Rotary equipment abnormality determining device and rotary equipment abnormality determining method

Abstract

Provided are a rotary equipment abnormality determining device and a rotary equipment abnormality determining method capable of accurately detecting the occurrence of an abnormality even when the scale of damage or the like occurring in the rotary equipment is small.　The rotary equipment abnormality determining device determines an abnormality of rotary equipment including a drive source unit that generates rotational power using electric power from a power source unit, a rotating shaft that rotates by receiving the rotational power from the drive source unit, a drive device that is driven by receiving the rotational power from the rotating shaft, and a support unit that supports the rotating shaft, the abnormality determining device comprising: an acquiring unit that acquires a load current value of the drive source unit; a calculating unit that subjects the load current value acquired by the acquiring unit to frequency analysis to calculate the spectral intensity of higher-order frequencies with respect to the rotational frequency of the drive source unit; an identifying unit that identifies statistical information relating to time variations in the spectral intensity of the higher-order frequencies calculated by the calculating unit; and a determining unit that determines an abnormality in the rotary equipment on the basis of the statistical information identified by the identifying unit.

Description

Abnormal Determination Device for Rotating Equipment and Abnormal Determination Method for Rotating Equipment 【0001】 The present invention relates to an abnormal determination device for rotating equipment that generates rotational power and an abnormal determination method for rotating equipment. 【0002】 In industrial plants and the like, rotating equipment is provided to drive various devices. The rotating equipment includes a drive source unit such as a motor (electric motor) that generates rotational power, and a drive device (load device) that is driven by receiving the rotational power transmitted from the drive source unit. The drive source unit is connected to the drive device via a rotating shaft (such as a coupling or gear) supported by a support unit such as a bearing, and transmits rotational power to the drive device. The drive device is a device that exhibits a predetermined function by using the rotational power from the drive source unit, and includes, for example, pumps, turbines, blowers, compressors, rolling mills, forging machines, and various conveying devices. 【0003】 Here, when driving a large drive device with the rotational power from the drive source unit, the load acting on the drive source unit increases. If this state continues, damage occurs to the internal mechanisms of the drive source unit, etc., and damage also occurs in the support unit (such as bearings) that supports the drive device and the rotating shaft (such as couplings). In some cases, it may develop into a major operation trouble. 【0004】 Based on the above circumstances, in industrial plants and the like equipped with rotating equipment, diagnosis of the occurrence of abnormalities in the rotating equipment is carried out. From the perspective of suppressing a decrease in the operating rate of production equipment and the like, it is more preferable to perform the diagnosis online while operating the rotating equipment than offline when the operation of the rotating equipment is stopped. For this reason, an abnormal determination technology has been developed to determine abnormalities online for rotating equipment including the drive source unit that drives the drive device and the support unit that supports the rotating shaft. 【0005】For example, Patent Document 1 discloses a method for diagnosing bearing abnormalities by measuring the vibration of the bearing supporting a load device (drive device). The method disclosed in Patent Document 1 is a method for diagnosing bearing abnormalities based on the frequency spectrum by performing frequency analysis of a vibration acceleration signal detected by a vibration acceleration sensor attached to the bearing or bearing housing. 【0006】 Furthermore, Patent Document 2 discloses a method for diagnosing abnormalities in rotating equipment by measuring the load current of an electric motor (drive source) that drives a load device (drive device). The method disclosed in Patent Document 2 first measures the load current of at least one phase of an induction motor and performs frequency analysis to identify sidebands that appear on both the high-frequency and low-frequency sides of the operating frequency applied to the induction motor. Subsequently, the method diagnoses abnormalities in rotating equipment based on the presence or absence of sidebands and their magnitude or position. 【0007】 Furthermore, Patent Document 3 discloses a method for performing spectral analysis of the load current signal of an electric motor (drive source) and calculating diagnostic parameters for identifying abnormalities in rotating equipment from the spectral analysis results. In the method disclosed in Patent Document 3, the power supply frequency of the electric motor and the mean order or variance order of its harmonic spectrum are applied as diagnostic parameters. Patent Document 3 also discloses a method for identifying abnormalities by determining that an overload has occurred when the proportion of higher-order components in the frequency spectrum is relatively larger than that under normal conditions compared to lower-order components. 