Calibrating device for testing frequency of pincerlike grounding resistance tester

Abstract

The utility model provides a clamp-shaped grounding resistance tester test frequency calibration device, and relates to the technical field of calibration systems. The device comprises a shielding system, a measuring system, a connecting system and a fixing system, and the shielding system is used for placing a pincerlike grounding resistance tester to be detected and shielding electromagnetic interference; the measuring system comprises a current transformer, a digital multimeter and a frequency counter; the connection system comprises a copper rod, a copper core wire and a BNC wire, the copper rod and the copper core wire form a detected loop, and the BNC wire is connected with the current transformer, the digital multimeter and the frequency counter; the fixing system comprises a copper rod support and an insulating plate, the copper rod support is used for fixing the copper rod and enabling the copper rod to be vertical to the test table top, and concentric circles with different diameters are drawn on the insulating plate and used for positioning the copper rod. According to the device, the test calibration problem of the test frequency of the pincer-like grounding resistance tester and the electromagnetic interference problem are solved, and the traceability of the pincer-like grounding resistance tester is standardized by analyzing test data.

Description

Technical Field

[0001] This utility model relates to the field of calibration system technology, specifically to a test frequency calibration device for a clamp-on grounding resistance tester. Background Technology

[0002] Currently, there are no national or enterprise standards in China for the testing frequency of clamp-on grounding resistance meters. The verification procedures for clamp-on grounding resistance meters do not clearly define the range of their resistance testing frequencies, only specifying that they are AC resistance meters. The calibration and measurement capability ranges recognized by multiple calibration institutions do not specify the exact measurement frequency for resistance, making it impossible to guarantee the accuracy of the traceability chain for clamp-on grounding resistance meters. Different manufacturers, both domestic and international, provide different testing frequencies in their instruction manuals. For clamp-on grounding resistance meters currently on the market, there is no suitable equipment for determining and calibrating their testing frequencies. Utility Model Content

[0003] The purpose of this invention is to address the shortcomings of the prior art by providing a clamp-on grounding resistance tester frequency calibration device to solve the problem of measuring and calibrating the test frequency of the resistance tester.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] This invention provides a test frequency calibration device for a clamp-on grounding resistance tester. The device includes a shielding system, a measurement system, a connection system, and a fixing system.

[0006] The shielding system is used to house the clamp-on grounding resistance tester under test and to shield against electromagnetic interference when the grounding resistance tester is working.

[0007] The measurement system includes a current transformer, a digital multimeter, and a frequency counter. The maximum short-circuit current range of the measurement system is 0.1 to 0.9 A, and the resistance test frequency range is 1.5 to 3.333 kHz.

[0008] The connection system includes two copper rods, two copper core wires, and one BNC wire. The copper rods and copper core wires form the circuit under test, and the BNC wire connects the current transformer, digital multimeter, and frequency counter.

[0009] The fixing system includes two sets of copper rod supports and an insulating plate. The copper rod supports are used to fix the copper rods and keep them vertical at 90° on the test platform. The insulating plate located below the copper rods has multiple concentric circles of different diameters drawn on it to position the copper rods so that the two copper rods are respectively located at the center of the clamp-on grounding resistance meter and the current transformer.

[0010] Optionally, the shielding system is a Faraday cage with a length, width and height of 600 mm and an openable top. The Faraday cage has two wire through holes on its side. The cage grounding terminal is connected to a preset grounding electrode by a copper wire with a length of 2000 mm and a cross-sectional area of ​​25 mm².

[0011] Optionally, the current transformer is a 4100 type broadband pulse current transformer, the digital multimeter is an 8588A digital multimeter, and the frequency counter is an SP3386 frequency counter.

[0012] Optionally, the copper rod in the connection system has a diameter of 10 mm and a length of 200 mm, and the cross-sectional area of ​​the copper core wire in the connection system is 6 mm². 2 It is 500 mm in length.

