High-precision low-voltage motor insulation resistance automatic measuring device

Abstract

The utility model discloses a high-precision low-voltage motor insulation resistance automatic measuring device, which comprises a shell and a main body circuit, the main body circuit comprises a main control unit, a measuring unit and an isolation boosting unit, the main control unit and the measuring unit are electrically connected with the isolation boosting unit, a measuring range change-over switch is arranged in the main control unit, and the measuring range change-over switch is electrically connected with the isolation boosting unit. The isolation boost unit comprises a calibration circuit, a measurement circuit, a K1 switch and a K2 switch. The measuring unit comprises a resistor R1 and an impedance Rz, the measuring unit is electrically connected with the isolation boosting unit, the main body circuit is arranged in the shell, and automatic high-precision measurement of the insulation impedance of the low-voltage motor is realized through the main control unit, the measuring unit, the isolation boosting unit, the calibration loop and the measuring loop. The device solves the problems of low efficiency, poor precision, certain risk of personnel safety, long measurement period and influence on industrial production progress due to the fact that manual megger is adopted to measure the insulation resistance of the low-voltage motor on site in an existing working condition enterprise.

Description

Technical Field

[0001] This utility model relates to the detection technology of insulation impedance of low-voltage motors, and in particular to a high-precision automatic measurement device for insulation impedance of low-voltage motors. Background Technology

[0002] Low-voltage motors are a common type of electromechanical equipment in modern industry. Their function is to convert electrical energy into mechanical energy to drive various mechanical devices. The normal operation of these motors is crucial to the stability and efficiency of the production line. However, the insulation system of low-voltage motors can be damaged due to various reasons, such as humidity, temperature, excessively high or low voltage. To ensure the normal operation of low-voltage motors, it is essential to regularly measure the insulation and perform insulation testing.

[0003] Insulation testing of low-voltage motors is one of the important measures to ensure their normal operation. Regularly measuring and testing the insulation, and repairing or replacing insulation materials, helps prevent motor failures and accidents, thus improving the reliability and lifespan of the low-voltage motor.

[0004] Currently, the insulation impedance of low-voltage motors is mainly tested manually. Manual measurement is very risky and can easily cause safety accidents. In addition, the manual measurement process is complicated, time-consuming, inefficient, has low accuracy, and the test data is not easy to store, making it impossible to conduct scientific and effective analysis of the test data.

[0005] Therefore, it is necessary to provide a high-precision automatic measurement device for the insulation resistance of low-voltage motors to solve the above-mentioned technical problems. Utility Model Content

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the present invention.

[0007] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a high-precision automatic measurement device for the insulation impedance of a low-voltage motor, comprising a housing and a main circuit. The main circuit includes a main control unit, a measurement unit, and an isolation boosting unit. The main control unit, the measurement unit, and the isolation boosting unit are electrically connected. The main control unit is equipped with a range switching switch. The isolation boosting unit includes a calibration circuit, a measurement circuit, a K1 switch, and a K2 switch. The measurement unit includes a resistor R1 and an impedance Rz. The measurement unit is electrically connected to the isolation boosting unit. The main circuit is located inside the housing. Through the main control unit, the measurement unit, the isolation boosting unit, the calibration circuit, and the measurement circuit, the automatic high-precision measurement of the insulation impedance of the low-voltage motor is realized.

[0008] As a preferred embodiment of the high-precision low-voltage motor insulation impedance automatic measuring device of this utility model, the device further includes a touch screen, a memory, input parameters and output parameters. The touch screen is mounted on the housing, and the touch screen, the memory, the input parameters and the output parameters are all electrically connected to the main control unit.

[0009] In a preferred embodiment of the high-precision automatic measurement device for low-voltage motor insulation impedance described in this utility model, the main control unit receives and saves the low-voltage motor insulation impedance test command sent by the host computer to its local storage via RS485, LoRa, and Ethernet communication technologies.

[0010] In a preferred embodiment of the high-precision low-voltage motor insulation impedance automatic measuring device of this utility model, after receiving the low-voltage motor insulation impedance detection command from the main control unit, the measuring unit first sends a boost command to the isolation boost unit to boost the DC voltage output for detection to DC500V or DC1000V. At the same time, it closes switch K2, K2 and high-precision resistor R1 form a complete circuit, and starts the calibration circuit of the measuring unit to calibrate the operational amplifier inside the measuring unit.

