwise so that the second - moving - contact contact moves away from the second contact. This double - contact circuit breaker can ensure that the first contact separates from the static - contact contact before the second contact, so that most of the arc energy is placed between the first contact and the static contact. In this way, when the second moving contact leaves the second contact, the extinction of the arc becomes very easy and stable at the completion of the opening operation. After the arc is extinguished, it will not reignite, and the arc extinction time becomes shorter and stable. However, the first moving contact and the second moving contact are in series in the main circuit. The second moving contact passes through all the working current and short - circuit current in the main circuit, but only bears a small part of the arc energy. Therefore, the cross - sectional area of the second moving contact is relatively large, and the corresponding opening drive rod is also large, resulting in high material costs. The structure for realizing the later separation of the second moving contact is relatively complex. And since the second moving contact is in series in the main circuit and most of the arc energy is placed between the first contact and the static contact, the double - break contact system is similar to a single - break contact system with an additional second moving contact. The entire structure can improve the breaking capacity of the single - break contact system, but cannot improve the breaking capacity of the double - break contact system. Summary of the Invention

[0004] The object of the present invention is to provide a contact system for a low - voltage circuit breaker, aiming at the problem that with the increasing requirements for the breaking capacity of low - voltage circuit breakers in new energy industries such as photovoltaic, it is difficult to improve the breaking capacity of existing low - voltage circuit breakers. Without changing the structure of the moving contact of the circuit breaker, only by improving the static contact can the breaking capacity of the circuit breaker be effectively and reliably increased.

[0005] Technical Solution

[0006] In order to achieve the above technical objectives, a contact system of a low-voltage circuit breaker provided by the present invention includes a static contact and a moving contact. The static contact includes a terminal, an inner arm, and outer arms. At least two outer arms are connected in parallel, with one end connected to the terminal and the other end connected to the non-contact end of the inner arm. The contact end of the inner arm is located between the terminal and the non-contact end of the inner arm. It is characterized in that: at least one outer arm is provided with a disconnection part, and an auxiliary moving contact is correspondingly arranged at the disconnection part. One end of the auxiliary moving contact is connected to the disconnection part when the circuit breaker is closed, and the auxiliary moving contact can be driven by the moving contact to separate from the disconnection part when the circuit breaker is tripped. The other end of the auxiliary moving contact is electrically connected to the non-contact end of the inner arm.

[0007] Further, the process of the auxiliary moving contact being driven by the moving contact to separate from the disconnection part when the circuit breaker is tripped includes a first stage and a second stage. The first stage is that the auxiliary moving contact remains connected to the disconnection part during the initial process of the moving contact and the static contact separating when the circuit breaker is tripped. The second stage is that the auxiliary moving contact is driven by the moving contact to separate from the disconnection part after the moving contact and the static contact have separated a certain distance when the circuit breaker is tripped.

[0008] Further, the at least two outer arms are located on both sides of the inner arm, and the contact end of the inner arm corresponds to the moving contact. The moving contact can be connected and disconnected from the contact end of the inner arm during the rotation process.

[0009] Further, the static contact further includes a bracket and a track plate. The track plate is provided with a track groove. The auxiliary moving contact is pivotally installed on the corresponding bracket. The auxiliary moving contact is connected with a torsion spring and uses the pressure provided by the torsion spring to keep connected to the disconnection part. When the auxiliary moving contact is closed, it is located below the moving contact;

[0010] A driving part is installed on the moving contact, and a follower part is provided on the auxiliary moving contact. During the disconnection process between the moving contact and the contact end of the inner arm, the driving part can drive the follower part to separate the auxiliary moving contact from the disconnection part;

[0011] The driving part includes a rotating shaft. Both ends of the rotating shaft are connected to a driving shaft through side plates. Both ends of the driving shaft pass through the side plates and extend out of the track groove to be linked with the follower part on the auxiliary moving contact. The follower part is arranged at a position behind the pivot center on the auxiliary moving contact;

[0012] The driving shaft is located below the moving contact and on the upper surface side of the auxiliary moving contact. During the rotation process of the rotating shaft, the driving shaft can be driven to move in the track groove;

[0013] The bracket and the track plate are installed at one end where the outer arm is connected to the inner arm.

[0014] Further, the structure of the outer arm can also be extended from one end connecting the terminal to the non-contact end of the inner arm, bent downward near the non-contact end of the inner arm and then bent back toward the terminal direction and extended for a section and then bent upward for a section, and a disconnection part one is arranged at the end of the upward-bent section; or extended from one end connecting the terminal to the non-contact end of the inner arm, bent upward near the non-contact end of the inner arm and then bent back toward the terminal direction and extended for a section, and a disconnection part four is arranged at the end; or extended from one end connecting the terminal to the non-contact end of the inner arm, bent upward near the non-contact end of the inner arm and then bent back toward the terminal direction and extended for a section and then bent downward for a section, and a disconnection part five is arranged at the end.

[0015] A driving part one is installed on the moving contact, the driving part one includes a driving shaft one, a following part one is arranged on the auxiliary moving contact, the following part one is arranged at a position on the auxiliary moving contact in front of the pivot center, and during the disconnection process of the moving contact and the contact end of the inner arm, the driving shaft one can drive the following part one to separate the auxiliary moving contact from the corresponding disconnection part one or disconnection part four or disconnection part five.

