Turn ratio testing device of mutual inductor
By designing conversion and connection modules, a double-pole double-throw switch is used to achieve lossless switching between the transformer winding coil and the detection coil, solving the problems of clamping damage and low efficiency in transformer testing in the prior art, and realizing efficient and stable multi-group transformer turns ratio testing.
Patent Information
- Application Number
- CN202520199777.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-08
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2035-02-08
AI Technical Summary
In existing methods for testing the turns ratio of current transformers, the test clamps are in close contact with the winding coil pins, which can cause damage. This results in low testing efficiency, and the wear of the clamp pin wires affects stability, increasing labor and material costs.
By employing conversion and connection modules, a double-pole double-throw switch is used to achieve non-destructive switching between the current transformer winding coil and the detection coil. Combined with tooling fixtures, multiple current transformers can be tested simultaneously, avoiding pin damage and improving testing efficiency.
It effectively avoids damage to the current transformer pins, improves testing efficiency, reduces labor and consumable costs, and enables efficient turns ratio testing of multiple current transformers.
Smart Images
Figure CN223870750U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of instrument transformer testing technology, and in particular to a turns ratio testing device for instrument transformers. Background Technology
[0002] Instrument transformers, also known as instrument transformers, are a general term encompassing current transformers and voltage transformers. They are devices used to convert high voltage and large current into low voltage and small current. Instrument transformers are widely used in various electrical equipment and facilities, primarily for metering electricity, detecting leakage current, and providing leakage protection. With the rapid development of industries such as electric vehicles, the development of instrument transformers is also facing new opportunities and challenges.
[0003] A current transformer consists of a magnetic core, a primary winding coil, a secondary winding coil, a housing, and terminals. During manufacturing, the performance of the current transformer needs to be tested, such as the turns ratio test. Therefore, a detection coil is set between the primary winding coil and the secondary winding coil for the turns ratio test.
[0004] For the three windings of a current transformer (including the primary winding coil, secondary winding coil, and detection coil mentioned above), the existing turns ratio testing method usually involves fixing one set of test clamps connected to the testing instrument to touch two pins of the detection coil, while the other test clamp alternately clamps either the primary winding coil or the secondary winding coil pins. The turns ratio is tested by switching between the two winding coils to achieve the testing purpose. However, the following problems still exist:
[0005] 1) During the process, the test clamp is in close contact with the pins of the winding coil, which can easily cause varying degrees of damage to the pins of the product, thus affecting the quality of the product; and only one product can be tested at a time, resulting in low testing efficiency.
[0006] 2) During long-term conversion testing, the pin header used for clamping the test clamp also wears out. After a certain number of tests, the pin header socket also enlarges, leading to unstable testing in the later stages. The pin header needs to be replaced regularly, which greatly affects testing efficiency and results in excessive labor and consumable costs. Utility Model Content
[0007] To address the problems existing in the prior art, this utility model provides a turns ratio testing device for current transformers, comprising:
[0008] A conversion module is connected to the detection coils and test module of several current transformers under test. The conversion module can selectively connect the test module to the detection coils of different current transformers under test.
[0009] The connection module connects the first winding coil and the second winding coil of each of the current transformers under test, as well as the conversion module. The connection module can selectively connect the first winding coil and the second winding coil of the same current transformer under test, and the conversion module can selectively connect to different connection modules.
[0010] Preferably, the conversion module includes a first conversion device and a second conversion device. Both the first conversion device and the second conversion device are provided with a first set of connection points, a second set of connection points and a third set of connection points. Each of the first set of connection points is connected to the test module.
[0011] In the first conversion device, the second set of connection points are respectively connected to two pins of the detection coil of one of the current transformers under test, and the third set of connection points are respectively connected to two pins of the detection coil of the other current transformer under test;
[0012] In the second conversion device, the second set of connection points and the third set of connection points are connected to the connection module.
[0013] Preferably, the connection module includes a first connection device and a second connection device, and both the first connection device and the second connection device are provided with a fourth set of connection points, a fifth set of connection points and a sixth set of connection points;
[0014] In the first connection device, the fourth set of connection points are respectively connected to the second set of connection points of the second conversion device, the fifth set of connection points are respectively connected to two pins of the first winding coil of one of the current transformers under test, and the sixth set of connection points are respectively connected to two pins of the second winding coil of one of the current transformers under test.
