A residual current transformer

Abstract

The utility model discloses a kind of residual current transformer with high precision and good balance. It relates to the field of mutual inductor manufacturing. By built-in two primary wire pins, and the position of built-in primary wire pin is fixed, on the one hand, threading operation is avoided, and work efficiency is improved;On the other hand, in the use process, the position of two primary wire pins is fixed, the balance is improved, the current direction of two primary wire pins is opposite, the direction of corresponding generated induction magnetic field is opposite and mutually offset, the closer the distance between two primary wire pins, the lower the residual intensity of offset magnetic field, and the higher the detection accuracy of mutual inductor.

Description

Technical Field

[0001] This utility model belongs to the field of instrument transformer manufacturing, and specifically relates to a residual current instrument transformer. Background Technology

[0002] Currently, electric vehicle charging piles are rapidly becoming widespread in my country, and the requirements for leakage detection of charging guns are also increasing. In particular, the high power and high current characteristics of fast charging piles place higher demands on the detection accuracy and balance of leakage detection devices, which traditional current transformers cannot meet.

[0003] Therefore, a residual current transformer with high detection accuracy and better balance is needed. Utility Model Content

[0004] The purpose of this invention is to disclose a residual current transformer with high detection accuracy and better balance.

[0005] To achieve the above objectives, this utility model discloses a residual current transformer, comprising two primary leads, a secondary winding, an annular core, and a housing; the housing is provided with an annular groove, the secondary winding is wound around the annular core, the annular core is embedded in the annular groove, the two primary leads are arranged at intervals and are both fixed to the housing, one end of the primary lead passes through the inner side of the annular core, and the other end of the primary lead is located on the circumferential outer side of the annular core.

[0006] As an optional implementation, the primary line pin is formed into a U-shape. The primary line pin includes a horizontal segment, a first vertical segment, and a second vertical segment. The horizontal segment is parallel to the bottom surface of the housing. The two ends of the horizontal segment are respectively connected to the first vertical segment and the second vertical segment. The first vertical segment and the second vertical segment are both perpendicular to the bottom surface of the housing. The first vertical segment passes through the cavity of the annular iron core, and the second vertical segment is located outside the annular iron core. The planes on which the two primary line pins are located are parallel to each other.

[0007] As an optional implementation, the housing is provided with a protrusion located at the center of the annular groove. The housing is also provided with two inner through holes and two outer positioning parts. The two inner through holes are arranged at intervals and both pass through the protrusion. The two outer positioning parts are arranged at intervals and both are located on the circumferential outer side of the annular groove. The primary wire pins are respectively provided with one inner through hole and one outer positioning part. The first longitudinal segment of the primary wire pin is embedded in the inner through hole and exposed to the outside as a wire end. The second longitudinal segment of the primary wire pin is embedded in the outer positioning part and exposed to the outside as a wiring terminal.

[0008] As an optional implementation, a protruding beam is also provided on the bottom outer wall of the housing. The beam is integrally formed with the housing, and the horizontal segments of the two primary wire pins are respectively located on both sides of the beam.

[0009] As an optional implementation, the convex beam has a Y-shaped structure, including a main beam and two oblique secondary beams. The two secondary beams extend obliquely to the outer circumference of the shell with the straight line direction of the main beam as the axis of symmetry. The transverse segments of the two primary line pins are respectively located on both sides of the main beam.

[0010] As an optional implementation, a protrusion is provided on the circumferential outer side of the housing, and an outer positioning part is provided on the protrusion.

[0011] As an optional implementation, the outer positioning part is in the shape of a circular groove or a hole.

[0012] As an optional implementation, the secondary winding includes a coil wound on a toroidal iron core and secondary wire pins led out from both ends of the coil. A boss is also provided on the outer wall of the housing, which is opposite to the protrusion, and the secondary wire pins are embedded in the boss.

[0013] As an optional implementation, the protruding post is also provided with a slot, which is located between the two inner through holes, and a shielding plate is inserted into the slot.

[0014] As an alternative implementation, the shielding plate is made of epoxy insulation material.