[0016] The bracket is installed on the circuit breaker, the auxiliary moving contact is pivotally installed on the bracket, and when the auxiliary moving contact is closed, it is located above the moving contact.

[0017] Further, an auxiliary moving contact is correspondingly arranged for the disconnection part four, one end of the auxiliary moving contact is connected to the disconnection part four when the circuit breaker is closed, and the auxiliary moving contact can be driven by the moving contact to rotate and separate from the disconnection part four when the circuit breaker is disconnected, and the length of the auxiliary moving contact behind the pivot center is greater than its length in front of the pivot center.

[0018] Further, an auxiliary moving contact is correspondingly arranged for the disconnection part five, one end of the auxiliary moving contact is connected to the disconnection part five when the circuit breaker is closed, and the auxiliary moving contact can be driven by the moving contact to rotate and separate from the disconnection part five when the circuit breaker is disconnected, and the auxiliary moving contact is between the lower bottom end and the upper top end of the outer arm.

[0019] Further, one of the outer arms is a short-circuit conductor;

[0020] One end of the short-circuit conductor is connected to the terminal, and the other end is connected to the non-contact end of the inner arm. When closed, the short-circuit conductor is located above the moving contact, and the short-circuit conductor is higher than or equal to the height of the auxiliary moving contact; or one end of the short-circuit conductor is connected to the terminal, and the other end is connected to the non-contact end or the contact end of the inner arm, and the length of the short-circuit conductor is the distance from the terminal to the corresponding non-contact end or contact end of the inner arm.

[0021] Further, one of the outer arms is a short - circuit conductor;

[0022] One end of the short - circuit conductor is connected to the terminal, and the other end is connected to the non - contact end of the inner arm. When it is switched on, the short - circuit conductor is located above the moving contact, or one end of the short - circuit conductor is connected to the terminal and the other end is connected to the non - contact end or the contact end of the inner arm, and the length of the short - circuit conductor is the distance from the terminal to the corresponding non - contact end or contact end of the inner arm.

[0023] Furthermore, the resistance of the short - circuit conductor is greater than or equal to the resistance of the other outer arm.

[0024] Preferably, the resistance value of the short - circuit conductor is between 2 and 5 times the resistance value of the other outer arm.

[0025] Beneficial effects

[0026] A contact system of a low - voltage circuit breaker provided by the present invention uses an auxiliary moving contact to assist in breaking on the outer arm of the static contact. The two outer arms are in parallel, and the auxiliary moving contact only passes through part of the working current and short - circuit current, so the auxiliary moving contact can be made smaller; the two outer arms and the moving contact are in series, and the structure of the moving contact does not need to be changed. It can not only improve the breaking capacity of a single - break circuit breaker but also improve the breaking capacity of a double - break circuit breaker; during the disconnection process of the moving contact, the driving shaft of the moving contact drives the follower part of the auxiliary moving contact, thereby driving the auxiliary moving contact to rotate so that the auxiliary moving contact moves away from the disconnection point of the outer arm. Since the moving contact disconnects first, the moving contact bears most of the arc energy, and the auxiliary moving contact can bear part of the arc energy to help break the current; or design one of the two outer arms as a short - circuit conductor, and only increase the total resistance of the circuit breaker after the driving shaft of the moving contact drives the auxiliary moving contact away from the disconnection point of the outer arm during breaking, which can also achieve the purpose of improving the breaking capacity; the entire contact system has a simple structure, does not need to change the structure of the moving contact of the circuit breaker, and only needs to improve the static contact to effectively and reliably increase the breaking capacity of the circuit breaker. Brief description of the drawings

[0027] Figure 1 It is the top view of the static contact in the first embodiment of the present invention.

[0028] Figure 2 It is the schematic structural diagram of the static contact in the first embodiment of the present invention.

[0029] Figure 3 It is the schematic structural diagram of the driving part of the moving contact in the first embodiment of the present invention.

[0030] Figure 4 It is the schematic assembly structure diagram of the moving contact and the driving part in the first embodiment of the present invention.

[0031] Figure 5 Schematic diagram of the contact system in the on state in the first embodiment of the present invention.

[0032] Figure 6 Schematic diagram of the contact system in the on state in the first embodiment of the present invention.

[0033] Figure 7 Schematic diagram of the state when the drive shaft of the contact system in the first embodiment of the present invention just contacts the auxiliary moving contact.

[0034] Figure 8 Schematic diagram of the state when the moving contact drives the auxiliary moving contact to break in the first embodiment of the present invention.

[0035] Figure 9 Schematic diagram of the static contact structure for suction compensation in the second embodiment of the present invention.

[0036] Figure 10 Schematic diagram of the contact system in the on state in the second embodiment of the present invention.

[0037] Figure 11 Schematic diagram of the contact system in the on state in the second embodiment of the present invention.

[0038] Figure 12 Schematic diagram of the state when the drive part of the contact system in the second embodiment of the present invention just contacts the auxiliary moving contact.

