Motor monitoring system

Abstract

To provide a motor monitoring system capable of accurately determining abnormality of a motor even when a rotation speed of the motor changes.SOLUTION: A motor monitoring system that monitors a facility including a first motor includes a motor monitoring device configured to execute a process of acquiring first data indicating vibration or current of the first motor and second data indicating a rotation speed of the first motor, a process of determining a first determination threshold for the first data for performing abnormality determination of the first motor based on the second data, and a process of performing abnormality determination of the first motor using the first data and the first determination threshold.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a motor monitoring system. [Background technology]

[0002] International Publication No. 2022 / 085425 (Patent Document 1) discloses a configuration for determining abnormalities in motor equipment from vibrations and sounds. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 085425 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, when a motor malfunction such as bearing deterioration occurs, vibration increases, so abnormalities are detected by determining the strength of the vibration against a threshold value.

[0005] However, abnormalities are not the only factor that can increase motor vibration. Vibration also increases when the motor's rotation speed increases depending on the operating mode of the equipment to which the motor is attached. Therefore, if maintenance work (such as replacing equipment bearings) is performed without taking into account changes in rotation speed like this, the work may end up being wasted.

[0006] The present disclosure is intended to solve such problems, and its purpose is to provide a motor monitoring system that can accurately determine whether a motor has an abnormality even when the rotation speed of the motor changes. [Means for solving the problem]

[0007] A motor monitoring system according to one embodiment of the present disclosure is a motor monitoring system that monitors equipment including a first motor, and includes a motor monitoring device configured to perform the following processes: acquiring first data indicating the vibration or current of the first motor and second data indicating the rotational speed of the first motor; determining a first judgment threshold for the first data for determining an abnormality in the first motor based on the second data; and determining an abnormality in the first motor using the first data and the first judgment threshold. [Effects of the Invention]

[0008] The motor monitoring system of the present disclosure can improve the accuracy of abnormality detection for motors whose vibration or current state changes depending on the rotation speed. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of a motor monitoring system 1000 including a motor monitoring device 10 according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an example of the configuration of the rotation sensor 514 in FIG. [Figure 3] FIG. 3 is a diagram showing the configuration of the motor monitoring device 10. As shown in FIG. [Figure 4] FIG. 4 is a diagram for explaining the contents of the monitoring process 100. As shown in FIG. [Figure 5] FIG. 5 is a diagram showing an example of a monitoring screen 300 based on monitoring screen information 300A generated and updated by the generation process 170. As shown in FIG. [Figure 6] FIG. 6 is a diagram showing a configuration for detecting an abnormality due to vibration in the motor monitoring system according to the first embodiment. [Figure 7] FIG. 7 is a diagram for explaining data when the sampling frequency is too high. [Figure 8] FIG. 8 is a diagram for explaining data when the sampling frequency is too low. [Figure 9] FIG. 9 is a diagram for explaining data when the sampling frequency is appropriate. [Figure 10] FIG. 10 is a diagram for explaining how to determine an appropriate sampling frequency. [Figure 11] FIG. 11 is a flowchart illustrating the process of calculating the rotation speed. [Figure 12] FIG. 12 is an example of a graph showing the relationship between rotation speed and vibration. [Figure 13] FIG. 13 is a diagram for explaining a method for determining a threshold value through learning. [Figure 14] FIG. 14 is a diagram for explaining an example of the arrangement of the magnetic sensor and the vibration sensor. [Figure 15] FIG. 15 is a diagram illustrating the configuration of the motor monitoring system according to the second embodiment. [Figure 16] FIG. 16 is a diagram illustrating the configuration of the motor monitoring system according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0011] (1) A motor monitoring system according to one embodiment of the present disclosure is a motor monitoring system that monitors equipment including a first motor, and includes a motor monitoring device configured to execute the following processes: acquiring first data indicating the vibration or current of the first motor and second data indicating the rotational speed of the first motor; determining a first judgment threshold for the first data for determining an abnormality in the first motor based on the second data; and determining an abnormality in the first motor using the first data and the first judgment threshold.

[0012] According to the above configuration, it is possible to improve the accuracy of abnormality detection for a motor whose vibration or current state changes depending on the rotation speed.

[0013] (2) In the motor monitoring system described in (1) above, the first data is data indicating vibration of the first motor, and the motor monitoring system further includes a first vibration sensor that detects vibration of the first motor and outputs the first data, and a first rotation sensor that detects the rotation speed of the first motor and outputs second data.

[0014] According to the above configuration, the rotation speed and vibrations can be detected, and abnormality detection can be performed with improved accuracy.

[0015] (3) In the motor monitoring system described in (2) above, the first rotation sensor includes a magnetic sensor and a rotation detection processing unit that outputs the rotation speed of the first motor based on the output of the magnetic sensor.

[0016] According to the above configuration, the magnetic sensor can detect the change in the magnetic field generated in the vicinity of the motor, thereby detecting the rotation speed.

[0017] (4) In the motor monitoring system described in (3) above, the rotation detection processing unit includes a memory. When M is a natural number indicating the number of data items limited by the memory capacity, the rotation detection processing unit is configured to determine a sampling frequency such that a waveform reproduced by the M pieces of data items includes three or more zero-crossing points. The M pieces of data items are obtained by subtracting an average value of the M measured values ​​from each of M measured values ​​obtained by sampling the output of the magnetic sensor. The rotation detection processing unit is configured to calculate the rotation speed of the first motor from the time interval between the first and third zero-crossing points obtained when sampling at the determined sampling frequency.

[0018] According to the above configuration, even if the memory size is insufficient, the rotation speed can be detected appropriately.

