Direct current contactor contact structure with high short circuit resistance
Through the L-shaped static contact and magnetic ring structure, the current direction is changed, the electric repulsive magnetic field is closed, and the transmission mechanism is combined with the problem of the DC contactor increasing the electric repulsive force at high short circuit current, which significantly improves the short circuit resistance and work resistance. reliability.
Patent Information
- Application Number
- CN202420891075.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-26
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2034-04-26
AI Technical Summary
When existing DC contactors face high short circuit currents, the electrical repulsion increases exponentially, and traditional measures are difficult to meet the demand, and the short circuit resistance of the magnet arrangement is limited, especially in the case of large over-range conditions, the working air gap is large. And the short circuit resistance is low.
The L-shaped static contact and magnetic ring structure are adopted to change the current direction to make the direction of the electric repulsive magnetic field parallel. The magnetic ring is used to retract the electric repulsive magnetic field, combined with the over-range spring and the spring transmission mechanism to improve the short-circuit resistance of the dynamic contact. ability.
It effectively reduces the size of the electrical repulsive magnetic field on the moving contact, improves the short-circuit resistance and working reliability of the DC contactor, is suitable for different over-range situations, and overcomes the defect of the traditional structure's low anti-short resistance when over-range is large.
Smart Images
Figure CN222214069U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of DC contactors, in particular to a DC contactor contact structure with high short-circuit resistance. Background Art
[0002] Contactors are a type of electrical products widely used in power and power distribution, among which DC contactors are components used in DC systems to transfer, control and protect power. The contact system structure of common DC contactors on the market is: two cylindrical static contacts arranged side by side are installed in the arc extinguishing chamber, and the moving contact and transmission mechanism are arranged in the vertical direction. The contact system is driven by the electromagnetic coil and the reaction force system composed of springs to achieve the conduction and disconnection of the contacts.
[0003] When the contact of the contactor is turned on, that is, the moving contact contacts the two stationary contacts and is energized, an electric repulsion will be generated between the moving and stationary contacts. This electric repulsion is mainly due to the fact that after the cylindrical stationary contact is energized, according to Ampere's law, a magnetic field will be generated at the moving contact to repel the current flowing through the moving contact, and the greater the current, the greater the magnetic field, and the greater the product of the magnetic field and the current value of the moving contact, so that the repulsion force on the moving contact is greater, which leads to a decrease in contact pressure or even repulsion.
[0004] At present, the measures commonly taken by the industry to improve the short-circuit current resistance of DC contactors are: by increasing the elastic force of the overtravel spring, increasing the pressure between the moving and static contacts, and thus maintaining the pull-in. However, with the increase in the current short-circuit current level, the electric repulsion increases exponentially, and it is gradually difficult to meet the demand by simply increasing the elastic force of the overtravel spring. In addition, if the elastic force of the overtravel spring is too high, it will also increase the difficulty of the DC contactor to pull in, affect the release process, and lead to poor working stability of the DC contactor.
[0005] In order to further improve the short-circuit current resistance of DC contactors, the measures currently taken in the industry are: by setting two magnets made of ferromagnetic materials, one magnet is fixed on the top bracket or connecting rod of the transmission mechanism, and the other magnet is fixed under the moving contact to follow the movement of the moving contact, and the two magnets are basically facing each other. When the short-circuit current flows through the moving contact, the magnetic circuit gap formed by the short-circuit current between the two magnets is used to provide the moving contact with an electromagnetic suction force to keep it closed. However, although the arrangement structure of the above-mentioned magnets can provide a certain holding force for the moving contact, the holding force is essentially compensated by the electromagnetic suction force of the contactor electromagnetic system. The upper limit of the holding force is the difference between the suction force and the reaction force of the electromagnetic system. The short-circuit resistance generated by the arrangement structure of this magnet is limited. If the electromagnetic suction force of the electromagnetic system is increased, it will be subject to power consumption, volume, saturation of ferromagnetic materials and other problems. At the same time, it is only suitable for DC contactors with smaller overtravel. When the overtravel is large, the working air gap is large, and the holding force it can provide is limited. Utility Model Content
[0006] In order to solve the shortcomings of the background technology, the utility model provides a DC contactor contact structure with high short-circuit resistance. While reducing the electric repulsion magnetic field acting on the moving contact, it also changes the direction of the electric repulsion magnetic field. Through the combined effect of the two, the effective value of the electric repulsion force is effectively reduced, thereby improving the short-circuit resistance and working reliability of the DC contactor.
