A detection device for preventing loose connections in the secondary crimping screws of a low-voltage current transformer to be tested

Abstract

This invention relates to the field of instrument transformer testing technology, specifically disclosing a detection device for preventing loose connections in the secondary crimping screws of a low-voltage current transformer under test. The detection mechanism has a probe push plate equipped with a first probe and a second probe electrically connected to two crimping screws, and a third probe electrically connected to the coil. The overall testing circuit includes an overall testing power supply, an overall testing switch, and an overall testing alarm. The first alarm is electrically connected between the first probe and the overall testing circuit, and the second alarm is electrically connected between the second probe and the overall testing circuit. The sub-testing circuit includes a sub-testing power supply and a sub-testing changeover switch. The sub-testing changeover switch includes a moving contact, a first stationary contact electrically connected between the first alarm and the overall testing circuit, and a second stationary contact electrically connected between the second alarm and the overall testing circuit. This invention first performs an overall test on the two crimping screws through the overall testing circuit, and then determines which crimping screw has a loose connection through the sub-testing circuit.

Description

Technical Field

[0001] This invention relates to the field of instrument transformer testing technology, specifically to a device for detecting the prevention of loose connections in the secondary crimping screws of a low-voltage current transformer to be tested. Background Technology

[0002] When calibrating a low-voltage current transformer, if the secondary crimping screws are loosely connected, it will cause an open circuit on the secondary side, making the calibration impossible. Furthermore, calibration personnel are easily misdiagnosed as a faulty calibration device, spending considerable time investigating before discovering that the loose connection in the secondary crimping screws is the cause. Therefore, it is crucial to develop a detection device for preventing loose connections in the secondary crimping screws of the low-voltage current transformer under calibration; currently, such devices are rare.

[0003] In the prior art, a detection device for preventing loose connections of the secondary crimping screws of a low-voltage current transformer under test, disclosed in publication number "CN203849397U", includes probe A1, probe A2, relay J, battery pack B, push-button switch S, freewheeling diode D1, first light-emitting diode D2, second light-emitting diode D3, and buzzer H. It can quickly determine whether the secondary crimping screws of the low-voltage current transformer are loosely connected and has audible and visual indications. It has the advantages of simple operation, fast detection speed, and low cost, which greatly improves the testing efficiency of low-voltage current transformers.

[0004] However, the existing technology still has significant shortcomings. For example, the existing technology can only identify that two crimping screws have a loose connection problem, but it cannot determine the specific type of loose connection. For instance, it cannot determine whether both crimping screws have a loose connection problem or which specific crimping screw has a loose connection problem. The two crimping screws still need to be tested separately. The effect of crimping screw loose connection detection is not ideal.

[0005] The above background information is provided only to aid in understanding the inventive concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0006] The purpose of this invention is to provide a detection device for preventing loose connections of the secondary crimping screws of a low-voltage current transformer under test. By setting up a whole inspection circuit to perform overall inspection on the two crimping screws, and when a loose connection problem is found, it switches to a separate inspection circuit to inspect the two crimping screws one by one, which can accurately locate the crimping screws in the loose connection state.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A detection device for preventing loose connections of secondary crimping screws in a low-voltage current transformer to be tested includes a detection mechanism, a main detection circuit, and a sub-detection circuit.

[0009] The detection mechanism includes a detection conductor, a probe pusher plate, a guide rod, and a driving device. The detection conductor passes through the central hole of the current transformer and is electrically connected to an AC power supply. A temperature sensing switch controlling the operation of the driving device is installed on the detection conductor. The probe pusher plate has a guide groove. Driven by the driving device, the probe pusher plate slides closer to the current transformer through the guide groove and the guide rod. The probe pusher plate is equipped with a first probe and a second probe, which are electrically connected to the two crimping screws respectively, and a third probe, which is electrically connected to the coil between the two crimping screws. An insulating sliding plate is slidably disposed in the guide groove and moves closer to the guide rod under the push of an elastic pusher. A disconnected connection mechanism is electrically connected between the first probe and the second probe. The guide rod protrudes in the middle and presses the insulating sliding plate to push the connection mechanism to close.