[0015] The residual current transformer of this invention has two built-in primary line pins with fixed positions. This eliminates the need for threading, improving work efficiency. Furthermore, the fixed positions of the two primary line pins improve balance during use. The currents in the two primary line pins are in opposite directions, resulting in opposite and mutually canceling induced magnetic fields. The closer the two primary line pins are, the lower the residual strength of the canceled magnetic field, and the higher the detection accuracy of the transformer. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a diagram showing the overall appearance of the current transformer.

[0018] Figure 2 This is an exploded view of a mutual inductor.

[0019] Figure 3 This is a view of the back of the current transformer.

[0020] Figure 4 This is a diagram showing the housing of the current transformer.

[0021] Explanation of key figure labels: 1. Primary winding pin; 10. Horizontal segment; 11. First vertical segment; 12. Second vertical segment; 2. Secondary winding; 20. Coil; 21. Secondary winding pin; 3. Toroidal core; 4. Housing; 40. Annular groove; 41. Protruding post; 410. Inner through hole; 411. Slot; 42. Protrusion; 420. Fixing part; 43. Protruding beam; 431. Main beam; 432. Secondary beam; 44. Boss; 5. Shielding plate. Detailed Implementation

[0022] 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.

[0023] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0024] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this utility model according to the specific circumstances.

[0025] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this utility model based on the specific circumstances.

[0026] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0027] The technical solution of this utility model will be further described below with reference to the embodiments and accompanying drawings.

[0028] See Figure 1 This utility model discloses a current transformer for detecting leakage current in a charging pile, comprising two primary leads 1, a secondary winding 2, a toroidal core 3, and a housing 4. The housing 4 has an annular groove 40. The secondary winding 2 is wound around the toroidal core 3, which is embedded within the annular groove 40. The two primary leads 1 are spaced apart and fixedly connected to the housing 4. One end of each primary lead 1 passes through the inner side of the toroidal core 3, and the other end is located on the outer circumferential side of the toroidal core 3. By incorporating two primary leads 1 and fixing their positions, the wiring operation is eliminated, improving work efficiency. Furthermore, the fixed positions of the two primary leads 1 during use improve balance. The current directions of the two primary leads 1 are opposite, resulting in opposite and mutually canceling induced magnetic fields. The closer the two primary leads 1 are, the lower the residual strength of the canceled magnetic field, and the higher the detection accuracy of the current transformer.

[0029] See Figure 1 and Figure 2 The primary wire pin 1 is U-shaped and includes a horizontal segment 10 parallel to the bottom surface of the housing 4. The two ends of the horizontal segment 10 are connected to a first vertical segment 11 and a second vertical segment 12 perpendicular to the bottom surface of the housing 4. The first vertical segment 11 passes through the cavity of the annular iron core 3, and the second vertical segment 12 is located outside the annular iron core 3. The planes of the two primary wire pins 1 are parallel to each other. The purpose of this design is that the U-shaped internal primary wire pin 1 has a semi-enclosed structure, allowing the primary wire to be directly connected to the two ends of the corresponding primary wire pin 1 to form a closed loop passing through the annular iron core 3 during use, eliminating the need for threading.

[0030] See Figures 1 to 4The inner annular space of the annular groove 40 is a protruding post 41, and the cylindrical sidewall of the protruding post 41 is the inner annular wall of the annular groove 40. Two parallel inner through holes 410 are provided along the axial direction of the protruding post 41, each penetrating both end faces of the protruding post 41. The two inner through holes 410 are respectively used to pass through the first longitudinal segments 11 of the two primary wire pins 1. The diameter of the two primary wire pins 1 is similar to the diameter of the inner through holes 410, so that the two first longitudinal segments 11 are tightly embedded in the protruding post 41 through the corresponding two inner through holes 410. The purpose of this arrangement is that, during use, the current directions of the two primary wire pins 1 are opposite, and the directions of the induced magnetic fields they generate are also opposite. When the two first longitudinal segments 11 are energized, they will be attracted to each other by their respective induced magnetic fields. Therefore, embedding the two first longitudinal segments 11 in the protruding post 41 avoids relative displacement between the two primary wire pins 1 and between the primary wire pins 1 and the annular iron core 3, thus preventing disordered fluctuations in the induced magnetic field and induced current.

