Grounding and overcurrent relay detection device

Abstract

The utility model discloses a grounding and overcurrent relay detection device which comprises a current control circuit, a switching control circuit, a first current detection circuit and a second current detection circuit. The input end of the current control circuit is connected with a power supply, and the output end is connected with the input end of the switching control circuit; the output end of the switching control circuit is respectively connected with the input ends of the first current detection circuit and the second current detection circuit; the output end of the first current detection circuit is connected with the grounding relay; the output end of the second current detection circuit is connected with the grounding relay, and the current detection range of the second current detection circuit is larger than that of the first current detection circuit, so that on-line detection can be directly carried out on the relay without dismounting the relay, the detection process is simplified, and the detection efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of motor vehicle auxiliary equipment, in particular to a grounding and overcurrent relay detection device. Background Art

[0002] Circuit safety in diesel locomotives is an essential component of railway transportation safety. Grounding and overcurrent relays are protective relays for the diesel locomotive's main circuit, used to de-excite the synchronous main generator and exciter, enabling locomotive unloading. Existing diesel locomotives commonly use the 5Q17 grounding relay and the 5Q6 overcurrent relay, both of which are main circuit protection devices. The 5Q17 grounding relay activates when a point in the locomotive's main circuit is grounded or the grounding relay coil current reaches 500mA, activating an alarm light, shutting off power to the coil, and unloading the diesel engine. The 5Q6 overcurrent relay monitors traction motor ring fire, traction silicon rectifier element short circuits, and overcurrent in the synchronous main generator. When the rectifier current reaches 7500A, the overcurrent relay coil current is approximately 7.5A, triggering the relay, activating an alarm light, shutting off power to the coil, and unloading the diesel engine.

[0003] In related technologies, grounding and overcurrent relays are tested on a test bench before each locomotive leaves the depot. During this testing process, the relays are removed from the locomotive's main circuit and connected to the test bench for calibration. This test ensures that the relays operate correctly under the specified current conditions, ensuring that faulty circuits can be disconnected promptly during locomotive operation, preventing accidents.

[0004] The conventional process of relay testing and calibration is cumbersome. Frequent disassembly and assembly of relays and associated cables for locomotive main circuit protection devices can lead to faults such as damaged terminals, incorrect wiring, and missing wires. This not only increases maintenance costs but also poses safety risks such as locomotive failure to load and protective device failure. Furthermore, manual operation is inefficient and cannot meet the requirements of modern railway transportation for efficient maintenance. Utility Model Content

[0005] In order to solve the problems and shortcomings of the above-mentioned prior art, the utility model provides a grounding and overcurrent relay detection device, which can be used to directly perform online detection on the relay without disassembling it, thereby simplifying the detection process and improving the detection efficiency.

[0006] The present application provides a grounding and overcurrent relay detection device, comprising: a current control circuit, a switching control circuit, a first current detection circuit, and a second current detection circuit;

[0007] The input end of the current control circuit is connected to the power supply, and the output end is connected to the input end of the switching control circuit, and is used to control the current input to the switching control circuit;

[0008] The output end of the switching control circuit is connected to the input end of the first current detection circuit and the second current detection circuit respectively, and is used to simultaneously cut off the connection between the current control circuit and the first current detection circuit and the second current detection circuit in a first mode, cut off the connection between the current control circuit and the first current detection circuit in a second mode, and connect the current control circuit to the second current detection circuit; in a third mode, cut off the connection between the current control circuit and the second current detection circuit and connect the current control circuit to the first current detection circuit;

[0009] An output end of the first current detection circuit is connected to the grounding relay for detecting the current of the grounding relay;

[0010] The output end of the second current detection circuit is connected to the grounding relay for detecting the current of the overcurrent relay. The current detection range of the second current detection circuit is greater than the current detection range of the first current detection circuit.

[0011] In the above embodiment, the current input to the first current detection circuit and the second current detection circuit can be accurately controlled by cooperating with the current control circuit and the switching control circuit. The current control circuit is used to control the current size, while the switching control circuit can flexibly switch the direction of the current so that the current can be input into different detection circuits respectively. By specifically designing two detection circuits with different ranges, the accuracy of the detection can be improved while ensuring the detection range. In short, by integrating current control, switching control and current detection circuits with different ranges, integrated automatic detection of grounding and overcurrent relays can be achieved. Compared with the traditional method of manually disassembling and assembling relays for bench testing, the device can directly perform online detection on them without disassembling the relays. This not only simplifies the detection process and improves detection efficiency, but also avoids problems such as damage to the terminal blocks and wiring errors that may occur due to frequent disassembly and assembly, thereby improving the reliability and safety of the detection.

[0012] In some embodiments, the apparatus further comprises a voltage detection circuit;

[0013] The input end of the voltage detection circuit is connected to the connection point between the input end of the current control circuit and the power supply, and is used to detect the voltage input to the switching control circuit.

