Motor fault detection system

Abstract

A fault detection system of a motor belongs to the technical field of motor fault detection, and aims to solve the problems that the existing motor fault detection device is high in detection difficulty and inaccurate in fault reason judgment. The fault detection system comprises the steps that a frequency converter is adopted as a motor starter, and the input voltage of the motor is gradually increased; a harmonic detection module is adopted to detect the harmonic component of a current signal output by the motor, and the harmonic detection module outputs a harmonic waveform; detecting whether the motor is in a normal operation state, a winding short-circuit fault state, a winding open-circuit fault state or a bearing fault state according to the harmonic waveform; a built-in insulation monitoring module of the frequency converter is adopted to detect the insulation resistance value of the motor; judging a motor leakage state according to the insulation resistance value; a torque measuring module arranged in the frequency converter is used for detecting the torque of the motor; judging a motor torque fault state according to the torque; a temperature sensor arranged in the frequency converter is used for detecting the temperature of the motor; and judging a motor fault state according to the temperature. The method is used for motor fault detection.

Description

Technical Field

[0001] The invention relates to a measuring device for a motor, and belongs to the technical field of motor fault detection. Background Art

[0002] With the advancement of science and technology and the development of productivity, the development of new technologies, new products and new energy and the expansion of the market, each industry has its core key equipment, and the core of all equipment is almost the motor, so the intact condition of the motor is extremely important. Once a motor failure occurs, it will not only cause significant economic losses, but also cause casualties.

[0003] Motors are the core tools and main resources for implementing production. Their operating status is extremely important. Once a motor fails, it will cause failures such as motor explosions after power is supplied, and the consequences are often disastrous. Therefore, how to accurately judge the quality of a motor and whether the motor can be powered normally is the most concerned and important issue in all industries today. It is also the current key research issue in the manufacturing industry, playing a very important role in ensuring national economic construction and social development. In recent years, the user department has put forward higher requirements for equipment operation. This requirement has led to a difficult problem in detecting the quality of motor failures under various external variables.

[0004] Therefore, a motor detection device that can accurately determine whether the motor can work normally and can easily determine the cause of the fault is an important device to ensure the reliability and service life of the equipment. The motor detection device can eliminate equipment faults in the primary stage and prevent the faults from further expanding, providing reliable detection technology and management guarantees for the safe, stable, long-term, full-performance, and high-quality operation of the equipment.

[0005] In the prior art, a traditional multimeter or megohmmeter is used to determine whether a motor is faulty. This can only detect whether the motor has a phase-to-phase short circuit fault or a ground fault, and in a bad environment, such as when it has just rained and the air humidity is too high, it will lead to inaccurate measurements. Summary of the invention

[0006] The purpose of the present invention is to solve the problems of great detection difficulty and inaccurate fault cause determination in existing motor fault detection devices, and to provide a motor fault detection system.

[0007] A motor fault detection system according to the present invention comprises:

[0008] Using a frequency converter as a motor starter, the input voltage to the motor gradually increases;

[0009] A harmonic detection module is used to detect the harmonic components of the output current signal of the motor, and the harmonic detection module outputs a harmonic waveform; based on the harmonic waveform, it is detected whether the motor is in a normal operating state, a winding short circuit fault state, a winding open circuit fault state, or a bearing fault state;

[0010] The built-in insulation monitoring module of the inverter is used to detect the insulation resistance value of the motor; the leakage state of the motor is determined according to the insulation resistance value;

[0011] The torque measurement module built into the inverter is used to detect the torque of the motor; the torque fault state of the motor is determined based on the torque;

[0012] The temperature of the motor is detected by the built-in temperature sensor of the inverter; the fault status of the motor is determined based on the temperature.

[0013] Preferably, it also includes: when the motor is in a grounding state, the frequency converter sends out an alarm signal and shuts down at the same time.

[0014] Preferably, the detecting whether the motor is in a normal operation state, a winding short circuit fault state, a winding open circuit fault state or a bearing fault state according to the harmonic waveform specifically includes:

[0015] When the harmonic waveform is a regular sine wave, the motor is in normal operation;

[0016] When the waveform of the odd harmonic component increases or is distorted, the motor is in a motor winding short-circuit fault state;

[0017] When the harmonic waveform is asymmetrical or the harmonic component increases, the motor is in a motor winding open circuit fault state;

[0018] When the harmonic component of the harmonic waveform increases, the motor is in a bearing fault state.

[0019] Preferably, judging the motor leakage state according to the insulation resistance value specifically includes:

[0020] When the insulation resistance value is lower than the standard value, the motor is in a leakage state.

[0021] Preferably, judging the motor torque fault state according to the torque specifically includes:

[0022] When the torque is unstable or peak-off occurs, the motor is in a torque fault state.

[0023] Preferably, judging the motor fault state according to the temperature specifically includes:

[0024] When the temperature detected by the temperature sensor is higher than the standard value, the motor is in a fault state.

