Heavy load test electric box

Abstract

The utility model discloses a heavy load test electric box in the technical field of power supply test. The heavy load test electric box comprises a three-phase four-wire system power supply, a plurality of test units and a terminal strip, each test unit comprises a heavy load connector, an air switch, three voltage and current sensors, three explosion-proof indicating lamps, a current and voltage display and a circuit current alarm. The power supply can supply power to a plurality of devices at the same time, achieves multiple purposes, improves the test efficiency, can carry out overload, short circuit and undervoltage protection, guarantees the safety of the circuit and the devices, can display the voltage and the current in real time, can detect the three-phase current in real time, gives an alarm when the devices go wrong, and improves the test efficiency. When a short-circuit fault occurs, rapid rising of current in the circuit can be restrained, impact force of short circuit on the circuit and equipment can be reduced, a power supply and a load can be prevented from being damaged, and the short-circuit protection circuit can be lightened when the short circuit occurs so as to send a warning signal to a tester, so that a short-circuit phase line can be conveniently, rapidly and accurately positioned.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply testing, in particular to a heavy-load testing electric box. Background Art

[0002] In industrial production, in order to verify whether the performance of high-power equipment under rated operating conditions meets expectations, ensure that it can operate normally in actual applications, and meet design requirements and user requirements, it is necessary to perform power supply testing on the high-power equipment after production is completed.

[0003] Power supply testing can promptly identify potential faults or defects in the machine's power supply, such as power module failure, overheating, short circuit, overload, and other safety hazards. By promptly identifying these problems and taking appropriate measures to correct them, more serious faults can be avoided in subsequent use, thereby reducing maintenance costs and time and ensuring the safety of the machine.

[0004] In the prior art, a heavy-load test box is usually used to test the power supply of the machine. The box has a heavy-load connector inside that can withstand a large load, transmit high current and high power, and ensure stable power supply.

[0005] However, the existing heavy-load test box still has the following problems:

[0006] 1. Only one high-power device can be tested at a time, which limits test efficiency;

[0007] 2. It does not have overvoltage protection and overcurrent protection, and cannot protect circuits and equipment;

[0008] 3. It does not have an alarm function and cannot promptly remind testers when problems such as short circuits occur in the equipment. Utility Model Content

[0009] The purpose of the utility model is to provide a heavy-load test electric box, which solves the technical problems of the heavy-load test electric box in the prior art, such as low test efficiency, lack of overvoltage protection and overcurrent protection, and inability to alarm.

[0010] The utility model discloses a heavy-load test electric box, comprising:

[0011] Three-phase four-wire power supply;

[0012] Several test units, each of which includes

[0013] Heavy-duty connectors;

[0014] An air switch, the input end of which is electrically connected to the three-phase four-wire power supply, and the load end of which is electrically connected to the input end of the heavy-duty connector via three phase wires and one neutral wire;

[0015] Three voltage and current sensors are installed on the three phase lines in a one-to-one correspondence;

[0016] Three explosion-proof indicator lights are connected in series to the three phase wires one by one;

[0017] A current and voltage display, the input end of which is electrically connected to the three voltage and current sensors, and is used to display voltage and current;

[0018] a circuit current alarm, the input end of which is electrically connected to the three voltage and current sensors;

[0019] The terminal block is connected to the ground terminal of each of the heavy-duty connectors.

[0020] This application can supply power to multiple devices at the same time, realizing multiple uses of one power source, thereby improving test efficiency. It can also perform overload, short circuit, and undervoltage protection to ensure the safety of circuits and equipment, and can display voltage and current in real time, so that testers can understand the circuit operation status in real time. It can also detect three-phase current in real time and issue an alarm when problems occur in the equipment, causing current imbalance or exceeding the error value, so as to remind testers to take corresponding measures in time; it can also effectively curb the sharp rise of current in the circuit when encountering a short circuit fault, thereby reducing the impact of the short circuit on the circuit and equipment, ensuring that the power supply and load are not damaged. At the same time, it will light up when a short circuit occurs to send a warning signal to the tester, so that the tester can quickly and accurately locate the phase line where the short circuit occurs.