[0014] In the above embodiment, by adding a voltage detection circuit between the input of the current control circuit and the power supply, the voltage input to the switching control circuit can be monitored in real time. This detection mechanism ensures that the input voltage is within the appropriate range, avoiding detection errors or device damage caused by voltage anomalies.

[0015] In some embodiments, the switching control circuit includes: button S1, button S2, button S3, relay KA2, relay KA3;

[0016] The output end of the current control circuit is connected to one end of the button S1;

[0017] The other end of button S1 is connected to one end of button S2 and one end of button S3 respectively;

[0018] The other end of button S2 is connected to one end of coil KA2-1 of relay KA2 through normally closed contact KA3-3 of relay KA3;

[0019] The other end of button S3 is connected to one end of coil KA3-1 of relay KA3 through normally closed contact KA2-3 of relay KA2;

[0020] The other end of the coil KA2-1 of the relay KA2 is connected to the first current detection circuit;

[0021] The other end of the coil KA3 - 1 of the relay KA3 is connected to the second current detection circuit.

[0022] In the above embodiment, in the first mode, only button S1 is pressed. Since neither button S2 nor button S3 is pressed, the respective branches are de-energized, thereby disconnecting the current control circuit from the first current detection circuit and the second current detection circuit. In the second mode, after pressing button S1, button S2 is pressed, and the branch of button S2 is energized, connecting the current control circuit and the first current detection circuit. The coil KA2-1 of relay KA2 is energized, and the normally closed contact KA2-3 of relay KA2 is disconnected, disconnecting the current control circuit from the second current detection circuit. In the third mode, after pressing button S1, button S3 is pressed, and the branch of button S3 is energized, connecting the current control circuit and the second current detection circuit. The coil KA3-1 of relay KA3 is energized, and the normally closed contact KA3-3 of relay KA3 is disconnected, disconnecting the current control circuit from the first current detection circuit. By rationally designing the contact connection method of the relay and coordinating the selection of buttons, it is possible to conveniently switch between the three operating modes to meet different detection requirements.

[0023] In some embodiments, the normally open contact KA2 - 2 of the relay KA2 is connected in parallel with the button S2 , and the normally open contact KA3 - 2 of the relay KA3 is connected in parallel with the button S3 .

[0024] In the above embodiment, the normally open contact KA2-2 of relay KA2 is connected in parallel to relay KA2, and the normally open contact KA3-2 of relay KA3 is connected in parallel to relay KA3, so that the self-locking function of the working mode can be realized. In the second mode, by pressing button S1 and button S2, the coil KA2-1 of relay KA2 is energized, and the normally open contact KA2-2 of relay KA2 is closed and connected in parallel with button S2. Even if button S2 is released, the second mode can still be maintained. Similarly, in the third mode, by pressing button S1 and button S3, the coil KA3-1 of relay KA3 is energized, and the normally open contact KA3-2 of relay KA3 is closed and connected in parallel with button S3. Even if button S3 is released, the third mode can still be maintained. This avoids damage to buttons S2 and S3 when they are powered on for a long time, thereby improving the service life of the switching control circuit.

[0025] In some embodiments, the switching control circuit further includes: a relay KA1;

[0026] Button S1 is connected to one end of button S2 and one end of button S3 through coil KA1-1 of relay KA1;

[0027] The normally open contact KA1-2 of relay KA1 is connected in parallel with button S1.

[0028] In the above embodiment, button S1 is connected to buttons S2 and S3 via coil KA1-1 of relay KA1, while relay KA1's normally open contact KA1-2 is connected in parallel with button S1. This means that when button S1 is pressed, coil KA1-1 of relay KA1 is energized, and normally open contact KA1-2 of relay KA1 closes, forming a self-locking connection with button S1. This prevents damage to button S1 from prolonged power-on, thereby extending the service life of the switching control circuit.

[0029] In some embodiments, the switching control circuit further includes: a resistor wire F1;

[0030] The button S1 is connected to one end of the coil KA1-1 of the relay KA1 through the resistor F1.

[0031] In the above embodiment, a resistor F1 is introduced between the button S1 and the coil KA1-1 of the relay KA1 to provide overcurrent protection. When the button S1 is closed and the current is excessive, the resistor F1 overheats and melts, disconnecting the circuit and protecting the coil KA1-1 of the relay KA1 from damage. This simple and effective design improves the reliability and service life of the relay KA1. Furthermore, the melting of the resistor F1 alerts the operator to any circuit anomalies, facilitating prompt troubleshooting and repair.

[0032] In some embodiments, the switching control circuit further includes: a resistance wire F2 and a resistance wire F3;

[0033] The coil KA2-1 of the relay KA2 is connected to the first current detection circuit via the resistor F2;

[0034] The coil KA3 - 1 of the relay KA3 is connected to the second current detection circuit via the resistor F3 .

