Low-voltage flame-proof main junction box with straight-through mutual inductor and motor
By embedding the through-hole current transformer within an explosion-proof enclosure, the problems of high cost and signal attenuation in existing technologies are solved, enabling efficient installation and stable signal transmission of low-pressure explosion-proof current transformers with through-hole current transformers.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- NANYANG FANGBAO GRP TONGAN FOUNDRY CO LTD
- Filing Date
- 2025-04-29
- Publication Date
- 2026-04-21
AI Technical Summary
In the prior art, the through-hole current transformers of low-voltage explosion-proof motors are usually configured with separate housings and mounting brackets, which leads to increased costs and signal attenuation or interference problems.
The through-hole current transformer is built into the explosion-proof box, sharing the explosion-proof box, avoiding the need for an additional outer shell, and allowing the current transformer to be installed closer to the motor power line, reducing the signal transmission distance.
It reduces costs and complexity, while minimizing or eliminating signal attenuation and interference, thus achieving efficient current monitoring.
Smart Images
Figure CN224154075U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of explosion-proof motor main junction boxes, and in particular to a low-voltage explosion-proof main junction box with a through-type current transformer and a motor. Background Technology
[0002] With the development of the times, electricity is increasingly widely used in social life, especially in industrial production. As a power source, electric motors have a wider range of applications. Electric motors can be divided into ordinary electric motors and explosion-proof electric motors according to requirements. In some flammable and explosive places, low-voltage explosion-proof motors have become the preferred power equipment. However, many users or design institutes in the market require the motor to be explosion-proof as a whole and equipped with a through-type current transformer. In order to meet the market requirements for the motor to be explosion-proof as a whole and equipped with a through-type current transformer, the existing technology often places the transformer outside the junction box, adds a separate explosion-proof shell, and separately configures the transformer mounting bracket and protective cover. This is more complicated and increases costs. At the same time, installing the transformer far away from the motor power line may cause signal attenuation or interference due to long-distance transmission.
[0003] Therefore, how to provide a low-voltage explosion-proof main junction box with a through-type current transformer to at least partially solve the above-mentioned drawbacks is a technical problem that needs to be solved by those skilled in the art. Utility Model Content
[0004] The purpose of this utility model is to provide a low-voltage explosion-proof main junction box and motor with a through-type current transformer. The built-in through-type current transformer can share the explosion-proof box, avoiding the cost and complexity of adding an additional explosion-proof shell. The through-type current transformer is installed closer to the motor power line, which can reduce or even avoid signal attenuation or interference caused by long-distance transmission.
[0005] To achieve the above objectives, this utility model provides a low-voltage explosion-proof main junction box with a through-type instrument transformer, comprising:
[0006] The box body includes a box base and a box cover. The box base has an internal cavity, and the top of the box base has a first opening communicating with the cavity. The box cover is detachably installed at the first opening so that the cavity forms an explosion-proof environment.
[0007] The through-type current transformer is installed in the housing cavity via a current transformer mounting block, and the through-type current transformer is fixed relative to the housing. The through-type current transformer is used to allow power cables entering the housing cavity to pass through, so as to monitor the current of the power cables.
[0008] In one possible implementation, a first gland is provided on the side wall of the housing. The first gland is used to allow the power cable to enter the receiving cavity. The first gland is also used to fix the power cable located on the side wall of the housing to limit the axial movement and radial rotation of the power cable located on the side wall of the housing.
[0009] In one possible implementation, a wiring assembly is also included, comprising:
[0010] The wiring bolt is fixed relative to the housing by a fixing component. The wiring bolt includes a first connecting end located inside the receiving cavity and a second connecting end extending outside the receiving cavity.
[0011] The pressure plate is connected to the first connection end. The pressure plate is located on the side of the through-type current transformer away from the first gland and is used to fix the power cable after the through-type current transformer is installed.
[0012] In one possible implementation, a second opening is provided at the bottom of the housing;
[0013] The fixed components include:
[0014] The mounting plate is assembled to the second opening to close the second opening. The mounting plate is provided with a number of mounting holes that communicate with the receiving cavity.
[0015] An insulating terminal sleeve is fitted around the outer circumference of the wiring bolt and inserted into the mounting hole corresponding to the insulating terminal sleeve, so that the wiring bolt is fixed relative to the housing.
[0016] In one possible implementation, there are two current transformer mounting rows, which are arranged in parallel and spaced apart, and both ends of the two current transformer mounting rows are connected to the bottom of the housing through a support body in their extension direction.