[0010] The inspection circuit includes an inspection power supply, an inspection switch, and an inspection alarm connected in series; the first alarm is electrically connected between the first probe and the inspection circuit, and the second alarm is electrically connected between the second probe and the inspection circuit.

[0011] The sorting circuit includes a sorting power supply and a sorting changeover switch connected in series. The sorting power supply is electrically connected between the third probe and the sorting changeover switch. The sorting changeover switch includes a moving contact electrically connected to the sorting power supply, a first stationary contact electrically connected between the first alarm and the inspection circuit, and a second stationary contact electrically connected between the second alarm and the inspection circuit.

[0012] Preferably, the driving device includes a drive motor mounted on the drive circuit and a threaded screw that rotates under the drive of the drive motor, and the temperature sensing switch and the drive motor on the drive circuit are connected in series, and an internal threaded plate for the threaded screw to pass through is fixedly connected to the probe push plate.

[0013] Preferably, the power connection mechanism includes two sets of two pairs of opposing probe power connection blocks and sliding power connection blocks, with the two probe power connection blocks electrically connected to the first probe and the second probe, respectively. There are two guide rods that pass through the corresponding two guide grooves. The two probe power connection blocks extend into the two guide grooves one-to-one. The insulating slide plate is located between the guide rods and the probe power connection blocks, and the sliding power connection blocks are fixedly connected to the end face of the insulating slide plate near the probe power connection blocks. The two sliding power connection blocks are electrically connected by a wire.

[0014] Preferably, the detection conductor includes a first conductor fixedly passing through the through hole of the current transformer and two second conductors respectively slidably disposed at both ends of the first conductor. The temperature sensing switch is fixedly installed on the first conductor, and the AC power supply is transmitted to the first conductor through the second conductors.

[0015] Preferably, the inspection power supply, inspection switch, and inspection alarm are connected in series, and the first alarm is electrically connected between the first probe and the inspection alarm, and the second alarm is electrically connected between the second probe and the inspection power supply.

[0016] Preferably, the first stationary contact is electrically connected between the first alarm and the inspection alarm, and the second stationary contact is electrically connected between the second alarm and the inspection power supply.

[0017] Preferably, an ammeter is electrically connected between the second probe and the second alarm, and the positive terminals of both the overall inspection power supply and the individual inspection power supply are connected to the positive terminal of the ammeter.

[0018] Preferably, a limiting plate is fixedly connected to the probe push plate, and a limiting rod slides through the limiting plate, with the axial direction of the limiting rod parallel to the sliding direction of the probe push plate.

[0019] Preferably, the inspection alarm is an electric bell.

[0020] Preferably, both the first and second warning lights are bidirectional LED lights.

[0021] Compared with existing technologies, the present invention has the following advantages:

[0022] The present invention provides a detection device for preventing loose connections of secondary crimping screws in low-voltage current transformers. By setting up a comprehensive inspection circuit to perform overall inspection on two crimping screws, and switching to a separate inspection circuit to inspect each of the two crimping screws individually when a loose connection problem is detected, the device can determine which crimping screw has a loose connection. This has the advantage of accurately locating the crimping screw that is in a loose connection state. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall circuit of the present invention;

[0024] Figure 2 This is a schematic diagram of the closure of the inspection switch in this invention;

[0025] Figure 3 This is a schematic diagram showing the connection between the moving contact and the first stationary contact of the sorting changeover switch in this invention;

[0026] Figure 4 This is a schematic diagram showing the connection between the moving contact and the second stationary contact of the sorting changeover switch in this invention;

[0027] Figure 5 This is a three-dimensional schematic diagram of the installation of the detection mechanism in this invention;

[0028] Figure 6 This is a schematic diagram of the guide rod in this invention;

[0029] Figure 7 This is a schematic diagram illustrating how the disconnection of the power connection mechanism in this invention causes the first and second probes to lose their electrical connection.