[0035] In the above embodiment, the coil KA2-1 of relay KA2 and the coil KA3-1 of relay KA3 are connected to the first current detection circuit and the second current detection circuit via resistors F2 and F3, respectively, to implement overcurrent protection. When an abnormally high current flows in the first current detection circuit or the second current detection circuit, resistors F2 and F3 quickly fuse, severing the corresponding circuit and preventing damage to the relay coils due to overcurrent.

[0036] In some embodiments, the switching control circuit further includes: an indicator light PL1, an indicator light PL2, and an indicator light PL3;

[0037] Button S1 is connected to indicator light PL1 through resistor wire F1;

[0038] The other end of the coil KA2-1 of the relay KA2 is connected to the indicator light PL2;

[0039] The other end of the coil KA3-1 of the relay KA3 is connected to the indicator light PL3.

[0040] In the above embodiment, the indicator lights PL1, PL2, and PL3 are introduced into the switching control circuit to intuitively display the current operating mode. Button S1 is connected to indicator light PL1 via resistor F1. When button S1 is closed and the circuit is functioning properly, indicator light PL1 illuminates, indicating that the switching control circuit is in the first operating mode. Coil KA2-1 of relay KA2 and coil KA3-1 of relay KA3 are connected to indicator lights PL2 and PL3, respectively. When the relay coils are energized, the corresponding indicator lights illuminate, indicating that the corresponding operating mode is activated. By observing the status of the indicator lights, operators can quickly determine the current operating mode and circuit status, facilitating monitoring and maintenance.

[0041] In some embodiments, a normally closed contact KA2 - 4 of the relay KA2 and a normally closed contact KA3 - 4 of the relay KA3 are connected between the resistance wire F1 and the indicator light PL1 .

[0042] In the above embodiment, when switching to the second mode or the third mode, the normally closed contacts of relay KA2 or relay KA3 are disconnected, cutting off the circuit of indicator light PL1, and indicator light PL1 goes out. At the same time, if the resistor F1 melts due to overcurrent, the indicator light PL1 will also go out, reminding the operator that the circuit is abnormal and needs to be checked and repaired.

[0043] In some embodiments, the switching control circuit further includes: a switch S4;

[0044] The current control circuit is connected to the button S1 through the switch S4.

[0045] In the above embodiment, the overall power control and protection of the switching control circuit can be achieved. When the switch S4 is open, the switching control circuit cannot operate regardless of whether the button S1 is closed, thus playing the role of a main switch and power-off protection.

[0046] The grounding and overcurrent relay detection device provided in the embodiments of the present application has at least the following technical effects or advantages:

[0047] 1. The utility model provides a grounding and overcurrent relay detection device, which can accurately control the current input to the first current detection circuit and the second current detection circuit through the cooperation of the current control circuit and the switching control circuit. The current control circuit is used to control the current size, while the switching control circuit can flexibly switch the direction of the current so that the current can be input into different detection circuits respectively. By specifically designing two detection circuits with different ranges, the accuracy of the detection can be improved while ensuring the detection range. In short, by integrating current control, switching control and current detection circuits with different ranges, integrated automatic detection of grounding and overcurrent relays can be achieved. Compared with the traditional method of manually disassembling and assembling relays for bench testing, the device can directly perform online detection on them without disassembling the relays. This not only simplifies the detection process and improves detection efficiency, but also avoids problems such as damage to terminal blocks and wiring errors that may occur due to frequent disassembly and assembly, thereby improving the reliability and safety of detection.

[0048] 2. The present invention provides a grounding and overcurrent relay detection device. In the first mode, only button S1 is pressed. Since buttons S2 and S3 are not pressed, the respective branches are de-energized, cutting off the connection between the current control circuit and the first current detection circuit and the second current detection circuit. In the second mode, after pressing button S1, button S2 is pressed, the branch of button S2 is energized, connecting the current control circuit and the first current detection circuit, energizing the coil KA2-1 of relay KA2, and disconnecting the normally closed contact KA2-3 of relay KA2, cutting off the connection between the current control circuit and the second current detection circuit. In the third mode, after pressing button S1, button S3 is pressed, the branch of button S3 is energized, connecting the current control circuit and the second current detection circuit, energizing the coil KA3-1 of relay KA3, and disconnecting the normally closed contact KA3-3 of relay KA3, cutting off the connection between the current control circuit and the first current detection circuit. By rationally designing the contact connection method of the relay and coordinating the selection of buttons, it is possible to conveniently switch between the three working modes to meet different detection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a schematic diagram of the present utility model.

[0050] Figure 2 It is a circuit diagram of the switching control circuit in the utility model.

[0051] Figure numerals: 1. current control circuit; 2. switching control circuit; 3. first current detection circuit; 4. second current detection circuit; 5. voltage detection circuit. DETAILED DESCRIPTION

[0052] The terms used in the following examples of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and appended claims of this application, the singular expressions "a," "an," "said," "above," "the," and "this" are intended to include plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used in this application refers to any or all possible combinations comprising one or more of the listed items.

