Alternating current and direct current combined load box for detecting electric power test power supply
By designing an AC/DC combined load box and connecting fixed resistors in series and parallel, the different resistance value requirements in power testing are solved, simplifying operation, reducing costs, and improving testing accuracy and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-23
- Publication Date
- 2026-03-13
AI Technical Summary
In the existing technology, the load resistor cannot meet the requirements of different resistance values in power tests, and the adjustable resistor is expensive and easily damaged, while the fixed load resistor is cumbersome to prepare and takes up space.
Design an AC/DC combined load box that combines fixed resistors in series and parallel to create various resistance values, including 220Ω, 110Ω, 55Ω, 20Ω, 10Ω and 5Ω, simplifying operation and connection nodes and reducing the number of fixed resistors.
It enables adaptability to diverse scenarios in power testing, simplifies operation procedures, reduces costs, improves testing accuracy and efficiency, and ensures the stability and reliability of load conditions.
Smart Images
Figure CN223992955U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of load boxes, specifically to an AC / DC combined load box for testing power supply. Background Technology
[0002] In the power industry, AC and DC 220V / 110V are the most common and frequently used voltage levels in low-voltage power transmission and distribution. They play a crucial role in power relay protection, high-voltage testing, and various other power testing scenarios. Power testing is a vital step in ensuring the performance and safety of power equipment. These tests typically require the current output characteristics to be calibrated or tested according to specific specifications. These specifications usually define different current ranges, such as 1A, 2A, 5A, 10A, and 20A, to simulate actual operating current conditions. By testing within these current ranges, the performance of the power equipment can be evaluated to determine whether it meets the requirements.
[0003] When conducting electrical tests, selecting an appropriate load resistor is crucial. In existing technologies, the load resistor can be either adjustable or fixed. For example, a 5A, 220Ω adjustable load resistor can withstand a maximum current of 5A. When connected to 220V, this adjustable resistor must be adjusted to at least 44Ω (220V / 5A), so its actual resistance range is 44Ω~220Ω, and its maximum power is 1.1kW. When a 10A current needs to be passed or measured, this 5A, 220Ω adjustable resistor cannot be used; another adjustable resistor, such as a 10A, 22Ω resistor, must be used. When connected to 220V, this 10A, 22Ω adjustable resistor must be adjusted to at least 22Ω (220V / 10A), meaning it can only be adjusted to 22Ω. When a 20A current needs to be passed or measured, the current far exceeds the maximum current handling capacity of 5A, 220Ω and 10A, 22Ω adjustable resistors. In this case, other adjustable resistors are required. Therefore, using a single or a small number of adjustable resistors cannot meet the needs of power testing for loads with different resistance values. Furthermore, if an adjustable resistor is adjusted to zero and then suddenly subjected to a high voltage, or vice versa, it can cause power supply overload and damage. Adjustable resistors are also relatively expensive. In such cases, using specially designed fixed load resistors can stably and reliably meet testing requirements while also saving costs.
[0004] Fixed load resistors have stable resistance values and are less susceptible to external factors, providing more stable and reliable load conditions during testing. This stability helps reduce test result errors and improve test accuracy. Furthermore, fixed load resistors are relatively simple to use, requiring no complex adjustment process, thus improving testing convenience and efficiency. The resistance value of a fixed load resistor is closely related to the voltage and current it can withstand. However, preparing a large number of fixed load resistors with different resistance values for each test not only increases costs but also occupies a significant amount of space and is cumbersome to manage.
[0005] Therefore, it is necessary to propose a new technical solution to overcome the problems existing in the current technology. Utility Model Content
[0006] This utility model addresses the above-mentioned problems and overcomes at least one deficiency of existing designs by proposing an AC / DC combined load box for testing power supply.
[0007] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:
[0008] An AC / DC combined load box for testing power supply for electrical tests, the AC / DC combined load box includes at least one first series branch, at least one second series branch, and at least one current sensing device;
[0009] The first series branch is formed by connecting at least two parts with a total resistance of 100Ω in series.