[0019] (5) In the motor monitoring system described in (3) above, the first motor includes a bearing and a coil, the first vibration sensor is positioned closer to the bearing than the coil, and the magnetic sensor is positioned closer to the coil than the bearing.

[0020] According to the above configuration, by appropriately arranging the vibration sensor and the magnetic sensor, it is possible to process the detected vibration and magnetic field with little noise.

[0021] (6) The motor monitoring system described in (2) above further includes a transmitter configured to receive the first data from the first vibration sensor and the second data from the first rotation sensor and transmit the data to the motor monitoring device.

[0022] According to the above configuration, even if the motor monitoring device is located at a location distant from the sensor, the data obtained from the sensor can be processed by the motor monitoring device.

[0023] (7) The motor monitoring system described in (6) above further includes a second vibration sensor that monitors a second motor in addition to the first motor, detects vibrations of the second motor, and outputs third data, and a second rotation sensor that detects the rotation speed of the second motor and outputs fourth data. The transmitter is configured to receive the third data from the second vibration sensor and the fourth data from the second rotation sensor, and transmit the data to the motor monitoring device. The motor monitoring device is configured to execute a process of determining a second determination threshold for the third data, based on the fourth data, for determining an abnormality in the second motor, and a process of determining an abnormality in the second motor using the third data and the second determination threshold.

[0024] According to the above configuration, the transmitter is used to monitor a plurality of motors, so the cost of the motor monitoring system can be reduced.

[0025] (8) In the motor monitoring system described in (6) above, the transmitter is configured so that the first rotation sensor can be detachably attached to the transmitter. The transmitter is configured so that a second vibration sensor can be connected to the transmitter instead of the first rotation sensor.

[0026] According to the above configuration, a vibration sensor can be attached instead of a rotation sensor to equipment with a constant load.

[0027] (9) The motor monitoring system described in (2) above further includes a first transmitter that receives first data from the first vibration sensor and transmits it to the motor monitoring device, and a second transmitter that receives second data from the first rotation sensor and transmits it to the motor monitoring device.

[0028] According to the above configuration, when a vibration sensor and a transmitter are already installed, the configuration related to the rotation sensor can be added later, thereby increasing the degree of freedom in design.

[0029] [Details of the embodiments of the present disclosure] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, identical or corresponding parts are designated by the same reference numerals, and their description will not be repeated. Furthermore, at least some of the embodiments described below may be combined in any manner.

[0030] [Embodiment 1] FIG. 1 is a diagram showing the configuration of a motor monitoring system 1000 including a motor monitoring device 10 according to an embodiment. The motor monitoring system 1000 includes a plurality of motor equipment 51, 53, 55, and 57 to be monitored, and the motor monitoring device 10. The motor equipment 51, 53, 55, and 57 are installed, for example, in a factory. The motor monitoring device 10 is connected to the motor equipment 51, 53, 55, and 57 via a network 70. The motor monitoring device 10 may be configured to remotely monitor the motor equipment 51, 53, 55, and 57, or may be configured to monitor the motor equipment 51, 53, 55, and 57 in the vicinity thereof. The network 70 may be, for example, a wired network or a wireless network.

[0031] The multiple motor equipment 51, 53, 55, 57 shown in Figure 1 include a first motor equipment 51, a second motor equipment 53, a third motor equipment 55, and a fourth motor equipment 57. There is no particular limit to the number of motor equipment 51, 53, 55, 57 to be monitored by the motor monitoring device 10. The second motor equipment 53, the third motor equipment 55, and the fourth motor equipment 57 shown in Figure 1 have the same configuration as the first motor equipment 51. However, the configurations of the motor equipment 51, 53, 55, 57 may be different from each other.

[0032] In the following, monitoring of the first motor equipment 51 by the motor monitoring device 10 will be described as an example, but the motor monitoring device 10 can also monitor the other motor equipment 53, 55, and 57 in the same manner.

[0033] As shown in FIG. 1 , the first motor equipment 51 includes a motor 518 and a motor circuit 510 for driving the motor. The motor 518 is, for example, a DC motor driven by a DC current or an AC motor driven by an AC current. In the following, as an example, the motor 518 is described as a DC motor. A polyphase AC power supply 501 supplies a polyphase AC current to the motor circuit 510 of the first motor equipment 51 to drive the motor 518. A polyphase AC current is a combination of two or more single-phase AC currents with different phases. In the following, as an example, the polyphase AC is described as a three-phase AC current. The three-phase AC is a combination of three single-phase AC currents, namely, R phase, S phase, and T phase. The three phases are shifted by 120 degrees from each other.

[0034] The motor circuit 510 shown in FIG. 1 includes a converter 520 that converts three-phase AC supplied from a power supply 501 into DC. The converter 520 shown in FIG. 1 is a three-phase full-wave rectifier circuit. The converter 520 includes a primary side 520A that receives three-phase AC and a secondary side 520B that outputs DC. The power supply 501 is connected to the primary side 520A. The motor 518 is connected to the secondary side 520B. The motor 518 is driven by the DC current output from the converter 520.

[0035] Hereinafter, the current flowing through primary side 520A of converter 520 is referred to as the primary side current. Of the primary side currents, the current flowing through the R phase is referred to as the R-phase current, the current flowing through the S phase is referred to as the S-phase current, and the current flowing through the T phase is referred to as the T-phase current. The current flowing through secondary side 520B of converter 520 is referred to as the secondary side current. The primary side current and secondary side current are collectively referred to as the motor current. Note that in motor circuit 510 shown in FIG. 1, an inductor 517 is provided between secondary side 520B and motor 518.