[0053] In the following, the terms "first" and "second" are used for descriptive purposes only and should not be understood to imply or suggest relative importance or implicitly indicate the number of the technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of this application, unless otherwise specified, "plurality" means two or more.

[0054] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0055] The following describes the grounding and overcurrent relay detection device in this embodiment:

[0056] like Figure 1 As shown, Figure 1 It is a schematic diagram of the present utility model.

[0057] A grounding and overcurrent relay detection device includes: a current control circuit 1, a switching control circuit 2, a first current detection circuit 3, and a second current detection circuit 4;

[0058] The input end of the current control circuit 1 is connected to the power supply, and the output end is connected to the input end of the switching control circuit 2, for controlling the current input to the switching control circuit 2;

[0059] The primary function of current control circuit 1 is to precisely regulate and control the current input to switching control circuit 2. By changing parameters of current control circuit 1, such as adjusting the resistor, the output current can be varied continuously or in steps within a certain range. This adjustable current provides a flexible and controllable power source for subsequent switching control and current sensing.

[0060] There are various current control methods. Analog circuits, such as variable resistor dividers, can be used. Digital control circuits, such as PWM (pulse width modulation) circuits and DAC (digital-to-analog conversion), can also be employed. The control signal can be manually adjusted using a potentiometer or automatically generated by a microcontroller based on a pre-set detection process. For example, if a variable resistor divider is used, a multi-turn precision potentiometer can be connected in series with current control circuit 1. By adjusting the potentiometer's resistance, the output current can be continuously adjusted from a few milliamperes to tens of amperes. If PWM digital control is used instead, the microcontroller outputs a square wave signal with an adjustable duty cycle, which is then converted into a smooth, adjustable DC current through an RC filter circuit. Digital control allows for programmable automated detection, but the circuit complexity is higher.

[0061] In a specific embodiment, the current control circuit 1 is a simple adjustable resistor.

[0062] It should be noted that the circuit for regulating current is already very mature in the relevant technology. The innovation of the present invention does not lie in the regulation of current, and the present invention does not require protection for the regulation of current.

[0063] In addition to regulating current, the current control circuit 1 can also provide overcurrent protection. This can be achieved using components such as fast-blow fuses and overcurrent protection relays. When the current exceeds the rated value, the protection component activates and disconnects the circuit, preventing excessive current from damaging components.

[0064] The output end of the switching control circuit 2 is connected to the input end of the first current detection circuit 3 and the second current detection circuit 4 respectively, and is used to simultaneously cut off the connection between the current control circuit 1 and the first current detection circuit 3 and the second current detection circuit 4 in the first mode; in the second mode, cut off the connection between the current control circuit 1 and the first current detection circuit 3 and connect the current control circuit 1 to the second current detection circuit 4; in the third mode, cut off the connection between the current control circuit 1 and the second current detection circuit 4 and connect the current control circuit 1 to the first current detection circuit 3;

[0065] Switching control circuit 2 receives input current from current control circuit 1 and distributes it to different current detection circuits according to a set pattern. By switching different combinations of switches, the current flow can be flexibly changed. This switching control method can be implemented using components such as relays, solid-state relays, and thyristors.

[0066] A relay is a common electromagnetic switching element. By energizing a coil, it generates electromagnetic force, which drives the armature to close or release, thereby closing the normally open contacts or opening the normally closed contacts. The relay's normally open and normally closed contacts can be used to create multiple controllable current paths. Relay contacts also offer good electrical isolation, allowing them to control relatively large currents.

[0067] It should be noted that the switching circuit is already very mature in the relevant technology. The innovation of the present invention does not lie in the switching of the circuit, and the present invention does not require protection for the switching of the circuit.

[0068] The output end of the first current detection circuit 3 is connected to the grounding relay for detecting the current of the grounding relay;

[0069] Specifically, the current detection range of the first current detection circuit 4 is 2A.

[0070] In some embodiments, the first current detection circuit 4 is an ammeter.

[0071] The output end of the second current detection circuit 4 is connected to the grounding relay for detecting the current of the overcurrent relay. The current detection range of the second current detection circuit 4 is greater than the current detection range of the first current detection circuit 3.

[0072] Specifically, the current detection range of the second current detection circuit 4 is 20A.

[0073] In some embodiments, the second current detection circuit 4 is an ammeter.

[0074] It can be seen that through the cooperation of the current control circuit 1 and the switching control circuit 2, the current input to the first current detection circuit 3 and the second current detection circuit 4 can be precisely controlled. The current control circuit 1 is used to control the current magnitude, while the switching control circuit 2 can flexibly switch the direction of the current flow, so that the current can be input into different detection circuits respectively. By specifically designing two detection circuits with different ranges, the accuracy of the detection can be improved while ensuring the detection range. In short, by integrating current control, switching control, and current detection circuits with different ranges, integrated automatic detection of grounding and overcurrent relays can be achieved. Compared with the traditional method of manually disassembling and assembling relays for bench testing, this device can directly perform online testing on them without disassembling the relays. This not only simplifies the detection process and improves detection efficiency, but also avoids problems such as terminal damage and wiring errors that may occur due to frequent disassembly and assembly, thereby improving the reliability and safety of the detection.