【0008】 Japanese Patent Publication No. 2018-155494, Japanese Patent Publication No. 2010-288352, Japanese Patent Publication No. 11-83686 【0009】 However, the conventional technologies described above have the following problems. 【0010】The invention disclosed in Patent Document 1 is a method for diagnosing abnormalities in rotating equipment by measuring the vibration of a bearing supporting a load device, and requires the installation of numerous vibration sensors on or near the support portion of the load device. However, depending on the rotating equipment to be diagnosed, it may be difficult to install vibration sensors, and in order to monitor abnormalities in rotating equipment over a long period of time, maintenance work such as inspection of all vibration sensors is also required, which presents a problem as it complicates the management of the equipment. 【0011】 Furthermore, the method disclosed in Patent Document 2 is a method for diagnosing abnormalities by identifying sidebands that appear on both the high-frequency and low-frequency sides of the operating frequency applied to an induction motor. However, sidebands that appear near the operating frequency appear due to fluctuations in the driving torque applied to the load device (drive device). Therefore, diagnosis of abnormalities based on sidebands can only be performed after torque fluctuations have occurred in the rotating equipment. In other words, by the time sidebands are detected, there is a high probability that some kind of major abnormality has already occurred in the rotating equipment. On the other hand, immediately after damage occurs in the rotating equipment, the scale of the damage is small, so the load current value of the motor fluctuates randomly over time, making it difficult to identify sidebands. Therefore, the method disclosed in Patent Document 2 has the problem of not being able to accurately detect abnormalities occurring in bearings, etc. 【0012】 The invention disclosed in Patent Document 3 is a method that uses an index comparing the balance or magnitude of lower-order and higher-order components of the frequency spectrum as a diagnostic parameter for identifying abnormalities in rotating equipment. By focusing on the higher-order components of the motor load current, it may be possible to diagnose abnormalities in rotating equipment relatively early. However, when the higher-order components in the frequency spectrum of the load current are larger than the lower-order components, it is highly likely that an abnormality in the rotating equipment has already manifested, such as an overload on the motor. Furthermore, when the scale of damage to the rotating equipment is small, the motor load current value fluctuates randomly over time, which presents a challenge in accurately detecting the abnormality. 【0013】The present invention has been made in view of the above circumstances, and its objective is to provide a rotating equipment abnormality detection device and a rotating equipment abnormality detection method that can accurately detect the occurrence of abnormalities even when the scale of damage or other issues occurring in the rotating equipment is small. 【0014】[1] A rotating equipment abnormality determination device for determining abnormalities in rotating equipment, comprising: a drive source unit that generates rotational power from power supply unit; a rotating shaft that rotates by receiving the rotational power from the drive source unit; a drive device that is driven by receiving the rotational power from the rotating shaft; and a support unit that supports the rotating shaft, the device comprising: an acquisition unit that acquires a load current value in the drive source unit; a calculation unit that performs frequency analysis on the load current value acquired by the acquisition unit and calculates the spectral intensity of higher-order frequencies with respect to the rotation frequency in the drive source unit; an identification unit that identifies statistical information relating to the time variation of the spectral intensity of higher-order frequencies calculated by the calculation unit; and a determination unit that determines an abnormality in the rotating equipment based on the statistical information identified by the identification unit. [2] The rotating equipment abnormality determination device according to [1], wherein the higher-order frequencies are frequencies of the third order or higher and the 21st order or lower with respect to the rotation frequency in the drive source unit. [3] The rotating equipment abnormality determination device according to [1] or [2], wherein the statistical information is the standard deviation or variance relating to the time variation of the spectral intensity of higher-order frequencies. [4] A method for determining abnormalities in rotating equipment, comprising: a drive source unit that generates rotational power from a power supply unit; a rotating shaft that rotates by receiving the rotational power from the drive source unit; a drive device that is driven by receiving the rotational power from the rotating shaft; and a support unit that supports the rotating shaft, the method comprising: an acquisition step of acquiring a load current value in the drive source unit; a calculation step of performing a