[0039] Figure 13 Schematic diagram of the state when the moving contact drives the auxiliary moving contact to break in the second embodiment of the present invention.

[0040] Figure 14 Schematic diagram in the third embodiment of the present invention.

[0041] Figure 15a Schematic diagram of the structure in the fourth embodiment of the present invention.

[0042] Figure 15b Schematic diagram of the structure in the fifth embodiment of the present invention.

[0043] Figure 16 Schematic diagram of the structure in the sixth embodiment of the present invention.

[0044] Figure 17 Schematic diagram of the structure in the seventh embodiment of the present invention

[0045] Figure 18 Schematic diagram of the structure in the eighth embodiment of the present invention.

[0046] Figure 19 Schematic diagram of the structure in the ninth embodiment of the present invention.

[0047] Figure 20Schematic diagram of the tenth embodiment of the present invention.

[0048] Figure 21 Schematic diagram of the eleventh embodiment of the present invention.

[0049] Figure 22 Schematic diagram of the twelfth embodiment of the present invention.

[0050] Figure 23a Schematic diagram of the existing arc extinguishing chamber

[0051] Figure 23b Schematic diagram of the arc extinguishing chamber of the present invention Detailed implementation manners

[0052] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0053] Embodiment 1

[0054] As shown in the attached Figure 1 and the attached Figure 5 shown, a contact system of a low-voltage circuit breaker includes a static contact 1 and a moving contact 2. The static contact 1 includes a terminal 101, an inner arm 102, and outer arms 103, 104. At least two outer arms 103, 104 are connected in parallel, one end is connected to the terminal 101, and the other end is connected to the non-contact end 102a of the inner arm 102. The at least two outer arms 103, 104 are located on both sides of the inner arm 102. The contact end 102b of the inner arm 102 is located between the terminal and the non-contact end 102a of the inner arm 102. Among them, as shown in the attached Figure 2 shown, disconnecting portions 103a, 104a are provided on the outer arms 103, 104, and auxiliary moving contacts 105, 106 are correspondingly provided for the disconnecting portions 103a, 104a. One end of the auxiliary moving contacts 105, 106 connects the disconnecting portions 103a, 104a when the circuit breaker is closed, and the auxiliary moving contacts 105, 106 can be separated from the disconnecting portions 103a, 104a when driven by the moving contact 2 during circuit breaker opening. The other ends of the auxiliary moving contacts 105, 106 are electrically connected to the non-contact end 102a of the inner arm 102. The static contact 1 and the moving contact 2 contact and disconnect at the contact end 102b of the inner arm 102.

[0055] As shown in the attached Figure 2As shown, the static contact 1 further includes brackets 107, 108 and track plates 109, 110. Track grooves 109a, 110a are provided on the track plates 109, 110. The brackets 107, 108 and the track plates 109, 110 are installed at the non-contact end 102a where the outer arms 103, 104 are connected to the inner arm 102. As shown in the appendix Figure 3 and 4 As shown, a driving part a is installed on the moving contact 2, and follower parts 105a, 106a are provided on the auxiliary moving contacts 105, 106. During the breaking process of the moving contact 2 and the contact end 102b of the inner arm 102, the driving part a can drive the follower parts 105a, 106a to separate the auxiliary moving contacts 105, 106 from the disconnection parts 103a, 104a;

[0056] In this embodiment, the driving part a includes a rotating shaft 201. Both ends of the rotating shaft 201 are connected to a driving shaft 203 through side plates 202. Both ends of the driving shaft 203 pass through the side plates 202 and extend out of the track grooves 109a, 110a to be linked with the follower parts 105a, 106a on the auxiliary moving contacts 105, 106. The follower parts 105a, 106a are arranged at the rear side position of the pivot center on the auxiliary moving contacts 105, 106. The driving shaft 203 is located below the moving contact 2 and on the upper surface side of the auxiliary moving contacts 105, 106. During the rotation of the rotating shaft 201, the driving shaft 203 can be driven to move in the track grooves 109a, 110a.

[0057] As shown in the appendix Figure 5As shown, the auxiliary moving contacts 105 and 106 are pivotally mounted on the corresponding brackets 107 and 108. The auxiliary moving contacts 105 and 106 are connected with torsion springs (not shown in the figure) and are kept in communication with the disconnection parts 103a and 104a by the pressure provided by the torsion springs; when the auxiliary moving contacts 105 and 106 are closed, they are located below the moving contact 2; the other ends of the auxiliary moving contacts 105 and 106 are electrically connected to the non-contact end 102a of the inner arm 102. In this embodiment, the other end of the auxiliary moving contact is electrically connected to the non-contact end 102a of the inner arm 102 through a flexible connection b, or the electrical connection between the other end of the auxiliary moving contact and the non-contact end 102a of the inner arm 102 can also be realized by a frictional electrical contact method. When the frictional electrical contact method is adopted, the electrical connection between 106 and 108 is realized by the frictional electrical contact method, further eliminating the flexible connection. In the closed state, the driving part a is not in contact with the follower parts 105a and 106a, and the moving contact 2 and the auxiliary moving contacts 105 and 106 are both in contact with the static contact 1. During the breaking process, the moving contact 2 rotates upward, driving the driving shaft 203 of the driving part a to move in the track grooves 109a and 110a. After the moving contact 2 is separated from the static contact 1 by a certain distance, the driving part a contacts the follower parts 105a and 106a, causing the auxiliary moving contacts 105 and 106 to be separated from the disconnection parts 103a and 104a of the outer arm.