[0030] Figure 8 for Figure 7 Enlarged schematic diagram of the internal structure of the guide groove;

[0031] Figure 9 This is a schematic diagram showing how the closing of the electrical connection mechanism in this invention electrically connects the first probe and the second probe.

[0032] In the diagram: 1-First probe, 2-Second probe, 3-Third probe, 4-Inspection power supply, 5-Inspection switch, 6-Inspection alarm, 7-First alarm, 8-Second alarm, 9-Separate inspection power supply, 10-Separate inspection switch, 11-Ammeter, 12-Detection conductor, 121-First conductor, 122-Second conductor, 13-Temperature sensor switch, 14-Probe push plate, 141-Guide slide, 15-Guide rod, 16-Probe contact block, 17-Insulated sliding plate, 18-Elastic push block, 19-Sliding contact block, 20-Wire, 21-Drive motor, 22-Threaded screw, 23-Internal thread plate, 24-Limiting rod, 25-Limiting plate, 26-Fixed connecting plate, 27-Detection block. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "top surface," "bottom surface," "inner," "outer," "inner side," and "outer side," 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 invention and simplifying the description, and do not indicate or imply that the device 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 on this invention.

[0035] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. Where the terms "first," "second," and "third" are used for descriptive purposes and to distinguish technical features, they should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the sequential relationship of the indicated technical features.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The embodiments of this invention will now be described according to its overall structure.

[0037] Please see Figures 1-9 A detection device for preventing loose connections in the secondary crimping screws of a low-voltage current transformer under test includes a detection mechanism. The detection mechanism includes a detection conductor 12 passing through the through-hole of the current transformer. The detection conductor 12 is connected in series with an AC power supply via a wire. When the secondary side of the current transformer is open-circuited, the current on the primary side of the current transformer is converted into an excitation current, causing an increase in the magnetic flux on the primary side and a sharp increase in iron loss. This results in a rapid increase in the temperature of the primary circuit of the current transformer, dissipating a large amount of heat. In this embodiment, it is necessary to detect whether a loose connection in the secondary crimping screws has caused an open circuit on the secondary side of the current transformer. The detection conductor 12, which is energized by alternating current, is inserted into the through hole of the current transformer for the primary circuit. If there is no open circuit fault on the secondary side of the current transformer, the detection conductor 12 will not heat up rapidly, indicating that there is no fault on the secondary side of the current transformer and that there is no loose connection problem with the secondary crimping screw of the current transformer. If there is an open circuit on the secondary side of the current transformer, the detection conductor 12 will heat up rapidly and dissipate a large amount of heat, indicating that there is an open circuit on the secondary side of the current transformer. Subsequent tests are then conducted to determine whether the open circuit on the secondary side of the current transformer is caused by a loose connection of the secondary crimping screw of the current transformer.

[0038] Specifically, the detection conductor 12 includes a first conductor 121 fixedly passing through the current transformer core hole, and two second conductors 122 respectively slidably disposed at both ends of the first conductor 121. The AC power supply is transmitted to the first conductor 121 through the second conductors 122. Specifically, the first conductor 121 is detachably fixed through the current transformer core hole by an external fixing mechanism. The two second conductors 122 are respectively connected to both ends of the first conductor 121, and both second conductors 122 are connected to wires and electrically connected to the two terminals of the AC power supply one by one through the wires. This allows the first conductor 121 passing through the current transformer core hole to be supplied with AC power. The second conductors 122 can be selected as terminals with elastic clamping elements to improve the stability of the electrical connection process between the first conductor 121 and the second conductor 122.