[0021] On the basis of the above technical solution, the solution of this application can also be improved as follows:

[0022] Preferably, it also includes:

[0023] The power supply indicator light is connected between any two live wires in the three-phase four-wire power supply. With this solution, it can be intuitively displayed whether the power supply is in normal working condition. During equipment maintenance or troubleshooting, it serves as a basis for judging whether the power supply is working normally, and plays a role in safety warning to avoid electric shock or other safety accidents caused by misoperation.

[0024] Preferably, the testing unit comprises:

[0025] The output indicator light is connected between any two of the phase lines. By adopting this solution, it can be intuitively displayed whether the current air switch has current output, and it can be judged whether it is in the closed or disconnected state, which is convenient for equipment maintenance or troubleshooting, and enables the operator to promptly discover the abnormal situation of the output part of the equipment, so as to quickly take necessary measures to avoid further expansion of the fault or affect the overall performance of the equipment, which helps to improve reliability and stability.

[0026] Preferably, the circuit current alarm includes:

[0027] Three detection units, each of which includes

[0028] Terminal block A1,

[0029] Terminal A2,

[0030] Resistor R1, one end of which is connected to the wiring terminal A1,

[0031] The comparator U1 has an inverting input terminal connected to the other end of the resistor R1 and a non-inverting output terminal connected to the wiring terminal A2.

[0032] The resistor R2 has one end connected to the output end of the comparator U1.

[0033] The diode D1, the anode of which is connected to the other end of the resistor R2;

[0034] a current limiting resistor R3, one end of which is connected to the cathode of each of the diodes D1;

[0035] Fixed resistor R4, one end is connected to the 15V power supply;

[0036] an adjustable resistor R5, one end of which is connected to the other end of the fixed resistor R4 and the other end of which is grounded;

[0037] An operational amplifier AR, wherein the non-inverting input terminal is connected to the other end of the current limiting resistor R3, the inverting input terminal is connected to the other end of the fixed resistor R4, the positive power supply is connected to the 5V power supply, and the negative power supply is grounded;

[0038] A photocoupler OC, an input end of which is connected to the output port of the operational amplifier AR, and a ground end of which is grounded;

[0039] One end of the buzzer HA is connected to the 24V power supply, and the other end is connected to the output end of the photoelectric coupler OC. With this solution, the currents of the three phase lines can be compared in pairs, and an alarm will be issued when a problem occurs in any line. It has high stability and is easy to debug and maintain.

[0040] Preferably, the detection unit comprises:

[0041] Capacitor C1 is connected in series between the inverting input terminal and the output terminal of the comparator U1. This solution enhances stability, reduces the impact of transient noise, and utilizes the hysteresis characteristic to make the output change smoother, thereby improving the overall performance of the system.

[0042] Preferably, it also includes:

[0043] a fixed resistor R6, one end of which is connected to the cathode of each of the diodes D1;

[0044] One end of the adjustable resistor R7 is connected to the other end of the fixed resistor R6, and the other end is grounded. This solution absorbs and diverts part of the noise current, thereby reducing the impact of noise on the input signal of the operational amplifier, reducing the oscillation tendency of the circuit, and improving the stability of the circuit.

[0045] Through the above technical solution, the utility model achieves the following beneficial effects:

[0046] 1. This application is configured with an explosion-proof indicator light to apply a certain load to the test unit. When the test equipment encounters a short-circuit fault, this load can effectively curb the sharp rise in current in the circuit, thereby reducing the impact of the short circuit on the circuit and equipment, and ensuring that the power supply and load are not damaged. At the same time, the explosion-proof indicator light will light up when a short circuit occurs, sending a warning signal to the tester, allowing the tester to quickly and accurately locate the short-circuited phase line.