frequency analysis on the load current value acquired in the acquisition step and calculating the spectral intensity of higher-order frequencies with respect to the rotational frequency in the drive source unit; a specification step of identifying statistical information relating to the time variation of the spectral intensity of higher-order frequencies calculated in the calculation step; and a determination step of determining an abnormality in the rotating equipment based on the statistical information identified in the specification step. [5] The method for determining abnormalities in rotating equipment according to [4], wherein the higher-order frequencies are frequencies of the third order or higher and the 21st order or lower with respect to the rotational frequency in the drive source unit. [6] The method for determining abnormalities in rotating equipment according to [4] or [5], wherein the statistical information is the standard deviation or variance relating to the time variation of the spectral intensity of higher-order frequencies.[7] The method for determining abnormalities in rotating equipment according to any one of [4] to [6], wherein the determination step determines an abnormality in the rotating equipment based on the statistical information identified in the identification step and the statistical normal information collected during the normal operation of the rotating equipment. [8] The method for determining abnormalities in rotating equipment according to any one of [4] to [7], wherein the acquisition step is performed after receiving a first load signal transmitted when a current command value less than or equal to a preset reference current command value is transmitted to the power supply unit. 【0015】 According to the present invention, even when the scale of damage or other abnormalities occurring in rotating equipment is small, the occurrence of an abnormality can be detected with high accuracy. 【0016】Figure 1 is a diagram showing an example of the schematic configuration of a rotating machine and an abnormality detection device. Figure 2 is a schematic diagram showing an example of the schematic configuration of an abnormality detection device in the first embodiment. Figure 3 is a diagram showing an example of spectral intensity calculated by frequency analysis. Figure 4 is a flowchart showing the flow of abnormality detection processing in the abnormality detection method for rotating machine. Figure 5 is a schematic diagram showing an example of the schematic configuration of an abnormality detection device in the second embodiment. Figure 6 is a schematic diagram showing an example of the schematic configuration in which a control device is added to the rotating machine and abnormality detection device as the third embodiment. Figure 7 is a diagram showing the status over time of the control signal (current command value) transmitted from the control device to the power supply unit and the load level signals (first load signal and second load signal) transmitted from the control device to the abnormality detection device in the third embodiment. Figure 8 is a flowchart showing the flow of abnormality detection processing in the abnormality detection method for rotating machine in the third embodiment. Figure 9 is a diagram showing the time change of the average value of spectral intensity calculated from the load current value in Example 1. Figure 10 is a diagram showing statistical information of spectral intensity at rotation frequency and higher-order frequencies in Example 1. Figure 11 shows the ratio of the standard deviation Sd values ​​for "defective outer ring" and "defective retainer" to the standard deviation Sn value for "normal" in Example 1. Figure 12 shows the standard deviation of spectral intensity for each frequency in the normal and abnormal conditions identified in Example 2. Figure 13 shows the ratio of the standard deviation of "abnormal" conditions to the standard deviation of "normal" conditions in Example 2. Figure 14 shows the standard deviation of spectral intensity at higher-order frequencies (5th, 7th, and 9th) in the normal conditions identified in Example 3. Figure 15 shows the ratio of the standard deviation of "abnormal" conditions to the standard deviation of "normal" conditions before grease supply in Example 3. Figure 16 shows the ratio of the standard deviation of "abnormal" conditions to the standard deviation of "normal" conditions after grease supply in Example 3. Figure 17 shows the average values ​​of spectral intensity in the "normal" and "abnormal" conditions in Example 2. Figure 18 shows the time progression of the load current value under "normal conditions" and "abnormal conditions" in Example 3. 【0017】<First Embodiment> Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. Figure 1 shows an example of the schematic configuration of the rotating equipment 10 and the abnormality detection device 40. As shown in Figure 1, the rotating equipment 10 has a power supply unit 1, a drive source unit 2, a rotating shaft 3, a drive device 4, and a support unit 5. 【0018】 The power supply unit 1 is supplied with an AC power supply that generates AC power. The specifications of the power supply unit 1 may be appropriately selected depending on whether the drive source unit 2 is a single-phase induction motor or a three-phase induction motor. In particular, if the drive source unit 2 is a three-phase induction motor, a three-phase AC power supply may be used as the power supply unit 1. The power supply unit 1 may be supplied with a commercial power supply or an inverter power supply. 