An electric switch magnetic tripping device

Abstract

The application provides a magnetic tripping device of an electric switch, the electric switch at least comprising an insulating shell and internal elements, the internal elements at least comprising: a magnetic tripping device, an overload protection device, a moving contact device, a stationary contact device, the magnetic tripping device at least comprising: a core assembly and a coil wound in a spiral shape outside the core assembly, the coil is arranged in multiple layers, at least comprising a first layer of coil close to the core assembly and a second layer of coil wound outside the first layer of coil, the number of turns of the first layer of coil and the second layer of coil is same or different; the cross-sectional area of the first layer of coil and the second layer of coil is same or different, at least one end of the first layer of coil and the second layer of coil is electrically connected to each other, the multiple layers of coil can pass current at the same time, the current carrying capacity is greatly increased, more ampere-turns can be obtained, higher inductance and higher magnetic field generated on the core assembly can be provided, the short-circuit breaking capacity is improved, the multiple layers of coil has more surface area, the current carrying capacity is obviously increased under the effect of skin effect, and the heat dissipation performance is also greatly improved.

Description

Technical Field

[0001] This invention relates to the field of low-voltage electrical appliances, and more specifically to a magnetic tripping device for an electrical switch. Background Technology

[0002] There are two types of magnetic tripping devices for electrical switches in the prior art. The first type is a spiral coil sleeved on the outer layer of the iron core assembly. The magnetic field generated by the energization of the spiral coil magnetizes the iron core assembly, causing the push rod inside the iron core assembly to push outward, thereby driving the switch to trip. The second type is to use a conductor to partially surround the iron core inside the electrical switch. Magnetic plates are set on both sides of the iron core, and an armature is set on one side of the magnetic plates. The magnetic field generated by the current passing through the conductor magnetizes the iron core. The magnetic field is conducted to the magnetic plates, and the magnetic plates attract the armature, thereby driving the switch to trip.

[0003] The key factor affecting the tripping speed of a switch during a short circuit is the number of turns in the coil, also known as the ampere-turns. The higher the ampere-turns, the faster the tripping. Setting more turns within a limited space can improve the tripping speed of a short circuit and also induce an electromotive force to suppress the rise rate of the short circuit current. This reduces the Joule integral of the time the switch withstands the short circuit current and the magnitude of the current, thus limiting the current.

[0004] In the two existing magnetic tripping devices, the spiral coil is generally a single-layer coil, which cannot be wound with a large number of turns within the limited space of the switch, resulting in a small ampere-turns. Especially when the rated current is slightly higher, the coil diameter increases and the winding process becomes difficult. Magnetic tripping devices using a conductor semi-encased iron core structure have a small ampere-turns due to insufficient turns. Because of the small ampere-turns of the magnetic tripping devices mentioned above, the induced electromotive force generated when current passes through is small, and the ability to limit short-circuit current is very weak. The magnetic field generated by the small ampere-turns is also small, and the tripping speed is slow. The Joule integral generated during short-circuit breaking is high, resulting in poor short-circuit breaking capacity. Summary of the Invention

[0005] Based on the above background, in order to solve the above problems, the present invention provides a magnetic tripping device for an electrical switch, which can solve the problems of achieving a larger ampere-turns in a limited space to improve the tripping speed of the switch and increasing the induced electromotive force to limit the rise rate of the short-circuit current, thereby improving the short-circuit breaking capacity of the switch, while reducing the difficulty of coil winding process and overcoming the above problems.

[0006] The present invention is as follows: This invention discloses a magnetic tripping device for an electrical switch. The electrical switch includes at least an insulating shell and internal components. The internal components include at least a magnetic tripping device, an overload protection device, a moving contact device, and a stationary contact device. The magnetic tripping device includes at least an iron core assembly and a coil wound in a spiral shape around the iron core assembly. The coil is arranged in multiple layers, including at least a first layer of coil adjacent to the iron core assembly and a second layer of coil wound around the first layer of coil. The number of turns of the first layer of coil and the second layer of coil may be the same or different. The cross-sectional areas of the first layer of coil and the second layer of coil may be the same or different. At least one end of the first layer of coil and the second layer of coil are electrically connected to each other.