[0039] The detection mechanism also includes a temperature sensing switch 13 fixedly mounted on the first conductor 121, a probe push plate 14 that approaches the current transformer under the drive of the driving device, and a guide rod 15 that guides the sliding process of the probe push plate 14. The probe push plate 14 is equipped with a first probe 1 and a second probe 2 that are electrically connected to the two crimping screws respectively, and a third probe 3 that is electrically connected to the coil between the two crimping screws. The probe push plate 14 has a guide groove 141 for the guide rod 15 to pass through. Specifically, the probe push plate 14 is slidably positioned above the current transformer. A fixed connecting plate 26 is fixedly connected to the upper end face of the current transformer. The guide rod 15 is set vertically and fixedly connected to the side wall of the fixed connecting plate 26. The probe push plate 14 slides vertically against the side wall of the fixed connecting plate 26 and has a guide groove 141 for the guide rod 15 to slide through. The cooperation between the guide rod 15 and the guide groove 141 guides the vertical sliding process of the probe push plate 14, improves the stability of the vertical sliding process of the probe push plate 14, and facilitates the probe push plate 14 to drive the first probe 1, the second probe 2 and the third probe 3 to be accurately inserted into the current transformer for electrical connection.

[0040] The first probe 1, the second probe 2, and the third probe 3 are all fixedly passed through the probe push plate 14 and extended downwards. The first probe 1 is aligned vertically with a crimping screw, the second probe 2 is aligned vertically with another crimping screw, and the third probe 3 is aligned vertically with the coil connection point between the two crimping screws. Specifically, the lower end of the third probe 3 is a thinner tip, and the coil part aligned with the lower end of the third probe 3 is an enameled wire. The third probe 3 is inserted downwards into the enameled wire and electrically connected to the internal wire of the coil. The puncture wound is small and will not damage the original insulation of the coil. In this embodiment, the upper end of the current transformer is also provided with three detection plugs 27 that are aligned vertically with the first probe 1, the second probe 2, and the third probe 3. The first probe 1, the second probe 2, and the third probe 3 pass downwards through the detection plugs 27 and are then electrically connected to the current transformer. The setting of the detection plugs 27 further guides and limits the first probe 1, the second probe 2, and the third probe 3.

[0041] When the secondary side of the current transformer is not open-circuited, the temperature on the detection conductor 12 cannot reach the switching threshold of the temperature sensing switch 13, so the temperature sensing switch 13 is in the open state, the drive device does not work, the probe push plate 14 is located above the current transformer and remains stable, and the first probe 1, the second probe 2 and the third probe 3 remain stable and away from the current transformer under the drive of the probe push plate 14. When the secondary side of the current transformer is open-circuited, the temperature on the detection conductor 12 rises sharply and reaches the switching threshold of the temperature sensing switch 13, that is, the temperature sensing switch 13 switches to the closed state, the drive device works and drives the probe push plate 14 to slide downward. The first probe 1, the second probe 2 and the third probe 3 slide downward together under the drive of the probe push plate 14, so that the first probe 1 is electrically connected to a crimping screw, the second probe 2 is electrically connected to another crimping screw, and the third probe 3 is electrically connected to the coil between the two crimping screws, thereby realizing the automated operation of the detection mechanism.

[0042] The inspection circuit, which performs overall inspection on the two crimped screws, includes an inspection power supply 4, an inspection switch 5, and an inspection alarm 6 connected in series. The inspection alarm 6 can be an electric bell that vibrates and sounds when powered on. A first alarm 7 is electrically connected between the first probe 1 and the inspection circuit, and a second alarm 8 is electrically connected between the second probe 2 and the inspection circuit. Both the first alarm 7 and the second alarm 8 are alarms that do not distinguish between DC power supply directions. For example, both the first alarm 7 and the second alarm 8 can be bidirectional LED lights that do not distinguish between DC power supply directions. Because the first probe 1 and the second probe 2 are electrically connected to the two crimped screws respectively, this ensures that the inspection circuit, the first probe 1, the second probe 2, the first alarm 7, and the second alarm 8... A series circuit is formed. During the inspection, the inspection switch 5 is closed. If neither of the two crimping screws has a loose connection problem, the series circuit in which the inspection circuit is located is a closed loop. The inspection alarm 6, the first alarm 7, and the second alarm 8 are all working. This indicates that the open circuit on the secondary side of the current transformer is not caused by a loose connection in the crimping screw. If one or both of the two crimping screws have a loose connection problem, the series circuit in which the inspection circuit is located is an open circuit. The inspection alarm 6, the first alarm 7, and the second alarm 8 are all not working. At this time, it is determined that one or both of the two crimping screws have a loose connection problem, which leads to the open circuit on the secondary side of the current transformer. Then, the inspection circuit is used to detect which crimping screw has a loose connection problem that caused the open circuit on the secondary side of the current transformer.