[0075] refer to Figure 1 , the device also includes a voltage detection circuit 5; the input end of the voltage detection circuit 5 is connected to the connection point between the input end of the current control circuit 1 and the power supply, for detecting the voltage of the input switching control circuit 2.

[0076] The voltage detection point should be as close to the power supply as possible. This is because the current control circuit 1 itself introduces a certain voltage drop. If the voltage is detected at its output, the result will be lower than the actual input voltage. Therefore, the optimal detection point is between the input of the current control circuit 1 and the power supply. This not only allows the true value of the power supply voltage to be measured, but also allows the determination of potential faults such as disconnection or poor connection in the power supply line.

[0077] In some embodiments, the voltage detection circuit 5 is a voltmeter.

[0078] It's important to emphasize that voltage detection circuit 5 is a crucial auxiliary component of the device. Together with the current control, switching control, and current detection circuits, it forms a complete relay detection system. Only with dual voltage and current detection can the operating status of the grounding and overcurrent relays be more accurately determined, allowing for the timely detection of potential fault risks.

[0079] As can be seen, by adding a voltage detection circuit 5 between the input terminal of the current control circuit 1 and the power supply, the voltage input to the switching control circuit 2 can be monitored in real time. This detection mechanism ensures that the input voltage is within the appropriate range, avoiding detection errors or equipment damage caused by voltage anomalies.

[0080] In some embodiments, reference Figure 2 , Figure 2It is a circuit diagram of the switching control circuit 2 in the present invention.

[0081] The switching control circuit 2 includes: button S1, button S2, button S3, relay KA2, relay KA3;

[0082] The output end of the current control circuit 1 is connected to one end of the button S1;

[0083] The other end of button S1 is connected to one end of button S2 and one end of button S3 respectively;

[0084] The other end of the button S2 is connected to one end of the coil KA2-1 of the relay KA2 through the normally closed contact KA3-3 of the relay KA3;

[0085] The other end of button S3 is connected to one end of coil KA3-1 of relay KA3 through normally closed contact KA2-3 of relay KA2;

[0086] The other end of the coil KA2-1 of the relay KA2 is connected to the first current detection circuit 3;

[0087] The other end of the coil KA3 - 1 of the relay KA3 is connected to the second current detection circuit 4 .

[0088] Button S1 acts as the master switch and is connected to the output of current control circuit 1. Only when button S1 is closed can current flow into switching control circuit 2, driving the relay coil. Buttons S2 and S3, on the other hand, control the on and off of relays KA2 and KA3, respectively, thereby determining the direction of current flow.

[0089] The other end of button S1 is connected to both buttons S2 and S3, forming two parallel branches. The other end of button S2 is connected to one end of relay KA2's coil KA2-1 via relay KA3's normally closed contact KA3-3, while the other end of button S3 is connected to one end of relay KA3's coil KA3-1 via relay KA2's normally closed contact KA2-3. The other ends of relay KA2's coil KA2-1 and relay KA3's coil KA3-1 are connected to the first current detection circuit 3 and the second current detection circuit 4, respectively. This cross-connection structure forms an interlocking circuit, reliably switching between the three operating modes.

[0090] The first mode is the initial state, in which only button S1 is closed and buttons S2 and S3 are both open. Therefore, in this mode, the device is in a waiting state and no actual detection action is taken.

[0091] In the second mode, after closing button S1, button S2 is also closed. This opens the branch circuit corresponding to button S2, energizing coil KA2-1 of relay KA2 and closing its contacts. Relay KA2's normally open contact KA2-2 closes, providing a self-locking mechanism for coil KA2-1. Meanwhile, relay KA2's normally closed contact KA2-3 opens, disconnecting the branch circuit corresponding to button S3. Current flows from button S1 through button S2 into first current detection circuit 3, detecting the ground relay.

[0092] The third mode is the exact opposite of the second. Closing buttons S1 and S3 energizes coil KA3-1 of relay KA3, opening its normally closed contact KA3-3 and disconnecting first current detection circuit 3. Relay KA2, however, loses power due to coil KA2-1, closing its normally closed contact KA2-3. Current flows entirely through the branch circuit of button S3 into second current detection circuit 4, dedicated to overcurrent relay detection. Similarly, first current detection circuit 3 is also de-energized at this point.