[0013] Optionally, the plurality of concentric circles consists of 5 concentric circles, and the diameter of each concentric circle ranges from 10 mm to 50 mm.

[0014] The beneficial effects of this utility model include:

[0015] The clamp-on grounding resistance tester frequency calibration device provided by this utility model includes a shielding system, a measurement system, a connection system, and a fixing system. The shielding system is used to place the clamp-on grounding resistance tester under test and to shield electromagnetic interference when the grounding resistance tester is working. The measurement system includes a current transformer, a digital multimeter, and a frequency counter. The maximum short-circuit current range of the measurement system is 0.1 to 0.9 A, and the resistance test frequency range is 1.5 to 3.333 kHz. The connection system includes two copper rods, two copper core wires, and one BNC wire. The copper rods and copper core wires form the circuit under test. The BNC wire connects the current transformer, the digital multimeter, and the frequency counter. The fixing system includes two sets of copper rod supports and an insulating plate. The copper rod supports are used to fix the copper rods and keep them vertical at 90° on the test platform. Concentric circles of different diameters are drawn on the insulating plate below the copper rods to position the copper rods so that the two copper rods are respectively centered on the clamp-on grounding resistance tester and the current transformer. This device solves the problem of test frequency calibration for clamp-on grounding resistance testers, eliminates electromagnetic interference during operation of clamp-on grounding resistance testers, and standardizes the traceability of clamp-on grounding resistance testers by analyzing test data. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments 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 diagram shows the overall structure of the clamp-on grounding resistance tester frequency calibration device provided in this embodiment of the present invention.

[0018] Figure 2 A schematic diagram of the shielding system provided in an embodiment of the present invention is shown;

[0019] Figure 3A A cross-sectional schematic diagram of the Faraday cage provided in an embodiment of the present invention is shown;

[0020] Figure 3B A side view of the Faraday cage provided in an embodiment of the present invention is shown;

[0021] Figure 4 A schematic diagram of the measurement system provided in an embodiment of the present invention is shown;

[0022] Figure 5 A schematic diagram of the connection system provided in an embodiment of the present invention is shown;

[0023] Figure 6 A schematic diagram of the fixing device provided in an embodiment of the present invention is shown. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0027] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model 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 utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" 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 connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0029] Currently available clamp-on grounding resistance meters lack suitable equipment for measuring and calibrating the test frequency. Therefore, this invention provides a test frequency calibration device for clamp-on grounding resistance testers.

[0030] Figure 1 This diagram illustrates the overall structure of the clamp-on grounding resistance tester frequency calibration device provided in an embodiment of the present invention. Figure 1 As shown, the clamp-on grounding resistance tester frequency calibration device provided by this utility model includes a shielding system 101, a measurement system 102, a connection system 103, and a fixing system 104.

[0031] Figure 2 A schematic diagram of the shielding system provided in an embodiment of the present invention is shown; Figure 3A A cross-sectional schematic diagram of the Faraday cage provided in an embodiment of the present invention is shown; Figure 3B A side view of the Faraday cage provided in an embodiment of the present invention is shown.

[0032] The shielding system 101 is used to house the clamp-on grounding resistance tester under test and to shield against electromagnetic interference when the grounding resistance tester is working. The shielding system 101 is a Faraday cage, with a length, width, and height of 600 mm each, and an openable top. Specifically, the top of the Faraday cage is an openable cover 201, which is connected to the cage body via a copper hinge 202, allowing the cover 201 to be opened and closed. Two wire through-holes 203, each 10 mm in diameter, are provided on the side of the Faraday cage. The cage body grounding terminal 204 is connected to a pre-set grounding electrode (e.g., a laboratory grounding electrode) via a copper wire 205, 2000 mm long and with a cross-sectional area of ​​25 mm².