[0047] 2. This application can provide overload, short circuit, and undervoltage protection by configuring an air switch, thereby ensuring the safety of circuits and equipment;

[0048] 3. This application is equipped with three voltage and current sensors and a current and voltage display, which can display voltage and current in real time, making it easier for testers to understand the circuit operation status in real time;

[0049] 4. This application is configured with three voltage and current sensors and a circuit current alarm to detect three-phase current in real time, and to issue an alarm when a problem occurs in the equipment, causing current imbalance or exceeding the error value, so as to remind the tester to take corresponding measures in time. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0051] Figure 1 This is a structural diagram of a heavy-load test electrical box according to a specific embodiment of the present utility model;

[0052] Figure 2 for Figure 1 The circuit diagram of the circuit current alarm in the heavy-duty test electrical box shown;

[0053] Description of reference numerals:

[0054] 1. Three-phase four-wire power supply; 2. Test unit; 3. Terminal block; 4. Power indicator light;

[0055] 21. Heavy-duty connector; 22. Air switch; 23. Voltage and current sensor; 24. Explosion-proof indicator light; 25. Current and voltage display; 26. Circuit current alarm; 27. Output indicator light. DETAILED DESCRIPTION

[0056] The following embodiments of the technical solution of the present utility model will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present utility model and are therefore only examples and cannot be used to limit the scope of protection of the present utility model.

[0057] First of all, it should be noted that in the following description, some directional words involved in order to clearly illustrate the technical solution of the utility model, such as the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., all have meanings that are inferred from the normal directions of components in the heavy-load test electrical box. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as a limitation on the utility model.

[0058] In this application, unless otherwise specified or limited, the terms "mounted" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0059] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0060] Example:

[0061] like Figure 1 As shown, an embodiment of the present application discloses a heavy-load test electrical box for power supply testing of high-power equipment, and its specific structure includes: a three-phase four-wire power supply 1, several test units 2 and a terminal block 3.

[0062] The three-phase four-wire power supply 1 can simultaneously supply two different voltages of 208V and 380V to meet the needs of different loads. It includes three live wires and one neutral wire. The three live wires represent phases A, B, and C respectively. The voltage phases between them are 120 degrees apart. The role of the neutral wire is to maintain the symmetry of the phase voltages and enable the circuit to operate normally when the load is asymmetrical.

[0063] Each test unit 2 can supply power to a high-power device for testing, so that multiple devices can be powered at the same time, thereby achieving multiple uses of one power source and improving test efficiency. In this embodiment, the test unit 2 is set to two, but is not limited to this. It can also be three, four or more. It is set accordingly according to the actual load capacity and is not specifically limited.

[0064] Specifically, each test unit 2 includes: a heavy-duty connector 21 , an air switch 22 , three voltage and current sensors 23 , three explosion-proof indicator lights 24 , a current and voltage display 25 and a circuit current alarm 26 .

[0065] The heavy-duty connector 21 has a locking mechanism that prevents the connection from loosening or falling off in harsh environments such as vibration or impact, thereby providing a long-lasting and stable connection and ensuring the stability of power output. Its specific structure belongs to the existing technology and will not be repeated here.

[0066] The input end of the air switch 22 is electrically connected to the three-phase four-wire power supply 1, and the load end is electrically connected to the input end of the heavy-load connector 21 through three phase wires and one neutral wire; the main function of the air switch 22 in the circuit is to provide protection against overload, short circuit and undervoltage, thereby ensuring the safety of the circuit and equipment.

[0067] The three voltage and current sensors 23 are installed on the three phase lines in a one-to-one correspondence; they can use the inductive coupling effect to perform non-contact measurement on the circuit being tested, and have the advantage of high test accuracy.

[0068] The three explosion-proof indicator lights 24 are connected in series with the three phase lines one by one. The working principle is as follows:

[0069] When the heavy-duty connector 21 is not connected to a high-power device or the device is disconnected, the explosion-proof indicator light 24 is connected in series with the phase line and is not connected to the neutral line or other phase lines. Therefore, a closed circuit cannot be formed, and thus a complete circuit is not formed and the indicator light will not light up.

