Megohmmeter with protection function and control method thereof

Abstract

The application relates to the technical field of measuring instruments, in particular to a megohmmeter with a protection function and a control method thereof. The megohmmeter with the protection function comprises a first control switch connected with an industrial control board and used for sending an open-circuit control signal to the industrial control board, a second control switch connected with the industrial control board, the industrial control board connected with a motor and a first controlled switch, the first controlled switch connected with two binding posts of a mechanical megohmmeter body, a power output end of the motor connected with a generator rotor of the mechanical megohmmeter body, and a power module connected with the industrial control board. The megohmmeter with the protection function can realize open-circuit and short-circuit tests without rotating the megohmmeter and operating a meter pen, so that the operation of the staff is simpler, the staff does not need to continuously shake and pay attention to the rotation speed, and the test safety is improved.

Description

Technical Field

[0001] This invention relates to the field of measuring instrument technology, and in particular to a megohmmeter with protection function and its control method. Background Technology

[0002] A megohmmeter is a commonly used measuring instrument in electrical engineering. It is named for its scale, which is measured in megohms (MΩ). In daily life, megohmmeters are mainly used to check the insulation resistance of electrical equipment, household appliances, or electrical circuits to ground and between phases, in order to ensure that these devices, appliances, and circuits have good insulation performance and avoid accidents such as electric shock and equipment damage.

[0003] There are many types of megohmmeters on the market, but they can be mainly divided into two types based on their working principle: mechanical megohmmeters based on the generator principle and digital megohmmeters based on the battery boost conversion principle. Among them, digital megohmmeters have more complex internal connections due to their structure of modulation integrated circuits and rectifier circuits, which makes them more prone to failure. Therefore, for situations such as field operations, people still prefer mechanical megohmmeters with more reliable structures.

[0004] Existing mechanical megohmmeters are prone to misoperation or accidental contact with the device under test (DUT) because they require simultaneous control of the probe connection or connection to the DUT during open circuit, short circuit, and testing. When using high-power megohmmeters or when the DUT has a large energy storage space, this can result in damage to the megohmmeter or even electric shock, making them relatively unsafe. Summary of the Invention

[0005] This invention provides a megohmmeter with protective functions and its control method to solve the problem of low safety of existing mechanical megohmmeters.

[0006] The first aspect of this invention provides a megohmmeter with protection function, comprising a mechanical megohmmeter body with two terminals, and further comprising: a first control switch, a second control switch, an industrial control board, a first controlled switch, a motor, and a power supply module, wherein:

[0007] The first control switch is connected to the industrial control board and is used to send an open-circuit control signal to the industrial control board;

[0008] The second control switch is connected to the industrial control board and is used to send a short-circuit control signal to the industrial control board;

[0009] The industrial control board is connected to the motor and is used to control the rotation of the motor according to the open circuit control signal and the short circuit control signal;

[0010] The industrial control board is connected to the first controlled switch and is used to control the first controlled switch to close according to the short-circuit control signal;

[0011] The first controlled switch is connected to two terminals of the mechanical megohmmeter body;

[0012] The power output terminal of the electric motor is connected to the generator rotor of the mechanical megohmmeter body.

[0013] The power module is connected to the industrial control board.

[0014] Furthermore, a megohmmeter with protection function also includes: a third control switch and a second controlled switch connected to the industrial control board;

[0015] The third control switch is used to send test control signals to the industrial control board;

[0016] The industrial control board is also used to control the rotation of the motor and the closing of the second controlled switch according to the test control signal;

[0017] The second controlled switch is connected between the mechanical megohmmeter body and the high-potential terminal of the two terminals.

[0018] Furthermore, a megohmmeter with protection function also includes: a fourth control switch connected to the industrial control board;

[0019] The fourth control switch is used to send a lockout control signal to the industrial control board;

[0020] The industrial control board is also used to enter the locked state when it receives the locking control signal.