[0010] The second series branch is formed by connecting at least two parts with a total resistance of 10Ω in series;
[0011] Each part of the first series branch and the second series branch consists of a fixed resistor. Both ends of the fixed resistor and both ends of the current sensing device have connection nodes. The input end of the current sensing device is connected to the beginning or end of the first series branch and / or the beginning or end of the second series branch.
[0012] The AC / DC combined load cell is configured to combine resistance values of 220Ω, 110Ω, 55Ω, 20Ω, 10Ω and 5Ω by shorting and / or connecting different connection nodes.
[0013] Optionally, the first series branch is formed by connecting a first part and a second part, both with a resistance value of 100Ω, and the second series branch is formed by connecting a third part and a fourth part, both with a resistance value of 10Ω, with connection nodes at both ends of the first part, the second part, the third part, and the fourth part.
[0014] Optionally, the first part, the second part, the third part and the fourth part are connected in series through connecting nodes, and the combined AC / DC load box has a resistance value of 220Ω;
[0015] The resistance of the combined AC / DC load box is 110Ω, achieved by connecting the first or second, third or fourth parts in series via connection nodes.
[0016] The combined AC / DC load box has a resistance of 55Ω after the first and second parts are connected in series and parallel, and the third and fourth parts are connected in parallel.
[0017] The resistance of the combined AC / DC load box is 20Ω, achieved by connecting the third and fourth parts in series via a connection node.
[0018] The resistance value of the combined AC / DC load box is 10Ω, which is connected to the third or fourth part through the connection node.
[0019] By connecting the third and fourth parts in parallel through the connection nodes, the combined AC / DC load box has a resistance value of 5Ω.
[0020] Optionally, the first series branch is formed by two fixed resistors, each with a resistance of 100Ω, connected in series, and the second series branch is formed by two fixed resistors, each with a resistance of 10Ω, connected in series.
[0021] Optionally, the input terminal of the current sensing device is connected to the beginning or end of the second series branch.
[0022] Optionally, the output terminal of the current sensing device includes at least a first output circuit and a second output circuit, wherein the first output circuit is connected to an internal AC / DC ammeter, and the second output circuit is connected to an external AC / DC ammeter.
[0023] Optionally, the switching between the first output circuit and the second output circuit is achieved by a relay. The common terminal of the relay is connected to one output terminal of the current sensing device, the normally closed contact of the relay is connected to an internal AC / DC ammeter, and the normally open contact of the relay is connected to an external AC / DC ammeter. When no control signal is applied, the normally open contact of the relay is open and the normally closed contact is closed.
[0024] Optionally, the measurement accuracy of the external AC / DC ammeter is not less than 0.1%.
[0025] Optionally, the AC / DC combined load box further includes a third series branch, which is formed by connecting at least two parts with a total resistance of 2Ω in series. Each part of the third series branch consists of a fixed resistor, and the two ends of the fixed resistor have connection nodes. The AC / DC combined load box is configured to be able to combine different connection nodes to form the resistance values of the AC / DC combined load box of 22Ω and 11Ω.
[0026] Optionally, the third series branch is formed by connecting two fixed resistors with a resistance of 2Ω in series.