[0058] As shown in the Figure 6 accompanying drawings, in the closed state, the auxiliary moving contacts 105 and 106 are below the moving contact 2, the driving part a is not in contact with the follower parts 105a and 106a, and the moving contact 2 and the auxiliary moving contacts 105 and 106 are both in contact with the static contact 1.

[0059] As shown in the Figure 7 accompanying drawings, when the circuit breaker breaks, the moving contact 2 is driven by the operating mechanism to rotate upward by a certain angle. At this time, the driving part moves in the track grooves 109a and 110a, and the driving shaft 203 just contacts the auxiliary moving contacts 105 and 106. At this time, the auxiliary moving contacts 105 and 106 still remain closed, and an arc appears on the moving contact 2. The moving contact 2 bears most of the arc energy; as shown in the Figure 8 accompanying drawings, when the moving contact 2 continues to rotate upward, the driving part continues to move in the track grooves 109a and 110a, the driving shaft 203 contacts the auxiliary moving contacts 105 and 106, driving the auxiliary moving contacts 105 and 106 to rotate upward. The auxiliary moving contacts 105 and 106 bear a part of the arc energy and help to break the current.

[0060] When the moving contact 2 is quickly repelled by the short-circuit current, after the moving contact 2 rotates upward by a certain angle, it drives the auxiliary moving contacts 105 and 106 to break; the moving contact 2 can also be driven by the operating mechanism to rotate upward by a certain angle and then drive the auxiliary moving contacts 105 and 106 to disconnect.

[0061] Example 2

[0062] As shown in the attached Figure 9 and 10 figure, the structures of the outer arms 103, 104 extend from one end connecting the terminal 101 towards the non-contact end 102a of the inner arm 102. After bending downward near the non-contact end 102a of the inner arm 102, they then bend towards the terminal 101 and extend for a certain distance before bending upward for a certain distance. Disconnection parts 103b, 104b are provided at the ends of the upward-bent part; brackets 107, 108 are provided on the circuit breaker, or the brackets 107, 108 are Figure 10 provided on the outer arms and have a high resistance value with the outer arms 103, 104 so as not to affect the current flow direction, or are provided at other similar places such as near the non-contact end 102a of the inner arm 102. The auxiliary moving contacts 105, 106 are pivotally mounted on the brackets 107, 108;

[0063] A first driving part a' is mounted on the moving contact 2. The first driving part a' includes a first driving shaft 201'. Follow-up parts 105a', 106a' are provided on the auxiliary moving contacts 105, 106. The follow-up parts 105a', 106a' are arranged at the front side positions of the auxiliary moving contacts 105, 106 with respect to the pivot center o. During the disconnection process between the moving contact 2 and the contact end 102b of the inner arm 102, the first driving shaft 201' can drive the follow-up parts 105a', 106a' to separate the auxiliary moving contacts 105, 106 from the disconnection parts 103b, 104b; The structures of other parts are the same as those in Example 1 and will not be further described in detail here;

[0064] As shown in the attached Figure 10 figure, in the on state, the current directions of the auxiliary moving contacts 105, 106 and the part of the outer arm below the auxiliary moving contacts 105, 106 are the same. Therefore, the downward suction force is generated on the auxiliary moving contacts 105, 106 by this part of the outer arm. This suction force makes the auxiliary moving contacts tend to rotate counterclockwise, thereby increasing the contact pressure between the auxiliary moving contacts 105, 106 and the static contact 1, and the requirements for the torsion springs of the auxiliary moving contacts can be reduced.

[0065] As shown in the attached Figure 11 figure, in the on state, the first driving shaft 201' does not contact the follow-up parts 105a', 106a'. The moving contact 2 and the auxiliary moving contacts 105, 106 are both connected to the static contact 1.

[0066] As shown in the attached Figure 12As shown, when the circuit breaker trips, the moving contact 2 rotates upward by a certain angle, and the first drive shaft 201’ just comes into contact with the first follower parts 105a’, 106a’. At this time, the auxiliary moving contacts 105, 106 are still closed, an arc appears on the moving contact 2, and the moving contact 2 bears most of the arc energy.

[0067] As shown in the Figure 13 attachment, when the moving contact 2 continues to rotate upward, the first drive shaft 201’ contacts the first follower parts 105a’, 106a’, driving the auxiliary moving contacts 105, 106 to rotate upward. The auxiliary moving contacts 105, 106 bear part of the arc energy and help to interrupt the current.

[0068] In this embodiment, in the closed state, the auxiliary moving contacts 105, 106 are located above the moving contact 2 and have the same current direction as the moving contact 2. When a short circuit occurs, the repulsion of the moving contact can be accelerated. The entire contact system reduces the requirements for the torsion springs of the auxiliary moving contacts by setting the outer arms as a suction compensation circuit.