[0043] In one implementation, the inspection power supply 4, the inspection switch 5, and the inspection alarm 6 are connected in series. The first alarm 7 is electrically connected between the first probe 1 and the inspection alarm 6, and the second alarm 8 is electrically connected between the second probe 2 and the inspection power supply 4. An ammeter 11 is electrically connected between the second probe 2 and the second alarm 8. The positive terminal of the inspection power supply 4 is connected to the positive terminal of the ammeter 11. The magnitude of the current reading in the ammeter 11 is used to detect whether there are abnormal phenomena such as aging in the coil between the two crimping screws.

[0044] The separate inspection circuit for separately inspecting two crimped screws includes a separate inspection power supply 9 and a separate inspection switch 10 connected in series. The positive terminal of the separate inspection power supply 9 is connected to the positive terminal of the ammeter 11. The separate inspection power supply 9 is electrically connected between the third probe 3 and the separate inspection switch 10. The separate inspection switch 10 includes a moving contact electrically connected to the separate inspection power supply 9, a first stationary contact electrically connected between the first alarm 7 and the inspection circuit, and a second stationary contact electrically connected between the second alarm 8 and the inspection circuit. Specifically, the first stationary contact is electrically connected between the first alarm 7 and the inspection alarm 6, and the second stationary contact is electrically connected between the second alarm 8 and the inspection power supply 4. During the inspection, the moving contact of the separate inspection switch 10 is not electrically connected to either the first stationary contact or the second stationary contact, so that the separate inspection circuit is not electrically connected to the first probe 1 or the second probe 2.

[0045] During the sorting process, disconnect the inspection switch 5 and electrically connect the moving contact and the first stationary contact of the sorting changeover switch 10. This creates a closed series circuit consisting of the third probe 3, the sorting circuit, the first alarm 7, and the first probe 1. If the first alarm 7 is working, it indicates that the crimping screw connected to the first probe 1 has no loose connection. Conversely, if the first alarm 7 is not working, it indicates that the crimping screw connected to the first probe 1 has a loose connection. Next, rotate the sorting changeover switch 10 to electrically connect the moving contact and the second stationary contact. This creates a closed series circuit consisting of the third probe 3, the sorting circuit, the second alarm 8, and the second probe 2. If the second alarm 8 is working, it indicates that the crimping screw connected to the second probe 2 has no loose connection. Conversely, if the second alarm 8 is not working, it indicates that the crimping screw connected to the second probe 2 has a loose connection. This method effectively determines which crimping screw has a loose connection.

[0046] Specifically, the drive device in this embodiment includes a drive motor 21 mounted on the drive circuit and a threaded screw 22 that rotates under the drive of the drive motor 21. The temperature sensing switch 13 is connected in series with the drive motor 21 on the drive circuit. An internal threaded plate 23 for the threaded screw 22 to pass through is fixedly connected to the probe push plate 14. The temperature sensing switch 13 is normally open at room temperature and switches to a closed state at high temperature. When there is no open circuit on the secondary side of the current transformer, the temperature on the detection conductor 12 has not reached the specified value. The switching threshold of the temperature sensor switch 13 is such that when the temperature sensor switch 13 is in the open state, the drive motor 21 does not work. When an open circuit occurs on the secondary side of the current transformer, the temperature on the conductor 12 is detected to rise and reach the switching threshold of the temperature sensor switch 13. The temperature sensor switch 13 switches to the closed state and the drive motor 21 works. The drive motor 21 drives the threaded screw 22 set in the up and down direction to rotate. The threaded engagement between the threaded screw 22 and the internal thread plate 23 causes the internal thread plate 23 to drive the probe push plate 14 to slide downward together.