[0007] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a DC contactor contact structure with high short-circuit resistance, including an arc extinguishing chamber with a closed top and an open bottom, a pair of L-shaped static contacts installed horizontally opposite to each other at the top of the arc extinguishing chamber, a moving contact arranged in the cavity of the arc extinguishing chamber, and a transmission mechanism connected to the bottom of the moving contact, the L-shaped static contact is composed of a cylindrical contact as a vertical arm and a plate-shaped conductor as a horizontal arm, the vertical arms of the two L-shaped static contacts are connected and fixed to the mounting holes preset at the corresponding positions on the top of the arc extinguishing chamber, and magnetic conductive rings are respectively set on the vertical arms of the two L-shaped static contacts, a gap is left between the horizontal arms of the two L-shaped static contacts and are located in the upper part of the cavity of the arc extinguishing chamber, the moving contact is a plate-shaped contact and is arranged in parallel at the lower part of the horizontal arms of the two L-shaped static contacts, and the transmission mechanism connects the moving contact and the armature of the DC contactor.
[0008] Furthermore, the transmission mechanism is composed of a retaining spring, an overtravel spring and a connecting rod. The connecting rod is vertically arranged at the bottom of the arc extinguishing chamber. The top end of the connecting rod extends from bottom to top through a preset center hole of the moving contact. The retaining spring is clamped and fixed in a groove processed at the top end of the connecting rod to limit the moving contact. A positioning plate is integrally arranged in the middle position of the connecting rod. The overtravel spring is mounted on the connecting rod and is compressively supported between the moving contact and the positioning plate.
[0009] Furthermore, the magnetic conductive ring is a closed circular ring made of ferromagnetic material.
[0010] Compared with the prior art, the utility model has the following beneficial effects: the utility model can effectively reduce the magnitude of the electric repulsion magnetic field acting on the moving contact when a short-circuit current is passed through it, and secondly, the direction of the current flowing out of the static contact and flowing into the moving contact is changed from vertical to parallel, which changes the direction of the electric repulsion magnetic field generated by the static contact current, thereby reducing the effective electric repulsion, and effectively reducing the effective value of the electric repulsion through the combined action of the two. In addition, the contact structure of the utility model can make the DC contactor have good working reliability at different overtravels, overcome the disadvantages of the traditional anti-short-circuit structure when the overtravel is relatively large, the working air gap is large, and the anti-short-circuit capability is low, and significantly improve the anti-short-circuit capability and working reliability of the DC contactor. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1It is a front cross-sectional schematic diagram of the contact structure of the utility model in the disconnected working state;
[0012] Figure 2 It is a side cross-sectional schematic diagram of the contact structure of the utility model in the disconnected working state;
[0013] Figure 3 It is an axonometric schematic diagram of the contact structure of the utility model, wherein the arc extinguishing chamber is not shown;
[0014] Figure 4 yes Figure 3 Exploded diagram.
[0015] In the figure: 1-arc extinguishing chamber, 2-L-type static contact, 3-moving contact, 4-magnetic ring, 5-circlip, 6-connecting rod, 7-overtravel spring. DETAILED DESCRIPTION
[0016] The technical solution of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model.
[0017] like Figure 1 to Figure 4 As shown, a DC contactor contact structure with high short-circuit resistance includes an arc extinguishing chamber 1, an L-shaped static contact 2, a moving contact 3, a magnetic ring 4, a retaining spring 5, an overtravel spring 6 and a connecting rod 7.
[0018] The arc extinguishing chamber 1 is a cavity structure with a closed top and an open bottom, and is used for mounting and supporting the L-shaped static contact 2 .