[0007] In this way, when the switch breaks a short circuit, the sudden increase in current is prevented from rising rapidly by the induced electromotive force generated after the coil winding is energized. Before the current reaches the expected peak short-circuit current, the switch can complete the breaking process and cut off the short-circuit current, significantly reducing the Joule integral generated by the short-circuit current. The multi-layer coil winding structure enhances the superposition of the induced electromotive force and provides a larger ampere-turns, making the magnetic field generated by the coil stronger and improving the tripping speed of the switch, thereby improving the breaking capacity of the switch. The multi-layer coil setting, with each layer carrying its own current, increases the overall current carrying capacity. In particular, the increased surface area of ​​the multi-layer coil significantly improves the current carrying capacity under the skin effect of alternating current. At the same time, the increased surface area in contact with the air also greatly improves the heat dissipation effect, making the switch generate less heat.

[0008] In some embodiments, the cross-sectional area of ​​the first layer coil is smaller than that of the second layer coil.

[0009] In the above embodiments, the wire diameter or cross-sectional area of ​​the first layer coil is smaller than that of the second layer coil. The wire diameter or cross-sectional area of ​​the coil is proportional to the current carrying capacity. When the rated current is high, the wire used is thicker, which makes winding difficult. Especially when space is limited, the inner diameter of the spiral tube is small, and the winding process of thick wire is difficult. It is simpler to use copper wire with a smaller wire diameter or cross-sectional area for the first layer winding process.

[0010] In some embodiments, the first layer of coils has more turns than the second layer of coils.

[0011] In the above embodiments, the number of turns of the first layer coil adjacent to the iron core is greater than that of the second layer coil. In other embodiments, the wire diameter or cross-sectional area of ​​the first layer coil adjacent to the iron core is smaller than that of the second layer coil. When the wire diameter or cross-sectional area is smaller, more turns can be wound. The magnetic field generated by the first layer coil with more turns acting on the iron core is weaker than that generated by the second layer coil which is separated from the iron core by the first layer coil. In order to make more efficient use of the magnetic field, the number of turns of the first layer coil adjacent to the iron core is set as large as possible, which is beneficial to enhance the magnetization efficiency of the multi-layer current limiting coil device on the iron core.

[0012] In some embodiments, the cross-sectional shape of the coil is at least one of circular, flat, rectangular, and square.

[0013] In the above embodiments, the cross-sectional shape of the coil is related to the selection of raw materials for the coil. Generally, it is enameled wire, which can be round or flat. Round wire is suitable for switches with a rated current of less than 63A. Flat wire has a larger cross-sectional area in the same space than round wire and is suitable for switches with a rated current of more than 63A. Among the coils with a specification of 100A or above, there are also coils with a rectangular cross-section formed by copper plates. The shape of the cross-section can be selected according to the actual requirements.

[0014] In some embodiments, the spiral portions of the first layer coil and the second layer coil are insulated from each other.

[0015] In the above embodiments, the spiral portion of the wound coil is used to superimpose a magnetic field to form an induced electromotive force, which impedes a sudden increase in current and plays a current-limiting role. It also generates a magnetic field that acts on the iron core to drive the switch to trip and improve the tripping speed. The spiral portions must be insulated from each other to prevent short circuits from forming between the turns of the spiral portions, which would prevent the magnetic field from being superimposed and thus lose its effect. Measures to prevent them from being insulated from each other can be to use enameled wire for winding, or to coat an insulating layer after winding, or to arrange the spiral portions with gaps.

[0016] In some embodiments, the first layer coil and the second layer coil are connected in parallel.