[0027] The beneficial effects of this utility model are:
[0028] This utility model provides an AC / DC combined load box for testing power supplies, specifically designed for power relay protection and high-voltage test power supplies. Through clever series and parallel connection of fixed resistors, the load box can be configured to provide various resistance values such as 220Ω, 110Ω, 55Ω, 20Ω, 10Ω, and 5Ω, perfectly adapting to diverse scenarios in power testing. Compared to traditional methods, this application eliminates the need for preparing a large number of fixed resistors with different resistance values, and avoids the cumbersome adjustment of adjustable resistors. Resistance value conversion can be quickly achieved simply by shorting and / or connecting different connection nodes. Furthermore, the number of fixed resistors in this application is significantly reduced, requiring a minimum of only four, effectively avoiding redundant design for single high-power loads. This not only simplifies the operation and connection nodes of the load box and lowers the technical threshold for operators, but also significantly improves the convenience and efficiency of testing, while effectively reducing production costs. The load box in this application uses only fixed resistors, ensuring the stability and reliability of load conditions during power testing, thereby significantly reducing test result errors, further improving test accuracy, and providing a more robust guarantee for power testing. Attached Figure Description
[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model, and not a limitation of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0030] Figure 1 This is a schematic diagram of the load cell according to an embodiment of the present invention;
[0031] Figure 2 This is a schematic diagram of the output circuit of the current sensing device in the load box according to an embodiment of the present invention. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the utility model will be further described in detail below with reference to the accompanying drawings. The components of the embodiments of this utility model described and shown in the accompanying drawings can be arranged and designed in various different configurations. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.
[0033] 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.
[0034] Unless otherwise defined, the technical or scientific terms used in this patent document shall have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar terms used in this utility model patent specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "an," "a," or "the" do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including" indicate that the element or object preceding "comprising" encompasses the element or object listed following "comprising" or its equivalents, and do not exclude other elements or objects. Terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are used only to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. 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, and therefore should not be construed as a limitation of this utility model.
[0035] The following describes some embodiments of the present invention in detail with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings.
[0036] This embodiment provides a technical solution: an AC / DC combined load box for testing power supply, the AC / DC combined load box including at least one first series branch, at least one second series branch, and at least one current sensing device; the first series branch is formed by connecting at least two parts with a total resistance of 100Ω, and the second series branch is formed by connecting at least two parts with a total resistance of 10Ω; each part of the first series branch and the second series branch is composed of a fixed resistor, and both ends of the fixed resistor and both ends of the current sensing device have connection nodes; the input end of the current sensing device is connected to the beginning or end of the first series branch and / or the beginning or end of the second series branch to monitor the current of the first series branch and / or the second series branch; the AC / DC combined load box is configured to combine resistance values of 220Ω, 110Ω, 55Ω, 20Ω, and 10Ω by shorting and / or connecting different connection nodes.
[0037] like Figure 1 As shown, in this embodiment, the first series branch is formed by connecting the first resistor R1 and the second resistor R2 in series, and the second series branch is formed by connecting the third resistor R3 and the fourth resistor R4 in series. Specifically, the first resistor R1 and the second resistor R2 are both fixed resistors with a resistance of 100Ω, and the third resistor R3 and the fourth resistor R4 are both fixed resistors with a resistance of 10Ω.
[0038] like Figure 1 As shown, in this embodiment, the primary current input terminal of the current sensing device is connected to the side connection node (start or end) of the second series branch, which can be either connected to connection node 0 or connection node 6. The current sensing device can detect both AC and DC current. By testing the circuit current value, the current sensing device can be used to calibrate and detect the accuracy of the power supply output current in power tests, and provide safety control functions such as overload protection and short-circuit protection. The current sensing device can also be connected to the side connection node (start or end) of the first series branch, but this design is not recommended because in power tests, the tested power is mostly above 2A, and during the use of the load bank, currents above 2A are usually selected using the second series branch. Therefore, adding a current sensing device to the first series branch is not very practical and increases the cost of the load bank. Therefore, the preferred solution is not to add a current sensing device to the first series branch. Of course, when selecting the first series branch, the current sensing device can be connected to the working circuit of the load bank through the connection node to detect the output current of the load bank. In addition, the current sensing device can be selected according to the requirements of the current sensor.