[0019] The L-shaped static contacts 2 are arranged in pairs and installed horizontally relative to each other on the top of the arc extinguishing chamber 1, wherein the L-shaped static contacts 2 are fixed by a combination of conventional cylindrical contacts as vertical arms and plate-type conductors as horizontal arms, and the vertical arms of the two L-shaped static contacts 2 are connected and fixed to the preset mounting holes at the corresponding positions on the top of the arc extinguishing chamber 1, and the horizontal arms of the two L-shaped static contacts 2 are spaced apart and located in the upper part of the cavity of the arc extinguishing chamber 1.
[0020] The moving contact 3 is a plate-shaped contact arranged in the cavity of the arc extinguishing chamber 1 and located at the lower part of the transverse arms of the two L-shaped static contacts 2, thereby ensuring that the moving contact 3 and the transverse arms of the two L-shaped static contacts 2 are parallel to each other, so that the direction of the current flowing out of the L-shaped static contact 2 and flowing into the moving contact 3 is changed from the traditional vertical form to the parallel form, thereby changing the direction of the magnetic field generated by the current of the L-shaped static contact 2 and located at the moving contact 3, which is manifested macroscopically as a change in the direction of the Lorentz force that repels the moving contact 3, thereby reducing the effective electric repulsion.
[0021] It is worth noting that the core of the utility model is that the current direction of the part where the lateral arm of the L-shaped static contact 2 connects with the moving contact 3 is parallel to the conduction current direction of the moving contact 3. The L-shaped static contact 2 is mainly considered that the conventional static contact contact is located at the top of the arc extinguishing chamber 1, which is a preferred form. If a straight-line arrangement is adopted to lead the cylindrical contact out from the side wall of the arc extinguishing chamber 1, the above-mentioned effect can also be achieved, and it should also fall within the protection scope of the utility model.
[0022] The magnetic conductive rings 4 are arranged in pairs and are respectively mounted on the vertical arms of the two L-shaped static contacts 2. The magnetic conductive rings 4 are closed circular rings made of ferromagnetic materials, and their specific dimensions are determined according to the dimensions of the cylindrical contacts of the vertical arms of the L-shaped static contacts 2. The installation positions of the two magnetic conductive rings 4 are not limited, and they can be located inside or outside the cavity of the arc extinguishing chamber 1. They can be connected and fixed to the arc extinguishing chamber 1 or to the cylindrical contacts of the vertical arms of the L-shaped static contacts 2. The two magnetic conductive rings 4 will form a magnetic circuit with very small magnetic resistance, and a large part of the electric repulsive magnetic field originally generated by the short-circuit current can be converged within the two magnetic conductive rings 4.
[0023] In summary, when a short-circuit current is generated, the magnetic field generated by the short-circuit current will act on the moving contact 3 and generate electric repulsion. The magnetic ring 4 arranged on the two L-shaped static contacts 2 will form a magnetic circuit with very small magnetic resistance, which will largely converge the electric repulsion magnetic field originally generated by the short-circuit current within the magnetic ring 4, and then no longer generate repulsion on the moving contact 3, thereby reducing the size of the electric repulsion at the contact position. In addition, due to the structural form of the L-shaped static contact 2, the direction of the current flowing out of the L-shaped static contact 2 and flowing into the moving contact 3 is changed from the traditional vertical form to the parallel form, thereby changing the direction of the magnetic field located at the moving contact 3 generated by the current of the L-shaped static contact 2, which is macroscopically manifested as a change in the direction of the Lorentz force that repels the moving contact 3, thereby reducing the effective electric repulsion. Through the synergistic effect of the two, the Lorentz force that repels the moving contact 3 due to the short-circuit current is greatly reduced, and the short-circuit resistance of the DC contactor is significantly improved.