[0017] There are three through-type current transformers. The three through-type current transformers are arranged sequentially along the extension direction of the current transformer mounting row on the side of the current transformer mounting row away from the support body, so that there is a gap between the bottom of the through-type current transformer and the bottom of the box base.
[0018] In one possible implementation, a first terminal block is fixed inside the cavity, and a first signal cable is provided inside the cavity. One end of the first signal cable is connected to the terminal block of the through-type current transformer, and the other end of the first signal cable is connected to the first terminal block for signal transmission.
[0019] In one possible implementation, a second gland is provided on the side wall of the housing. The second gland is used for the second signal cable to enter the receiving cavity to connect to the first terminal block. The second gland is also used to fix the second signal cable located on the side wall of the housing to limit the axial movement and radial rotation of the second signal cable located on the side wall of the housing.
[0020] In one possible implementation, there are four first glands and one second gland, with the first and second glands located on different side walls of the housing.
[0021] In one possible implementation, explosion-proof mating surfaces are provided between the box base and the box cover, between the box base and the mounting plate, and between the mounting plate and the insulating terminal sleeve. A threaded explosion-proof surface is also provided between the wiring bolt and the insulating terminal sleeve.
[0022] An electric motor comprising a low-voltage explosion-proof main junction box with a through-type current transformer as described in any of the above.
[0023] Compared to the aforementioned background technology, the low-voltage explosion-proof main junction box with a through-type current transformer provided by this utility model includes a box body and a through-type current transformer. The box body includes a box base and a box cover. The box base has an internal receiving cavity, and the top of the box base has a first opening communicating with the receiving cavity. The box cover is detachably disposed at the first opening so that the receiving cavity forms an explosion-proof environment. The through-type current transformer is installed in the receiving cavity through a current transformer mounting strip, and the through-type current transformer is fixed relative to the box body. The through-type current transformer is used for power cables entering the receiving cavity to pass through, so as to monitor the current of the power cables.
[0024] Specifically, the cover is detachably mounted at the first opening, so that the box body and the cover together form an explosion-proof environment cavity. The current transformer mounting strip for installing the through-type current transformer is installed in the cavity, thereby allowing the through-type current transformer to be installed and fixed in the cavity. The built-in through-type current transformer can share the explosion-proof box body, avoiding the cost and complexity of adding an additional explosion-proof shell. At the same time, placing the through-type current transformer inside the box body, compared to placing it outside the box body, allows the through-type current transformer to be installed closer to the motor power line, which can reduce or even avoid signal attenuation or interference caused by long-distance transmission. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0026] Figure 1 A cross-sectional view of the low-pressure explosion-proof main junction box with a through-type current transformer provided in an embodiment of this utility model;
[0027] Figure 2 This is a partial cross-sectional view from another perspective of the low-pressure explosion-proof main junction box with a through-type current transformer provided in an embodiment of this utility model.
[0028] in:
[0029] 100 - Box body, 110 - Box base, 111 - First gland, 112 - Second gland, 120 - Box cover, 130 - Receiving cavity, 131 - First terminal block, 132 - First signal cable, 140 - First opening;
[0030] 200-Through-type current transformer, 210-Current transformer mounting bar;
[0031] 300-Power cable;
[0032] 400-Connecting bolt;
[0033] 500-Wire clamp;
[0034] 600 - Mounting plate;
[0035] 700 - Insulating terminal sleeve. Detailed Implementation
[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0037] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0038] In the description of this utility model, it should be understood that the terms "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the position or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations of this utility model.
[0039] The purpose of this utility model is to provide a low-voltage explosion-proof main junction box and motor with a through-type current transformer. The built-in through-type current transformer can share the explosion-proof box, avoiding the cost and complexity of adding an additional explosion-proof shell. The through-type current transformer is installed closer to the motor power line, which can reduce or even avoid signal attenuation or interference caused by long-distance transmission.
[0040] Please see Figure 1 and Figure 2To achieve the above objectives, this utility model provides a low-voltage explosion-proof main junction box with a through-type current transformer 200, including a box body 100 and a through-type current transformer 200. The box body 100 includes a box base 110 and a box cover 120. The box base 110 has an internal cavity 130, and the top of the box base 110 has a first opening 140 communicating with the cavity 130. The box cover 120 is detachably disposed at the first opening 140 so that the cavity 130 forms an explosion-proof environment. The explosion-proof environment means that the explosion energy inside the cavity 130 is completely isolated or blocked to prevent the explosion energy from transferring to the outside of the box body 100.