[0017] In the above embodiment, the two layers of coils are connected in parallel, and each layer of coil carries current separately, which plays a role in current shunting and increases the current carrying capacity of the electrical switch. Each layer of coil is equivalent to an independent inductor, generating its own induced electromotive force. While increasing the current carrying capacity of the electrical switch, it also provides inductive current limiting. The parallel connection of the input and output pins between the multiple layers of coils can effectively improve the current carrying capacity of the electrical switch, and at the same time provide a superimposed magnetic field effect, which enhances the induced electromotive force and magnetic field force to limit the short-circuit current and improve the tripping speed of the switch, effectively improving the short-circuit breaking capacity of the electrical switch.

[0018] In some embodiments, the core assembly is an independent core, with magnetic plates at both ends of the core and an armature on one side of the magnetic plate that can form a closed magnetic circuit with the core assembly.

[0019] In the above embodiment, since the core assembly is located at the center of the multilayer coil, the induced magnetic field generated after the coil is energized will magnetize the core assembly. Magnetic plates are set at both ends of the core assembly, and the magnetic field of the core assembly is conducted to the magnetic plates. The magnetic field on the magnetic plates can be used to generate a magnetic blowing force on the arc interrupted by the switch, accelerating the arc into the arc extinguishing chamber. On the other hand, the magnetic force is used to drive the armature for short circuit protection. The magnetic plates conduct the magnetic field on the core to the required position to achieve the required function, providing short circuit protection and magnetic arc extinguishing function at the same time.

[0020] In some embodiments, the core assembly includes at least a moving core, a stationary core, and an ejector section.

[0021] In the above embodiments, the multilayer coil generates a magnetic field on the iron core after being energized. The electromagnetic attraction of the iron core is used to drive the electrical switch to trip and open, thereby achieving overcurrent protection. The ampere-turns generated by the multilayer coil are higher than those of the single-layer coil, and the switch trips faster.

[0022] In some embodiments, the ratio of the cross-sectional area of ​​the first layer coil to that of the second layer coil is 4:6, 3:7, or 2:8.

[0023] In the above embodiment, the cross-sectional area of ​​the first layer coil adjacent to the iron core is smaller than that of the second layer coil. On the one hand, this simplifies the winding process, and on the other hand, the first layer coil can be wound with more turns in a limited space. The induced magnetic field generated by the iron core coil adjacent to the first layer coil directly acts on the iron core, resulting in higher magnetization efficiency. The specific ratio of cross-sectional areas can be matched according to the cross-sectional area required for conduction and the magnitude of the required induced electromotive force. Using a coil with a relatively small cross-sectional area in the first layer can reduce the difficulty of coil winding and increase the number of turns. By changing the cross-sectional area between multiple layers, the current carrying capacity and the intensity of the induced electromotive force of the multi-layer coil current limiting device can be adjusted, thereby improving the current limiting capacity while meeting the requirements of large capacity.

[0024] By adopting a multi-layer helical coil structure, a larger ampere-turns can be achieved in a limited space. Each multi-layer helical coil can carry current and generate induced electromotive force to limit the rise rate of short-circuit current. On the one hand, it meets the current carrying capacity of high-current products, and on the other hand, it improves the breaking capacity of the switch by increasing the tripping speed of the switch and limiting the rise rate of short-circuit current.

[0025] By shunting the current through multi-layer helical coils, the problem of the difficulty in winding helical coils with excessively large cross-sectional areas for high rated current can be solved. By shunting the current through multiple layers of coils, the cross-sectional area of ​​each layer of helical coil can be reduced and the number of turns can be increased, which not only solves the manufacturing process problem, but also enhances the current limiting capability of the inductor. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the internal structure of an electric switch according to the first embodiment of the present invention; Figure 2 This is a schematic diagram of the magnetic tripping device according to the first embodiment of the present invention; Figure 3 This is a schematic diagram of the internal structure of the magnetic tripping device according to the second embodiment of the present invention; Figure 4 This is a schematic diagram of the internal structure of an electric switch according to the third embodiment of the present invention; Figure 5 This is a cross-sectional view of the magnetic tripping device according to the third embodiment of the present invention.