[0033] Figure 4 A schematic diagram of the measurement system provided in this embodiment of the present invention is shown. The measurement system 102 includes a current transformer 401, a digital multimeter 402, and a frequency counter 403. The maximum short-circuit current range of the measurement system 102 is 0.1 to 0.9 A, and the resistance test frequency range is 1.5 to 3.333 kHz. For example, the current transformer 401 is a 4100 type broadband pulse current transformer, the digital multimeter 402 is an 8588A digital multimeter, and the frequency counter 403 is an SP3386 frequency counter.

[0034] Figure 5 A schematic diagram of the connection system provided in this embodiment of the present invention is shown. The connection system 103 includes two copper rods 501, two copper core wires 502, and one BNC wire 503. The copper rods 501 and the copper core wires 502 form the circuit under test. The BNC wire 503 connects the current transformer 401, the digital multimeter 402, and the frequency counter 403. The copper rods 501 in the connection system 103 have a diameter of 10 mm and a length of 200 mm, and the copper core wires 502 in the connection system 103 have a cross-sectional area of ​​6 mm². 2 The length is 600 mm. When the current transformer 401 is connected to the digital multimeter 402, the BNC wire 503 is a BNC male-to-BNC banana plug; when the current transformer 401 is connected to the frequency counter 403, the BNC wire 503 is a BNC male-to-BNC male plug; when the current transformer 401 is connected to both the digital multimeter 402 and the frequency counter 403, the BNC wire 503 is a BNC male-to-BNC male plug connected to a BNC bus tee, with one end connected to the multimeter and the other end connected to the frequency counter.

[0035] Figure 6A schematic diagram of the fixing device provided in this embodiment of the present invention is shown. The fixing system 104 includes two sets of copper rod supports 601 and an insulating plate 602. The copper rod supports 601 are used to fix the copper rods 501 and keep them vertical at 90° on the test platform, thus solving the problem of fixing the copper rods in the test circuit. Multiple concentric circles of different diameters are drawn on the insulating plate 602 located below the copper rods 501 to position the copper rods 501 so that the two copper rods 501 are respectively located at the center of the clamp-on grounding resistance meter and the current transformer 401, thereby solving the positioning problem of the clamp-on grounding resistance meter and the broadband pulse current transformer. It should be noted that because there are two copper rods 501, each copper rod 501 is fixed by a corresponding copper rod support 601, and an insulating plate 602 is correspondingly provided below each copper rod 501. Optionally, the multiple concentric circles are five concentric circles, and the diameter of each concentric circle ranges from 10 mm to 50 mm. Figure 6 The diagram shows only one set of fixing devices; the entire fixing system includes two identical sets of fixing devices.

[0036] The working principle of this calibration device is as follows: it consists of current measurement and frequency measurement principles, which will be described separately below. Current Measurement Principle: The grounding terminal of the Faraday cage is connected to the laboratory grounding electrode using a 2000mm long, 25mm² cross-sectional area soft copper wire; the copper rod outside the Faraday cage is inserted into the current transformer, fixed, and positioned at the center of the current transformer. The current transformer is connected to a multimeter using a BNC-to-banana connector wire. The multimeter is turned on and set to the AC voltage range; the top cover of the Faraday cage is opened, the clamp-on grounding resistance tester is turned on, and the clamp-on grounding resistance tester to be measured is clamped onto the copper rod inside the cage, with the copper rod in the center of the clamp jaws. The top cover of the Faraday cage is then closed; the AC voltage display value of the multimeter is read. V 0; Since the transformer ratio is 1V / 1A, the current to be measured is V 0 / (1V / 1A). Frequency measurement principle: The Faraday cage grounding terminal is connected to the laboratory grounding electrode using a 2000mm long, 25mm² cross-sectional area soft copper wire; the copper rod outside the Faraday cage is inserted into the current transformer, fixed, and positioned at the center of the current transformer. The current transformer is connected to the frequency counter using a BNC male-to-BNC female wire, and the frequency counter is turned on; the top cover of the Faraday cage is opened, the clamp-on grounding resistance tester is turned on, and the clamp-on grounding resistance tester to be measured is clamped onto the copper rod inside the cage, with the copper rod in the center of the clamp jaws. The top cover of the Faraday cage is closed; the display value of the frequency counter is read. f 0.