[0015] In the second connection device, the fourth set of connection points are respectively connected to the third set of connection points of the second conversion device, the fifth set of connection points are respectively connected to two pins of the first winding coil of another current transformer under test, and the sixth set of connection points are respectively connected to two pins of the second winding coil of another current transformer under test.
[0016] Preferably, the first set of connection points of the first conversion device is connected to the first input port and the first output port of the test module, respectively, and the first set of connection points of the second conversion device is connected to the second input port and the second output port of the test module, respectively.
[0017] Preferably, the first conversion device and the second conversion device are double-pole double-throw switches. The first set of connection points is provided on both sides of one moving end of the double-pole double-throw switch, and the second set of connection points and the third set of connection points are respectively provided on both sides of the two stationary ends of the double-pole double-throw switch.
[0018] Preferably, when switching the connection circuit, the stationary ends of the first conversion device and the second conversion device are switched synchronously.
[0019] Preferably, the first connecting device and the second connecting device are double-pole double-throw switches, and the fourth set of connection points are provided on both sides of one moving end of the double-pole double-throw switch, and the fifth set of connection points and the sixth set of connection points are provided on both sides of the two stationary ends of the double-pole double-throw switch, respectively.
[0020] Preferably, the device also includes a tooling fixture, which has a plurality of through holes, each of which is respectively connected to two pins of the detection coil, two pins of the first winding coil, and two pins of the second winding coil of the current transformer under test.
[0021] Preferably, each of the through holes is provided with a metal sheet, which is electrically connected to the conversion module and the connection module via a connecting wire.
[0022] Preferably, the tooling fixture has limiting members around each through hole corresponding to the insertion position of each current transformer under test, which are adapted to the shape of the current transformer under test.
[0023] The above technical solution has the following advantages or beneficial effects: By setting up conversion modules and connection modules to reasonably connect the current transformer under test and the test module of the testing equipment, after connecting the current transformer under test, switching between different current transformers under test or between different windings of the same current transformer under test can be performed simply by switching the conversion module or the connection module, which can effectively avoid damage to the pins of the current transformer; in addition, multiple sets of current transformer turns ratio tests can be performed simultaneously, and the switching operation is simple, which greatly improves the testing efficiency. Attached Figure Description
[0024] Figure 1 A schematic diagram of the structure of a turns ratio testing device for a current transformer is shown in a preferred embodiment of this utility model.
[0025] Figure 2 This is a schematic diagram of the structure of the first connecting device K1 in a preferred embodiment of the present invention.
[0026] Figure 3 This is a schematic diagram of the pin distribution of the current transformer under test in a preferred embodiment of the present invention. Detailed Implementation
[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The present invention is not limited to this embodiment; other embodiments that conform to the spirit of the present invention may also fall within its scope.
[0028] In a preferred embodiment of this utility model, based on the above-mentioned problems existing in the prior art, a turns ratio testing device for a current transformer is provided, such as... Figure 1 As shown, it includes:
[0029] The conversion module 1 is connected to the detection coils 2 of several current transformers under test and the test module 3. The conversion module 1 can selectively connect the test module 3 to the detection coils 2 of different current transformers under test.
[0030] The connection module 4 is connected to the first winding coil 5, the second winding coil 6 of each current transformer under test, and the conversion module 1. The connection module 4 can be selectively connected to the first winding coil 5 and the second winding coil 6 of the same current transformer under test, and the conversion module 1 can be selectively connected to different connection modules 4.
[0031] Specifically, in this embodiment, the conversion module 1 is used to connect the test module 3 and the detection coil 2, and to switch between the detection coils 2 of different transformers under test. The conversion module 1 is also used to connect the test module 3 and the first winding coil 5 and the second winding coil 6 in conjunction with the connection module 1, and to switch between the first winding coil 5 and the second winding coil 6.