[0093] It can be seen that in the first mode, only button S1 is pressed. Since buttons S2 and S3 are not pressed, their respective branches are de-energized, cutting off the connection between the current control circuit 1 and the first current detection circuit 3 and the second current detection circuit 4. In the second mode, after pressing button S1, button S2 is pressed, and the branch of button S2 is energized, connecting the current control circuit 1 and the first current detection circuit 3, energizing the coil KA2-1 of relay KA2, and disconnecting the normally closed contact KA2-3 of relay KA2, cutting off the connection between the current control circuit 1 and the second current detection circuit 4. In the third mode, after pressing button S1, button S3 is pressed, and the branch of button S3 is energized, connecting the current control circuit 1 and the second current detection circuit 4, energizing the coil KA3-1 of relay KA3, and disconnecting the normally closed contact KA3-3 of relay KA3, cutting off the connection between the current control circuit 1 and the first current detection circuit 3. By rationally designing the contact connection method of the relay and coordinating with the selection of buttons, it is possible to conveniently switch between the three operating modes to meet different detection requirements.

[0094] refer to Figure 2 In some embodiments, the normally open contact KA2-2 of the relay KA2 is connected in parallel with the button S2, and the normally open contact KA3-2 of the relay KA3 is connected in parallel with the button S3.

[0095] This parallel connection enables a self-locking function in the operating mode. Specifically, in the second mode, when buttons S1 and S2 are pressed, coil KA2-1 of relay KA2 is energized, and normally open contact KA2-2 of relay KA2 is closed. At this point, normally open contact KA2-2 of relay KA2 is connected in parallel with button S2. Even if button S2 is released, coil KA2-1 of relay KA2 remains energized, maintaining the second mode.

[0096] Similarly, in the third mode, when buttons S1 and S3 are pressed, coil KA3-1 of relay KA3 is energized, and normally open contact KA3-2 of relay KA3 is closed. Normally open contact KA3-2 of relay KA3 is connected in parallel with button S3. Even if button S3 is released, coil KA3-1 of relay KA3 remains energized, maintaining the third mode.

[0097] It can be seen that by connecting the normally open contact KA2-2 of relay KA2 in parallel to relay KA2 and the normally open contact KA3-2 of relay KA3 in parallel to relay KA3, the self-locking function of the working mode can be realized. In the second mode, pressing buttons S1 and S2, the coil KA2-1 of relay KA2 is energized, the normally open contact KA2-2 of relay KA2 is closed, and is connected in parallel with button S2. Even if button S2 is released, the second mode can still be maintained. Similarly, in the third mode, pressing buttons S1 and S3, the coil KA3-1 of relay KA3 is energized, the normally open contact KA3-2 of relay KA3 is closed, and is connected in parallel with button S3. Even if button S3 is released, the third mode can still be maintained. This avoids damage to buttons S2 and S3 when they are powered on for a long time, thereby improving the service life of the switching control circuit 2.

[0098] refer to Figure 2 , in some embodiments, the switching control circuit 2 further includes: a relay KA1;

[0099] Button S1 is connected to one end of button S2 and one end of button S3 through coil KA1-1 of relay KA1;

[0100] The normally open contact KA1-2 of relay KA1 is connected in parallel with button S1.

[0101] This structure actually protects the main switch button S1. In the previous circuit, button S1 directly controls the on and off of the coils of relays KA2 and KA3, which operate under heavy load for a long time. Now relay KA1 is added to act as a buffer and protection.

[0102] Now, button S1 is no longer directly connected to buttons S2 and S3, but instead is connected through coil KA1-1 of relay KA1. When button S1 is pressed, coil KA1-1 of relay KA1 is energized, energizing relay KA1. This closes the normally open contact KA1-2, creating a self-locking connection with button S1. Even after button S1 is released, relay KA1 remains energized. Relay KA1 can only be released by disconnecting the main power supply. Because relay KA1's contacts have a much greater load-carrying capacity than button S1, they effectively share the load of button S1, preventing damage due to overload. Relay KA1 itself is more resilient to current surges and oscillations, ensuring reliable circuit switching.

[0103] As can be seen, button S1 is connected to buttons S2 and S3 via relay KA1's coil KA1-1, while relay KA1's normally open contact KA1-2 is connected in parallel with button S1. This means that when button S1 is pressed, relay KA1's coil KA1-1 is energized, and relay KA1's normally open contact KA1-2 closes, forming a self-locking mechanism with button S1. This prevents damage to button S1 from being energized for extended periods, thereby extending the service life of switching control circuit 2.

[0104] refer to Figure 2 , in some embodiments, the switching control circuit 2 further includes: a resistance wire F1;

[0105] The button S1 is connected to one end of the coil KA1-1 of the relay KA1 through the resistor F1.

[0106] Inserting resistor F1 between button S1 and relay KA1's coil KA1-1 provides overcurrent protection. When button S1 is closed and the current exceeds the specified value for some reason, resistor F1 will overheat and melt, breaking the circuit and protecting relay KA1's coil KA1-1 from damage.

[0107] A resistor is a common overcurrent protection component that operates by utilizing the thermal effect of current. When the current exceeds the rated value, the resistor melts due to heat, thus breaking the circuit. In some embodiments, an air switch can also be used instead.