[0036] Converter 520 includes, as rectifying elements, thyristors 521, 522, 524, 525, 527, and 528. In Fig. 1, thyristors 521 and 522 are rectifying elements for the R phase, thyristors 524 and 525 are rectifying elements for the S phase, and thyristors 527 and 528 are rectifying elements for the T phase.

[0037] A control circuit (not shown) performs thyristor phase control in converter 520. Thyristor phase control is a method of controlling the output voltage of converter 520 by changing the phase (timing) at which 521, 522, 524, 525, 527, and 528 are turned on.

[0038] The motor circuit 510 includes an electromagnetic switch (not shown). The electromagnetic switch opens and closes the electrical path through which current flows to the motor 518 by the operation of an electromagnet. The electromagnetic switch can turn on and off the current flowing to the motor 518. The electromagnetic switch is also called a magnet switch.

[0039] The first motor equipment 51 also includes a mechanical equipment (not shown) that is connected to the rotating shaft (not shown) of the motor 518 and is driven to rotate, and a mechanical structure (not shown) for installing the motor 518 in a factory. The rotating shaft of the motor 518 and the rotating shaft of the mechanical equipment that is driven to rotate by the motor are rotatably supported by bearings. The rotating shaft of the motor 518 and the rotating shaft of the mechanical equipment that is driven to rotate by the motor are centered (shaft aligned) so that they are positioned on the same axis.

[0040] The motor circuit 510 described above is an element of the electrical system of the first motor equipment 51. On the other hand, the mechanical equipment that is rotationally driven by the motor 518 and the mechanical structure for installing the motor 518 are elements of the mechanical system of the first motor equipment 51. The motor 518 is both an element of the electrical system and an element of the mechanical system of the first motor equipment 51. For example, the electrical wiring provided in the motor 518 is an element of the electrical system, and the rotating shaft provided in the motor 518 is an element of the mechanical system. In addition, the casing provided in the motor 518 is an element of the mechanical system because it has a mechanical structure, and is also an element of the electrical system because it is a part through which leakage current flows.

[0041] Motor equipment such as the first motor equipment 51 may experience malfunctions. Malfunctions include mechanical abnormalities occurring in the mechanical system of the first motor equipment 51 and electrical abnormalities occurring in the electrical system of the first motor equipment 51. Mechanical abnormalities include, for example, motor bearing deterioration, poor shaft alignment, and mechanical overload. Electrical abnormalities include, for example, insulation deterioration, failure or poor contact of thyristors 521, 522, 524, 525, 527, and 528, and an open state in an electromagnetic switch (magnetic switch).

[0042] To detect mechanical and electrical abnormalities occurring in the first motor equipment 51, the first motor equipment 51 is provided with a sensor unit 530 including one or more sensors. Similarly, each of the other motor equipments 53, 55, and 57 is provided with a sensor unit including one or more sensors. As an example, the sensor unit 530 shown in FIG. 1 includes multiple sensors 511, 512, 513, 514, 515, and 516. The multiple sensors are, for example, a current sensor 511, a vibration sensor 512, a temperature sensor 513, a rotation sensor 514, a leakage current sensor 515, and an electromagnetic switch contact sensor 516.

[0043] Hereinafter, the measurement value output from the current sensor 511 may be referred to as first sensor data 130, the measurement value output from the vibration sensor 512 as second sensor data 135, the measurement value output from the temperature sensor 513 as third sensor data 136, the measurement value output from the rotation sensor 514 as fourth sensor data 137, the measurement value output from the leakage current sensor 515 as fifth sensor data 138, and the measurement value output from the contact sensor 516 as sixth sensor data 139. In the embodiment, each of the sensor data 130, 135, 136, 137, 138, and 139 is time-series data that changes over time. These sensor data 130, 135, 136, 137, 138, and 139 are collectively referred to as sensor data 90. The sensor data 90 is stored in a database 13, which will be described later.

[0044] Current sensor 511 measures the motor current. If the load on motor 518 becomes too large, the current flowing through motor 518 increases. Furthermore, if a malfunction occurs in converter 520, an abnormality occurs in the motor current.

[0045] In the embodiment, the current sensor 511 is an AC sensor provided on the primary side 520A of the converter 520 to measure the currents of each of the three phases. That is, the current sensor 511 is provided to measure the primary side current. The current sensor 511 of the embodiment outputs an R-phase current value 131, an S-phase current value 132, and a T-phase current value 133 as the first sensor data 130. By providing the current sensor 511 on the primary side 520A of the converter 520, it becomes easier to grasp a malfunction or a sign of a malfunction in each phase of the converter 520. Note that the current sensor 511 may also be provided on the secondary side 520B of the converter 520 to measure the secondary side current flowing to the motor 518.

[0046] The vibration sensor 512 measures the vibration of the first motor equipment 51. Vibration increases when the bearing of the motor 518 deteriorates. Vibration also increases when there is a lack of shaft alignment. Generally, when there is a lack of bearing deterioration in the motor 518, high-frequency vibration increases, and when there is a lack of shaft alignment, low-frequency vibration increases. These vibrations are measured by the vibration sensor 512.

[0047] The temperature sensor 513 measures the temperature of the first motor equipment 51. The temperature sensor 513 is provided to measure the temperature of the casing of the motor 518, for example. The temperature of the motor 518 may rise due to factors such as leakage current caused by insulation deterioration of the casing. The temperature sensor 513 measures such a temperature rise.