[0041] The box 100 is a low-voltage explosion-proof junction box for motors. This junction box typically has an IP54 / IP66 protection rating. An explosion-proof mating surface is provided between the box base 110 and the box cover 120. This explosion-proof mating surface is formed by the precision mating surfaces between the box base 110 and the box cover 120. The gap between the precision mating surfaces can be set to 0.05-0.2mm, and the precision mating surfaces are set to an L-shaped structure. By using the material of the box 100 (such as a metal material with high thermal conductivity), limiting the size of the gap, and extending the path through the L-shaped structure, the flame energy entering the gap can be quickly absorbed and cooled below the ignition point, ensuring that the internal electrical sparks or explosion energy are completely isolated or blocked, and preventing the ignition of dangerous gases or dust outside the box 100.
[0042] The through-type current transformer 200 is installed in the housing cavity 130 via the current transformer mounting strip 210, and the through-type current transformer 200 is fixed relative to the housing 100. The through-type current transformer 200 is a special type of current transformer with a core designed as an openable ring or rectangular window, allowing the primary conductor to pass directly through the center of the core for non-intrusive installation. Current measurement can be achieved without disconnecting the original circuit. The through-type current transformer 200 is used for the power cable 300 entering the housing cavity 130 to monitor the current of the power cable 300.
[0043] The housing 100 can be, but is not limited to, made of metal. A metal housing 100 can shield external electromagnetic noise and ensure the integrity of the output signal (e.g., 4-20mA or Modbus RTU) of the through-hole current transformer 200. At the same time, by embedding the through-hole current transformer 200 in a low-voltage explosion-proof junction box, external accessories are reduced, and there is no need to configure a separate current transformer mounting bar 210 or protective cover, thereby reducing the overall bill of materials (BOM) cost.
[0044] Specifically, the cover 120 is detachably disposed at the first opening 140, so that the box body 100 and the cover 120 together form an explosion-proof environment accommodating cavity 130. The transformer mounting strip 210 for installing the through-type transformer 200 is installed in the accommodating cavity 130, thereby allowing the through-type transformer 200 to be installed and fixed in the accommodating cavity 130. The built-in through-type transformer 200 can share the explosion-proof box body 100, avoiding the cost and complexity of adding an additional explosion-proof shell. At the same time, placing the through-type transformer 200 inside the box body 100, compared to placing it outside the box body 100, allows the through-type transformer 200 to be installed closer to the motor power line, which can reduce or even avoid signal attenuation or interference caused by long-distance transmission.
[0045] In one possible implementation, the side wall of the housing 110 is provided with four first glands 111. The number of first glands 111 can be increased or decreased according to actual needs. The first glands 111 are used to allow the power cable 300 to enter the receiving cavity 130. The first glands 111 are also used to fix the power cable 300 located on the side wall of the housing 110, so as to limit the axial movement and radial rotation of the power cable 300 located on the side wall of the housing 110.
[0046] It is understood that the through-type current transformer 200 includes a first side and a second side located in the extension direction of the annular or rectangular window. The first gland 111 can be set to be connected to either the first side or the second side of the housing 110, so that after the power cable 300 enters the receiving cavity 130 through the first gland 111, it can easily pass through the annular or rectangular window in the through-type current transformer 200, avoiding excessive bending of the power cable 300 and its occupation of the space in the receiving cavity 130.
[0047] It should be noted that the power cable 300 connected to the power line enters the receiving cavity 130 from the first gland 111, which allows the through-type current transformer 200 to be placed close to the first gland 111. This makes the through-type current transformer 200 more closely mounted to the power line, so as to accurately capture transient current signals such as motor start-up and load fluctuations, and further reduce signal attenuation or interference caused by long-distance transmission.
[0048] In one possible implementation, a wiring assembly is also included, comprising a wiring bolt 400 and a pressure plate 500. The wiring bolt 400 is fixed relative to the housing 110 by a fixing assembly. The wiring bolt 400 includes a first connecting end located inside the receiving cavity 130 and a second connecting end extending outside the receiving cavity 130. The pressure plate 500 is connected to the first connecting end and is located on the side of the through-type current transformer 200 away from the first gland 111, for fixing the power cable 300 after passing through the through-type current transformer 200. There are six wiring bolts 400, including three long wiring bolts and three short wiring bolts. The power cable 300 enters the receiving cavity 130 through the first gland 111, passes through the annular or rectangular window of the through-type current transformer 200, and is then fixed to the wiring bolt 400 by the pressure plate 500.