[0011] In a preferred embodiment of the high-precision low-voltage motor insulation impedance automatic measuring device of this utility model, after the calibration circuit formed by the K2 switch and the resistor R1 completes the calibration work, the measuring unit issues a command to close the switch K2, disconnecting the calibration circuit. After a delay of a specified time, the measuring unit issues a command to open the K1 switch. When K1 is closed, the insulation impedance resistance Rz of the low-voltage motor forms a measuring circuit.

[0012] In a preferred embodiment of the high-precision automatic measurement device for low-voltage motor insulation impedance described in this utility model, after the K1 switch and the low-voltage motor insulation impedance Rz form a measurement circuit, the measurement unit starts the high-precision operational amplifier to start detecting Rz. In order to improve the detection accuracy, the measurement unit will continuously and automatically switch the detection range according to the detection situation, adjust the detection window to the calibration position, and then continuously detect Rz at the calibration position, and finally obtain the final Rz value of the low-voltage motor insulation impedance.

[0013] As a preferred embodiment of the high-precision low-voltage motor insulation impedance automatic measuring device of this utility model, after the measuring circuit formed by switch K1 and the low-voltage motor insulation impedance Rz completes the detection of Rz, the measuring unit issues a command to set the output voltage of the isolation boost switch to 0V, disconnect the DC voltage output, disconnect switch K1, and then send the measured value Rz to the main control unit through the internal communication interface.

[0014] In a preferred embodiment of the high-precision low-voltage motor insulation impedance automatic measuring device of this utility model, after the main control unit receives the measurement result Rz from the measuring unit, it uploads the measured value to the host computer through RS485, LoRa or Ethernet communication interface, stores it locally, and displays the measured value on the touch screen.

[0015] The beneficial effects of this invention are as follows: By employing a high-precision automatic measurement device for the insulation impedance of low-voltage motors, it features high measurement accuracy, short measurement cycle, and a combination of fully automatic and manual measurement capabilities. This effectively improves worker safety. Simultaneously, the measurement results can be uploaded to the backend via various communication methods such as RS485, Ethernet, or LoRa, generating a time curve of the motor's insulation impedance. This effectively prevents the decline in insulation impedance of low-voltage motors, eliminating the adverse consequences of insulation impedance drop causing damage during motor startup. This invention can also automatically measure the insulation impedance of low-voltage motors, and includes a calibration circuit. It allows for effective analysis and prediction of test results, thereby ensuring the normal and efficient operation of low-voltage motor equipment. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Among them:

[0017] Figure 1 This is a schematic diagram of the overall principle connection of the high-precision low-voltage motor insulation impedance automatic measuring device described in this utility model. Detailed Implementation

[0018] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0019] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0020] Secondly, this utility model is described in detail with reference to the schematic diagrams. When describing the embodiments of this utility model, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of this utility model. In addition, actual manufacturing should include the three-dimensional spatial dimensions of length, width, and depth.

[0021] Furthermore, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that excludes other embodiments.

[0022] Example 1

[0023] Reference Figure 1 A high-precision automatic measurement device for the insulation impedance of a low-voltage motor includes a housing and a main circuit. The main circuit includes a main control unit, a measurement unit, and an isolation boosting unit. The main control unit, the measurement unit, and the isolation boosting unit are electrically connected. The main control unit has a range switching switch inside. The isolation boosting unit includes a calibration circuit, a measurement circuit, a K1 switch, and a K2 switch. The measurement unit includes a resistor R1 and an impedance Rz. The measurement unit and the isolation boosting unit are electrically connected. The main circuit is located inside the housing. Through the main control unit, the measurement unit, the isolation boosting unit, the calibration circuit, and the measurement circuit, the automatic high-precision measurement of the insulation impedance of the low-voltage motor is realized. Specifically, the main circuit includes: a main control unit that controls the measurement process; a measurement unit equipped with a high-precision operational amplifier, which has multiple range switching switches inside; during the measurement process of the isolation boost unit circuit, it outputs DC500 or DC1000V DC voltage for low-voltage motors of different specifications and voltages. The output circuit is divided into two loops: one is a calibration circuit before measurement, and the other is a low-voltage motor insulation impedance measurement circuit. Through the main control unit, measurement unit, isolation boost unit, calibration circuit, and measurement circuit, automatic high-precision measurement of low-voltage motor insulation impedance can be achieved.