[0048] The rotation sensor 514 measures the rotation speed of the motor 518 of the first motor equipment 51. Vibrations may vary depending on the rotation speed. Therefore, if vibrations are judged using a uniform threshold, it is expected that even normal vibrations may be judged as abnormal. The rotation speed is used to determine the threshold for judging vibrations.

[0049] The leakage current sensor 515 measures the leakage current occurring in the first motor equipment 51. The leakage current sensor 515 is provided to measure the leakage current of, for example, the motor 518. The leakage current may increase due to insulation deterioration of the casing of the motor 518. The leakage current sensor 515 measures such leakage current.

[0050] The contact sensor 516 measures the connection state (ON / OFF state) of the contacts of the electromagnetic switch included in the first motor equipment 51. When an overload is applied to the motor 518, the electromagnetic switch opens, cutting off the supply of current to the motor 518. The contact sensor 516 detects the connection state (ON / OFF state) of the setting of such an electromagnetic switch.

[0051] The sensor unit 530 includes a transmitter 519 for transmitting the sensor data 90 to the motor monitoring device 10. The transmitter 519 is connected to each of the sensors 511, 512, 513, 514, 515, and 516 by wire or wirelessly so as to acquire the sensor data 90. The transmitter 519 transmits the acquired sensor data 90 to the motor monitoring device 10 via the network 70.

[0052] Fig. 2 is a diagram showing an example of the configuration of rotation sensor 514 in Fig. 1. Rotation sensor 514 includes a magnetic sensor 600 and a rotation detection processing unit 610. Rotation detection processing unit 610 includes an A / D converter 612 that samples the output of magnetic sensor 600 and converts it into digital data, a CPU 613, and a memory 614. Details of the rotation detection processing will be described later.

[0053] Fig. 3 is a diagram showing the configuration of motor monitoring device 10. Motor monitoring device 10 shown in Fig. 3 constantly monitors first motor equipment 51 based on acquired sensor data 90. Motor monitoring device 10 is made up of a computer including a processor 11 and a memory 12 connected to processor 11. The computer constituting motor monitoring device 10 further includes a communication interface 15.

[0054] The processing unit 11 is, for example, a CPU. The memory 12 has, for example, a primary storage device and a secondary storage device. The primary storage device is, for example, a random access memory (RAM). The secondary storage device is, for example, a hard disk drive (HDD) or a solid state drive (SSD). The communication interface 15 is used, for example, for communication with the transmitter 519 and with the user terminal 30 described below.

[0055] A computer constituting motor monitoring device 10 executes monitoring processing 100. Memory 12 stores a computer program 14 for causing the computer to operate as motor monitoring device 10. Computer program 14 includes program code for causing processing device 11 to execute monitoring processing 100. Processing device 11 reads and executes computer program 14 from memory 12. Monitoring processing 100 will be described later.

[0056] The memory 12 includes a database 13. The database 13 is configured to store the sensor data 90 received from the transmitter 519. That is, the database 13 stores first sensor data 130, second sensor data 135, third sensor data 136, fourth sensor data 137, fifth sensor data 138, and sixth sensor data 139, each of which includes an R-phase current value, an S-phase current value 132, and a T-phase current value 133. The sensor data 90 stored in the database 13 is time-series data of the sensor data 90.

[0057] The database 13 is also configured to store a determination result 95 obtained by a determination process 160, which will be described later. The database 13 is also configured to store threshold data 220 indicating various threshold values ​​used in the determination process 160, which will be described later. The threshold values ​​will be described later. The database 13 may be provided on a computer separate from the motor monitoring device 10.

[0058] Fig. 4 is a diagram for explaining the contents of the monitoring process 100. As shown in Fig. 4, the monitoring process 100 includes a sensor data acquisition process 150. The sensor data acquisition process 150 is configured so that the motor monitoring device 10 acquires sensor data 90 obtained from sensors 511, 512, 513, 514, and 516. In the sensor data acquisition process 150, the motor monitoring device 10 receives the sensor data 90 from the network 70 via the communication interface 15. The sensor data acquisition process 150 may also be configured to acquire sensor data 90 stored in an external database.

[0059] The sensors 511, 512, 513, 514, and 516 constantly monitor the first motor equipment 51, and therefore the sensor data acquisition process 150 constantly acquires the sensor data 90. The sensor data acquisition process 150 stores the acquired sensor data 90 in the database 13.

[0060] The monitoring process 100 shown in Fig. 4 includes a determination process 160. The determination process 160 is configured to perform a determination on each of the first sensor data 130, the second sensor data 135, the third sensor data 136, the fourth sensor data 137, the fifth sensor data 138, and the sixth sensor data 139. To achieve continuous monitoring, the determination process 160 is performed each time new sensor data 90 is accumulated in the database 13. In the determination process 160, it is determined whether each piece of sensor data 130, 135, 136, 137, 138, and 139 is normal or abnormal. In the determination process 160, a threshold value indicated by the threshold data 220 is used.

[0061] The determination process 160 includes a current value determination process 161A, a current difference determination process 161B, a vibration determination process 162, a temperature determination process 163, a leakage current determination process 165, and a switch connection determination process 166.

[0062] The current value determination process 161A determines whether the motor current is an overcurrent based on the first sensor data 130. An overcurrent can occur due to either a mechanical or electrical abnormality. For example, an overcurrent can occur when an overload is placed on the motor 518 due to a mechanical abnormality. An overcurrent can also occur due to an electrical abnormality such as a missing phase.