[0032] Furthermore, taking two current transformers under test as an example, when the test coil 2 of one of the current transformers under test, A, is connected to the test module 3 via the conversion module 1, the detection signal input to the test module 3 is received by the test module 3 after passing through the corresponding connection loop of the test coil 2. When the first winding coil 5 of the current transformer under test, A, is connected to the test module 3 via the conversion module 1 and the connection module 4, the detection signal input to the test module 3 is received by the test module 3 after passing through the corresponding connection loop of the first winding coil 5. When the current transformer under test, A, is switched to be connected to the second winding coil 6 via the conversion module 1 and the connection module 4, the detection signal input to the test module 3 is received by the test module 3 after passing through the corresponding connection loop of the second winding coil 6.
[0033] Since the detection coil 2 is typically a coil with a small number of turns, such as 5 or 10 turns, for ease of counting, it can usually be determined visually. By using the detection signal received when the test module 3 is connected to the detection coil 2, and the detection signal received when the test module 3 is connected to the first winding coil 5, the vector relationship between the detection coil 2 and the first winding coil 5 can be determined. Based on the number of turns of the detection coil 2, the number of turns of the first winding coil 5 can be obtained. Similarly, the number of turns of the second winding coil 6 can be obtained.
[0034] When conversion module 1 switches to connect the test coil 2 of another current transformer B to test module 3, the detection signal input by test module 3 is received by test module 3 after passing through the corresponding connection loop of test coil 2. Subsequently, test module 3 is connected to the first winding coil 5 and the second winding coil 6 of the current transformer B through conversion module 1 and connection module 4 respectively. By receiving the corresponding detection signal and combining it with the number of turns of test coil 2 of current transformer B, the number of turns of the first winding coil 5 and the second winding coil 6 can be obtained.
[0035] During the above turns ratio test, there is no need to repeatedly adjust the wiring between the current transformer under test and the conversion module 1 and the connection module 4. The current transformer under test only needs to be connected once. Subsequently, the connection of different connected circuits can be achieved by switching the conversion module 1 and the connection module 4. That is, switching between different current transformers under test or between different windings of the same current transformer under test, thereby completing the turns ratio test and effectively avoiding damage to the pins of the current transformer under test.
[0036] In a preferred embodiment of the present invention, the conversion module 1 includes a first conversion device K2 and a second conversion device K3. The first conversion device K2 and the second conversion device K3 are each provided with a first set of connection points, a second set of connection points and a third set of connection points. Each first set of connection points is connected to the test module 3.
[0037] In the first conversion device K2, the second set of connection points are respectively connected to the two pins of the detection coil of one of the current transformers under test, and the third set of connection points are respectively connected to the two pins of the detection coil of the other current transformer under test.
[0038] In the second conversion device K3, the second set of connection points and the third set of connection points are connected to the connection module 4.
[0039] In a preferred embodiment of the present invention, the connection module 4 includes a first connection device K2 and a second connection device K4. The first connection device K1 and the second connection device K4 are each provided with a fourth set of connection points, a fifth set of connection points and a sixth set of connection points.
[0040] In the first connecting device K1, the fourth set of connection points are respectively connected to the second set of connection points of the second conversion device K3, the fifth set of connection points are respectively connected to the two pins of the first winding coil 5 of one of the current transformers under test, and the sixth set of connection points are respectively connected to the two pins of the second winding coil 6 of one of the current transformers under test.
[0041] In the second connecting device K4, the fourth set of connection points are respectively connected to the third set of connection points of the second conversion device K3, the fifth set of connection points are respectively connected to the two pins of the first winding coil 5 of another current transformer under test, and the sixth set of connection points are respectively connected to the two pins of the second winding coil 6 of another current transformer under test.
[0042] In a preferred embodiment of the present invention, the first set of connection points of the first conversion device K2 is connected to the first input port D1 and the first output port D2 of the test module 3, respectively, and the first set of connection points of the second conversion device K3 is connected to the second input port D3 and the second output port D4 of the test module 3, respectively.
[0043] In a preferred embodiment of the present invention, the first conversion device K2 and the second conversion device K3 are double-pole double-throw switches. A first set of connection points is provided on both sides of one moving end 100 of the double-pole double-throw switch, and a second set of connection points and a third set of connection points are provided on both sides of the two stationary ends 200 of the double-pole double-throw switch, respectively.