[0021] Specifically, the industrial control board includes eleven pins, wherein:

[0022] Pin 1 and pin 8 are common terminals;

[0023] The second pin is connected to the first pin via the first control switch;

[0024] The third pin is connected to the first pin via the second control switch;

[0025] The fourth pin is connected to the first pin via the third control switch;

[0026] The fifth pin is connected to the first pin via the fourth control switch;

[0027] Pins 6 and 7 are connected to the power module, respectively.

[0028] The ninth pin is connected to the eighth pin via the motor;

[0029] The tenth pin is connected to the eighth pin via the first controlled switch;

[0030] The eleventh pin is connected to the eighth pin via the second controlled switch.

[0031] Furthermore, the industrial control board also includes: a first transition relay and a first time relay;

[0032] The first transition relay is connected to the third pin, the first time relay and the ninth pin respectively, and is used to send a timing signal to the first time relay when a short-circuit control signal is received, and to send the short-circuit control signal to the ninth pin when a timing completion signal is received from the first time relay.

[0033] The first time relay is used to start timing when the timing signal is received, and to return the timing completion signal to the first transition relay when the timing reaches a first preset duration.

[0034] Furthermore, the industrial control board also includes: a second transition relay and a second time relay;

[0035] The second transition relay is connected to the first transition relay, the second time relay and the tenth pin respectively, and is used to send the short-circuit control signal to the tenth pin, and send a timing signal to the second time relay at the same time as receiving the short-circuit control signal. When the timing completion signal sent by the second time relay is received, the transmission of the short-circuit control signal to the tenth pin is stopped.

[0036] The second time relay is used to receive the timing signal and send the timing completion signal to the second transition relay when the timing reaches the second preset duration.

[0037] Furthermore, a megohmmeter with protective functions also includes: an insulating housing;

[0038] The insulating enclosure is used to house the mechanical megohmmeter body, the motor, the industrial control board, the first control switch, the second control switch, and the power module.

[0039] Furthermore, the side wall of the insulating box is provided with an opening, and a control panel of a size adapted to the opening is provided at the opening;

[0040] The control panel is used to set the first control switch and the second control switch, and also to display the reading of the mechanical megohmmeter body.

[0041] In another aspect, the present invention provides a short-circuit control method for a megohmmeter with protection function, comprising the following steps:

[0042] A short-circuit control signal is sent to the industrial control board via the second control switch;

[0043] When the industrial control board receives the short-circuit control signal, it sends the short-circuit control signal to the motor and the first controlled switch respectively.

[0044] The electric motor drives the power output terminal to rotate according to the short-circuit control signal, thereby driving the generator inside the mechanical megohmmeter to generate electricity.

[0045] The first controlled switch closes according to the short-circuit control signal, causing a short circuit connection between the two terminals of the mechanical megohmmeter body.

[0046] In another aspect, the present invention provides an open-circuit control method for a megohmmeter with protection function, comprising the following steps:

[0047] An open-circuit control signal is sent to the industrial control board via the first control switch;

[0048] When the industrial control board receives an open-circuit control signal, it sends the open-circuit control signal to the motor;

[0049] The electric motor drives the power output terminal to rotate according to the open circuit control signal, thereby driving the generator inside the mechanical megohmmeter to generate electricity.

[0050] The present invention provides a megohmmeter with protective functions, comprising: a mechanical megohmmeter body, a motor, an industrial control board, a first control switch, a second control switch, and a power module; wherein: the first control switch is connected to the industrial control board and is used to send an open-circuit control signal to the industrial control board; the second control switch is connected to the industrial control board and is used to send a short-circuit control signal to the industrial control board; the industrial control board is connected to the motor and is used to control the rotation of the motor according to the open-circuit control signal and the short-circuit control signal; the industrial control board is connected to the first controlled switch and is used to control the closure of the first controlled switch according to the short-circuit control signal; the first controlled switch is connected to two terminals of the mechanical megohmmeter body; the power output terminal of the motor is connected to the generator rotor of the mechanical megohmmeter body; and the power module is connected to the industrial control board.