[0049] In one possible implementation, the bottom of the housing 110 has a second opening; the fixing assembly includes a mounting plate 600 and an insulating terminal sleeve 700. The mounting plate 600 is assembled to the second opening to close it. The mounting plate 600 has a plurality of mounting holes communicating with the receiving cavity 130. The insulating terminal sleeve 700 is sleeved on the outer periphery of the wiring bolt 400 and is inserted into the mounting hole corresponding to the insulating terminal sleeve 700, so that the wiring bolt 400 is fixed relative to the housing 110. The insulating terminal sleeve 700 electrically isolates the wiring bolt 400 and the housing 110. The number of mounting holes, insulating terminal sleeves 700, and wiring bolts 400 are the same and correspond one-to-one. Among them, there are explosion-proof mating surfaces between the housing 110 and the mounting plate 600, and between the mounting plate 600 and the insulating terminal sleeve 700. There is also a threaded explosion-proof surface between the wiring bolt 400 and the insulating terminal sleeve 700 to ensure that internal electrical sparks or explosion energy are completely isolated or blocked to prevent ignition of external dangerous gases or dust.
[0050] In one possible implementation, there are two current transformer mounting rows 210, which are arranged in parallel and spaced apart. Both ends of the two current transformer mounting rows 210 are connected to the bottom of the housing 110 through a support body. The two parallel current transformer mounting rows 210 are fixed at both ends of the support body to form a stable support frame, which avoids deformation caused by the weight or vibration of the through-type current transformer 200, and at the same time improves the overall mechanical strength.
[0051] There are three through-type current transformers 200. The three through-type current transformers 200 are arranged sequentially along the extension direction of the current transformer mounting row 210 on the side of the current transformer mounting row 210 away from the support body to ensure magnetic field uniformity and avoid measurement errors caused by magnetic field superposition between the through-type current transformers 200. The support body and the current transformer mounting row 210 create a gap between the bottom of the through-type current transformer 200 and the bottom of the box 110. The gap between the bottom of the through-type current transformer 200 and the bottom of the box 110 forms a heat dissipation channel, while preventing dust or moisture accumulation and improving insulation performance.
[0052] In one possible implementation, a first terminal block 131 is fixed inside the receiving cavity 130, and a first signal cable 132 is provided inside the receiving cavity 130. One end of the first signal cable 132 is connected to the terminal block of the through-type current transformer 200, and the other end of the first signal cable 132 is connected to the first terminal block 131 for signal transmission. Each through-type current transformer 200 is connected to two first signal cables 132. The first terminal block 131 can be used to centrally fix the ends of all the first signal cables 132 away from the through-type current transformer 200, so that the first signal cables 132 are neatly arranged inside the receiving cavity 130, and at the same time, it is convenient for the second signal cable to establish a connection with all the first signal cables 132 through the second gland 112.
[0053] The side wall of the housing 110 is also provided with a second gland 112. The second gland 112 is used for the second signal cable to enter the receiving cavity 130 to connect to the first terminal 131. The second gland 112 is also used to fix the second signal cable located on the side wall of the housing 110 to limit the axial movement and radial rotation of the second signal cable located on the side wall of the housing 110. There is one second gland 112, and the first gland 111 and the second gland 112 are located on different side walls of the housing 110 to avoid the first gland 111 and the second gland 112 being set on the same side wall, which would cause the cabling to be too crowded.
[0054] The second signal cable can be used as a user signal cable to bring out the signal of the through-type current transformer 200 and realize the function of monitoring the current magnitude. The integrated design of the through-type current transformer 200 and the low-voltage explosion-proof junction box of the motor achieves efficient and reliable motor status monitoring through space adaptation, safety enhancement and functional integration. It is especially suitable for industrial scenarios with limited space, harsh environment or high-density deployment.
[0055] An electric motor includes a low-voltage explosion-proof main junction box with a through-type current transformer as described above, which also has all the beneficial effects of a low-voltage explosion-proof main junction box with a through-type current transformer. The remaining structure of the motor can be referred to the prior art, and will not be described in detail here.
[0056] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.
[0057] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0058] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principles of this utility model, and these improvements and modifications also fall within the protection scope of this utility model.