【0019】 The drive source unit 2 is equipped with an induction motor. The drive source unit 2 may be a single-phase induction motor or a three-phase induction motor. In particular, from the viewpoint of equipment versatility, the use of a three-phase induction motor, which is widely used in large industrial equipment, is preferred. 【0020】 The drive unit 4 may include pumps, turbines, blowers, compressors, rolling mills, forging machines, and various other conveying devices. Specifically, when the drive unit 4 is a conveying device, table rolls or pinch rolls for conveying steel materials may be used. Alternatively, the drive unit 4 may include side guides for positioning steel materials at the entry and exit sides of a rolling mill. 【0021】 The rotating shaft 3 transmits the rotational power generated in the drive source unit 2 to the drive unit 4. The diameter and material of the rotating shaft 3 are appropriately designed to have the necessary strength to transmit rotational power from the drive source unit 2 to the drive unit 4. The connection configuration of the rotating shaft 3 is not limited as long as it can transmit the rotational power generated in the drive source unit 2 to the drive unit 4. In other words, the rotating shaft 3 does not need to be directly connected to the drive source unit 2 and the drive unit 4, and may be connected between the drive source unit 2 and the drive unit 4 using a power transmission device such as a coupling, belt, or gear. 【0022】The support portion 5 supports the rotating shaft 3 in order to suppress fluctuations in rotational motion such as runout in the rotating shaft 3. Here, runout in the rotating shaft 3 is a behavior that occurs in the rotating shaft 3 due to the reaction force from the drive device 4 which is driven by rotational power. The support portion 5 is configured as a bearing that supports the rotating shaft 3. The support portion 5 may be configured as, for example, a rolling bearing or a sliding bearing. As shown in Figure 1, the support portion 5 in the rotating equipment 10 may have a first support portion 5a and a second support portion 5b. The first support portion 5a may be provided between the drive source unit 2 and the drive device 4. The second support portion 5b may be provided in the drive device 4 at a position opposite to the position where the drive source unit 2 is located. In some cases, depending on the specifications of the drive device 4, a configuration may be adopted in which the position opposite to the position where the drive source unit 2 is located is open. In this case, the support portion 5 may consist only of the first support portion 5a. Furthermore, in this embodiment, it is preferable to use rolling bearings as the configuration of the support section 5 in order to detect abnormalities when damage (such as minute cracks) occurs to a part of the rolling balls or rollers. 【0023】 Furthermore, the support portion 5 may be provided at multiple locations between the drive source unit 2 and the drive device 4. Similarly, the support portion 5 may also be provided at multiple locations on the drive device 4 opposite to the location where the drive source unit 2 is positioned. In other words, the support portion 5 may be provided at any location along the rotating shaft 3 that transmits rotational power from the drive source unit 2, regardless of the number of support portions installed. 【0024】 In the drive source unit 2, the magnetic field of the stator coil installed inside is rotated to generate an induced current in the rotor electrodes, and the rotor is rotated based on the interaction between the induced current in the rotor and the magnetic field of the stator coil to generate rotational power. This rotational power based on the rotation of the rotor is then transmitted to the rotating shaft 3. That is, the rotor rotates in the drive source unit 2 due to the power supply from the power supply unit 1, and the rotating shaft 3 rotates against the rotational resistance in the drive device 4. Subsequently, the rotational power is transmitted to the drive device 4 via the rotating shaft 3. 【0025】The drive unit 4 performs a predetermined function based on the rotational power transmitted via the rotating shaft 3. Specifically, if the drive unit 4 is a pump, it may drive the device by generating pressure in the fluid using an impeller that rotates in accordance with the rotational power. If the drive unit 4 is a rolling mill, it may transmit the torque related to the rotational power to the rotating shaft of the rolling rolls to rotate the rolling rolls. In addition, the drive unit 4 may use a reduction gear or transmission to reduce or change the torque and rotational speed transmitted from the rotating shaft 3 and use it as power suitable for the function of the drive unit 4. 【0026】 Furthermore, if the drive unit 4 is a conveying device, it may perform its function as a conveying device by converting the rotational motion of the rotating shaft 3 into linear motion, intermittent motion, reciprocating motion, etc. That is, the drive unit 4 may perform a predetermined function by changing the rotational speed (deceleration or speed change) and changing the direction of rotation of the rotational power transmitted via the rotating shaft 3 as needed. 