[0051] The megohmmeter with protection function provided in this invention can send open-circuit and short-circuit control signals through a first control switch and a second control switch, respectively. These signals control the rotation of the motor and the opening and closing of the first controlled switch. This replaces the traditional hand-cranked power generation operation by having the internal motor of the megohmmeter generate electricity through motor rotation, and replaces the traditional test lead connection operation by opening and closing the first controlled switch. The entire process is simple and convenient, allowing operators to perform a self-test of the megohmmeter before testing with a single button, avoiding erroneous operations caused by cumbersome procedures and effectively solving the problem of low safety in existing mechanical megohmmeters. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a schematic diagram of the connection relationship of a megohmmeter with protection function;

[0054] Figure 2 A schematic diagram of the control panel of a megohmmeter with protective functions;

[0055] Figure 3 A flowchart of a short-circuit control method for a megohmmeter with protection function;

[0056] Figure 4 A flowchart of an open-circuit control method for a megohmmeter with protection function;

[0057] Figure 5 PLC program design diagram for reset, test, and short circuit;

[0058] Figure 6 PLC program design diagram for open circuit, protection and motor control. Detailed Implementation

[0059] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] The first aspect of this invention provides a megohmmeter with protection function; please refer to [link to relevant documentation]. Figure 1 , Figure 1 This is a connection diagram of a megohmmeter with protection function, including a mechanical megohmmeter body with two terminals, and further including: a first control switch, a second control switch, an industrial control board, a first controlled switch, a motor, and a power supply module, wherein:

[0061] The first control switch is connected to the industrial control board and is used to send an open-circuit control signal to the industrial control board;

[0062] The second control switch is connected to the industrial control board and is used to send a short-circuit control signal to the industrial control board;

[0063] The industrial control board is connected to the motor and is used to control the motor rotation based on open-circuit control signals and short-circuit control signals.

[0064] The industrial control board is connected to the first controlled switch and is used to control the first controlled switch to close according to the short-circuit control signal;

[0065] The first controlled switch is connected to two terminals of the mechanical megohmmeter body and is used to control the two terminals to form a circuit when closed.

[0066] The power output end of the electric motor is connected to the generator rotor of the mechanical megohmmeter body to drive the generator to generate electricity;

[0067] The power module is connected to the industrial control board and is used to provide power to the industrial control board and to provide power to the motor through the industrial control board.

[0068] In the specific implementation process, before conducting the formal insulation test, the staff can close the first control switch to enable the mechanical megohmmeter to perform an open circuit test. When the pointer reading is infinite, it indicates that the mechanical megohmmeter is in normal condition. Furthermore, the staff can disconnect the first control switch and close the second control switch to perform a short circuit test. When the mechanical megohmmeter reading is zero, it indicates that the condition is normal. At this point, the open circuit and short circuit tests before the actual test are completed.

[0069] After the open circuit and short circuit tests are completed before the test, the staff connects the object under test to the two terminals of the mechanical megohmmeter body and performs the insulation test by pressing the first control switch.

[0070] The megohmmeter with protective function provided in this embodiment of the invention can perform open circuit and short circuit tests as well as insulation resistance tests on the test object without shaking, making the operation simpler for the operator. The operator does not need to be distracted by shaking or pay attention to the shaking speed not reaching the specified speed, thus improving the safety of the test.

[0071] In one specific embodiment of the present invention, the power module can be configured with a rechargeable battery, and the battery can be removed and replaced.

[0072] In a specific embodiment of the present invention, based on the foregoing embodiments, a megohmmeter with protection function further includes: a third control switch and a second controlled switch connected to an industrial control board;

[0073] The third control switch is used to send test control signals to the industrial control board;

[0074] The industrial control board is also used to control the rotation of the motor and the closing of the second controlled switch according to the test control signal;

[0075] The second controlled switch is connected between the mechanical megohmmeter body and the high-potential terminal of the two terminals.

[0076] In a specific embodiment of the present invention, the first controlled switch and the second controlled switch are magnetic switches, which can be turned on when energized and turned off when de-energized.

[0077] In a specific embodiment of the present invention, based on the foregoing embodiments, the mechanical megohmmeter body provided by the present invention includes two terminals: an L terminal and an E terminal, wherein:

[0078] The high-potential terminal is the L terminal of the mechanical megohmmeter body.