[0028] 10: Insulating outer shell; 20: Multi-layer coil current limiting device; 201: Inner coil; 202: Outer coil; 205: Iron core; 30: Incoming terminal; 301: Incoming terminal block; 40: Overcurrent protection device; 401: Armature; 402: Magnetic guide plate; 403: Armature spring; 50: Stationary contact; 60: Moving contact; 70: Operating mechanism; 80: Outgoing terminal; 90: Overload protection device; 2051: Moving iron core; 2052: Top part; 2053: Stationary iron core; 2054: Iron core spring. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this invention. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this invention, and should not be construed as limiting the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0030] In the description of embodiments of this disclosure, the term "comprising" and similar terms should be understood as open-ended inclusion, i.e., "including but not limited to". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below. Example

[0031] like Figure 1 and Figure 2 As shown, this embodiment provides a magnetic tripping device 20 for an electric switch. The electric switch includes at least an insulating shell 10 and internal components. The internal components include at least: a magnetic tripping device 20, an overload protection device 90, a moving contact device 60, a stationary contact device 50, an inlet terminal 30, an outlet terminal 80, and an operating mechanism 70. The magnetic tripping device 20 includes at least a core assembly 205, a coil wound spirally around the core assembly, an armature 401, an armature spring 403, and a magnetic guide plate 402. The coil is arranged in multiple layers, including at least a first layer coil 201 adjacent to the core assembly 205 and a second layer coil 202 wound around the first layer coil 201. The cross-sectional areas of the first layer coil 201 and the second layer coil 202 are different. Preferably, the cross-sectional area of ​​the first layer coil 201 is larger than that of the second layer coil 202. At least one end of the first layer coil 201 and the second layer coil 202 are electrically connected. The cross-sectional shape of the coil is rectangular. After the input pin 2011 is soldered together with the input pin 2021 of the second layer coil 202, it is electrically connected to the input terminal 30. After the output pins 2012 of the first layer coil 201 and 2022 of the second layer coil 202 are soldered together, they are electrically connected to the stationary contact device 50. The other parts of the first layer coil 201 and the second layer coil 202 are insulated from each other, so that the first layer coil 201 and the second layer coil 202 form a parallel relationship. The spiral parts of the coils are insulated from each other. The insulation method can be to set an insulating coating on the surface of the coil, or the coil can be wound with gaps. The iron core assembly 205 is an independent iron core assembly. The magnetic guide plate 402 is disposed at both ends of the iron core assembly 205. The armature 401 is disposed on one side of the magnetic guide plate 402 and can form a closed magnetic circuit with the iron core assembly 205. The armature spring 403 is disposed between the armature 401 and the magnetic guide plate 402. The armature spring 403 is used to keep the armature 401 and the magnetic guide plate 402 in an open state.

[0032] It should be noted that the number of coil layers of the magnetic tripping device 20 in this application is not limited to two layers, but can be three, four or more layers. Those skilled in the art can configure it according to the needs of current carrying capacity and the required ampere-turns.

[0033] In this embodiment, the first layer coil 201 and the second layer coil 202 of the magnetic tripping device 20 have the same number of turns, and the cross-sectional area of ​​the first layer coil 201 is smaller than that of the second layer coil.

[0034] It should be noted that the coil of the magnetic tripping device 20 of this application can be composed of two coils with the same number of turns, or two or more coils with different numbers of turns. The number of turns is configured according to the cross-sectional area of ​​the coil and the difficulty of winding. The larger the cross-sectional area of ​​the coil, the more difficult it is to wind, especially when the diameter of the spiral tube of the spiral coil is small. From the perspective of processing technology, using copper wire with a slightly smaller cross-sectional area for the first layer of coil close to the iron core assembly not only greatly reduces the winding difficulty, but also increases the number of turns. In particular, the first layer of coil is set close to the iron core, so its magnetic field effect on the iron core is the strongest and the efficiency is the highest. It should also be noted that the cross-sectional area of ​​the coil directly affects the current carrying capacity. The higher the rated current of the electrical switch, the larger the cross-sectional area required. The cross-sectional area of ​​two or more layers of coils can carry higher current. Compared with a single-layer coil structure, a multi-layer coil has more surface area and a stronger current carrying capacity under the skin effect of alternating current.