[0069] Embodiment 3

[0070] As shown in the Figure 14 attachment, on the basis of Embodiment 2, in this embodiment, the structures of the outer arms 103, 104 can also extend from one end connecting the terminal 101 to the non-contact end 102a of the inner arm 102, bend upward near the non-contact end 102a of the inner arm 102 and then extend in the direction of the terminal 101 for a section, and a fourth disconnecting part 103e, 104e is provided at the end. The fourth disconnecting part 103e, 104e corresponds to the auxiliary moving contacts 105, 106. One end of the auxiliary moving contacts 105, 106 is connected to the fourth disconnecting part 103e, 104e when the circuit breaker is closed. The auxiliary moving contacts 105, 106 can be driven by the moving contact 2 to rotate and separate from the fourth disconnecting part 103e, 104e when the circuit breaker trips; the length of the auxiliary moving contacts 105, 106 behind the pivot center o is greater than the length in front of the pivot center o. The structures of other parts are the same as those in Embodiment 2 and will not be further described in detail here;

[0071] In the closed state, the current directions of the auxiliary moving contacts 105, 106 and the part of the outer arm below the auxiliary moving contacts are opposite. Since the length of the auxiliary moving contacts 105, 106 behind the pivot center o is greater than the length in front of the pivot center o, the electric repulsive force of the conductive loop behind the auxiliary moving contacts 105, 106 is greater than the electric repulsive force in front, causing the auxiliary moving contacts 105, 106 to have a counterclockwise rotation tendency and pressing the auxiliary moving contacts 105, 106 towards the disconnecting point.

[0072] Embodiment 4

[0073] As shown in theFigure 15a As shown, on the basis of Embodiment 2, in this embodiment, the outer arms 103 and 104 can also extend from one end connecting the terminal 101 towards the non-contact end 102a of the inner arm 102. At a position near the non-contact end 102a of the inner arm 102, two bends are made upwards in parallel and then folded in parallel towards the direction of the terminal 101 and extended for a section, and then folded downwards in parallel and extended for a section. Disconnection parts five 103f and 104f are provided at the end. Auxiliary moving contacts 105 and 106 are correspondingly arranged at the disconnection parts five 103f and 104f. One end of the auxiliary moving contacts 105 and 106 is connected to the disconnection parts five 103f and 104f when the circuit breaker is closed. When the circuit breaker is opened, the auxiliary moving contacts 105 and 106 can be driven by the moving contact 2 to rotate and separate from the disconnection parts five 103f and 104f, and the auxiliary moving contacts 105 and 106 are between the lower bottom end d and the upper top end c of the outer arms 103 and 104.

[0074] In the closed state, the auxiliary moving contact is between the lower bottom end d and the upper top end c of the outer arm. The current direction of the auxiliary moving contact is the same as that of the lower bottom end d of the outer arm and opposite to that of the upper top end c of the outer arm. The electrodynamic forces of the lower bottom end d and the upper top end c of the outer arm on the conductive circuit of the auxiliary moving contact both make the auxiliary moving contact tend to rotate counterclockwise, pressing the auxiliary moving contact towards the disconnection point. The structures of other parts are the same as those in Embodiment 2, and no further detailed description will be given here;

[0075] Embodiment 5

[0076] As shown in the appendix Figure 15b As shown, on the basis of Embodiment 4, in this embodiment, the outer arms 103 and 104 can also extend from one end connecting the terminal 101 towards the non-contact end 102a of the inner arm 102. At a position near the non-contact end 102a of the inner arm 102, one bend is made upwards and then folded towards the direction of the terminal 101 and extended for a section, and then folded downwards and extended for a section. Disconnection parts five 103f and 104f are provided at the end; the structures of other parts are the same as those in Embodiment 4, and no further detailed description will be given here;

[0077] Embodiment 6

[0078] In the above Embodiments 2, 3, 4, and 5, one of the two outer arms is a short-circuit conductor. As shown in the appendix Figure 16 As shown, on the basis of Embodiment 2, in this embodiment, one of the two outer arms 103 and 104 is provided with a disconnection part two 103c, and the other outer arm is a short-circuit conductor. One end of the short-circuit conductor is connected to the terminal 101, and the other end is connected to the non-contact end 102a of the inner arm 102. The structures of other parts are the same as those in Embodiment 2, and no further detailed description will be given here;

[0079] When it is turned on, the short - circuit conductor is above the moving contact 2 and has the same height as the corresponding auxiliary moving contact on the other outer arm. When a short - circuit occurs, since the current directions of the two outer arms 103, 104 are the same as that of the moving contact, the two outer arms 103, 104 simultaneously provide an upward suction force to the moving contact 2, accelerating the repulsion of the moving contact. Since the short - circuit conductor has a simple structure, the structure is simplified and the cost is reduced.