[0079] In practice, the presence of a controlled switch between the megohmmeter and the test object eliminates the need for operators to test the mechanical megohmmeter itself before conducting the test. Instead, after connecting the test object, operators can directly test both the mechanical megohmmeter and the test object by sequentially opening and closing the first, second, and third control switches.

[0080] It is understandable that the L terminal is a high-potential terminal, which will generate a potential difference with the ground. Therefore, when the mechanical megohmmeter needs to be disconnected from the object under test, it must be ensured that the L terminal is disconnected from the object under test.

[0081] In another embodiment of the present invention, based on the foregoing embodiments, a megohmmeter with protection function further includes: a fourth control switch connected to an industrial control board;

[0082] The fourth control switch is used to send a lockout control signal to the industrial control board;

[0083] The industrial control board is also used to enter the lockout state when it receives a lockout control signal.

[0084] Understandably, the fourth control switch can lock itself out, stopping the feedback of control signals to the first and second controlled switches. By locking the internal control circuit, it ensures that the motor will not continue to rotate under open-circuit, short-circuit, or test control signals. Since the second controlled switch is a magnetic switch, it can be disconnected when no signal is received, further preventing the electrical energy generated by the motor under inertia from harming workers.

[0085] In another embodiment of the present invention, the industrial control board includes first to eleventh pins, wherein:

[0086] Pin 1 and pin 8 are common terminals used to provide power;

[0087] The second pin is connected to the first pin via the first control switch and is used to receive the open-circuit control signal.

[0088] The third pin is connected to the first pin via the second control switch and is used to receive short-circuit control signals.

[0089] The fourth pin is connected to the first pin via the third control switch and is used to receive test control signals;

[0090] The fifth pin is connected to the first pin via the fourth control switch and is used to receive protection control signals;

[0091] Pins 6 and 7 are connected to the power module to supply power to the industrial control board and, through the industrial control board, to provide power to the motor.

[0092] The ninth pin is connected to the eighth pin via the motor and is used to control the rotation of the motor according to the open-circuit control signal and the short-circuit control signal.

[0093] The tenth pin is connected to the eighth pin through the first controlled switch, and is used to control the first controlled switch to close according to the short-circuit control signal;

[0094] The eleventh pin is connected to the eighth pin via the second controlled switch, and is used to control the closing of the second controlled switch according to the test control signal.

[0095] In another specific embodiment of the present invention, a DC24VFX2N industrial control board is used, wherein:

[0096] S / S is the first pin, I0.1 is the second pin, I0.2 is the third pin, I0.3 is the fourth pin, I0.4 is the fifth pin, N is the sixth pin, L is the seventh pin, COM1 is the eighth pin, Q0.1 is the ninth pin, Q0.2 is the tenth pin, and Q0.3 is the eleventh pin.

[0097] In another embodiment of the present invention, based on the foregoing embodiments, the industrial control board further includes: a first transition relay and a first time relay;

[0098] The first transition relay is connected to the third pin, the first time relay and the ninth pin respectively. When a short-circuit control signal is received, it sends a timing signal to the first time relay. When a timing completion signal is received from the first time relay, it turns on the internal control circuit and sends the short-circuit control signal to the ninth pin.

[0099] The first time relay is used to receive the timing signal and return a timing completion signal to the first transition relay when the timing reaches the first preset duration.

[0100] It should be noted that, in order to avoid the motor's rotation occurring before the first controlled switch closes during the short-circuit test, which would cause the internal resistance of the mechanical megohmmeter to suddenly drop from infinity to 0 and thus damage the mechanical megohmmeter, it is necessary to delay the signal transmission of the third pin to ensure that the two terminals of the mechanical megohmmeter are short-circuited before the short-circuit test is performed.

[0101] In a more specific embodiment of the present invention, based on the foregoing embodiments, the first preset time can be 1 second.