[0047] In addition, a limiting plate 25 is fixedly connected to the probe push plate 14, and a limiting rod 24 slides through the limiting plate 25. The axial direction of the limiting rod 24 is parallel to the sliding direction of the probe push plate 14, that is, the limiting rod 24 is set to face up and down. The cooperation between the limiting plate 25 and the limiting rod 24 guides the up and down sliding process of the probe push plate 14, thereby improving the stability of the up and down sliding process of the probe push plate 14.

[0048] Specifically, the self-testing mechanism in this embodiment is as follows: an insulating slide plate 17 is slidably disposed in the guide groove 141, which is close to the guide rod 15 under the push of the elastic push block 18. The elastic push block 18 is fixedly connected between the insulating slide plate 17 and the inner wall of the guide groove 141. The first probe 1 and the second probe 2 are electrically connected by a disconnected power-on mechanism. During the downward movement of the probe push plate 14, the probe push plate 14 moves to the point where the middle protrusion of the guide rod 15 is located in the guide groove 141. The middle protrusion of the guide rod 15 presses the insulating slide plate 17 to cause displacement, thereby closing the power-on mechanism of the insulating slide plate 17 push plate, which in turn makes the first probe 1 and the second probe 2 electrically connected, closing the inspection switch 5, so that the first probe 1, the second probe 2, and the first alarm... The indicator 7, the second alarm 8, and the inspection circuit form a closed series circuit. If they do not work, it indicates that there is an abnormality in the inspection circuit, the first probe 1, the second probe 2, the first alarm 7, and the second alarm 8. The detection mechanism and the inspection circuit need to be tested before subsequent work can proceed. If the first alarm 7, the second alarm 8, and the inspection alarm 6 all work, it indicates that there is no abnormality in the inspection circuit, the first probe 1, the second probe 2, the first alarm 7, and the second alarm 8. The probe push plate 14 continues to slide down and leaves the protrusion in the middle of the guide rod 15. The insulating slide plate 17 slides back to reset under the elastic push of the elastic push block 18 and leaves the power connection mechanism. The power connection mechanism switches to the disconnected state again, so that the first probe 1 and the second probe 2 are disconnected from the electrical connection.

[0049] In one embodiment, the electrical connection mechanism includes two sets of opposing probe electrical connection blocks 16 and sliding electrical connection blocks 19. The two probe electrical connection blocks 16 are electrically connected to the first probe 1 and the second probe 2, respectively. There are two guide rods 15, and the probe push plate 14 has two guide grooves 141 through which the guide rods 15 pass. The two probe electrical connection blocks 16 extend into the two guide grooves 141 respectively. The insulating slide plate 17 is located between the guide rods 15 and the probe electrical connection blocks 16, and the sliding electrical connection blocks 19 are fixedly connected to the end face of the insulating slide plate 17 near the probe electrical connection blocks 16. The two sliding electrical connection blocks 19 are electrically connected by a wire 20. Under the elastic push of the elastic push block 18, the insulating slide plate 17 moves away from the probe electrical connection blocks 16, so that the sliding electrical connection blocks 19 move away from the insulating slide plate 17 together. The probe contact block 16 and the sliding contact block 19 are not electrically connected to the probe contact block 16, causing the first probe 1 and the second probe 2 to lose their electrical connection. When the insulating slide plate 17 moves together with the probe push plate 14 to the middle protrusion of the guide rod 15, the insulating slide plate 17 slides towards the probe contact block 16 under the pressure of the middle protrusion of the guide rod 15, so that the sliding contact block 19 and the probe contact block 16 are electrically connected. Thus, the first probe 1 and the second probe 2 are electrically connected through the probe contact block 16, the sliding contact block 19 and the wire 20. When the insulating slide plate 17 moves together with the probe push plate 14 to leave the middle protrusion of the guide rod 15, the insulating slide plate 17 is pushed away from the probe contact block 16 again by the elastic push of the elastic push block 18, so that the first probe 1 and the second probe 2 lose their electrical connection.