[0070] When the high-power device connected to the heavy-duty connector 21 is operating normally, it is equivalent to connecting the explosion-proof indicator light 24 and the high-power device in series. At this time, since the resistance value of the high-power device is much greater than that of the explosion-proof indicator light 24, according to the voltage division principle of the series circuit, the voltage distributed across the two ends of the explosion-proof indicator light 24 will be very small. Therefore, according to the electric power calculation formula: , the power consumed by the explosion-proof indicator light 24 will be very small, from which it can be seen that it will not light up or will only light up very weakly;

[0071] When the high-power device connected to the heavy-duty connector 21 is short-circuited, it is equivalent to directly connecting the explosion-proof indicator light 24 between the two phase lines. At this time, the explosion-proof indicator light 24 will light normally.

[0072] The present application is configured with an explosion-proof indicator light 24 to apply a certain load to the test unit 2; thus, when the test equipment encounters a short-circuit fault, the load can effectively curb the sharp rise of current in the circuit, thereby reducing the impact of the short circuit on the circuit and equipment, and ensuring that the power supply and load are protected from damage; at the same time, the explosion-proof indicator light 24 will light up when a short circuit occurs to send a warning signal to the tester, so that the tester can quickly and accurately locate the phase line where the short circuit occurs.

[0073] The input end of the current and voltage display 25 is electrically connected to the three voltage and current sensors 23 for displaying voltage and current, so that the tester can understand the circuit operation status in real time.

[0074] The input end of the circuit current alarm 26 is electrically connected to the three voltage and current sensors 23, and is used to detect the three-phase current in real time. When there is a problem with the equipment, which causes current imbalance or exceeds the error value, an alarm is issued to remind the tester to take corresponding measures in time.

[0075] The terminal block 3 is connected to the ground wire end of each heavy-duty connector 21. It can connect the ground wires together and connect to the ground wire, thereby ensuring the safety of equipment and personnel. When electrical equipment leaks or fails, it can quickly conduct current to the ground, thereby preventing electric shock accidents and protecting the safety of equipment and personnel.

[0076] In some embodiments, as Figure 1 As shown, it also includes: a power supply indicator light 4, which is connected between any two live wires in the three-phase four-wire power supply 1, and is used to intuitively display whether the power supply is in normal working condition. During equipment maintenance or troubleshooting, it serves as a basis for judging whether the power supply is working normally, and plays a safety warning role to avoid electric shock or other safety accidents caused by misoperation.

[0077] In some embodiments, as Figure 1 As shown, the test unit 2 includes: an output indicator light 27, which is connected between any two phase lines and can intuitively display whether the current air switch 22 has current output, thereby judging whether it is in a closed or disconnected state, which is convenient for equipment maintenance or troubleshooting, and enables the operator to promptly discover abnormal conditions in the output part of the equipment, so as to quickly take necessary measures to avoid further expansion of the fault or affect the overall performance of the equipment, which helps to improve reliability and stability.

[0078] In some embodiments, as Figure 2 As shown, the circuit current alarm 26 includes: three detection units, a current limiting resistor R3, a fixed resistor R4, an adjustable resistor R5, an operational amplifier AR and a buzzer HA.

[0079] Specifically, each detection unit includes: a terminal A1, a terminal A2, a resistor R1, a comparator U1, a resistor R2, and a diode D1. One end of resistor R1 is connected to terminal A1; the inverting input of comparator U1 is connected to the other end of resistor R1, and its non-inverting output is connected to terminal A2; one end of resistor R2 is connected to the output of comparator U1; and the anode of diode D1 is connected to the other end of resistor R2.

[0080] It should be noted that resistor R1 acts as a current limiter to prevent excessive current from damaging comparator U1 and to limit the amplitude of the input voltage to protect the circuit from the impact of excessive input voltage. Resistor R2 acts as a voltage divider to prevent the voltage across diode D1 from exceeding the maximum withstand voltage, thereby effectively preventing diode D1 from breaking down due to excessive voltage. Diode D1 prevents current from flowing in the reverse direction in the circuit, thereby preventing comparator U1 from being damaged.