[0102] In another embodiment of the present invention, based on the foregoing embodiments, the industrial control board further includes: a second transition relay and a second time relay;

[0103] The second transition relay is connected to the first transition relay, the second time relay and the tenth pin respectively. It is used to send the short-circuit control signal to the tenth pin and output it to the first controlled switch through the tenth pin. It is also used to send a timing signal to the second time relay when a short-circuit control signal is received, and to stop sending the short-circuit control signal to the tenth pin when a timing completion signal is received from the first time relay.

[0104] The second time relay is used to receive the timing signal and send a timing completion signal to the second transition relay when the timing reaches the second preset duration.

[0105] It is understandable that prolonged short-circuit connection will damage the mechanical megohmmeter, so the short-circuit control signal needs to be disconnected some time after the short-circuit test ends.

[0106] In a more specific embodiment of the present invention, based on the foregoing embodiments, the second preset time can be 1 second.

[0107] In another embodiment of the present invention, based on the foregoing embodiments, the industrial control board further includes: a third transition relay and a third time relay;

[0108] The third transition relay is connected to the fourth pin, the third time relay and the eleventh pin respectively. When a test control signal is received, it sends a timing signal to the third time relay. When a timing completion signal is received from the third time relay, it turns on the internal control circuit and sends the test control signal to the eleventh pin.

[0109] The first time relay is used to receive the timing signal and return the timing completion signal to the third transition relay when the timing reaches the third preset duration.

[0110] In a specific embodiment of the present invention, based on the foregoing embodiments, the third preset time can be selected as 0.2 to 0.5 seconds according to the actual situation.

[0111] In a specific embodiment of the present invention, based on the foregoing embodiments, the electric motor used in the present invention has a rotational speed of 120 revolutions per minute or more.

[0112] In a specific embodiment of the present invention, based on the foregoing embodiments, the electric motor used in the present invention is a uniform speed rotating electric motor.

[0113] In another embodiment of the present invention, based on the foregoing embodiments, a megohmmeter with protective function further includes: an insulating housing;

[0114] The insulating enclosure is used to house the mechanical megohmmeter body, motor, industrial control board, first control switch, second control switch and power module.

[0115] In another embodiment of the present invention, please refer to Figure 2 , Figure 2 This is a schematic diagram of the panel of a megohmmeter with protective functions. Based on the aforementioned embodiment, the side wall of the insulating housing is provided with an opening, and a control panel of a size adapted to the opening is provided at the opening.

[0116] The control panel includes a display module, a control module, and wiring holes.

[0117] The display module is used to display the readings of the mechanical megohmmeter body;

[0118] The control module is used to set the first control switch and the second control switch;

[0119] The wiring hole is used to bring the terminal block out of the insulating box through the connecting wire.

[0120] In a specific embodiment of the present invention, based on the foregoing embodiments, a plurality of support legs with adjustable lengths are provided on the outer side of the opposite sidewall of the opening on the insulating box.

[0121] In practice, there are at least three supporting legs.

[0122] Understandably, because the support legs are flexible and extendable, the entire housing can always remain parallel to the ground, thus improving the accuracy of the mechanical megohmmeter.

[0123] In a specific embodiment of the present invention, based on the foregoing embodiments, the display module is made of transparent material, so that staff can directly view the reading of the mechanical megohmmeter body through the panel.

[0124] In a specific embodiment of the present invention, based on the foregoing embodiments, a megohmmeter with protective function further includes: a temperature and humidity detection module;

[0125] The temperature and humidity detection module is located on the panel, which allows for intuitive observation of the ambient temperature and humidity, making it more intuitive and convenient to calculate the resistivity of the object under test.

[0126] This invention also provides a short-circuit control method for a megohmmeter with protection function; please refer to [link to relevant documentation]. Figure 3 Specifically, it includes the following steps:

[0127] A short-circuit control signal is sent to the industrial control board via the second control switch;

[0128] When the industrial control board receives the short-circuit control signal, it sends the short-circuit control signal to the motor and the first controlled switch respectively.

[0129] The electric motor drives the power output terminal to rotate according to the short-circuit control signal, thereby driving the generator inside the mechanical megohmmeter to generate electricity.

[0130] The first controlled switch closes according to the short-circuit control signal, causing a short circuit connection between the two terminals of the mechanical megohmmeter body.