[0025] Preferably, it further comprises: a power supply and a connection terminal; the power supply comprises an inverter device and a 12V battery;

[0026] The inverter device inverts the output voltage of the 12V battery into a 220V voltage, and uses the wiring terminal to connect the 220V voltage to the inverter to power the inverter.

[0027] Advantages of the present invention: The motor fault detection system proposed in the present invention can accurately judge whether the motor is good or bad and the cause of the fault. When the motor running in a humid environment cannot be powered, it can accurately detect whether the motor has a fault and accurately find the cause of the fault, thereby solving the fault in time, preventing safety hazards, and resolving the fault as soon as possible to ensure stable and reliable operation of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a principle block diagram of a motor fault detection system described in the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0031] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0032] Embodiment 1:

[0033] Combine the following Figure 1 The present embodiment is described as follows. The present embodiment is a motor fault detection system, which includes:

[0034] Using a frequency converter as a motor starter, the input voltage to the motor gradually increases;

[0035] A harmonic detection module is used to detect the harmonic components of the output current signal of the motor, and the harmonic detection module outputs a harmonic waveform; based on the harmonic waveform, it is detected whether the motor is in a normal operating state, a winding short circuit fault state, a winding open circuit fault state, or a bearing fault state;

[0036] The built-in insulation monitoring module of the inverter is used to detect the insulation resistance value of the motor; the leakage state of the motor is determined according to the insulation resistance value;

[0037] The torque measurement module built into the inverter is used to detect the torque of the motor; the torque fault state of the motor is determined based on the torque;

[0038] The temperature of the motor is detected by the built-in temperature sensor of the inverter; the fault status of the motor is determined based on the temperature.

[0039] Furthermore, it also includes: when the motor is in a grounding state, the frequency converter sends out an alarm signal and stops at the same time.

[0040] Furthermore, the detecting of whether the motor is in a normal operation state, a winding short circuit fault state, a winding open circuit fault state or a bearing fault state according to the harmonic waveform specifically includes:

[0041] When the harmonic waveform is a regular sine wave, the motor is in normal operation;

[0042] When the waveform of the odd harmonic component increases or is distorted, the motor is in a motor winding short-circuit fault state;

[0043] When the harmonic waveform is asymmetrical or the harmonic component increases, the motor is in a motor winding open circuit fault state;

[0044] When the harmonic component of the harmonic waveform increases, the motor is in a bearing fault state.

[0045] Furthermore, judging the motor leakage state according to the insulation resistance value specifically includes:

[0046] When the insulation resistance value is lower than the standard value, the motor is in a leakage state.

[0047] Furthermore, judging the motor torque fault state according to the torque specifically includes:

[0048] When the torque is unstable or peak-off occurs, the motor is in a torque fault state.

[0049] Furthermore, judging the motor fault state according to the temperature specifically includes:

[0050] When the temperature detected by the temperature sensor is higher than the standard value, the motor is in a fault state.

[0051] In the present invention, the traditional detection method is combined with the detection function of the frequency converter, the frequency converter is used to start the motor, and the detection alarm function of the frequency converter is used to detect the quality of the motor and the fault point. By using the frequency converter to drive the motor to start, the voltage can be increased step by step, the quality of the motor can be determined more accurately, and the motor can be protected. The cause of the fault can also be determined based on the alarm information of the frequency converter. It is beneficial to improve the utilization rate of the equipment and reduce the failure downtime rate of the equipment, ensure the reliability of the equipment and the service life of the equipment, eliminate the equipment failure in the primary stage, and prevent the failure from further expanding. It provides reliable detection technology and management guarantee for the safe, stable, long-term, full-performance, and high-quality operation of the equipment.

[0052] In the present invention, since the normal frequency converter is powered by 220V, it can only be powered by connecting to a power source, which lacks portability. First, we make a power supply, hang a 12V rechargeable battery on the frequency converter, and use an inverter to invert it into a 220V power supply to power the frequency converter.

[0053] In the present invention, input and output terminals are added to the device to facilitate connection to a power source and to a motor.

[0054] In the present invention, the frequency converter is used to start the motor, and the starting time is prolonged, which can effectively protect the motor and accurately determine the cause of the motor failure.

[0055] Combine the following Figure 1 The working principle of the present invention is explained as follows: using a frequency converter to detect the motor. When the on-site environment is humid or other extreme environmental changes occur, it is inaccurate to use a traditional multimeter or megohmmeter to measure the motor. We just need to use the function of the frequency converter to detect the motor. Using the frequency converter to start the motor can achieve a gradual increase in voltage without damaging the motor.