[0050] Working principle: When the secondary side of the current transformer is open-circuited, the temperature on the detection conductor 12 rises sharply, causing the temperature sensing switch 13 to close. The driving device works and drives the probe push plate 14 to slide downward. The first probe 1, the second probe 2 and the third probe 3 slide downward together under the action of the probe push plate 14, so that the first probe 1 is electrically connected to a crimping screw, the second probe 2 is electrically connected to another crimping screw, and the third probe 3 is electrically connected to the coil between the two crimping screws.

[0051] Close the inspection switch 5. If neither of the two crimping screws has a loose connection, the series circuit containing the inspection circuit is a closed loop. The inspection alarm 6, the first alarm 7, and the second alarm 8 are all working. This indicates that the open circuit on the secondary side of the current transformer is not caused by a loose connection in the crimping screws. If one or both of the two crimping screws have a loose connection, the series circuit containing the inspection circuit is an open circuit. The inspection alarm 6, the first alarm 7, and the second alarm 8 are all not working. In this case, it is determined that one or both of the two crimping screws have a loose connection, which leads to an open circuit on the secondary side of the current transformer.

[0052] Disconnect the inspection switch 5. First, electrically connect the moving contact and the first stationary contact of the sorting switch 10, so that the third probe 3, the sorting circuit, the first alarm 7, and the first probe 1 form a closed series circuit. If the first alarm 7 works, it means that the crimping screw connected to the first probe 1 has no loose connection problem. Conversely, if the first alarm 7 does not work, it means that the crimping screw connected to the first probe 1 has a loose connection problem. Next, rotate the sorting switch 10, so that the moving contact and the second stationary contact of the sorting switch 10 are electrically connected, so that the third probe 3, the sorting circuit, the second alarm 8, and the second probe 2 form a closed series circuit. If the second alarm 8 works, it means that the crimping screw connected to the second probe 2 has no loose connection problem. Conversely, if the second alarm 8 does not work, it means that the crimping screw connected to the second probe 2 has a loose connection problem.

[0053] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is obvious that many changes and variations can be made based on the above teachings. Although embodiments of the invention have been shown and described, these specific embodiments are merely explanations of the invention and are not intended to limit it. The specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. The purpose of selecting and describing exemplary embodiments is to explain the specific principles of the invention and its practical application, so that those skilled in the art, after reading this specification, can make modifications, substitutions, variations, and various choices and changes to the embodiments as needed without departing from the principles and spirit of the invention, provided that such modifications, substitutions, variations, and choices and changes are within the scope of the claims of the invention and are protected by patent law.

Claims

1. A low-voltage current transformer secondary pressure contact screw false connection detection device to be detected, characterized in that, Includes a testing mechanism, a complete inspection circuit, a sorting circuit, a first alarm (7), and a second alarm (8); The detection mechanism includes a detection conductor (12), a probe push plate (14), a guide rod (15), and a driving device. The detection conductor (12) passes through the central hole of the current transformer and is electrically connected to an AC power supply. A temperature sensing switch (13) for controlling the operation of the driving device is installed on the detection conductor (12). A guide groove (141) is provided on the probe push plate (14). Under the drive of the driving device, the probe push plate (14) approaches the current transformer through the action of the guide groove (141) and the guide rod (15). The transformer slides, and the probe push plate (14) is equipped with a first probe (1) and a second probe (2) that are electrically connected to the two crimping screws one by one, and a third probe (3) that is electrically connected to the coil between the two crimping screws. An insulating slide plate (17) that is pushed by the elastic push block (18) and close to the guide rod (15) is slidably arranged in the guide groove (141). The first probe (1) and the second probe (2) are electrically connected to a disconnected connection mechanism, and the middle part of the guide rod (15) protrudes and presses the insulating slide plate (17) to push the connection mechanism to close. The inspection circuit includes an inspection power supply (4), an inspection switch (5), and an inspection alarm (6) connected in series; the first alarm (7) is electrically connected between the first probe (1) and the inspection circuit, and the second alarm (8) is electrically connected between the second probe (2) and the inspection circuit. The sorting circuit includes a sorting power supply (9) and a sorting changeover switch (10) connected in series. The sorting power supply (9) is electrically connected between the third probe (3) and the sorting changeover switch (10). The sorting changeover switch (10) includes a moving contact electrically connected to the sorting power supply (9), a first stationary contact electrically connected between the first alarm (7) and the inspection circuit, and a second stationary contact electrically connected between the second alarm (8) and the inspection circuit.