[0081] Specifically, one end of the current limiting resistor R3 is connected to the cathode of each diode D1; one end of the fixed resistor R4 is connected to a 15V power supply; one end of the adjustable resistor R5 is connected to the other end of the fixed resistor R4, and the other end is grounded; the non-inverting input end of the operational amplifier AR is connected to the other end of the current limiting resistor R3, the inverting input end is connected to the other end of the fixed resistor R4, the positive power supply is connected to the 5V power supply, and the negative power supply is grounded; the input end of the photoelectric coupler OC is connected to the output port of the operational amplifier AR, and the ground end is grounded; one end of the buzzer HA is connected to a 24V power supply, and the other end is connected to the output end of the photoelectric coupler OC.

[0082] For example, to illustrate the working principle of the circuit current alarm 26 of this embodiment, it is as follows: Figure 2 The method shown is connected with three voltage and current sensors 23, specifically:

[0083] In the first detection unit: the connection terminal A1 is connected to the voltage and current sensor 23 corresponding to the L1 phase line, and the connection terminal A2 is connected to the voltage and current sensor 23 corresponding to the L2 phase line;

[0084] In the second detection unit: the connection terminal A1 is connected to the voltage and current sensor 23 corresponding to the L2 phase line, and the connection terminal A2 is connected to the voltage and current sensor 23 corresponding to the L3 phase line;

[0085] In the third detection unit: the connection terminal A1 is connected to the voltage and current sensor 23 corresponding to the L3 phase line, and the connection terminal A2 is connected to the voltage and current sensor 23 corresponding to the L1 phase line.

[0086] For example, when a fault occurs in the test equipment, causing the three-phase current to fluctuate, resulting in a sudden increase in the current of the L1 phase line, the voltage signal coupled out by the voltage and current sensor 23 corresponding to the L1 phase line will also increase accordingly. Therefore, in the third detection unit: the voltage signal received by the same-direction input terminal IN+ of the comparator U1 will be greater than the voltage signal received by the reverse output terminal IN-, so that the output terminal of the comparator U1 will output a high level. This high level reaches one end of the resistor R3 after passing through the resistor R2 and the diode D1, and then passes through the resistor R3 to the non-inverting input terminal IN+ of the operational amplifier AR. The fixed resistor R4 supplies 15V, and the adjustable resistor R5 is used as the ground. Then the voltage signal between the two is taken as the reference voltage of the inverting input terminal IN- of the operational amplifier AR. The operational amplifier AR supplies 5V for operation, and then outputs a voltage signal that flows into the optocoupler OC to turn it on, so that the power supply circuit of the buzzer HA is closed, thereby generating an alarm at the output end of the operational amplifier.

[0087] It should be noted that the current limiting resistor R3 plays a current limiting role. When excessive current passes through it, it will be damaged by overheating and open circuit, thereby protecting the back-end components such as the operational amplifier AR.

[0088] It should be noted that by changing the resistance of the adjustable resistor R5, the reference voltage of the inverting input terminal IN- of the operational amplifier AR can be adjusted, thereby adjusting the amplification factor of the operational amplifier AR. This has many advantages, such as improving circuit design flexibility, enhancing circuit stability, optimizing circuit performance, and facilitating debugging and maintenance.

[0089] The present application sets a circuit current alarm 26, and groups three voltage and current sensors 23 in pairs during installation, and connects them to the terminal A1 and the terminal A2 in the three detection units respectively; thereby, the current sizes of the three phase lines can be compared in pairs, and when a problem occurs in any line, a group of high levels will flow into the operational amplifier AR to cause the buzzer HA to alarm.