[0035] When a short-circuit current occurs in the circuit, the magnetic trip device 20 experiences a sudden increase in current. Utilizing the increased magnetic field generated by the current passing through the coil, the core assembly 205, induced by the magnetic field, transmits the magnetic field to the magnetically conductive plates 402 on both sides. The magnetically conductive plates 402 attract the armature 401 located on one side. The armature 401 overcomes the elastic force of the armature spring 403, causing the armature 401 to engage with the magnetically conductive plate 402, thereby driving the operating mechanism 70 of the electrical switch to trip and open. The moving contact device 50 separates from the stationary contact device 60 to cut off the fault current. The magnetic trip device 20 utilizes the magnetic field generated by the multi-layer coil acting on the core assembly 205 to provide short-circuit protection while also generating an induced electromotive force to limit the rapid rise of the short-circuit current. This design significantly simplifies the structure and manufacturing process of the components, while saving internal space in the electrical switch. Of course, the multi-layer coil of the magnetic trip device 20 can also be independently configured to generate an induced electromotive force for inductive current limiting, thereby improving the short-circuit breaking capacity of the electrical switch, and is not limited to short-circuit protection.

[0036] In this embodiment, the ratio of the cross-sectional areas of the first layer coil 201 and the second layer coil 202 of the magnetic tripping device 20, which are adjacent to the core assembly 205, is 4:6.

[0037] It should be noted that the cross-sectional areas of each layer of the coil in the magnetic tripping device 20 can be equal or unequal. When they are unequal, the preferred ratio of the cross-sectional area of ​​the first layer coil to the cross-sectional area of ​​the second layer coil can be 4:6, 3:7, or 2:8. When the ratio is unequal, the first layer coil adjacent to the core assembly 205 can be selected to reduce the winding difficulty and increase the number of turns of the inner layer coil. This optimizes the process, increases the ampere-turns and enhances the induced electromotive force to limit the rapid rise of the short-circuit current, and accelerates the tripping speed of the switch to improve the short-circuit breaking capacity.

[0038] The coil has a rectangular cross-sectional shape. The rectangular cross-section coil uses enameled flat wire, which, compared to round enameled wire, achieves a larger cross-sectional area within the same space. This makes it suitable for specifications with higher rated currents, offering better space utilization and current carrying capacity. Example

[0039] like Figure 3 As shown, the difference between this embodiment and the first embodiment is that the cross-section of the coil of the magnetic tripping device 20 is circular, the cross-sectional area of ​​the first layer coil 201 adjacent to the iron core assembly 205 is smaller than that of the second layer coil 202, and the ratio of their cross-sectional areas is approximately 3:7. The number of turns of the first layer coil 201 adjacent to the iron core assembly 205 is more than that of the second layer coil 202. The coil is wound with enameled wire.

[0040] The magnetic tripping device 20 has a circular coil. The coil is wound with enameled round wire, which is cheaper and simpler to wind than enameled flat wire, making it suitable for applications with low rated current and ample internal space. Example