[0080] Embodiment 7

[0081] Based on the above - mentioned Embodiment 6, as shown in the appendix Figure 17 shown, the short - circuit conductor can also be one end connected to the terminal 101 and the other end connected to the non - contact end 102a of the inner arm 102; when it is turned on, the short - circuit conductor is above the moving contact 2 and higher than the heights of the auxiliary moving contacts 105, 106. When a short - circuit occurs, since the current directions of the auxiliary moving contacts 105, 106 are the same as that of the moving contact 2, an upward suction force is provided to the moving contact 2, accelerating the repulsion of the moving contact 2. When the moving contact 2 drives the auxiliary moving contacts 105, 106 to disconnect after repulsion, since the current direction of the short - circuit conductor is the same as that of the moving contact 2 and it is close to the moving contact 2 at this time, it continues to provide an upward suction force to the moving contact 2, accelerating the repulsion of the moving contact. Since the short - circuit conductor has a simple structure, the structure is simplified and the cost is reduced.

[0082] Embodiment 8

[0083] Based on the above - mentioned Embodiment 6, as shown in the appendix Figure 18 shown, one of the two outer arms 103, 104 is provided with a disconnection part three 103d, and the other outer arm is a short - circuit conductor. One end of the short - circuit conductor is connected to the terminal 101 and the other end is connected to the non - contact end 102a of the inner arm 102, and the length of the short - circuit conductor is the distance from the terminal 101 to the non - contact end 102a of the inner arm 102. Other structures are the same as those in Embodiment 5 and will not be further described in detail here;

[0084] When it is turned on, all the current flows through the inner arm 102, and the repulsive force on the moving contact 2 does not decrease. The length of the short - circuit conductor is the shortest distance allowed in the actual static contact space from the terminal 101 to the non - contact end 102a of the inner arm 102, further simplifying the structure and reducing the cost.

[0085] Embodiment 9

[0086] Based on the above - mentioned Embodiment 8, as shown in the appendix Figure 19 shown, one end of the short - circuit conductor is connected to the terminal 101 and the other end is connected to the contact end 102b of the inner arm 102. And the length of the short - circuit conductor is the distance from the terminal 101 to the contact end 102b of the inner arm 102;

[0087] When it is turned on, the current flowing through the inner arm 102 decreases, the repulsive force on the moving contact decreases, and the length of the short - circuit conductor is the shortest distance from the terminal 101 to the contact end 102b of the inner arm 102 that is allowed in the actual static contact space, which further simplifies the structure and reduces the cost.

[0088] Embodiment 10

[0089] As shown in the Figure 20 accompanying figure, in the above - mentioned Embodiment 1, one of the outer arms 103, 104 is a short - circuit conductor;

[0090] One end of the short - circuit conductor is connected to the terminal 101, and the other end is connected to the non - contact end 102a of the inner arm 102. When it is turned on, the short - circuit conductor is located above the moving contact 2;

[0091] When it is turned on, the short - circuit conductor is above the moving contact 2. When a short - circuit occurs, since the current directions of the short - circuit conductor and the moving contact are the same, the short - circuit conductor provides an upward suction force to the moving contact 2, accelerating the repulsion of the moving contact. Since the structure of the short - circuit conductor is simple, the structure is simplified and the cost is reduced.

[0092] Embodiment 11

[0093] As shown in the Figure 21 accompanying figure, in the above - mentioned Embodiment 10, one end of the short - circuit conductor can also be connected to the terminal 101, and the other end is connected to the non - contact end 102a of the inner arm 102, and the length of the short - circuit conductor is the distance from the terminal 101 to the corresponding non - contact end 102a of the inner arm 102.

[0094] When it is turned on, all the current flows through the inner arm 102, the repulsive force on the moving contact 2 does not decrease, and the length of the short - circuit conductor is the shortest distance from the terminal 101 to the non - contact end 102a of the inner arm 102 that is allowed in the actual static contact space, which further simplifies the structure and reduces the cost.

[0095] Embodiment 12

[0096] As shown in the Figure 22 accompanying figure, in the above - mentioned Embodiment 10, one end of the short - circuit conductor can also be connected to the terminal 101, and the other end is connected to the contact end 102b of the inner arm 102, and the length of the short - circuit conductor is the distance from the terminal 101 to the corresponding contact end 102b of the inner arm 102.

[0097] When connected, the current flowing through the inner arm 102 decreases, the repulsive force on the moving contact decreases, and the length of the short-circuit conductor is the shortest distance from the wiring terminal 101 to the contact end 102b of the inner arm 102 that is allowed in the actual static contact space, further simplifying the structure and reducing the cost.