[0039] The first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, and the two ends of the current sensing device all have connection nodes (connection nodes 0, 1, 2, 3, 4, 5, 6) for electrical connection. Connection node 4 is located between the current sensing device and the second series circuit. Since the AC / DC combined load box needs to detect the current in the second series branch during use, connection node 4 is not used for connection in practice. Theoretically, if connection node 4 needs to be connected / short-circuited, it can be done by connecting / short-circuiting connection node 0. The AC / DC combined load box can combine the required resistance values of the load box by connecting different connection nodes, thereby meeting the voltage and current testing requirements of different scenarios in power testing. In electrical testing, 220V or 110V are specific voltages used in the power industry. The power supplies for instruments and equipment are all set to these voltages as their basic range. Generally, the test power supply voltage is adjustable from 0 to 220V or 0 to 110V. Typically, 1A and 2A tests use the specific voltage of 110V or 220V, while 5A, 10A, and 20A tests use the adjusted voltage of 200V or 100V. Based on these requirements, as shown in Table 1, the required resistance values (Ω) for different voltages (V) and currents (A) of the AC / DC combined load box used for testing electrical power supplies are specified.
[0040] Table 1. Resistance values (Ω) corresponding to different voltages (V) and currents (A) of the AC / DC combined load box used for power test.
[0041]
[0042] As can be seen from Table 1, the AC / DC combined load box for power testing in this application can be combined into several resistance values of 220Ω, 110Ω, 55Ω, 20Ω, 10Ω and 5Ω to meet the power load requirements of power testing. Table 2 shows the resistance connection method and connection node connection method of the AC / DC combined load box of this application with different resistance values.
[0043] Table 2 Connection methods for AC / DC combined load boxes with different resistance values for power test power supplies
[0044]
[0045] Short-circuiting refers to directly connecting two connection nodes in a conductive manner, forming a short circuit. Connecting A and B refers to the electrical connection points established between external equipment and the load box when the AC / DC combined load box is used as a load. As can be seen from Table 2, by connecting and short-circuiting different connection nodes, the fixed resistors in the first series branch and the second series branch of this application can also be used individually, in series, and in parallel, thereby obtaining different resistance values of the AC / DC combined load box for power testing power supply required in power testing.
[0046] In this embodiment, as Figure 2 The diagram shown is a schematic of the output circuit of the current sensing device in the load box of this embodiment. The secondary current output terminal of the current sensing device has two output circuits:
[0047] (1) First output circuit: The first output circuit of the current sensing device is connected to an AC / DC ammeter built into the load box, i.e., an internal AC / DC ammeter. The internal AC / DC ammeter can display the current value of AC or DC flowing through the load box in real time and intuitively, so as to quickly understand the working status of the load box.
[0048] (2) Second output circuit: The second output circuit of the current sensing device is connected to an external AC / DC ammeter, the accuracy of which is at least 0.1%. On the one hand, the external AC / DC ammeter has higher measurement accuracy than the internal AC / DC ammeter, and can provide more accurate current readings, which is crucial for test scenarios that require precise current measurement. On the other hand, the external AC / DC ammeter can be used as a standard ammeter to check whether the internal AC / DC ammeter of the load box for power testing is accurate.
[0049] The two output circuits of a current sensing device cannot be used simultaneously, such as... Figure 2As shown, the two output circuits can be switched equally using a relay. Since external AC / DC ammeters are not commonly used, the built-in AC / DC ammeter is the more common one, meaning the first output circuit is usually connected. Therefore, the common terminal of the relay is connected to the positive / negative output terminal of the current sensor. The negative / positive output terminal of the current sensor is divided into the first and second output circuits. One end of the built-in AC / DC ammeter is connected to the first output circuit, and the other end is connected to the normally closed contact (NC) of the relay to connect to the first output circuit. One end of the external AC / DC ammeter is connected to the second output circuit, and the other end is connected to the normally open contact (NO) of the relay to connect to the second output circuit. When no control signal is applied, the normally closed contact NC of the relay is closed, and the normally open contact NO is open, the first output circuit is connected (the built-in AC / DC ammeter operates), and the second output circuit is disconnected (the external AC / DC ammeter cannot be used). When a control signal is applied to the relay coil, the normally closed contact opens (the built-in AC / DC ammeter cannot operate), and the normally open contact closes (an external AC / DC ammeter can be used). The first output circuit is disconnected, and the second output circuit is connected. The relay device allows the user to switch the output channels of the current sensing device by pressing a button. This means that the user can freely switch between the built-in ammeter and an external high-accuracy ammeter to select the appropriate current measurement method according to the test requirements. This design not only saves on the cost of AC / DC combined load boxes for power supply testing but also improves the flexibility and applicability of these load boxes, enabling them to meet test requirements with varying accuracy.