[0063] The vibration determination process 162 shown in FIG. 4 determines whether vibration in the first motor equipment 51 is normal or abnormal based on the second sensor data 135. In the vibration determination process 162, high-frequency and low-frequency components of the second sensor data 135, which are vibration measurement values, are obtained. The high-frequency and low-frequency components are obtained, for example, by filtering the second sensor data 135. The high-frequency components of the second sensor data 135 are high-frequency vibrations caused by bearing deterioration of the motor 518, etc. The low-frequency components of the second sensor data 135 are low-frequency vibrations caused by insufficient shaft alignment, etc. In the vibration determination process 162, a determination is made by comparing each of the high-frequency and low-frequency vibrations with the vibration threshold indicated by the threshold data 220. If the vibration exceeds the vibration threshold, it is determined to be abnormal. If the vibration does not exceed the vibration threshold, it is determined to be normal. The determination result 95 is stored in the database 13 and reflected in the display on the monitoring screen 300, which will be described later. It should be noted that high-frequency vibrations and low-frequency vibrations do not necessarily need to be distinguished in the vibration determination process 162. Here, the vibration threshold indicated by the threshold data 220 is determined based on the rotation speed. The method for determining the vibration determination threshold will be described later.

[0064] 4 determines whether the temperature of the first motor equipment 51 is normal or abnormal based on the third sensor data 136. In the temperature determination process 163, the determination is made by comparing the third sensor data 136 with the temperature threshold indicated by the threshold data 220. If the temperature indicated by the third sensor data 136 exceeds the temperature threshold, it is determined to be abnormal, and if it does not exceed the temperature threshold, it is determined to be normal. The determination result 95 is stored in the database 13 and reflected in the display on the monitoring screen 300 described below.

[0065] 4 determines whether the leakage current in the first motor equipment 51 is normal or abnormal based on the fifth sensor data 138. In the leakage current determination process 165, the determination is made by comparing the fifth sensor data 138 with the leakage current threshold indicated by the threshold data 220. If the magnitude of the leakage current indicated by the fifth sensor data 138 exceeds the leakage current threshold, it is determined to be abnormal, and if it does not exceed the leakage current threshold, it is determined to be normal. The determination result 95 is stored in the database 13 and reflected in the display on the monitoring screen 300 described below.

[0066] 4 determines whether the electromagnetic switch is open or closed (ON / OFF) based on the sixth sensor data 139. The determination result 95 is stored in the database 13 and reflected in the display on a monitoring screen 300 described later.

[0067] 4 includes a generation process 170 for generating monitoring screen information 300A and an output process 180 for outputting monitoring screen information 300A. The monitoring screen information 300A is generated based on sensor data 90 stored in the database 13 and a determination result 95 by a determination process 160.

[0068] The monitoring screen information 300A is used to display the monitoring screen 300. The monitoring screen information 300A is display data for configuring the monitoring screen 300 displayed on a display (not shown). The monitoring screen 300 is a screen referenced by an observer to monitor the motor equipment 51, 53, 55, and 57. In the embodiment, the monitoring screen information 300A is transmitted to a user terminal 30 (see FIG. 1) used by the observer by a monitoring screen information output process 180. The user terminal 30 displays the monitoring screen 300 based on the monitoring screen information 300A on the display of the user terminal 30. The user terminal 30 is connected to the motor monitoring device 10 via a network 70. The monitoring screen 300 may also be displayed on a display provided in the motor monitoring device 10.

[0069] In the generation process 170 of the monitoring screen information 300A, the processing device 11 updates the monitoring screen information 300A so as to reflect the latest sensor data 90 and determination result 95. The updated monitoring screen information 300A is successively transmitted to the user terminal 30.

[0070] The monitoring process shown in FIG. 4 includes a threshold adjustment process 200. The threshold adjustment process 200 is a process for adjusting various thresholds stored in the database 13. The adjustment is performed by a user operation such as an observer. The user operation is performed, for example, by operating an input device such as a keyboard or mouse provided on the user terminal 30 (see FIG. 1). The operation for adjusting the threshold includes, for example, selecting the threshold to be adjusted and inputting the adjusted threshold. The adjusted threshold is stored in the database 13 and is used in the subsequent determination process 160. The ability to adjust the threshold makes it possible to appropriately change the threshold according to the condition of the motor equipment.

[0071] The adjustment may be performed by a user operation such as by a monitor, or an appropriate threshold may be automatically selected based on the rotation speed, as will be described later.

[0072] FIG. 5 illustrates an example of a monitoring screen 300 based on the monitoring screen information 300A generated and updated by the generation process 170. Here, the monitoring screen 300 is also referred to as a “motor diagnostic board.” The monitoring screen 300 includes a first motor equipment screen 301 showing the status of the first motor equipment 51, a second motor equipment screen 302 showing the status of the second motor equipment 53, a third motor equipment screen 303 showing the status of the third motor equipment 55, and a fourth motor equipment screen 304 showing the status of the fourth motor equipment 57. As shown in FIG. 5 , the monitoring screen 300 is configured to simultaneously display the statuses of multiple motor equipment. By simultaneously displaying the statuses of multiple motor equipment 51, 53, 55, and 57 on a single monitoring screen 300, a monitor can compare and understand the statuses of the multiple motor equipment 51, 53, 55, and 57, making it easier to detect changes and abnormalities in the motor equipment 51, 53, 55, and 57.

[0073] Of the multiple motor equipment screens 301, 302, 303, and 304, the first motor equipment screen 301 will be described below, but the other motor equipment screens 302, 303, and 304 also have the same configuration in Fig. 5. However, the other motor equipment screens 302, 303, and 304 may be different from the first motor equipment screen 301.