【0027】 Next, the inventors will explain their findings regarding the determination of abnormalities in the rotating equipment 10. The inventors considered that equipment failures (abnormalities) frequently occur in components other than the drive source unit 2 and the drive device 4 during the operation of the rotating equipment 10. In particular, they focused on the support unit 5 of the rotating equipment 10 and considered that the equipment failure process proceeds through the following abnormality stages 1 and 2 in order. Abnormality stage 1: When ball bearings or roller bearings are used in the support unit 5, damage (such as minute cracks) occurs to some of the rolling balls or rollers. Also, while the bearing is rotating, damage occurs to some of the inner ring, outer ring, and cage that collide with the balls or rollers. Abnormality stage 2: The damage to the bearing expands, and partial chipping occurs on the outer ring, inner ring, cage, etc. of the bearing. As a result, vibration occurs in the support unit 5, and the rotational resistance of the rotating shaft 3 increases. 【0028】Furthermore, we diligently investigated methods for accurately detecting abnormalities in the rotating equipment 10, even in conditions corresponding to "abnormal stage 1," where the scale of damage is small. As a result, the inventors concluded that in conditions corresponding to "abnormal stage 1," when a ball or the like with partial damage (such as a minute crack) rolls in the support part 5, fluctuations in the air gap occur between the rotor and the stator inside the drive source unit 2. They also concluded that these fluctuations in the air gap cause fluctuations in the magnetic flux density in the air gap inside the drive source unit 2, and consequently, the value of the load current of the drive source unit 2 also fluctuates. 【0029】 Furthermore, the inventors have concluded that, in a state corresponding to "abnormality stage 1," the impact when the balls or rollers rolling inside the bearing collide with the bearing components, namely the inner ring, outer ring, and cage, appears as a value at a higher frequency than the rotation frequency of the drive source unit 2. Based on this conclusion, the inventors decided to measure the load current value at the drive source unit 2 and perform frequency analysis on the measured load current value, focusing on the spectral intensity of higher frequencies calculated by the frequency analysis, in order to detect abnormalities occurring in the rotating equipment 10. 【0030】 Furthermore, the inventors have concluded that in a state corresponding to "abnormal stage 1," the impacts when balls or rollers collide with the inner ring, outer ring, and cage occur randomly over time, and their magnitude is also non-uniform. For example, if there is minor damage to a part of the outer ring of the bearing, the inventors have concluded that the impact force when rolling balls or rollers collide with the damaged area appears as a higher frequency and varies over time. Therefore, they have concluded that by identifying statistical information regarding the time variation of the spectral intensity of higher frequencies, it is possible to determine that damage has occurred to a part of the bearing's components. Accordingly, the inventors have focused on statistical information regarding the time variation of the spectral intensity of higher frequencies. 【0031】The inventors also investigated whether it is possible to accurately determine abnormalities by comparing the magnitude of the spectral intensity of higher-order frequencies (average value over time) with a preset threshold. However, the inventors concluded that in a state corresponding to "abnormal stage 1," the impact force when rolling balls or rollers collide with the damaged area is generated unevenly, and therefore the spectral intensity of a specific higher-order frequency does not necessarily increase. For this reason, they concluded that in order to accurately detect a state corresponding to "abnormal stage 1," it is more appropriate to focus on statistical information regarding variability rather than an index related to the magnitude of the spectral intensity of higher-order frequencies, such as the average value. On the other hand, in a state corresponding to "abnormal stage 2," where the damage to bearings, etc., has progressed, the impact force due to collisions between constituent members develops to a certain degree of a steady state, and the magnitude of the spectral intensity of a specific higher-order frequency increases. Therefore, when detecting a state corresponding to "abnormal stage 2," an index related to the magnitude of the spectral intensity of higher-order frequencies, such as the average value, may be used. 【0032】 Here, the abnormality detection method described in Patent Document 3 is a method for determining abnormalities in rotating equipment by comparing the higher-order and lower-order components in the frequency spectrum of the load current. However, this method focuses on the average value of the spectral intensity of higher-order frequencies, making it possible to detect a state corresponding to "abnormality stage 2," but difficult to detect a state corresponding to "abnormality stage 1." 