[0050] 220V and 110V are specific voltages used in my country's power transmission and transformation. The power industry has extremely high requirements for voltage stability, safety, and reliability. Test results under specific voltages are more representative and comparable, and can more accurately reflect the performance and characteristics of equipment. Although voltage adjustments are sometimes made for specific testing needs, these adjustments are usually fine-tuned based on the specific voltage, and it must be ensured that the adjusted voltage does not significantly affect the test results. At the same time, voltage adjustments must also consider the safety and stability of the equipment to avoid damage or safety hazards caused by excessively high or low voltage. Therefore, in power testing, if conditions permit, the specific voltage of 220V or 110V is usually preferred for testing.
[0051] In this embodiment, the third series branch is formed by connecting the fifth resistor R5 and the sixth resistor R6 in series, where both the fifth resistor R5 and the sixth resistor R6 are fixed resistors with a resistance value of 2Ω. Both ends of the fifth resistor R5 and the sixth resistor R6 have connection nodes. The AC / DC combined load box can be combined to achieve resistance values of 22Ω and 11Ω by shorting and / or connecting different connection nodes. If it is necessary to measure 5A, 10A, and 20A at specific voltages of 220V and 110V, the load box needs to be able to combine to produce resistance values of at least 22Ω and 11Ω. In this embodiment, a load box with a resistance value of 22Ω can be obtained by connecting the third resistor R3, the fourth resistor R4, and the fifth resistor R5 in series, and a load box with a resistance value of 11Ω can be obtained by connecting the fifth resistor R5 and the sixth resistor R6 in parallel and then connecting the third resistor R3 in series. In practical applications, the same resistance value of the load box can be obtained through other connection methods, or more resistance values of the load box can be obtained through other connection methods or according to application requirements; these are not listed in this application.
[0052] It should be noted that the number and resistance value of the fixed resistors in each embodiment of this application are not constant. The fixed resistors in this embodiment can be replaced by multiple, series-connected fixed resistors with the same or different resistance values. For example, a 10Ω fixed resistor can be replaced by two 5Ω fixed resistors, a 100Ω fixed resistor can be replaced by two 44Ω and one 12Ω fixed resistor, or two 50Ω fixed resistors, or a 2Ω fixed resistor can be replaced by two 1Ω fixed resistors. This design can meet the needs of different resistance values in the load box in each embodiment and also allows for more flexible acquisition of load boxes with a wider range of resistance values to meet the needs of practical applications. It is well known to those skilled in the art that fewer resistors result in fewer connection nodes, making the operation of the load box simpler and reducing the probability of incorrect connection. In practical applications, the number and resistance value of the fixed resistors in the load box can be set according to the diversity of resistance values and ease of operation.
[0053] It should also be noted that the resistor connection method and the connection node connection method in this application are not the only connection methods to obtain the corresponding resistance value. In practical applications, the same resistance value can also be obtained through other connection methods. This application is only to illustrate that the load box of this embodiment can obtain different resistance values to meet the needs of existing power tests. More connection methods are not listed in this application.
[0054] The above description is only a preferred embodiment of the present utility model and does not limit the scope of patent protection of the present utility model. Any equivalent structural transformations made based on the content of the present utility model specification and drawings, whether directly or indirectly applied to other related technical fields, are similarly included within the scope of protection of the present utility model.