[0098] It should be noted that increasing the total resistance of the circuit breaker can enhance the current-limiting effect and improve the breaking capacity. For example, the total resistance of the circuit breaker can be increased by increasing the resistance of the static contact. However, increasing the total resistance of the circuit breaker will increase heat generation and power consumption. If the total resistance of the circuit breaker is only increased during breaking, the effect will be better. To increase the total resistance of the circuit breaker only during breaking, one of the outer arms is designed as a short-circuit conductor. The two outer arms were originally in parallel, and the resistance after parallel connection was small. During a short circuit, after the moving contact repels and drives the outer arm with the auxiliary moving contact to disconnect, the current all flows through the short-circuit conductor, increasing the resistance of the static contact, increasing the total resistance of the circuit breaker, enhancing the current-limiting effect, and improving the breaking capacity. In the embodiment of the present invention, when the resistance of the short-circuit conductor is twice the resistance of the other outer arm, the current flowing through the other outer arm increases slightly compared to when their resistances are the same. And after the moving contact repels and drives the outer arm with the auxiliary moving contact to disconnect, the resistance of the static contact increases more, and the breaking effect is more obvious. As the resistance of the short-circuit conductor increases, the total resistance of the circuit breaker increases more during breaking. However, if the resistance of the short-circuit conductor is too large, more current will flow through the auxiliary moving contact of the outer arm, increasing the cross-sectional area of the moving contact, increasing the requirements for the spring, and also increasing the space requirements. Therefore, the resistance of the short-circuit conductor is preferably not greater than 5 times the resistance of the other outer arm.

[0099] At the same time, since there is also an arc during the auxiliary breaking of the auxiliary moving contact, in this embodiment, the auxiliary moving contact can also be equipped with an arc extinguishing chamber. As shown in the appendix Figure 23a As shown, the grid pieces of the existing arc extinguishing chamber include an extension part, which is located in the extension part of the insulating cover. Its structure is based on the existing arc extinguishing chamber shown. As shown in the appendix Figure 23b As shown, the extension part of the insulating cover is lengthened to accommodate the auxiliary moving contacts 105 and 106. A groove is opened at the end face I of the extension part of the insulating cover to allow the auxiliary moving contact to move in the groove. The end face of the grid piece extension part II is preferably concave to facilitate the arc to enter the grid piece; or arc extinguishing chambers are installed separately. An arc extinguishing chamber is installed at the moving contact, and an arc extinguishing chamber is installed at the auxiliary moving contact.

[0100] In the description of this specification, the description with reference to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0101] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A contact system for a low-voltage circuit breaker, which includes a static contact (1) and a moving contact (2). The static contact (1) includes a terminal (101), an inner arm (102), and outer arms (103, 104). At least two outer arms (103, 104) are connected in parallel, with one end connected to the terminal (101) and the other end connected to the non-contact end (102a) of the inner arm (102). The contact end (102b) of the inner arm (102) is located between the terminal (101) and the non-contact end (102a) of the inner arm (102). It is characterized in that: At least one of the outer arms (103, 104) is provided with a disconnection part (103a, 104a), and an auxiliary moving contact (105, 106) is correspondingly arranged for the disconnection part (103a, 104a). One end of the auxiliary moving contact (105, 106) connects the disconnection part (103a, 104a) when the circuit breaker is closed. When the circuit breaker is tripped, the auxiliary moving contact (105, 106) can be driven by the moving contact (2) to separate from the disconnection part (103a, 104a). The other end of the auxiliary moving contact (105, 106) is electrically connected to the non-contact end (102a) of the inner arm (102). The process of the auxiliary moving contact (105, 106) being driven by the moving contact (2) to separate from the disconnection part (103a, 104a) when the circuit breaker is tripped includes a first stage and a second stage. In the first stage, when the circuit breaker is tripped and the moving contact (2) and the static contact (1) start to separate, the auxiliary moving contact (105, 106) still connects the disconnection part (103a, 104a). In the second stage, after the moving contact (2) and the static contact (1) are separated by a certain distance when the circuit breaker is tripped, the auxiliary moving contact (105, 106) is driven by the moving contact (2) to separate from the disconnection part (103a, 104a).

2. A contact system for a low-voltage circuit breaker as claimed in claim 1, It is characterized in that: The at least two outer arms (103, 104) are located on both sides of the inner arm (102). The contact end (102b) of the inner arm (102) corresponds to the moving contact (2). During the rotation of the moving contact (2), it can achieve connection and disconnection with the contact end (102b) of the inner arm (102).

3. A contact system for a low-voltage circuit breaker as claimed in claim 1, It is characterized in that: The static contact (1) further includes brackets (107, 108) and track plates (109, 110). Track grooves (109a, 110a) are provided on the track plates (109, 110). The auxiliary moving contacts (105, 106) are pivotally installed on the corresponding brackets (107, 108). The auxiliary moving contacts (105, 106) are connected with torsion springs and use the pressure provided by the torsion springs to keep connecting the disconnection parts (103a, 104a). When the auxiliary moving contacts (105, 106) are closed, they are located below the moving contact (2). A driving part (a) is installed on the moving contact (2), a follower part (105a, 106a) is provided on the auxiliary moving contacts (105, 106), and during the breaking process of the moving contact (2) and the contact end (102b) of the inner arm (102), the driving part (a) can drive the follower part (105a, 106a) to separate the auxiliary moving contacts (105, 106) from the breaking parts (103a, 104a). The driving part (a) includes a rotating shaft (201), both ends of the rotating shaft (201) are connected to a driving shaft (203) through side plates (202), both ends of the driving shaft (203) pass through the side plates (202) and extend out of the track grooves (109a, 110a) to be linked with the follower parts (105a, 106a) on the auxiliary moving contacts (105, 106), and the follower parts (105a, 106a) are arranged at the rear side position of the pivot center on the auxiliary moving contacts (105, 106). The driving shaft (203) is located below the moving contact (2) and on the upper surface side of the auxiliary moving contacts (105, 106), and during the rotation of the rotating shaft (201), it can drive the driving shaft (203) to move in the track grooves (109a, 110a). The brackets (107, 108) and the track plates (109, 110) are installed at one end where the outer arms (103, 104) are connected to the inner arm (102).