[0037] The specific operating steps of this calibration device are as follows: First, turn on the multimeter and frequency counter and warm them up for 30 minutes, then begin the calibration work. The current calibration steps are as follows: Connect the Faraday cage grounding terminal to the laboratory grounding electrode using a 2000mm long, 25mm² cross-sectional area soft copper wire; insert the copper rod outside the Faraday cage into the current transformer, fix it, and place it in the center of the current transformer. Connect the current transformer to the multimeter using a BNC banana head wire, and set the multimeter to the AC voltage range; open the top cover of the Faraday cage, turn on the clamp-on grounding resistance tester, clamp the clamp-on grounding resistance tester to be measured onto the copper rod inside the cage, so that the copper rod is in the center of the clamp jaws, and close the top cover of the Faraday cage; read the AC voltage display value of the multimeter. V 0; Since the transformer ratio is 1V / 1A, the current to be measured is V 0 / (1V / 1A). The frequency calibration steps are as follows: Insert the copper rod outside the Faraday cage into the current transformer, fix it, and place it in the center of the current transformer. Connect the current transformer to the frequency counter using a BNC male-to-BNC female wire. Open the top cover of the Faraday cage, turn on the clamp-on grounding resistance tester, clamp the clamp-on grounding resistance tester to be measured onto the copper rod inside the cage, so that the copper rod is in the center of the clamp jaws, and close the top cover of the Faraday cage; read the displayed value of the frequency counter. f 0.

[0038] In summary, this device solves the problem of test frequency calibration for clamp-on grounding resistance testers, eliminates electromagnetic interference during operation, and standardizes the traceability of clamp-on grounding resistance testers by analyzing test data.

[0039] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A test frequency calibration device for a clamp-on grounding resistance tester, characterized in that, The device includes a shielding system, a measuring system, a connection system, and a fixing system. The shielding system is used to house the clamp-on grounding resistance tester under test and to shield electromagnetic interference when the grounding resistance tester is working. The measurement system includes a current transformer, a digital multimeter, and a frequency counter. The maximum short-circuit current range of the measurement system is 0.1 to 0.9 A, and the resistance test frequency range is 1.5 to 3.333 kHz. The connection system includes two copper rods, two copper core wires, and one BNC wire. The copper rods and copper core wires form the circuit under test, and the BNC wire connects the current transformer, digital multimeter, and frequency counter. The fixing system includes two sets of copper rod supports and an insulating plate. The copper rod supports are used to fix the copper rods and keep them vertical at 90° on the test platform. Multiple concentric circles of different diameters are drawn on the insulating plate below the copper rods to position the copper rods so that the two copper rods are respectively located at the center of the clamp-on grounding resistance meter and the current transformer.

2. The test frequency calibration device for the clamp-on grounding resistance tester according to claim 1, characterized in that, The shielding system is a Faraday cage, which is 600mm long, wide and high, and the top can be opened. The side of the Faraday cage is provided with two wire through holes. The cage grounding terminal is connected to the preset grounding electrode through a copper wire with a length of 2000mm and a cross-sectional area of ​​25 mm².

3. The test frequency calibration device for the clamp-on grounding resistance tester according to claim 1, characterized in that, The current transformer is a 4100 type broadband pulse current transformer, the digital multimeter is an 8588A digital multimeter, and the frequency counter is an SP3386 frequency counter.

4. The test frequency calibration device for the clamp-on grounding resistance tester according to claim 1, characterized in that, The copper rod in the connection system has a diameter of 10 mm and a length of 200 mm, and the cross-sectional area of ​​the copper core wire in the connection system is 6 mm². 2 It is 500 mm in length.

5. The test frequency calibration device for the clamp-on grounding resistance tester according to claim 1, characterized in that, The plurality of concentric circles consists of 5 concentric circles, and the diameter of each concentric circle ranges from 10 mm to 50 mm.

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