Claims
1. A combined AC / DC load box for testing power supply in electrical tests, characterized in that, The AC / DC combined load box includes at least one first series branch, at least one second series branch, and at least one current sensing device. The first series branch is formed by connecting at least two parts with a total resistance of 100Ω in series. The second series branch is formed by connecting at least two parts with a total resistance of 10Ω in series; Each part of the first series branch and the second series branch consists of a fixed resistor. Both ends of the fixed resistor and both ends of the current sensing device have connection nodes. The input end of the current sensing device is connected to the beginning or end of the first series branch and / or the beginning or end of the second series branch. The AC / DC combined load cell is configured to combine resistance values of 220Ω, 110Ω, 55Ω, 20Ω, 10Ω and 5Ω by shorting and / or connecting different connection nodes.
2. The AC / DC combined load box for testing power supply according to claim 1, characterized in that, The first series branch is formed by connecting the first part and the second part, both with a resistance value of 100Ω, and the second series branch is formed by connecting the third part and the fourth part, both with a resistance value of 10Ω, and there are connection nodes at both ends of the first part, the second part, the third part, and the fourth part.
3. The AC / DC combined load box for testing power supply according to claim 2, characterized in that: The resistance of the combined AC / DC load box is 220Ω, achieved by connecting the first, second, third, and fourth parts in series via connection nodes. The resistance of the combined AC / DC load box is 110Ω, achieved by connecting the first or second, third or fourth parts in series via connection nodes. The combined resistance of the AC / DC combined load box is 55Ω, achieved by connecting the first and second parts in series and the third and fourth parts in parallel. The resistance of the combined AC / DC load box is 20Ω, achieved by connecting the third and fourth parts in series via a connection node. The resistance value of the combined AC / DC load box is 10Ω, which is connected to the third or fourth part through the connection node. By connecting the third and fourth parts in parallel through the connection nodes, the combined AC / DC load box has a resistance value of 5Ω.
4. The AC / DC combined load box for testing power supply according to claim 1, characterized in that, The first series branch is formed by two fixed resistors, each with a resistance of 100Ω, connected in series, and the second series branch is formed by two fixed resistors, each with a resistance of 10Ω, connected in series.
5. The AC / DC combined load box for testing power supply according to claim 1, characterized in that, The input terminal of the current sensing device is connected to the beginning or end of the second series branch.
6. The AC / DC combined load box for testing power supply according to claim 1, characterized in that, The output terminal of the current sensing device includes at least a first output circuit and a second output circuit. The first output circuit is connected to an internal AC / DC ammeter, and the second output circuit is connected to an external AC / DC ammeter.
7. The AC / DC combined load box for testing power supply according to claim 6, characterized in that, The switching between the first output circuit and the second output circuit is achieved by a relay. The common terminal of the relay is connected to one output terminal of the current sensing device. The normally closed contact of the relay is connected to an internal AC / DC ammeter, and the normally open contact of the relay is connected to an external AC / DC ammeter. When no control signal is applied, the normally open contact of the relay is open and the normally closed contact is closed.
8. The AC / DC combined load box for testing power supply according to claim 6, characterized in that, The measurement accuracy of the external AC / DC ammeter is not less than 0.1%.
9. The AC / DC combined load box for testing power supply according to claim 1, characterized in that, The AC / DC combined load box further includes a third series branch, which is formed by connecting at least two parts with a total resistance of 2Ω. Each part of the third series branch consists of a fixed resistor, and the two ends of the fixed resistor have connection nodes. The AC / DC combined load box is configured to be able to combine different connection nodes to form the resistance values of the AC / DC combined load box of 22Ω and 11Ω.
10. The AC / DC combined load box for testing power supply according to claim 9, characterized in that, The third series branch is formed by connecting two fixed resistors with a resistance of 2Ω in series.