[0108] As can be seen, the introduction of resistor F1 between button S1 and coil KA1-1 of relay KA1 provides overcurrent protection. When button S1 is closed and the current is excessive, resistor F1 overheats and melts, shutting off the circuit and protecting coil KA1-1 of relay KA1 from damage. This simple and effective design improves the reliability and service life of relay KA1. Furthermore, the melting of resistor F1 alerts the operator to any circuit anomalies, facilitating prompt troubleshooting and repair.

[0109] refer to Figure 2 In some embodiments, the switching control circuit 2 further includes: a resistance wire F2 and a resistance wire F3;

[0110] The coil KA2-1 of the relay KA2 is connected to the first current detection circuit 3 via the resistor F2;

[0111] The coil KA3 - 1 of the relay KA3 is connected to the second current detection circuit 4 via the resistor F3 .

[0112] A resistor is also added between the relay coil and the detection circuit. When an abnormally high current flows through the first current detection circuit 3 or the second current detection circuit 4, the corresponding resistor F2 or F3 will quickly melt, severing the connection to the relay coil and preventing overcurrent from damaging relays KA2 and KA3.

[0113] Thus, resistors F1, F2, and F3 form a relatively complete overcurrent protection system. They protect the main switch, the first detection circuit, and the second detection circuit, respectively, covering all key aspects of switching control circuit 2. If an overcurrent fault occurs somewhere in the circuit, the resistors will quickly trip, effectively blocking the spread of the fault current and minimizing losses.

[0114] As can be seen, coil KA2-1 of relay KA2 and coil KA3-1 of relay KA3 are connected to first current detection circuit 3 and second current detection circuit 4 via resistor wire F2 and resistor wire F3, respectively, providing overcurrent protection. When an abnormally high current flows through first current detection circuit 3 or second current detection circuit 4, resistor wire F2 or resistor wire F3 quickly fuses, severing the corresponding circuit and preventing damage to the relay coils due to overcurrent.

[0115] refer to Figure 2 In some embodiments, the switching control circuit 2 further includes: an indicator light PL1, an indicator light PL2, and an indicator light PL3;

[0116] Button S1 is connected to indicator light PL1 through resistor wire F1;

[0117] The other end of the coil KA2-1 of the relay KA2 is connected to the indicator light PL2;

[0118] The other end of the coil KA3-1 of the relay KA3 is connected to the indicator light PL3.

[0119] The introduction of indicator lights PL1, PL2, and PL3 in switching control circuit 2 visually displays the current operating mode. Specifically, when button S1 is closed and the circuit is functioning normally, indicator light PL1 illuminates, indicating that switching control circuit 2 is in the first operating mode, or standby mode. When coil KA2-1 of relay KA2 is energized, indicator light PL2 illuminates, indicating that the second operating mode is activated and the ground relay is tested. Similarly, when coil KA3-1 of relay KA3 is energized, indicator light PL3 ​​illuminates, indicating that the third operating mode is activated and the overcurrent relay is tested. The indicator lights allow operators to quickly determine the current operating mode and circuit status, greatly facilitating monitoring and maintenance. In the event of a fault or misoperation, the indicator lights immediately reflect the anomaly, alerting personnel to address it promptly. This is crucial for improving system availability and maintenance efficiency.

[0120] As can be seen, the introduction of indicator lights PL1, PL2, and PL3 in switching control circuit 2 allows for a visual display of the current operating mode. Button S1 is connected to indicator light PL1 via resistor F1. When button S1 is closed and the circuit is functioning properly, indicator light PL1 illuminates, indicating that switching control circuit 2 is in the first operating mode. Coil KA2-1 of relay KA2 and coil KA3-1 of relay KA3 are connected to indicator lights PL2 and PL3, respectively. When the relay coils are energized, the corresponding indicator lights illuminate, indicating that the corresponding operating mode is active. By observing the status of the indicator lights, operators can quickly determine the current operating mode and circuit status, facilitating monitoring and maintenance.

[0121] refer to Figure 2 In some embodiments, the normally closed contact KA2-4 of the relay KA2 and the normally closed contact KA3-4 of the relay KA3 are connected between the resistance wire F1 and the indicator light PL1.

[0122] This connection method further optimizes the functionality of indicator light PL1. In its initial state, relays KA2 and KA3 are deactivated, normally closed contacts KA2-4 and KA3-4 are closed, and indicator light PL1 illuminates normally. Once the system switches to the second or third mode, relay KA2 or KA3 closes, opening the corresponding normally closed contact and severing the circuit for indicator light PL1, turning it off. This way, the status of indicator light PL1 not only indicates the main power supply status but also reflects the current state of the operating mode.

[0123] It can be seen that when switching to the second mode or the third mode, the normally closed contacts of relay KA2 or relay KA3 are disconnected, cutting off the circuit of indicator light PL1, and indicator light PL1 goes out. At the same time, if the resistor wire F1 melts due to overcurrent, the indicator light PL1 will also go out, reminding the operator that the circuit is abnormal and needs to be checked and repaired.