【0033】 Furthermore, the method described in Patent Document 2 is a method for determining abnormalities in rotating equipment by measuring the sidebands that appear near the rotation frequency in response to the torque fluctuations of the load current corresponding to the torque fluctuations applied to the motor (drive source), and by calculating the spectral intensity corresponding to the torque fluctuations. However, according to the inventors' findings, when frequency analysis is performed on the motor's load current, sidebands appear on both sides of the rotation frequency only when the load current corresponding to the torque fluctuations fluctuates by about ±20%. Therefore, by the time sidebands are detected, some kind of major abnormality has already occurred in the rotating equipment, and it is difficult to detect a state corresponding to "abnormality stage 1". 【0034】Next, the abnormality detection device 40 in this embodiment will be described with reference to Figure 1. As shown in Figure 1, the abnormality detection device 40 is connected to the current transformer 20 via the ammeter 30. The current transformer 20 is connected to the power supply system that connects the power supply unit 1 and the drive source unit 2. 【0035】 The current transformer 20 converts the current flowing through the power system into a current that can be measured by the abnormality detection device 40 and transmits it to the ammeter 30. The ammeter 30 measures the current value flowing through the power system based on the current transformation ratio (CT ratio) of the current in the current transformer 20. The ammeter 30 then transmits the measured current value to the abnormality detection device 40 as the load current value in the drive source unit 2. 【0036】 Furthermore, if the drive source unit 2 is a three-phase induction motor, it is sufficient to transmit the load current value of any one phase to the abnormality detection device 40. That is, in this case, the current transformer 20 is connected to any of the U, V, and W phases of the power supply system, and the measured load current value is transmitted to the abnormality detection device 40. 【0037】 Next, the detailed configuration of the abnormality detection device 40 in this embodiment will be described with reference to Figure 2. Figure 2 is a schematic diagram showing an example of the general configuration of the abnormality detection device 40. The abnormality detection device 40 is, for example, a general-purpose computer such as a workstation or personal computer. As shown in Figure 2, the abnormality detection device 40 has an acquisition unit 41, a processing unit A, an input unit 45, an output unit 46, and a storage unit 47. The processing unit A has a calculation unit 42, a identification unit 43, and a determination unit 44. The abnormality detection device 40 is connected to a terminal device 50. 【0038】The processing unit A is, for example, a CPU, and by executing various programs stored in the storage unit 47, the processing unit A functions as a calculation unit 42, a specification unit 43, and a determination unit 44. The input unit 45 is, for example, a keyboard, a touch panel integrated with a display, etc. The output unit 46 is, for example, an LCD or CRT display, etc. The output unit 46 may include one or more output interfaces that output information to notify the user. The storage unit 47 is, for example, an information recording medium such as an updatable flash memory, a built-in or data communication terminal-connected hard disk, or a memory card, and a device for reading and writing the same. The storage unit 47 stores programs, calculation formulas, thresholds used by the determination unit 44 when performing threshold processing, etc., which are necessary for the processing unit A to determine abnormalities in the rotating equipment 10. 【0039】 The acquisition unit 41 acquires the load current values ​​transmitted from the ammeter 30 while the rotating equipment 10 is in operation (online). Each load current value also includes time information of when the load current value was measured by the ammeter 30. If the load current value measured by the ammeter 30 is analog data, the acquisition unit 41 converts the load current value into digital data. The acquisition unit 41 transmits the information regarding the acquired load current values ​​to the calculation unit 42 of the processing unit A. 【0040】 The acquisition unit 41 acquires the load current value transmitted from the ammeter 30 at a period of, for example, 20 to 200 μs. From the viewpoint of accurately detecting the occurrence of abnormalities in the rotating equipment 10, a shorter period is preferable for acquiring the load current value in the acquisition unit 41. However, considering the processing capacity of the abnormality determination device 40, it is preferable to set it to 50 μs or more. On the other hand, if the period for acquiring the load current value exceeds 200 μs, the number of data points decreases, and the accuracy of the frequency analysis in the calculation unit 42 decreases. Therefore, it is preferable to set the period for acquiring the load current value in the acquisition unit 41 to 150 μs or less. 【0041】The calculation unit 42 first collects load current value data transmitted from the acquisition unit 41. After collecting load current values ​​for data number Na, the calculation unit 42 performs frequency analysis on the collected load current values. Fast Fourier analysis (FFT analysis) may be applied to the frequency analysis. Here, data number Na (where Na is an integer of 2 or more) may be set in advance as the number of data for which frequency analysis can be performed by the calculation unit 42. Data number Na may be set, for example, within the range of 500 to 10000. Furthermore, the collected load current values ​​for data number Na will have the same time information as when they were measured by the ammeter 30. 