[0074] As an example of the display, the first motor equipment screen 301 includes vibration display areas 311, 315, a heat generation display area 312, a rotational speed display area 313, an overcurrent display area 314, a switch display area 316, a leakage current display area 317, and a missing phase display area 318.

[0075] In addition, for each display area that displays a measured value, it is also possible to display whether the measured value is normal or abnormal as a result of judging it using a judgment threshold, as in the switch display area 316.

[0076] The following description will focus particularly on the processing using the rotation sensor 514. Figure 6 is a diagram showing the configuration related to abnormality detection due to vibration in the motor monitoring system of embodiment 1. For ease of explanation, Figure 6 simply shows only the relevant elements of the configuration in Figure 1.

[0077] 6 includes a magnetic sensor 600 as described in FIG. 2, and is configured to calculate the rotation speed from acquired magnetic data. The motor monitoring device 10 receives the rotation speed data 140 calculated by the rotation sensor 514 via a transmitter 519 and a network 70.

[0078] Motor monitoring device 10 also receives vibration data 135 from vibration sensor 512 and temperature data 136 from temperature sensor 513 via transmitter 519 and network 70 .

[0079] The motor monitoring device 10 displays an indicator of an abnormality calculated from the vibration data 135, the temperature data 136, and the rotation speed data 140.

[0080] <Rotation speed detection process> The process of detecting the rotation speed in the rotation sensor 514 will be described below.

[0081] In principle, a motor changes its magnetic field as it rotates. The rotation sensor 514 measures the change in the magnetic field using the magnetic sensor 600, and can obtain the rotation speed by calculating the period. A simple way to calculate the period is to find the time interval during which the magnetic field strength repeats the same value.

[0082] However, in general, sensor devices do not have large memories to reduce costs, so there is a limit to the amount of data that can be stored.

[0083] Figure 7 is a diagram explaining the data when the sampling frequency is too high. Let the number of samples that can be stored in the memory of the sensor device be M. In Figure 7, the M samples are indicated by white circles. If the sampling frequency fs is too high compared to the rotation speed, the sampling interval becomes short, and the M samples are concentrated in one part of the waveform, as shown in Figure 7.

[0084] Figure 8 illustrates the data when the sampling frequency is too low. If the sampling frequency fs is too low compared to the rotation speed, the sampling interval becomes long, and the M samples are spread over multiple periods of the waveform, making it impossible to accurately capture the waveform, as shown in Figure 8.

[0085] Figure 9 is a diagram explaining the data when the sampling frequency is appropriate. If the sampling frequency fs is appropriate for the rotation speed, the M samples will be appropriately scattered over a range slightly exceeding one period of the waveform, as shown in Figure 9, and the time for one period of the waveform can be read.

[0086] As can be seen from FIGS. 7 to 9 above, in order to calculate the rotation speed, data for at least one waveform period of the magnetic field strength is required. Therefore, even if the sampling frequency is too high, it is not good, and it can be understood that if it is too low, the change in the magnetic field cannot be appropriately captured.

[0087] Therefore, as a countermeasure, in this embodiment, the rotation sensor 514 changes the sampling frequency and measures multiple times. When waveform data for at least one period can be obtained, if the value when the sampling frequency is the highest is adopted, the rotation speed can be detected accurately.

[0088] When the range of the rotation speed is from Vr1 [rotations / s] to Vr2 [rotations / s] and the number of samplings determined from the memory size is M, the method for determining the sampling frequency fs [Hz] will be described.

[0089] When the memory is large and the number of samplings M is sufficiently large, according to the sampling theorem, fs may be set higher than 2×Vr2.

[0090] However, when the memory capacity is small like that of a microcontroller, if the sampling frequency fs is set too high, as shown in FIG. 7, there is a possibility that samples of one-period waveforms cannot be captured.

[0091] When the rotation speed is Vr1, which is the lowest value in the planned range, the time for one period 1 / Vr1 [s] is the longest. In order to measure the time for at least one period of this waveform with M samplings at the sampling frequency fs, it is necessary to satisfy the condition 1 / Vr1 < M / fs, that is, fs < M×Vr1.

[0092] From the above, if there is a sampling frequency fs that satisfies 2×Vr2 < fs < M×Vr1, then that fs can be used. However, when M is not sufficiently large, it may be considered that 2×Vr2 > M×Vr1 and there is no fs that can be used for all of Vr1 to Vr2.

[0093] In such a case, for example, start from a sampling frequency fs that satisfies fs > 2 × Vr2, and gradually lower fs (lengthen the sampling interval) until you can sample exactly one cycle of the current rotation speed waveform. A more specific example would be to start from fs = M × Vr1 / 2, and then lower fs by half at a time.

[0094] Next, we will explain how to determine whether one period of a waveform has been captured when the waveform is captured at a certain sampling frequency fs.

[0095] Fig. 10 is a diagram for explaining how to determine an appropriate sampling frequency. First, the waveform is sampled to obtain M pieces of data X[n] (n = 1, ..., M). Then, the average value X' of the M pieces of data X[n] is subtracted from each piece of data. As a result, the waveform data shows a waveform with an amplitude centered around zero, as shown in Fig. 10.

[0096] At this time, it is checked whether there are three or more zero crossing points in the data, as shown by n1, n2, and n3 in Figure 10. Specifically, it searches for a point n that satisfies X[n]<=0<=X[n+1] or X[n]>=0>=X[n+1], and checks whether three points exist, as shown by X[n1], X[n2], and X[n3] in Figure 10.