[0044] Specifically, in this embodiment, the two terminals on both sides of the moving end 100 of the first conversion device K2 and the second conversion device K3 correspond to the first set of connection points, the two terminals on both sides of the stationary end 200 above the moving end 100 correspond to the second set of connection points, and the two terminals on both sides of the stationary end 200 below the moving end 100 correspond to the third set of connection points.
[0045] In a preferred embodiment of the present invention, when switching the connection circuit, the stationary ends 200 of the first conversion device K2 and the second conversion device K3 are switched synchronously.
[0046] In a preferred embodiment of the present invention, the first connecting device K1 and the second connecting device K4 are double-pole double-throw switches. A fourth set of connection points is provided on both sides of one moving end 100 of the double-pole double-throw switch, and a fifth set of connection points and a sixth set of connection points are provided on both sides of the two stationary ends 200 of the double-pole double-throw switch, respectively.
[0047] Specifically, in this embodiment, the two terminals on both sides of the moving end 100 of the first connecting device K1 and the second connecting device K4 correspond to the fourth group of connection points, the two terminals on both sides of the stationary end 200 above the moving end 100 correspond to the fifth group of connection points, and the two terminals on both sides of the stationary end 200 below the moving end 100 correspond to the sixth group of connection points.
[0048] As a preferred embodiment, the turns ratio testing process will be described using the turns ratio testing device of this utility model to test the turns ratio of the first and second current transformers under test.
[0049] Among them, such as Figure 2 The diagram shows the structure of the first connecting device K1, where K13 and K14 are the first set of connection points, K11 and K12 are the second set of connection points, and K15 and K16 are the third set of connection points. The second connecting device K2, the first conversion device K2, and the second conversion device K3 have the same structure and connection point marking order as the first connecting device K1, and will not be shown one by one.
[0050] like Figure 3 As shown, the six pins of the first current transformer under test are marked as A1, A2, A3, A4, A5, and A6, respectively. A1 and A2 correspond to two pins of the first winding coil 5, A3 and A4 correspond to two pins of the detection coil 2, and A5 and A6 correspond to two pins of the second winding coil 6. The six pins of the second current transformer under test are marked as B1, B2, B3, B4, B5, and B6, respectively. B1 and B2 correspond to two pins of the first winding coil 5, B3 and B4 correspond to two pins of the detection coil 2, and B5 and B6 correspond to two pins of the second winding coil 6.
[0051] Before performing the turns ratio test, pins A3 and A4 of the detection coil 2 of the first current transformer under test are connected to terminals K21 and K22 on both sides of the fixed end 200 above the first conversion device K2, respectively. Similarly, pins B3 and B4 of the detection coil 2 of the second current transformer under test are connected to terminals K25 and K26 on the fixed end 200 below the first conversion device K2. This allows the first conversion device K2 to switch between the detection coils 2 of the first and second current transformers under test.
[0052] Before performing the turns ratio test, the first connection device K1 connects two pins A1 and A2 of the first winding coil 5 of the first transformer under test to two terminals K11 and K22 of the fixed terminal 200 above the first connection device K1, respectively. It also connects two pins A5 and A6 of the second winding coil 6 of the first transformer under test to two terminals K15 and K16 of the fixed terminal 200 below the first connection device K1. Thus, the first connection device K1 enables switching between the first winding coil 5 and the second winding coil 6 of the first transformer under test.
[0053] Before performing the turns ratio test, the process includes connecting two pins B1 and B2 of the first winding coil 5 of the second current transformer under test to two terminals K41 and K42 of the fixed end 200 above the second connecting device K4, respectively. Similarly, the process involves connecting two pins B5 and B6 of the second winding coil 6 of the second current transformer under test to two terminals K45 and K46 of the fixed end 200 below the second connecting device K4. This allows the second connecting device K4 to switch between the first winding coil 5 and the second winding coil 6 of the second current transformer under test.
[0054] Before conducting the turns ratio test, the test module 4's first input port D1 and first output port D2 are connected to the two terminals K23 and K24 on both sides of the moving end 100 of the first conversion device K2, respectively, and the test module 4's second input port D3 and second output port D4 are connected to the two terminals K33 and K34 on both sides of the moving end 100 of the second conversion device K3, respectively.