【0042】 For example, the calculation unit 42 may set the number of data points Na for which frequency analysis can be performed to "4096", receive load current data (one data point) every 100 μs, and perform frequency analysis after collecting data points Na. In this case, the time required for the calculation unit 42 to finish collecting data points Na will be 409.6 ms. In this case, the period for performing frequency analysis in the calculation unit 42 may be set to 500 ms, and the frequency analysis may be performed according to this period. 【0043】 Here, the spectral intensity calculated by frequency analysis will be explained using Figure 3. Figure 3 is a diagram showing an example of spectral intensity calculated by frequency analysis in the calculation unit 42. In Figure 3, the horizontal axis represents frequency (Hz), and the vertical axis represents spectral intensity P(A). The relationship between "frequency (Hz)" and "spectral intensity P(A)" shown in Figure 3 represents the result calculated based on the load current value of the number of data points Na that were the subject of the frequency analysis. Therefore, the relationship between "frequency (Hz)" and "spectral intensity P(A)" shown in Figure 3 represents the result obtained based on the load current value at the same time. The calculation unit 42 calculates the spectral intensity P for each time point, and calculates the relationship between "frequency (Hz)" and "spectral intensity P(A)" (see Figure 3) each time. 【0044】As shown in FIG. 3, as a result of the frequency analysis, a peak in the spectral intensity can be confirmed in the vicinity of the frequency of 50 Hz. This is due to the application of a commercial power supply (frequency: 50 Hz) as the power supply unit 1 in the present embodiment. Therefore, in the frequency analysis of the load current value, it can be confirmed that the frequency related to the rotation of the drive source unit 2 corresponds to the primary frequency with respect to the peak of the spectral intensity that appears for each frequency. Thus, the primary frequency at which the peak of the spectral intensity appears may be regarded as the rotation frequency of the drive source unit 2. 【0045】 The calculation unit 42 also calculates the spectral intensity P of the higher-order frequencies with respect to the rotation frequency of the drive source unit 2 in the frequency analysis of the load current value. Here, the higher-order frequencies mean the frequencies of the second order or higher with respect to the primary frequency regarded as the rotation frequency of the drive source unit 2. More specifically, the higher-order frequencies mean the frequencies that become NΩ (N is an integer of 2 or more) with respect to the rotation frequency Ω that is the primary frequency. 【0046】 Also, as shown in FIG. 3, the spectral intensity P calculated by the frequency analysis of the load current value has a tendency for a peak to appear at odd-order frequencies (higher-order frequencies where N in NΩ is an odd number). And as the order increases, the spectral intensity tends to decrease. Based on these tendencies, from the viewpoint of accurately detecting the occurrence of an abnormality in the rotating equipment 10, it is preferable to calculate the spectral intensity P at higher-order frequencies from the third order to the twenty-first order in the frequency analysis of the load current value. Further, in order to more accurately detect the occurrence of an abnormality, it is more preferable to calculate the spectral intensity P at higher-order frequencies from the third order to the fifteenth order. 【0047】Here, regarding the spectral intensity P (see FIG. 3) calculated in the present embodiment, for example, the spectral intensity P3 at the third frequency (N = 3) is 3.1 A, and the spectral intensity P5 at the fifth frequency (N = 5) is 2.0 A. As shown in FIG. 3, the calculation unit 42 calculates the spectral intensity P corresponding to the high-order frequency NΩ by performing frequency analysis on the load current value. Then, the calculation unit 42 transmits the spectral intensity P of the high-order frequency calculated by the frequency analysis to the specifying unit 43. Specifically, for each time when the load current value is measured by the ammeter 30, the relationship between "frequency (Hz)" and "spectral intensity P (A)" (see FIG. 3) is calculated, and the calculated information is transmitted to the specifying unit 43. 【0048】 The calculation unit 42 may select an arbitrary order frequency selected from the second-order or higher high-order frequencies with respect to the rotation frequency Ω (first-order frequency) of the drive source unit 2, and calculate the spectral intensity P corresponding thereto. The calculation unit 42 may select an arbitrary high-order frequency from the third-order or higher and 21st-order or lower high-order frequencies, and calculate the spectral intensity P corresponding thereto. Further, the calculation unit 42 may select two or more high-order frequencies from the third-order or higher and 21st-order or lower high-order frequencies, and calculate the spectral intensity P corresponding thereto. The calculation unit 42 may select a plurality of odd-order high-order frequencies from the third-order or higher and 21st-order or lower high-order frequencies, and calculate the spectral intensity P corresponding to each of them. Further, it is preferable that the calculation unit 42 selects all odd-order high-order frequencies from the third-order or higher and 21st-order or lower high-order frequencies, and calculates the spectral intensity P corresponding to each of them. 