[0024] The retaining spring 5, the overtravel spring 6 and the connecting rod 7 are combined into a transmission mechanism connected to the bottom of the moving contact 3. When the DC contactor is in operation, the armature drives the transmission mechanism to realize the conduction and disconnection of the moving contact 3 and the two L-shaped static contacts 2. Among them, the connecting rod 7 is vertically arranged at the bottom of the cavity of the arc extinguishing chamber 1, and the top of the connecting rod 7 extends from the bottom to the top through the preset center hole of the moving contact 3. The retaining spring 5 is clamped and fixed at the clamping groove processed at the top of the connecting rod 7 to limit the moving contact 3. A positioning plate is integrally provided in the middle position of the connecting rod 7. The overtravel spring 6 is sleeved on the connecting rod 7 and compressed and supported between the moving contact 3 and the positioning plate. In order to further improve the stability of the overtravel spring 6, an annular groove matching the bottom end of the overtravel spring 6 can be processed on the upper surface of the positioning plate.
[0025] The utility model is provided with an L-shaped static contact 2 and a magnetic ring 4 made of ferromagnetic material. The magnetic ring 4 can well converge the electric repulsion magnetic field generated by the static contact current, thereby reducing the size of the electric repulsion magnetic field actually acting on the moving contact 3. In addition, the special L-shaped static contact 2 can realize that the direction of the current flowing out of the L-shaped static contact 2 is parallel to the direction of the current flowing into the moving contact 3, thereby changing the direction of the electric repulsion magnetic field, and reducing the effective value of the electric repulsion force of the moving contact 3. In addition, the anti-short circuit effect of the structure is not affected by the design parameters such as the contactor opening distance and overtravel, and can still play a role in the case of a large overtravel, and has a wide range of applications. In summary, from the perspective of the generation of electric repulsion, the utility model reduces the electric repulsion magnetic field acting on the moving contact 3 while also changing the direction of the electric repulsion magnetic field. The two work together to effectively reduce the effective value of the electric repulsion force, greatly improving the short circuit resistance and reliable working ability of the DC contactor.
[0026] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other forms of assembly without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes within the meaning and scope of the equivalents of the claims be included in the present invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.
[0027] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.
Claims
1. A DC contactor contact structure with high short-circuit resistance, characterized in that: The invention comprises an arc extinguishing chamber (1) with a closed top and an open bottom, a pair of L-shaped stationary contacts (2) installed horizontally opposite to each other at the top of the arc extinguishing chamber (1), a moving contact (3) arranged in the cavity of the arc extinguishing chamber (1), and a transmission mechanism connected to the bottom of the moving contact (3), wherein the L-shaped stationary contact (2) is composed of a cylindrical contact as a vertical branch arm and a plate-shaped conductor as a horizontal branch arm, the vertical branches of the two L-shaped stationary contacts (2) are connected and fixed to the mounting holes preset at the corresponding positions on the top of the arc extinguishing chamber (1), and magnetic conductive rings (4) are respectively mounted on the vertical branches of the two L-shaped stationary contacts (2), a gap is left between the horizontal branches of the two L-shaped stationary contacts (2) and they are located in the upper part of the cavity of the arc extinguishing chamber (1), the moving contact (3) is a plate-shaped contact and is arranged in parallel at the lower part of the horizontal branches of the two L-shaped stationary contacts (2), and the transmission mechanism connects the moving contact (3) and the armature of the DC contactor.
2. A DC contactor contact structure with high short-circuit resistance according to claim 1, characterized in that: The transmission mechanism is composed of a retaining spring (5), an overtravel spring (6) and a connecting rod (7). The connecting rod (7) is vertically arranged at the bottom of the cavity of the arc extinguishing chamber (1). The top end of the connecting rod (7) extends upward from the bottom through a preset center hole of the moving contact (3). The retaining spring (5) is clamped and fixed at a clamping groove processed at the top end of the connecting rod (7) to limit the moving contact (3). A positioning plate is integrally arranged at the middle position of the connecting rod (7). The overtravel spring (6) is sleeved on the connecting rod (7) and is compressed and supported between the moving contact (3) and the positioning plate.
3. A DC contactor contact structure with high short-circuit resistance according to claim 1, characterized in that: The magnetic conductive ring (4) is a closed circular ring made of ferromagnetic material.