[0024] The main control unit can be used independently or synchronously via RS485, LoRa, and Ethernet communication technologies. It receives low-voltage motor insulation impedance test commands from the host computer and saves them locally. The main control unit detects two conditions simultaneously: the test time has elapsed and the tested motor is powered off. When both conditions are met, the main control unit sends a low-voltage motor insulation impedance test command to the measurement unit via its internal serial communication interface. The measurement unit is grounded at its end. Upon receiving the low-voltage motor insulation impedance test command from the main control unit, the measurement unit first sends a boost command to the isolation boost unit, increasing the DC voltage output for testing to DC500V or DC1000V. Simultaneously, it closes switch K2. When the measurement unit and the isolation boost unit are electrically connected, K2 and the high-precision resistor R1 form a complete circuit, activating the calibration circuit of the measurement unit to calibrate the operational amplifiers inside the measurement unit. The measurement unit is connected to the isolation boost unit. After calibration, the K2 switch and the high-precision resistor R1 form a calibration circuit. Once calibration is complete, the measurement unit commands the K2 switch to close, disconnecting the calibration circuit. After a certain delay, the measurement unit commands the K1 switch to open. When K1 is closed, and the measurement unit is electrically connected to the isolation boost unit, the K1 switch and the insulation resistance Rz of the low-voltage motor form a measurement circuit. When the measurement unit is electrically connected to the isolation boost unit, and the K1 switch and the low-voltage motor insulation resistance Rz form a measurement circuit, the measurement unit starts the high-precision generator to detect Rz. To improve detection accuracy, the measurement unit continuously and automatically switches the detection range based on the detection results, adjusting the detection window to the optimal position. It then continuously detects Rz at the optimal position, ultimately obtaining the final Rz value of the low-voltage motor insulation resistance. When the measuring unit is electrically connected to the isolation boost unit, after the measuring circuit formed by switch K1 and the low-voltage motor insulation impedance Rz completes the detection of Rz, the measuring unit issues a command to set the output voltage of the isolation boost switch to 0V, simultaneously disconnecting the DC voltage output and disconnecting switch K1. Then, the measured value Rz is sent to the main control unit through the internal communication interface. After receiving the measurement result Rz from the measuring unit, the main control unit uploads the measured value to the host computer via RS485, LoRa, or Ethernet communication interface, stores it locally, and displays the measured value on the touch screen.

[0025] In summary, this invention can automatically measure the insulation impedance of low-voltage motors, has a calibration circuit, high testing accuracy, short measurement cycle, and can effectively analyze and predict the test results, thereby ensuring the normal and efficient operation of low-voltage motor equipment.

[0026] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., changes in the size, dimensions, structure, shape and proportion of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application). For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of elements may be inverted or otherwise altered, and the nature or number or position of discrete elements may be changed or altered. Therefore, all such modifications are intended to be included within the scope of this utility model. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and not only structural equivalents but also equivalent structures. Without departing from the scope of this invention, other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments. Therefore, this invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0027] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments (i.e., those features that are not relevant to the best mode of carrying out the present invention as currently considered, or those features that are not relevant to the implementation of the present invention) may be omitted.

[0028] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0029] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A high-precision automatic measuring device for insulation resistance of low-voltage motors, comprising a housing and a main circuit, characterized in that: The main circuit includes a main control unit, a measurement unit, and an isolation boost unit. The main control unit, the measurement unit, and the isolation boost unit are electrically connected. The main control unit has a range switching switch inside. The isolation boost unit includes a calibration circuit, a measurement circuit, a K1 switch, and a K2 switch. The measurement unit includes a resistor R1 and an impedance Rz. The measurement unit is electrically connected to the isolation boost unit. The main circuit is located inside the housing. Through the main control unit, the measurement unit, the isolation boost unit, the calibration circuit, and the measurement circuit, automatic high-precision measurement of the insulation impedance of low-voltage motors is achieved.

2. The high-precision automatic measuring device for insulation resistance of low-voltage motors according to claim 1, characterized in that: The device also includes a touch screen, a memory, input signals, and output signals. The touch screen is mounted on the housing, and the touch screen, the memory, the input signals, and the output signals are all electrically connected to the main control unit.

3. The high-precision automatic measuring device for insulation resistance of low-voltage motors according to claim 1, characterized in that: The main control unit receives and saves the low-voltage motor insulation impedance test command sent by the host computer to its local machine through three communication technologies: RS485, LoRa, and Ethernet.

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