[0131] This invention also provides an open-circuit control method for a megohmmeter with protection function; please refer to [link to relevant documentation]. Figure 4 Specifically, it includes the following steps:

[0132] An open-circuit control signal is sent to the industrial control board via the first control switch;

[0133] When the industrial control board receives an open-circuit control signal, it sends the open-circuit control signal to the motor;

[0134] The electric motor drives the power output terminal to rotate according to the open circuit control signal, thereby driving the generator inside the mechanical megohmmeter to generate electricity.

[0135] In another embodiment of the present invention, the control of the controlled switch and the motor can be achieved through program control, such as... Figure 5 and Figure 6 As shown, based on the aforementioned embodiments, the industrial control board further includes:

[0136] The following relays are used in the control process: reset contact SM0.1, test auxiliary relay M0.1, short-circuit auxiliary relay M0.2, open-circuit auxiliary relay M0.3, protection auxiliary relay M0.4, first transition relay M0.5, second transition relay M0.6, third transition relay M0.7, first time relay T32, second time relay T33, motor drive contact Q0.1, short-circuit control contact Q0.2, and open-circuit control contact Q0.3.

[0137] Reset control program such as Figure 4 As shown in network1, when the power is turned on, the reset contact SM0.1 is energized, resetting all auxiliary relays;

[0138] Test control program such as Figure 4 As shown in network2, when I0.3 is powered on, a test control signal is sent to the third transition relay M0.7. The third transition relay M0.7 sends a test control signal to the time relay T34. After receiving the signal, the time relay T34 starts timing. After the timing is completed, it sends the test control signal to the eleventh pin.

[0139] Short-circuit procedure such as Figure 4 As shown in network 3, when I0.2 is powered on, the short-circuit control signal is sent to the transition auxiliary relay M0.5 through the input pin I0.2. The first transition relay M0.5 sends the short-circuit control signal to the first time relay T32. After receiving the signal, the first time relay T32 starts timing. After the timing is completed, it sends the short-circuit control signal to the second time relay T33 through the second transition relay M0.6 (not shown in the figure). After the second time relay T33 finishes timing, it sends the short-circuit control signal to the short-circuit auxiliary relay M0.2.

[0140] Open circuit control program such as Figure 5 As shown in network4, when I0.1 is energized, the open-circuit control signal is sent to the open-circuit auxiliary relay M0.3 through the input pin I0.3;

[0141] Protection control procedures such as Figure 5 As shown in network 5, when I0.4 is energized, the protection control signal is sent from I0.4 to the protection auxiliary relay M0.4, resetting all auxiliary relays;

[0142] Motor control program such as Figure 5As shown in network6, when the test auxiliary relay M0.1, open-circuit auxiliary relay M0.2, and short-circuit auxiliary relay M0.3 receive signals, the signals are output through Q0.1.

[0143] It should be noted that, in order to more vividly illustrate the program operation process, test auxiliary relays, open-circuit auxiliary relays, short-circuit auxiliary relays, and protection auxiliary relays used for intermediate quantity storage are included in the embodiment.

[0144] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0145] It should be understood that in this application, "and / or" is used to describe the relationship between related objects, indicating that there can be three relationships. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the related objects before and after it are in an "or" relationship.

[0146] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0147] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0148] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0149] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A megohmmeter with protective function, comprising a mechanical megohmmeter body with two terminals, characterized in that, Also includes: The system comprises: a first control switch, a second control switch, an industrial control board, a first controlled switch, a motor, and a power supply module, wherein: The first control switch is connected to the industrial control board and is used to send an open-circuit control signal to the industrial control board; The second control switch is connected to the industrial control board and is used to send a short-circuit control signal to the industrial control board; The industrial control board is connected to the motor and is used to control the rotation of the motor according to the open circuit control signal and the short circuit control signal; The industrial control board is connected to the first controlled switch and is used to control the first controlled switch to close according to the short-circuit control signal; The first controlled switch is connected to two terminals of the mechanical megohmmeter body; The power output terminal of the electric motor is connected to the generator rotor of the mechanical megohmmeter body. The power module is connected to the industrial control board; The industrial control board also includes: a first transition relay and a first time relay; The first transition relay is connected to the second control switch, the first time relay and the motor respectively. When a short-circuit control signal is received, it sends a timing signal to the first time relay, and when a timing completion signal is received from the first time relay, it sends the short-circuit control signal to the motor. The first time relay is used to start timing when the timing signal is received, and to return the timing completion signal to the first transition relay when the timing reaches a first preset duration.