[0031] See Figure 3 The outer wall of the bottom of the shell 4 is provided with a protruding Y-shaped beam 43. The beam 43 is integrally formed with the shell 4. The beam 43 includes a main beam 431 and two secondary beams 432. The main beam 431 is arranged radially along the shell 4. The two secondary beams 432 extend obliquely to the outer circumference of the shell 4 with the straight line direction of the main beam 431 as the axis of symmetry. The primary line pin 1 passes through the bottom of the shell 4 and extends to the outer circumference of the shell 4, closely attached to both sides of the main beam 431. The purpose of this arrangement is twofold: First, after the two primary wire pins 1 pass through the bottom of the housing 4, the magnetic fields generated by each pin in opposite directions still exist, and there is still a magnetic attraction between the two primary wire pins 1. Therefore, placing the two primary wire pins 1 on both sides of the protruding beam 43 can avoid the risk of short circuit caused by the two pins getting close or even contacting each other. Second, the two primary wires are close to each other, and their currents are large, so their magnetic attraction is strong. In order to avoid the magnetic force of the two primary wire pins 1 exerting a lateral torsional force on the main beam 431, which would cause the main beam 431 to deform or be damaged, two oblique secondary beams 432 extend from the side of the main beam 431 near the inner through hole 410, thereby improving the torsional resistance and structural stability of the main beam 431.

[0032] See Figure 1 and Figure 4 The outer wall of the housing 4 is also provided with an integrally formed protrusion 42. The protrusion 42 has two fixing parts 420 parallel to the inner through hole 410. The two fixing parts 420 are in the shape of a circular groove or hole, and the two second longitudinal segments 12 are correspondingly embedded in the two fixing parts 420. (See reference...) Figure 1 and Figure 4A protrusion 42 is provided at the end of the outer wall of the housing 4 away from the secondary winding 2. The protrusion 42 is integrally formed with the housing 4 and the protruding beam 43. The protrusion 42 is W-shaped in general. There are two fixing parts 420 on the protrusion 42 parallel to the inner through hole 410. The two fixing parts 420 are in the shape of a circular groove or hole and are parallel to the inner through hole 410. The two second longitudinal segments 12 are embedded into the protrusion 42 through the two fixing parts 420. It should be noted that, in addition to the method of using the protrusion 42 to support the fixing parts 420 as described in this embodiment, in other embodiments, the thickness of the outer wall of the housing 4 can be increased, and a groove can be provided on the outer wall of the housing 4 to fix the second longitudinal segment 12 of the primary line pin 1. Or other methods can be used, as long as the second longitudinal segment 12 can be fixed. Therefore, they will not be discussed in this embodiment.

[0033] The two fixing parts 420, together with the main beam 431 and the two inner through holes 410, firmly fix the two primary wire pins 1 to the housing 4. Combined with the aforementioned annular iron core 3 embedded in the annular groove 40 of the housing 4, the position of the two primary wire pins 1 and the annular iron core 3 is indirectly fixed by the fixing effect of the housing 4, thereby achieving the effect of stabilizing the induced magnetic field.

[0034] See Figure 1 and Figure 2 The secondary winding 2 includes a coil 20 wound around a toroidal iron core 3 and secondary wire pins 21 extending from both ends of the coil 20. On the outer wall of the housing 4, there is a boss 44 opposite to the protrusion 42. The secondary wire pins 21 are embedded in the boss 44 and have their terminals exposed. In this embodiment, each of the two primary wire pins 1 has only one turn wound around the toroidal iron core 3, while the coil 20 of the secondary winding 2 has far more than one turn wound around the toroidal iron core 3. The purpose of this arrangement is that the current in the primary winding is too large, far exceeding the range of the induction ammeter. Therefore, a higher turns ratio is used to reduce the induced current intensity in the secondary winding 2, thereby enabling the use of an induction ammeter with a smaller range and higher accuracy, thus improving the detection accuracy. It should be noted that in other embodiments, the turns ratio of the primary winding to the secondary winding 2 can be adjusted according to actual needs, which will not be discussed in this embodiment.