[0041] like Figure 4 and Figure 5As shown, the difference between this embodiment and other embodiments lies in that the coil of the magnetic tripping device 20 has a horizontal structure, and the core assembly 205 includes at least: a moving core 2051, a stationary core 2053, a push rod 2052, and a core spring 2054. The coil includes a first layer of coil 201 and a second layer of coil 202. The core assembly 205 is located at the center of the coil. The input pins (2011 / 2021) and output pins (2012 / 2022) of the first layer of coil 201 and the second layer of coil 202 are connected to each other in parallel. When current flows through the coil, it generates a magnetic field on the moving core 2051 and the stationary core 2053, magnetizing them and causing them to attract each other. The moving core 2051 moves towards the stationary core 2053, and the moving core 2053 drives the push rod 2054. 2. Overcoming the elastic force of the core spring 2054, the spring pushes out to the right, driving the operating mechanism 70 to trip, causing the moving contact device 60 to separate from the stationary contact device 50. The force value of the core spring 2054 is set according to the ampere-turns of the coil. When the current flowing through the coil exceeds the preset current, the generated magnetic field causes the attraction between the moving core 2051 and the stationary core 2053 to overcome the reaction force of the core spring 2054. The push rod 2052 pushes out to the right, driving the operating mechanism 70 to trip, thereby realizing the short circuit protection function. The coil of the magnetic trip device 20 is made of enameled wire and consists of two layers. The two layers of coils are connected in parallel. The cross-sectional area of ​​the first layer coil 201 is smaller than that of the second layer coil 202, and the number of turns of the first layer coil 201 is greater than that of the second layer coil 202. This arrangement simplifies the winding process. Smaller cross-sectional area coils are wound in the first layer, while larger cross-sectional area coils are wound in the outer layer, making winding easier. Placing the coils with more turns in the first layer, close to the moving core 2051 and stationary core 2053, increases magnetic efficiency. The first-layer coil 201 uses enameled wire with a smaller cross-sectional area, allowing for more turns. Combined with the second-layer coil 202, which uses a larger cross-sectional area coil with relatively fewer turns, the resulting ampere-turns are higher than with a single-layer coil. This strengthens the induced electromotive force during short-circuit breaking, resulting in a stronger magnetic field on the core assembly 205. This significantly limits the rapid rise of short-circuit current and accelerates the operating speed of the core assembly 205, thereby improving the short-circuit breaking capability of the electrical switch.

[0042] This invention may be implemented in other specific forms without departing from its spirit and essential characteristics. The present embodiments are to be regarded in all respects as exemplary rather than limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and all modifications falling within the meaning of the claims and their equivalents are thus included within the scope of the invention.

Claims

1. A magnetic tripping device for an electrical switch, the electrical switch comprising at least an insulating housing and internal components, the internal components comprising at least: a magnetic tripping device, an overload protection device, a moving contact device, and a stationary contact device, the magnetic tripping device comprising at least: A core assembly and a coil wound in a spiral shape around the core assembly, characterized in that: the coil is arranged in multiple layers, including at least a first layer of coil adjacent to the core assembly and a second layer of coil wound around the first layer of coil, the first layer of coil and the second layer of coil having the same or different number of turns; the first layer of coil and the second layer of coil having the same or different cross-sectional areas, and at least one end of the first layer of coil and the second layer of coil being electrically connected to each other.

2. The magnetic tripping device for an electrical switch according to claim 1, characterized in that, The cross-sectional area of ​​the first layer coil is smaller than that of the second layer coil.

3. The magnetic tripping device for an electrical switch according to claim 1, characterized in that, The first layer of coils has more turns than the second layer of coils.

4. The magnetic tripping device for an electrical switch according to claim 1, characterized in that, The cross-sectional shape of the coil is at least one of the following: circular, flat, rectangular, and square.

5. The magnetic tripping device for an electrical switch according to claim 1, characterized in that, The spiral portions of the first and second layer coils are insulated from each other.

6. The magnetic tripping device for an electrical switch according to claim 1, characterized in that, The first layer coil and the second layer coil are connected in parallel.

7. The magnetic tripping device for an electrical switch according to claim 1, characterized in that, It also includes a magnetic guide plate and an armature. The core assembly is an independent core. The magnetic guide plate is disposed at both ends of the core assembly, and the armature is disposed on one side of the magnetic guide plate and forms a closed magnetic circuit with the core assembly.

8. The magnetic tripping device for an electrical switch according to claim 1, characterized in that, The core assembly includes at least a moving core, a stationary core, and a top-out section.

9. The magnetic tripping device for an electrical switch according to claim 2, characterized in that, The ratio of the cross-sectional area of ​​the first layer coil to that of the second layer coil is 4:6, 3:7, or 2:8.

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