[0124] refer to Figure 2 , in some embodiments, the switching control circuit 2 further includes: a switch S4;

[0125] The current control circuit 1 is connected to the button S1 via the switch S4.

[0126] A master switch S4 is added between current control circuit 1 and switching control circuit 2. When switch S4 is open, switching control circuit 2 receives no power, regardless of whether button S1 is closed. This effectively provides both master power control and power-off protection. The introduction of switch S4 makes power control in switching control circuit 2 more flexible and safer. During normal operation, switch S4 is closed, and switching control circuit 2 is controlled by button S1. During maintenance or long-term outages, switch S4 can be opened to completely shut off power and prevent accidents caused by accidental operation.

[0127] It can be seen that the total power control and protection of the switching control circuit 2 can be achieved. When the switch S4 is open, no matter whether the button S1 is closed or not, the switching control circuit 2 cannot work, playing the role of a main switch and power-off protection.

Claims

1. A grounding and overcurrent relay detection device, comprising a grounding relay and an overcurrent relay, characterized in that: include: A current control circuit, a switching control circuit, a first current detection circuit, and a second current detection circuit; The input end of the current control circuit is connected to the power supply, and the output end is connected to the input end of the switching control circuit, and is used to control the current input to the switching control circuit; The output end of the switching control circuit is connected to the input end of the first current detection circuit and the input end of the second current detection circuit, respectively, and is used to simultaneously cut off the connection between the current control circuit and the first current detection circuit and the second current detection circuit in a first mode; cut off the connection between the current control circuit and the first current detection circuit and connect the current control circuit to the second current detection circuit in a second mode; and cut off the connection between the current control circuit and the second current detection circuit and connect the current control circuit to the first current detection circuit in a third mode; The output end of the first current detection circuit is connected to the grounding relay, and is used to detect the current of the grounding relay; The output end of the second current detection circuit is connected to the grounding relay for detecting the current of the overcurrent relay. The current detection range of the second current detection circuit is greater than the current detection range of the first current detection circuit.

2. A grounding and overcurrent relay detection device according to claim 1, characterized in that: The device also includes a voltage detection circuit; The input end of the voltage detection circuit is connected to the connection point between the input end of the current control circuit and the power supply, and is used to detect the voltage input to the switching control circuit.

3. A grounding and overcurrent relay detection device according to claim 1, characterized in that: The switching control circuit includes: button S1, button S2, button S3, relay KA2, relay KA3; The output end of the current control circuit is connected to one end of the button S1; The other end of the button S1 is connected to one end of the button S2 and one end of the button S3 respectively; The other end of the button S2 is connected to one end of the coil KA2-1 of the relay KA2 through the normally closed contact KA3-3 of the relay KA3; The other end of the button S3 is connected to one end of the coil KA3-1 of the relay KA3 through the normally closed contact KA2-3 of the relay KA2; The other end of the coil KA2-1 of the relay KA2 is connected to the first current detection circuit; The other end of the coil KA3 - 1 of the relay KA3 is connected to the second current detection circuit.

4. A grounding and overcurrent relay detection device according to claim 3, characterized in that: The normally open contact KA2-2 of the relay KA2 is connected in parallel with the button S2, and the normally open contact KA3-2 of the relay KA3 is connected in parallel with the button S3.

5. A grounding and overcurrent relay detection device according to claim 4, characterized in that: The switching control circuit further includes: a relay KA1; The button S1 is connected to one end of the button S2 and one end of the button S3 through the coil KA1-1 of the relay KA1; The normally open contact KA1 - 2 of the relay KA1 is connected in parallel with the button S1 .

6. A grounding and overcurrent relay detection device according to claim 5, characterized in that: The switching control circuit further includes: a resistance wire F1; The button S1 is connected to one end of the coil KA1 - 1 of the relay KA1 through the resistance wire F1 .

7. A grounding and overcurrent relay detection device according to claim 6, characterized in that: The switching control circuit further includes: a resistance wire F2 and a resistance wire F3; The coil KA2-1 of the relay KA2 is connected to the first current detection circuit through the resistor F2; The coil KA3 - 1 of the relay KA3 is connected to the second current detection circuit through the resistor F3 .

8. A grounding and overcurrent relay detection device according to claim 7, characterized in that: The switching control circuit further includes: an indicator light PL1, an indicator light PL2, and an indicator light PL3; The button S1 is connected to the indicator light PL1 through the resistance wire F1; The other end of the coil KA2-1 of the relay KA2 is connected to the indicator light PL2; The other end of the coil KA3 - 1 of the relay KA3 is connected to the indicator light PL3 ​​.

9. A grounding and overcurrent relay detection device according to claim 8, characterized in that: The normally closed contact KA2 - 4 of the relay KA2 and the normally closed contact KA3 - 4 of the relay KA3 are connected between the resistance wire F1 and the indicator light PL1 .

10. A grounding and overcurrent relay detection device according to claim 9, characterized in that: The switching control circuit further includes: a switch S4; The current control circuit is connected to the button S1 through the switch S4.

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