[0035] For further details, please refer to [link / reference]. Figure 1 and Figure 4 A slot 411 is provided between the two inner through holes 410. A shielding plate 5 made of epoxy insulation can be inserted into the slot 411 for electrical insulation between the two primary line pins 1, reducing interference and improving the stability of the transformer.

[0036] The technical means disclosed in this utility model are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications are also considered within the scope of protection of this utility model.

Claims

1. A residual current transformer, characterized in that, include: Two primary wire pins (1), secondary winding (2), toroidal core (3), and housing (4); The housing (4) is provided with an annular groove (40), the secondary winding (2) is wound on the annular core (3), the annular core (3) is embedded in the annular groove (40), the two primary wire pins (1) are arranged at intervals and are both fixed to the housing (4), one end of the primary wire pin (1) passes through the inner side of the annular core (3), and the other end of the primary wire pin (1) is located on the circumferential outer side of the annular core (3).

2. The residual current transformer according to claim 1, characterized in that, The primary line pin (1) is formed in a U-shape. The primary line pin (1) includes a horizontal segment (10), a first vertical segment (11), and a second vertical segment (12). The horizontal segment (10) is parallel to the bottom surface of the housing (4). The two ends of the horizontal segment (10) are respectively connected to the first vertical segment (11) and the second vertical segment (12). The first vertical segment (11) and the second vertical segment (12) are both perpendicular to the bottom surface of the housing (4). The first vertical segment (11) passes through the cavity of the annular iron core (3). The second vertical segment (12) is located outside the annular iron core (3), and the planes on which the two primary line pins (1) are located are parallel to each other.

3. The residual current transformer according to claim 2, characterized in that, The housing (4) is provided with a protruding post (41) located at the center of the annular groove (40). The housing (4) is also provided with two inner through holes (410) and two outer positioning parts. The two inner through holes (410) are arranged at intervals and both pass through the protruding post (41). The two outer positioning parts are arranged at intervals and both are located on the circumferential outer side of the annular groove (40). The primary line pin (1) is respectively provided with one inner through hole (410) and one outer positioning part. The first longitudinal segment (11) of the primary line pin (1) is embedded in the inner through hole (410) and exposed to the outside as a line end. The second longitudinal segment (12) of the primary line pin (1) is embedded in the outer positioning part and exposed to the outside as a wiring terminal.

4. The residual current transformer according to claim 3, characterized in that, The outer wall of the bottom of the housing (4) is also provided with a protruding beam (43), the beam (43) is integrally formed with the housing (4), and the horizontal segments (10) of the two primary line pins are respectively disposed on both sides of the beam (43).

5. The residual current transformer according to claim 4, characterized in that, The convex beam (43) has a Y-shaped structure, including a main beam (431) and two oblique secondary beams (432). The two secondary beams (432) extend obliquely to the outer circumference of the shell (4) with the straight line direction of the main beam (431) as the axis of symmetry. The transverse segments (10) of the two primary line pins are respectively located on both sides of the main beam (431).

6. The residual current transformer according to claim 3, characterized in that, The outer circumferential side of the housing (4) is provided with a protrusion (42), and the outer positioning part is provided on the protrusion (42).

7. The residual current transformer according to claim 6, characterized in that, The outer positioning part is in the shape of a circular groove or a hole.

8. The residual current transformer according to claim 6, characterized in that, The secondary winding (2) includes a coil (20) wound on the annular iron core (3) and secondary wire pins (21) led out from both ends of the coil (20). A boss (44) is also provided on the outer wall of the housing (4) opposite to the protrusion (42), and the secondary wire pins (21) are embedded in the boss (44).

9. The residual current transformer according to claim 3, characterized in that, The protruding post (41) is also provided with a slot (411), which is located between the two inner through holes (410), and a shielding plate (5) is inserted into the slot (411).

10. The residual current transformer according to claim 9, characterized in that, The shielding plate (5) is made of epoxy insulating material.

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