2. A megohmmeter with protective function according to claim 1, characterized in that, Also includes: The third control switch and the second controlled switch are connected to the industrial control board; The third control switch is used to send test control signals to the industrial control board; The industrial control board is also used to control the rotation of the motor and the closing of the second controlled switch according to the test control signal; The second controlled switch is connected between the mechanical megohmmeter body and the high-potential terminal of the two terminals.

3. A megohmmeter with protective function according to claim 2, characterized in that, It also includes: a fourth control switch connected to the industrial control board; The fourth control switch is used to send a lockout control signal to the industrial control board; The industrial control board is also used to enter the locked state when it receives the locking control signal.

4. A megohmmeter with protective function according to claim 3, characterized in that, The industrial control board includes pins one through eleven, wherein: Pin 1 and pin 8 are common terminals; The second pin is connected to the first pin via the first control switch; The third pin is connected to the first pin via the second control switch; The fourth pin is connected to the first pin via the third control switch; The fifth pin is connected to the first pin via the fourth control switch; Pins 6 and 7 are connected to the power module, respectively. The ninth pin is connected to the eighth pin via the motor; The tenth pin is connected to the eighth pin via the first controlled switch; The eleventh pin is connected to the eighth pin via the second controlled switch.

5. A megohmmeter with protective function according to claim 4, characterized in that, The first transition relay is connected to the third pin, the first time relay, and the ninth pin respectively. When a short-circuit control signal is received, it sends a timing signal to the first time relay, and when a timing completion signal is received from the first time relay, it sends the short-circuit control signal to the ninth pin.

6. A megohmmeter with protective function according to claim 5, characterized in that, The industrial control board also includes: a second transition relay and a second time relay; The second transition relay is connected to the first transition relay, the second time relay and the tenth pin respectively, and is used to send the short-circuit control signal to the tenth pin, and send a timing signal to the second time relay at the same time as receiving the short-circuit control signal. When the timing completion signal sent by the second time relay is received, the transmission of the short-circuit control signal to the tenth pin is stopped. The second time relay is used to receive the timing signal and send the timing completion signal to the second transition relay when the timing reaches the second preset duration.

7. A megohmmeter with protective function according to claim 1, characterized in that, Also includes: Insulating enclosure; The insulating enclosure is used to house the mechanical megohmmeter body, the motor, the industrial control board, the first control switch, the second control switch, and the power module.

8. A megohmmeter with protective function according to claim 7, characterized in that, The side wall of the insulating box is provided with an opening, and a control panel of a size adapted to the opening is provided at the opening; The control panel is used to set the first control switch and the second control switch, and also to display the reading of the mechanical megohmmeter body.

9. A short-circuit control method based on a megohmmeter with protection function as described in any one of claims 1-8, characterized in that, Includes the following steps: A short-circuit control signal is sent to the industrial control board via the second control switch; When the industrial control board receives the short-circuit control signal, it sends the short-circuit control signal to the motor and the first controlled switch respectively. The electric motor drives the power output terminal to rotate according to the short-circuit control signal, thereby driving the generator inside the mechanical megohmmeter to generate electricity. The first controlled switch closes according to the short-circuit control signal, causing a short circuit connection between the two terminals of the mechanical megohmmeter body.

10. An open-circuit control method based on a megohmmeter with protection function according to any one of claims 1-8, characterized in that, Includes the following steps: An open-circuit control signal is sent to the industrial control board via the first control switch; When the industrial control board receives an open-circuit control signal, it sends the open-circuit control signal to the motor; The electric motor drives the power output terminal to rotate according to the open circuit control signal, thereby driving the generator inside the mechanical megohmmeter to generate electricity.

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