[0097] If there are fewer than three zero-crossing points, it is determined that one period of the waveform has not been captured, and the sampling frequency is reduced. On the other hand, if there are three zero-crossing points, t[n1] to t[n3] is one period of the waveform, so the rotation speed Vr can be expressed as Vr=fs / (t[n3]-t[n1]). Here, t[n1] is the time of the first zero-crossing point, and t[n3] is the time of the third zero-crossing point. To be precise, in the example of Figure 10, the time of the first zero-crossing point is between t[n1] and t[n1+1], and the time of the third zero-crossing point is between t[n3] and t[n3+1], but the rotation speed Vr is calculated by approximating the time of the immediately preceding data.

[0098] FIG. 11 is a flowchart illustrating the process of calculating the rotation speed. First, in step S1, the rotation sensor 514 sets the sampling frequency fs=M×Vr1 / 2, where M is the number of sampled data limited by the memory size, and Vr1 (revolutions / second) is the lower limit of the rotation speed range of the motor to be observed. Note that the initial value of the sampling frequency fs may be another value.

[0099] Next, in step S2, rotation sensor 514 acquires M pieces of data X[1] to X[M] at a sampling frequency fs. Then, in step S3, rotation sensor 514 calculates an average value X' (=Σ(X[1] to X[M]) / M), and in step S4, the value obtained by subtracting X' from each piece of data X[1] to X[M] is used as new data X[1] to X[M].

[0100] Then, in step S5, the rotation sensor 514 determines whether there are three or more zero-crossing points. Specifically, it searches for a point n that satisfies X[n]<=0<=X[n+1] or X[n]>=0>=X[n+1], and checks whether there are three points, such as X[n1], X[n2], and X[n3] in FIG. 10.

[0101] If the number of zero crossing points is less than three (NO in S5), in step S6, the rotation sensor 514 reduces the sampling frequency fs. For example, the sampling frequency is halved. Then, the processing from step S2 onwards is executed again.

[0102] On the other hand, if there are three or more zero crossing points (YES in S5), in step S7, rotation sensor 514 calculates the rotation speed Vr. As explained in FIG. 10, the rotation speed Vr is calculated by Vr=fs / (t[n3]-t[n1]).

[0103] The rotation speed is calculated through the above process. Upon receiving the rotation speed information, the motor monitoring device 10 determines a vibration determination threshold based on the rotation speed.

[0104] Figure 12 is an example of a graph showing the relationship between rotation speed and vibration. As shown in Figure 12, vibration generally increases with rotation speed. However, the relationship between rotation speed and vibration may differ depending on the equipment, depending on factors such as the natural frequency of each piece of equipment.

[0105] There are three possible methods for determining the vibration determination threshold: The first method is a method in which Y=vibration / rotation speed is used as an index and a predetermined determination threshold is applied to the index Y.

[0106] The second method is to change the vibration judgment threshold depending on the rotation speed. For example, if the vibration judgment threshold is set to 100 when the rotation speed is 1000 rpm or less, the vibration judgment threshold can be changed to 300 when the rotation speed is 1000 to 2000 rpm.

[0107] The third method is to set a learning period to learn the vibration acceleration f(Vr) corresponding to the normal rotation speed Vr, and then multiply that by a (a>1) to set the threshold value as the vibration acceleration a×f(Vr).In this case, a map or the like is prepared in which threshold values ​​corresponding to the rotation speed are predetermined after the learning period, and this map can be used to determine the threshold value.

[0108] Fig. 13 is a diagram for explaining a method of determining a threshold value through learning. In Fig. 13, if vibration intensity f(Vr) corresponds to normal rotation speed Vr learned during a learning period, abnormality determination threshold fth(Vr) is set to be greater than vibration intensity f(Vr) (for example, 1.2 times) to allow for a margin indicated by the arrow. Note that, in the first embodiment, an example has been given of correcting the abnormality determination threshold for vibration in consideration of the rotation speed, but the abnormality determination threshold for the current value detected by current sensor 511 may also be corrected in consideration of the rotation speed.

[0109] 14 is a diagram illustrating an example of the arrangement of a magnetic sensor and a vibration sensor. Motor 518 includes a coil and a bearing. The coil is located near the center of motor 518 in the axial direction, and two bearings are located at the ends of motor 518, sandwiching the coil.

[0110] Therefore, it is preferable to house the rotation detection processing unit 610 of the rotation sensor 514 in FIG. 2 in the transmitter 519, and as shown in FIG. 14, the magnetic sensor 600 of the rotation sensor 514 is placed near the center where the coil is located, and the vibration sensor 512 is placed near the end where the bearing is located.

[0111] Combining the vibration sensor and magnetic sensor into one sensor head can reduce costs, but separating the vibration sensor and magnetic sensor as shown in Figure 14 is expected to improve the accuracy of anomaly detection.

[0112] In addition, the transmitter 519 may be configured to be able to connect a second vibration sensor instead of the rotation sensor 514, and for equipment with a constant load, vibration data may be obtained using the second vibration sensor instead of the rotation sensor 514, and a detailed analysis of the vibrations may be performed by the motor monitoring device 10.

[0113] [Embodiment 2] Fig. 15 is a diagram illustrating the configuration of the motor monitoring system of embodiment 2. As shown in Fig. 15, a configuration in which rotation sensor 514B is connected to a separate transmitter 519 is also possible. For example, if motor 518 is already equipped with an existing configuration in which data from vibration sensor 512A and temperature sensor 513A is transmitted by transmitter 519A, this is convenient when data from the rotation sensor needs to be acquired additionally.

[0114] Furthermore, since a rotation sensor is not necessary for a motor whose load or rotation speed does not fluctuate during operation, a flexible configuration of the monitoring system can be achieved by configuring the rotation sensor separately. Furthermore, transmitter 519B may be configured to be able to connect other vibration sensors, etc., instead of the rotation sensor. This allows for further adaptation to various system configurations.