[0056] The current harmonic method is a method that analyzes the harmonic components of the motor current signal to detect whether there is a short circuit or grounding problem in the motor. When the motor is short-circuited, obvious harmonic components will appear in the current signal, which can be monitored and diagnosed in real time by the harmonic monitoring module inside the inverter. When the AC motor is operating normally, the harmonic waveform generated by the power supply voltage and the motor current is a very regular sine wave. However, when the motor fails, the state of the harmonic waveform will change, and this change can be judged by detecting the harmonic components. When a short circuit occurs in the motor winding, it will cause an increase in harmonic components and distortion of the waveform. Especially under high load, the harmonic waveform will be more obvious. At this time, it is usually possible to determine whether there is a winding short circuit fault by detecting odd harmonic components; winding open circuit faults are usually caused by loose or broken wires inside the winding. In this case, the current waveform will be asymmetric and the harmonic components will increase when the motor is running. At this time, the location and severity of the fault can be analyzed by detecting the fundamental wave and higher harmonic components. When the bearing of the motor fails, it will cause vibration and increased noise when the motor is running. At this time, when the motor is running, the harmonic components of the current waveform will increase. According to the changes in the harmonic components, the location and severity of the bearing fault can be analyzed.

[0057] The insulation monitoring method is to determine whether the motor is grounded by detecting the change in insulation impedance between the motor and the ground. The inverter generally has a built-in insulation monitoring module, which is used to detect the insulation resistance of the motor. After the detection is completed, check the insulation resistance value on the inverter screen. If the insulation resistance value is lower than the standard value, it means that the motor has leakage. When the motor is grounded, the inverter will issue an alarm signal and shut down to ensure safe operation.

[0058] When the motor loses torque, it will cause the motor to fail to work properly. At this time, the inverter parameter monitoring can be used to determine whether the motor has lost torque. The torque and speed of the motor can be read through the inverter display. Under normal circumstances, the output torque of the motor should be stable. If the motor torque is unstable or there is a peak break, it may indicate that the motor has a fault. Further testing can be performed afterwards.

[0059] Motors heat up during operation, and if a motor fails, the heating of the motor is often aggravated. The temperature of the motor can be monitored by the frequency converter, which is usually equipped with a built-in temperature sensor that can measure the temperature inside the frequency converter and the temperature of the motor. If the temperature of the motor exceeds a set threshold, the frequency converter will sound an alarm or shut down to prevent overheating; the frequency converter can also monitor the temperature of the motor based on the running time of the motor. By recording the running time of the motor, the frequency converter can estimate the temperature of the motor and sound an alarm or shut down if necessary. If the temperature of the motor rises abnormally, it may indicate that the motor has failed.

[0060] If the motor vibrates greatly when it is working, it may indicate that there is a problem inside the motor. In this case, the inverter can be used to detect the operation of the motor. By monitoring the vibration frequency of the motor itself and the frequency output by the inverter, it can be determined whether the motor is in normal working condition.

[0061] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. A motor fault detection system, characterized in that: It includes: Using a frequency converter as a motor starter, the input voltage to the motor gradually increases; A harmonic detection module is used to detect the harmonic components of the output current signal of the motor, and the harmonic detection module outputs a harmonic waveform; Detect whether the motor is in normal operation, winding short circuit fault, winding open circuit fault or bearing fault state according to the harmonic waveform; The built-in insulation monitoring module of the inverter is used to detect the insulation resistance value of the motor; the leakage state of the motor is determined according to the insulation resistance value; The torque of the motor is detected using the torque measurement module built into the inverter; Determine the motor torque fault status based on the torque; The temperature of the motor is detected by the built-in temperature sensor of the inverter; the fault status of the motor is determined based on the temperature.

2. A motor fault detection system according to claim 1, characterized in that: It also includes: when the motor is grounded, the inverter sends out an alarm signal and stops at the same time.

3. A motor fault detection system according to claim 1, characterized in that: The detecting, based on the harmonic waveform, whether the motor is in a normal operating state, a winding short circuit fault state, a winding open circuit fault state, or a bearing fault state specifically includes: When the harmonic waveform is a regular sine wave, the motor is in normal operation; When the waveform of the odd harmonic component increases or is distorted, the motor is in a motor winding short-circuit fault state; When the harmonic waveform is asymmetrical or the harmonic component increases, the motor is in a motor winding open circuit fault state; When the harmonic component of the harmonic waveform increases, the motor is in a bearing fault state.

4. A motor fault detection system according to claim 1, characterized in that: The method of judging the motor leakage state according to the insulation resistance value specifically includes: When the insulation resistance value is lower than the standard value, the motor is in a leakage state.

5. A motor fault detection system according to claim 1, characterized in that: Determining the motor torque fault state according to the torque specifically includes: When the torque is unstable or peak-off occurs, the motor is in a torque fault state.

6. A motor fault detection system according to claim 1, characterized in that: Determining the motor fault state according to the temperature specifically includes: When the temperature detected by the temperature sensor is higher than the standard value, the motor is in a fault state.

7. A motor fault detection system according to any one of claims 1 to 6, characterized in that: It also includes: a power supply and a wiring terminal; the power supply includes an inverter and a 12V battery; The inverter device inverts the output voltage of the 12V battery into a 220V voltage, and uses the wiring terminal to connect the 220V voltage to the inverter to power the inverter.

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