[0055] At this point, the wiring of the two current transformers under test and test module 4 is complete, and the turns ratio test can begin. First, the turns ratio test will be performed on the first current transformer under test. The operating steps are as follows:
[0056] Simultaneously move the switch handles of the moving ends 100 of the first conversion device K2 and the second conversion device K3 upwards, so that K23 and K21 of the first conversion device K2 are connected, and K24 and K22 are connected, and K33 and K31 of the second conversion device K3 are connected, and K34 and K32 are connected. At this time, a detection signal is input through the first input port D1. The detection signal passes sequentially through K23 and K21 of the first conversion device K2, pins A3 and A4 of the detection coil 2 (A3 and A4 are connected by enameled wire forming a winding), and K22 and K24 of the first conversion device K2, and is finally received by the first output port D2.
[0057] Then, the switch handle of the first connecting device K1 is moved upward, so that K13 and K11 of the first connecting device K1 are connected and K14 and K12 are connected, and the first winding coil 5 of the first transformer under test is detected. At this time, the detection signal is input into the second input port D3. The detection signal passes through K33 and K31 of the second conversion device K3, K13 and K11 of the first connecting device K1, pins A1 and A2 of the first winding coil 5, K12 and K14 of the first connecting device K1, and K32 and K34 of the second conversion device K3 in sequence. Finally, the relevant detection signal is received by the second output port D4. The turns ratio between the first winding coil 5 of the first transformer under test and the detection coil 2 can be calculated by the signal value between the first output port D2 and the second output port D4, so as to obtain the number of turns of the first winding coil 5 of the first transformer under test.
[0058] Correspondingly, the switch handle of the first connecting device K1 is moved downwards, so that K13 and K15 of the first connecting device K1 are connected, and K14 and K16 are connected, to detect the second winding coil 6 of the first current transformer under test. At this time, the detection signal is input into the second input port D3. The detection signal passes through K33 and K31 of the second conversion device K3, K13 and K15 of the first connecting device K1, pins A5 and A6 of the second winding coil 6, K14 and K16 of the first connecting device K1, and K32 and K34 of the second conversion device K3 in sequence. Finally, the relevant detection signal is received by the second output port D4. The turns ratio between the second winding coil 6 of the first current transformer under test and the detection coil 2 can be calculated by the signal value between the first output port D2 and the second output port D4, thereby obtaining the number of turns of the second winding coil 6 of the first current transformer under test.
[0059] After completing the turns ratio test of the first transformer under test, simultaneously move the switch handles of the moving ends 200 of the first conversion device K2 and the second conversion device K3 downwards to switch to the position of the detection coil 2 and the winding coil under test of the second transformer under test. Repeat a process similar to the above to perform the turns ratio test on the first winding coil 5 and the second winding coil 6 of the second transformer under test.
[0060] As can be seen, apart from wiring the first and second current transformers under test with the corresponding first conversion device K2, second conversion device K3, first connecting device K1 and second connecting device K4 before the turns ratio test, no wiring adjustment is required during the entire test process. Only the positions of the switch handles of the first conversion device K2, second conversion device K3, first connecting device K1 and second connecting device K4 need to be adjusted accordingly. This effectively avoids damage to the current transformer pins, simplifies the switching operation, and effectively improves the test efficiency.
[0061] In a preferred embodiment of the present invention, a tooling fixture is further included. The tooling fixture is provided with a plurality of through holes, each through hole corresponding to two pins of the detection coil 2, two pins of the first winding coil 5, and two pins of the second winding coil 6 of the current transformer under test.
[0062] In a preferred embodiment of this utility model, each through hole is provided with a metal sheet, which is electrically connected to the conversion module 1 and the connection module 4 via a connecting wire.
[0063] In a preferred embodiment of this utility model, the tooling fixture has limiting members around each through hole corresponding to the insertion position of each current transformer under test, which are adapted to the shape of the current transformer under test.