[0090] Based on the above embodiment, Figure 2 As shown in FIG, the detection unit includes a capacitor C1 connected in series between the inverting input terminal and the output terminal of the comparator U1. Therefore, when the output terminal of the comparator U1 outputs a high level, it can be compensated to the inverting input terminal IN- of the comparator U1 through the capacitor C1. As a result, the voltage of the inverting input terminal IN- will increase as the output high level lasts.

[0091] It can be understood that the above-mentioned feedback mechanism can keep the output of the comparator U1 at a high level for a longer time, so that even if the signal at the positive input terminal IN+ changes, the high level of the output can be temporarily continued, thereby enhancing stability, reducing the impact of transient noise, and utilizing the hysteresis characteristic to make the output change smoother, which can improve the overall performance of the system.

[0092] Based on the above embodiment, Figure 2 As shown, it also includes: a fixed resistor R6 and an adjustable resistor R7; wherein, one end of the fixed resistor R6 is connected to the cathode of each diode D1, one end of the adjustable resistor R7 is connected to the other end of the fixed resistor R6, and the other end is grounded.

[0093] The above arrangement plays a role in absorbing and diverting a portion of the noise current, thereby reducing the impact of noise on the input signal of the operational amplifier, reducing the oscillation tendency of the circuit, and improving the stability of the circuit.

[0094] In the specification of the present invention, a large number of specific details are described. However, it is understood that the embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this specification.

[0095] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A heavy-load test electric box, characterized in that: include: Three-phase four-wire power supply; Several test units, each of which includes Heavy-duty connectors, The air switch has an input end electrically connected to the three-phase four-wire power supply, and a load end electrically connected to the input end of the heavy-duty connector through three phase wires and one neutral wire. Three voltage and current sensors are installed on the three phase lines in a one-to-one correspondence. Three explosion-proof indicator lights are connected in series to the three phase lines one by one. The current and voltage display, whose input end is electrically connected to the three voltage and current sensors, is used to display voltage and current. a circuit current alarm, the input end of which is electrically connected to the three voltage and current sensors; The terminal block is connected to the ground terminal of each of the heavy-duty connectors.

2. The heavy-load test electric box according to claim 1, characterized in that: Also includes: The power supply indicator light is connected between any two live wires of the three-phase four-wire power supply.

3. The heavy-load test electric box according to claim 1, characterized in that: The testing unit comprises: The output indicator light is connected between any two of the phase wires.

4. The heavy-load test electric box according to claim 1, characterized in that: The circuit current alarm includes: Three detection units, each of which includes Terminal block A1, Terminal block A2, Resistor R1, one end of which is connected to the wiring terminal A1, The comparator U1 has an inverting input terminal connected to the other end of the resistor R1 and a non-inverting output terminal connected to the wiring terminal A2. The resistor R2 has one end connected to the output end of the comparator U1. The diode D1, the anode of which is connected to the other end of the resistor R2; a current limiting resistor R3, one end of which is connected to the cathode of each of the diodes D1; Fixed resistor R4, one end of which is connected to the 15V power supply; an adjustable resistor R5, one end of which is connected to the other end of the fixed resistor R4 and the other end of which is grounded; An operational amplifier AR, wherein the non-inverting input terminal is connected to the other end of the current limiting resistor R3, the inverting input terminal is connected to the other end of the fixed resistor R4, the positive power supply is connected to the 5V power supply, and the negative power supply is grounded; A photocoupler OC, an input end of which is connected to the output port of the operational amplifier AR, and a ground end of which is grounded; The buzzer HA has one end connected to the 24V power supply, and the other end connected to the output end of the photoelectric coupler OC.

5. The heavy-load test electric box according to claim 4, characterized in that: The detection unit comprises: The capacitor C1 is connected in series between the inverting input terminal and the output terminal of the comparator U1.

6. The heavy-load test electric box according to claim 5, characterized in that: Also includes: a fixed resistor R6, one end of which is connected to the cathode of each of the diodes D1; The adjustable resistor R7 has one end connected to the other end of the fixed resistor R6 and the other end grounded.

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