Claims
1. A low-voltage explosion-proof type of a main terminal box of a through-type mutual inductor, characterized by, include: The box body (100) includes a box base (110) and a box cover (120). The box base (110) has an internal cavity (130), and the top of the box base (110) has a first opening (140) communicating with the cavity (130). The box cover (120) is detachably disposed at the first opening (140) so that the cavity (130) forms an explosion-proof environment. A through-type current transformer (200) is installed in the receiving cavity (130) via a current transformer mounting block (210), and the through-type current transformer (200) is fixed relative to the housing (100). The through-type current transformer (200) is used for the power cable (300) entering the receiving cavity (130) to pass through, so as to monitor the current of the power cable (300).
2. The low voltage flameproof type of the through- core transformer bushing main terminal box according to claim 1, characterized in that, The side wall of the housing (110) is provided with a first gland (111), which is used to allow the power cable (300) to enter the receiving cavity (130). The first gland (111) is also used to fix the power cable (300) located on the side wall of the housing (110) to limit the axial movement and radial rotation of the power cable (300) located on the side wall of the housing (110).
3. The low voltage flameproof through-type instrument transformer terminal box according to claim 2, characterized in that, It also includes a wiring assembly, the wiring assembly comprising: A wiring bolt (400) is fixed relative to the housing (110) by a fixing assembly. The wiring bolt (400) includes a first connecting end located inside the receiving cavity (130) and a second connecting end extending outside the receiving cavity (130). A pressure plate (500) is connected to the first connection end. The pressure plate (500) is located on the side of the through-type current transformer (200) away from the first gland (111) and is used to fix the power cable (300) after the through-type current transformer (200) is inserted.
4. The low voltage flameproof instrument transformer with a through- core mutual inductor terminal box according to claim 3, characterized in that, The bottom of the box base (110) has a second opening; The fixing component includes: Mounting plate (600) is assembled to the second opening to close the second opening. The mounting plate (600) is provided with a plurality of mounting holes communicating with the receiving cavity (130). An insulating terminal sleeve (700) is fitted around the outer periphery of the wiring bolt (400) and inserted into the mounting hole corresponding to the insulating terminal sleeve (700) so that the wiring bolt (400) is fixed relative to the housing (110).
5. The low voltage flameproof instrument transformer with a through- core mutual inductor terminal box according to claim 3, characterized in that, There are two current transformer mounting rows (210), which are parallel and spaced apart. Both ends of the two current transformer mounting rows (210) are connected to the bottom of the box base (110) through a support body in their own extension direction. There are three through-type current transformers (200). The three through-type current transformers (200) are arranged sequentially along the extension direction of the current transformer mounting row (210) on the side of the current transformer mounting row (210) away from the support body, so that there is a gap between the bottom of the through-type current transformer (200) and the bottom of the box base (110).
6. The low voltage flameproof instrument transformer with a through- core mutual inductor terminal box according to claim 3, characterized in that, The cavity (130) is fixed with a first terminal (131) and a first signal cable (132) is provided in the cavity (130). One end of the first signal cable (132) is connected to the terminal of the through-type current transformer (200) and the other end of the first signal cable (132) is connected to the first terminal (131) for signal transmission.
7. The low voltage flameproof through-connection transformer main terminal box according to claim 6, characterized in that, The side wall of the housing (110) is also provided with a second gland (112), which is used for the second signal cable to enter the receiving cavity (130) to connect to the first terminal (131). The second gland (112) is also used to fix the second signal cable located on the side wall of the housing (110) to limit the axial movement and radial rotation of the second signal cable located on the side wall of the housing (110).
8. The low-voltage explosion-proof main junction box with a through-type instrument transformer according to claim 7, characterized in that, There are four first gliders (111) and one second glider (112), and the first gliders (111) and the second gliders (112) are located on different side walls of the housing (110).
9. The low voltage flameproof instrument transformer with a through- core mutual inductor terminal box according to claim 4, characterized in that, An explosion-proof mating surface is provided between the box base (110) and the box cover (120), between the box base (110) and the mounting plate (600), and between the mounting plate (600) and the insulating terminal sleeve (700). A threaded explosion-proof surface is also provided between the wiring bolt (400) and the insulating terminal sleeve (700).
10. An electric machine characterized by Includes the low-voltage explosion-proof main junction box with through-type instrument transformer as described in any one of claims 1-9.