2. The secondary crimping screw anti-virtual connection detection device of a low-voltage current transformer to be detected according to claim 1, characterized in that, The driving device includes a drive motor (21) mounted on the drive circuit and a threaded screw (22) that rotates under the drive of the drive motor (21). The temperature sensing switch (13) and the drive motor (21) on the drive circuit are connected in series. An internal threaded plate (23) is fixedly connected on the probe push plate (14) for the threaded screw (22) to pass through.

3. The secondary crimping screw anti-virtual connection detection device of the low-voltage current transformer to be detected according to claim 1, characterized in that, The power connection mechanism includes two sets of two pairs of opposing probe power connection blocks (16) and sliding power connection blocks (19), and the two probe power connection blocks (16) are electrically connected to the first probe (1) and the second probe (2) respectively. There are two guide rods (15), which pass through the corresponding two guide grooves (141). The two probe power connection blocks (16) extend into the two guide grooves (141) one by one. The insulating slide plate (17) is located between the guide rod (15) and the probe power connection blocks (16), and the sliding power connection blocks (19) are fixedly connected to the end face of the insulating slide plate (17) near the probe power connection blocks (16). The two sliding power connection blocks (19) are electrically connected through a wire (20).

4. The secondary crimping screw anti-virtual connection detection device of the low-voltage current transformer to be detected according to claim 1, characterized in that, The detection conductor (12) includes a first conductor (121) fixedly passing through the through hole of the current transformer and two second conductors (122) respectively slidably disposed at both ends of the first conductor (121). The temperature sensing switch (13) is fixedly installed on the first conductor (121), and the AC power of the AC power supply is delivered to the first conductor (121) through the second conductors (122).

5. The secondary crimping screw anti-virtual connection detection device of the low-voltage current transformer to be detected according to claim 1, characterized in that, The inspection power supply (4), inspection switch (5) and inspection alarm (6) are connected in series, and the first alarm (7) is electrically connected between the first probe (1) and the inspection alarm (6), and the second alarm (8) is electrically connected between the second probe (2) and the inspection power supply (4).

6. The secondary crimping screw anti-virtual connection detection device of the low-voltage current transformer to be detected according to claim 5, characterized in that, The first stationary contact is electrically connected between the first alarm (7) and the inspection alarm (6), and the second stationary contact is electrically connected between the second alarm (8) and the inspection power supply (4).

7. The secondary crimping screw anti-virtual connection detection device of the low-voltage current transformer to be detected according to claim 1, characterized in that, An ammeter (11) is electrically connected between the second probe (2) and the second alarm (8), and the positive terminals of the power supply (4) for overall inspection and the power supply (9) for individual inspection are connected to the positive terminal of the ammeter (11).

8. The secondary crimping screw anti-virtual connection detection device of the low-voltage current transformer to be detected according to claim 2, characterized in that, A limiting plate (25) is fixedly connected to the probe push plate (14), and a limiting rod (24) slides through the limiting plate (25), with the axial direction of the limiting rod (24) parallel to the sliding direction of the probe push plate (14).

9. A detection device for preventing loose connections of the secondary crimping screws of a low-voltage current transformer to be tested, as described in claim 1, is characterized in that... The inspection warning device (6) is an electric bell.

10. A detection device for preventing loose connections of the secondary crimping screws of a low-voltage current transformer to be tested, as described in claim 1, is characterized in that... Both the first warning device (7) and the second warning device (8) are bidirectional LED lights.

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