[0115] [Embodiment 3] Fig. 16 is a diagram illustrating the configuration of a motor monitoring system according to embodiment 3. As shown in Fig. 16, a single transmitter 519CD may be connected to vibration sensor 512C, temperature sensor 513C, and rotation sensor 514C for monitoring motor 518C, and may also be connected to vibration sensor 512D, temperature sensor 513D, and rotation sensor 514D for monitoring motor 518D. Although two sets of sensors are connected in Fig. 16, three or more sets of sensors may be connected to one transmitter.

[0116] In the third embodiment, the cost for configuring a motor monitoring system can be reduced by using a common transmitter for a plurality of motor monitoring sensors.

[0117] Each process (each function) in the above-described embodiments is realized by a processing circuit including one or more processors. The processing circuit may be configured as an integrated circuit or the like that combines one or more memories, various analog circuits, and various digital circuits in addition to the one or more processors. The one or more memories store programs (instructions) that cause the one or more processors to execute each of the processes. The one or more processors may execute each of the processes according to the programs read from the one or more memories, or according to logic circuits pre-designed to execute each of the processes. The processor may be any of various processors suitable for computer control, such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit). Note that the physically separate processors may execute each of the processes in cooperation with each other. For example, the processors mounted on a plurality of physically separated computers may cooperate with each other to execute the above processes via a network such as a LAN (Local Area Network), a WAN (Wide Area Network), the Internet, etc. The program may be installed into the memory from an external server device or the like via the network, or may be distributed in a state stored on a recording medium such as a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), or a semiconductor memory, and installed into the memory from the recording medium.

[0118] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims rather than the above-described embodiments, and it is intended to include any modifications within the scope of the claims and meanings equivalent to the claims. [Explanation of symbols]

[0119] 10 Motor monitoring device 11 Processing equipment 12 Memory 13 Database 15 Communication Interface 30 User terminals 70 Network 90 Sensor Data 501 Polyphase AC power supply 510 Motor Circuit 511 Current Sensor 512, 512A, 512C, 512D Vibration Sensors 513, 513A, 513C, 513D Temperature Sensors 514, 514B, 514C, 514D Rotation Sensor 515 Leakage Current Sensor 516 Contact Sensor 517 Inductor 518, 518C, 518D motor 519, 519A, 519CD transmitter 520 Converter 521,522,524,525,527,528 Thyristor 530 Sensor Unit 600 Magnetic Sensor 610 Rotation detection processing unit 612 A / D converter 614 memory 1000 Motor Monitoring System

Claims

1. A motor monitoring system for monitoring equipment including a first motor, acquiring first data indicating a vibration or a current of the first motor and second data indicating a rotation speed of the first motor; a process of determining a first determination threshold value for the first data for determining an abnormality of the first motor based on the second data; a motor monitoring device configured to execute a process of determining an abnormality in the first motor using the first data and the first determination threshold;

2. the first data is data indicating vibration of the first motor, a first vibration sensor that detects vibration of the first motor and outputs the first data; The motor monitoring system according to claim 1 , further comprising: a first rotation sensor that detects a rotation speed of the first motor and outputs the second data.

3. The first rotation sensor A magnetic sensor; The motor monitoring system according to claim 2 , further comprising a rotation detection processing unit that outputs a rotation speed of the first motor based on an output of the magnetic sensor.

4. the rotation detection processing unit includes a memory, When M is a natural number indicating the number of data items limited by the capacity of the memory, the rotation detection processing unit is configured to determine a sampling frequency so that a waveform reproduced by M pieces of data includes three or more zero crossing points; the M pieces of data are data obtained by subtracting an average value of the M measured values ​​from each of the M measured values ​​obtained by sampling the output of the magnetic sensor, 4. The motor monitoring system according to claim 3, wherein the rotation detection processing unit is configured to calculate the rotation speed of the first motor from the time interval between a first zero crossing point and a third zero crossing point obtained when sampling at the determined sampling frequency.

5. the first motor includes a bearing and a coil; the first vibration sensor is disposed at a position closer to the bearing than the coil; The motor monitoring system of claim 3 , wherein the magnetic sensor is disposed at a position closer to the coil than the bearing.

6. The motor monitoring system of claim 2 , further comprising a transmitter configured to receive the first data from the first vibration sensor and the second data from the first rotation sensor and transmit the data to the motor monitoring device.

7. the motor monitoring system monitors a second motor in addition to the first motor; a second vibration sensor that detects vibration of the second motor and outputs third data; a second rotation sensor that detects the rotation speed of the second motor and outputs fourth data; the transmitter is configured to receive the third data from the second vibration sensor and the fourth data from the second rotation sensor and transmit the third data to the motor monitoring device; the motor monitoring device determines a second determination threshold value for the third data for determining an abnormality of the second motor based on the fourth data; The motor monitoring system according to claim 6 , further comprising: a process for determining whether or not an abnormality has occurred in the second motor by using the third data and the second determination threshold value.

8. the transmitter is configured to allow the first rotation sensor to be detachably attached thereto; 7. The motor monitoring system according to claim 6, wherein the transmitter is configured to be able to connect a second vibration sensor instead of the first rotation sensor.

9. a first transmitter that receives the first data from the first vibration sensor and transmits the first data to the motor monitoring device; 3. The motor monitoring system of claim 2, further comprising a second transmitter that receives the second data from the first rotation sensor and transmits the second data to the motor monitoring device.

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