[0064] Specifically, in this embodiment, since the pins of the current transformer typically extend from one direction, the aforementioned fixture can be designed according to the pin distribution during turns ratio testing. Specifically, six through holes are set on the fixture based on the positions of the six pins. The through hole size can be slightly larger than the pin size. A metal plate can be installed at the inner end of the through hole to connect to the connecting wire of the conversion module or connection module. This way, when the pin is inserted into the corresponding through hole, it only contacts the metal plate, avoiding damage to the pin. Furthermore, corresponding fixing or limiting structures can be set on the fixture according to the shape of the current transformer as limiting members to ensure the stability of the current transformer during testing. The aforementioned limiting members can be multiple fixing posts or fixing slots distributed circumferentially according to the shape of the current transformer; no limitation is made here.
[0065] The above description is only a preferred embodiment of the present utility model and does not limit the implementation method and protection scope of the present utility model. Those skilled in the art should realize that all solutions obtained by equivalent substitutions and obvious changes made using the content of this specification and illustrations should be included within the protection scope of the present utility model.
Claims
1. A turns ratio testing device for a current transformer, characterized in that, include: A conversion module is connected to the detection coils and test module of several current transformers under test. The conversion module can selectively connect the test module to the detection coils of different current transformers under test. The connection module connects the first winding coil and the second winding coil of each of the current transformers under test, as well as the conversion module. The connection module can selectively connect the first winding coil and the second winding coil of the same current transformer under test, and the conversion module can selectively connect to different connection modules.
2. The turns ratio testing device according to claim 1, characterized in that, The conversion module includes a first conversion device and a second conversion device. Both the first conversion device and the second conversion device are provided with a first set of connection points, a second set of connection points and a third set of connection points. Each of the first set of connection points is connected to the test module. In the first conversion device, the second set of connection points are respectively connected to two pins of the detection coil of one of the current transformers under test, and the third set of connection points are respectively connected to two pins of the detection coil of the other current transformer under test; In the second conversion device, the second set of connection points and the third set of connection points are connected to the connection module.
3. The turns ratio testing device according to claim 2, characterized in that, The connection module includes a first connection device and a second connection device, and both the first connection device and the second connection device are provided with a fourth set of connection points, a fifth set of connection points and a sixth set of connection points. In the first connection device, the fourth set of connection points are respectively connected to the second set of connection points of the second conversion device, the fifth set of connection points are respectively connected to two pins of the first winding coil of one of the current transformers under test, and the sixth set of connection points are respectively connected to two pins of the second winding coil of one of the current transformers under test. In the second connection device, the fourth set of connection points are respectively connected to the third set of connection points of the second conversion device, the fifth set of connection points are respectively connected to two pins of the first winding coil of another current transformer under test, and the sixth set of connection points are respectively connected to two pins of the second winding coil of another current transformer under test.
4. The turns ratio testing device according to claim 2, characterized in that, The first set of connection points of the first conversion device is connected to the first input port and the first output port of the test module, respectively, and the first set of connection points of the second conversion device is connected to the second input port and the second output port of the test module, respectively.
5. The turns ratio testing device according to claim 2, characterized in that, The first conversion device and the second conversion device are double-pole double-throw switches. The first set of connection points is provided on both sides of one moving end of the double-pole double-throw switch, and the second set of connection points and the third set of connection points are respectively provided on both sides of the two stationary ends of the double-pole double-throw switch.
6. The turns ratio testing apparatus according to claim 5, characterized in that, When switching the connection circuit, the stationary ends of the first conversion device and the second conversion device switch synchronously.
7. The turns ratio testing device according to claim 3, characterized in that, The first connecting device and the second connecting device are double-pole double-throw switches. The fourth set of connection points is provided on both sides of one moving end of the double-pole double-throw switch, and the fifth set of connection points and the sixth set of connection points are provided on both sides of the two stationary ends of the double-pole double-throw switch, respectively.
8. The turns ratio testing device according to claim 1, characterized in that, It also includes a tooling fixture, which has several through holes, each of which is respectively connected to two pins of the detection coil, two pins of the first winding coil, and two pins of the second winding coil of the transformer under test.
9. The turns ratio testing apparatus according to claim 8, characterized in that, Each of the through holes is provided with a metal sheet, which is electrically connected to the conversion module and the connection module via a connecting wire.
10. The turns ratio testing apparatus according to claim 8, characterized in that, The tooling fixture has limiting members around each through hole corresponding to the insertion position of each current transformer under test, which are adapted to the shape of the current transformer under test.