4. A contact system of a low-voltage circuit breaker according to claim 1, characterized in that: The structure of the outer arms (103, 104) can also be extended from one end connecting the terminal (101) towards the non-contact end (102a) of the inner arm (102), bent downward near the non-contact end (102a) of the inner arm (102) and then bent towards the terminal (101) direction and extended for a section and then bent upward for a section, and a first breaking part (103b, 104b) is arranged at the end of the upward-bent section, or extended from one end connecting the terminal (101) towards the non-contact end (102a) of the inner arm (102), bent upward near the non-contact end (102a) of the inner arm (102) and then bent towards the terminal (101) direction and extended for a section, and a fourth breaking part (103e, 104e) is arranged at the end, or extended from one end connecting the terminal (101) towards the non-contact end (102a) of the inner arm (102), bent upward near the non-contact end (102a) of the inner arm (102) and then bent towards the terminal (101) direction and extended for a section and then bent downward and extended for a section, and a fifth breaking part (103f, 104f) is arranged at the end. A driving part one (a') is installed on the moving contact (2). The driving part one (a') includes a driving shaft one (201'). A follower part one (105a', 106a') is provided on the auxiliary moving contacts (105, 106). The follower part one (105a', 106a') is arranged at a position on the auxiliary moving contacts (105, 106) that is on the front side of the pivot center. During the breaking process of the moving contact (2) and the contact end (102b) of the inner arm (102), the driving shaft one (201') can drive the follower part one (105a', 106a') to separate the auxiliary moving contacts (105, 106) from the corresponding breaking part one (103b, 104b) or breaking part four (103e, 104e) or breaking part five (103f, 104f). The brackets (107, 108) are installed on the circuit breaker. The auxiliary moving contacts (105, 106) are pivotally installed on the brackets (107, 108). When the auxiliary moving contacts (105, 106) are closed, they are located above the moving contact (2).

5. A contact system of a low-voltage circuit breaker according to claim 4, characterized in that: The breaking part four (103e, 104e) is correspondingly provided with the auxiliary moving contacts (105, 106). One end of the auxiliary moving contacts (105, 106) is connected to the breaking part four (103e, 104e) when the circuit breaker is closed. When the circuit breaker is opened, the auxiliary moving contacts (105, 106) can be driven by the moving contact (2) to rotate and separate from the breaking part four (103e, 104e). The length of the auxiliary moving contacts (105, 106) behind the pivot center (o) is greater than the length in front of the pivot center (o).

6. A contact system of a low-voltage circuit breaker according to claim 4, characterized in that: The breaking part five (103f, 104f) is correspondingly provided with the auxiliary moving contacts (105, 106). One end of the auxiliary moving contacts (105, 106) is connected to the breaking part five (103f, 104f) when the circuit breaker is closed. When the circuit breaker is opened, the auxiliary moving contacts (105, 106) can be driven by the moving contact (2) to rotate and separate from the breaking part five (103f, 104f), and the auxiliary moving contacts (105, 106) are between the lower bottom end (d) and the upper top end (c) of the outer arms (103, 104).

7. A contact system of a low-voltage circuit breaker according to claim 4, characterized in that: One of the outer arms (103, 104) is a short-circuit conductor; One end of the short - circuit conductor is connected to the terminal (101), and the other end is connected to the non - contact end (102a) of the inner arm (102). When it is switched on, the short - circuit conductor is located above the moving contact (2), and the short - circuit conductor is higher than or equal to the height of the auxiliary moving contacts (105, 106). Or one end of the short - circuit conductor is connected to the terminal (101), and the other end is connected to the non - contact end (102a) or the contact end (102b) of the inner arm (102), and the length of the short - circuit conductor is the distance from the terminal (101) to the corresponding non - contact end (102a) or contact end (102b) of the inner arm (102).

8. A contact system of a low - voltage circuit breaker according to claim 3, characterized in that: One of the outer arms (103, 104) is a short - circuit conductor; One end of the short - circuit conductor is connected to the terminal (101), and the other end is connected to the non - contact end (102a) of the inner arm (102). When it is switched on, the short - circuit conductor is located above the moving contact (2). Or one end of the short - circuit conductor is connected to the terminal (101), and the other end is connected to the non - contact end (102a) or the contact end (102b) of the inner arm (102), and the length of the short - circuit conductor is the distance from the terminal (101) to the corresponding non - contact end (102a) or contact end (102b) of the inner arm (102).

9. A contact system of a low - voltage circuit breaker according to claim 7 or 8, characterized in that: The resistance of the short - circuit conductor is greater than or equal to the resistance of the other outer arm.

10. A contact system of a low - voltage circuit breaker according to claim 9, characterized in that: The resistance value of the short - circuit conductor is between 2 and 5 times the resistance value of the other outer arm.

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