【0049】 When calculating the spectral intensity P, the calculation unit 42 may set a certain frequency band centered on the high-order frequency for the high-order frequency, and calculate the average value of the spectral intensity P over the range of the frequency band as the spectral intensity P at the high-order frequency. In this case, the frequency band may be set as a frequency band that is centered on the high-order frequency (high-order frequency NΩ (Hz)) and has a minimum of ±2.5 Hz and a maximum of ±4.7 Hz with respect to the central frequency. 【0050】Furthermore, in the frequency analysis results shown in Figure 3, the minimum frequency interval shown on the horizontal axis is 2.4 Hz. Therefore, depending on the frequency band set for higher-order frequencies, the peak value of the spectral intensity can be averaged with the peak values ​​of the spectral intensity at the frequencies immediately before and after it to obtain the spectral intensity corresponding to the higher-order frequencies. Thus, the influence of disturbances can be suppressed when calculating the spectral intensity corresponding to higher-order frequencies. 【0051】 The identification unit 43 collects spectral intensity P data transmitted from the calculation unit 42. When the number of collected spectral intensity P data reaches Ns (where Ns is an integer of 2 or more), the identification unit 43 identifies statistical information regarding the time variation of spectral intensity P. The spectral intensity P data transmitted from the calculation unit 42 is data in which the relationship between "frequency (Hz)" and "spectral intensity P (A)" at a specific time when the load current value is measured by the ammeter 30 (see Figure 3) is used as a single unit. 【0052】 The number of data points Ns for spectral intensity P is preferably between 10 and 1000, from the viewpoint of accurately detecting the occurrence of abnormalities in the rotating equipment 10. That is, it is preferable to collect a number of data points between 10 and 1000 regarding the relationship between "frequency (Hz)" and "spectral intensity P (A)" for each time period. If the number of data points Ns is less than 10, the number of data points related to spectral intensity P will be small, making it difficult to accurately identify the time variation of spectral intensity P. If the number of data points Ns exceeds 1000, further improvement in accuracy cannot be obtained, and it will take time to identify the time variation of spectral intensity P. 【0053】 The identification unit 43 identifies statistical information D relating to the time variation (variation corresponding to the passage of time) of spectral intensity P based on a time series of spectral intensities P with Ns data points. Specifically, the statistical information D may be based on multiple spectral intensity P data points at specific higher frequencies P over time, and may be values ​​such as the standard deviation, variance, interquartile range, mean difference, and mean absolute deviation of these multiple spectral intensities P. 【0054】Furthermore, from the viewpoint of ease and speed of identification (calculation) in data processing, it is preferable to apply the standard deviation to statistical information D. Also, since the standard deviation is defined as the square root of the variance, and the standard deviation and variance are mutually convertible indicators, the variance may also be applied to statistical information D. However, the application of the mean, median, mode, etc., to statistical information D is unsuitable. This is because it differs from the technical concept of the present invention, which focuses on the time variation of the spectral intensity P of higher frequencies calculated by frequency analysis, based on the objective of the present invention to accurately detect when damage has occurred to a part of the component member of the rotating equipment 10. 【0055】 For the identification of statistical information D in the identification unit 43, for example, the calculation unit 42 calculates the spectral intensity P of higher-order frequency NΩ every 500 ms, and the identification unit 43 is set to identify statistical information D when it has collected 10 spectral intensity P data. In this case, the identification unit 43 can identify statistical information D every 5000 ms (5 seconds). 【0056】 Alternatively, the identification unit 43 may store the spectral intensity P data corresponding to the higher-order frequency NΩ calculated by the calculation unit 42 in the storage unit 47, and then read out a predetermined number Ns of spectral intensity P from the storage unit 47 to identify the statistical information D. In this case, the calculation unit 42 calculates the spectral intensity P data for the higher-order frequency NΩ, and the statistical information D can be identified each time the data stored in the storage unit 47 is updated (for example, every 500 ms). 【0057】 In the identification unit 43, statistical information D corresponding to the higher-order frequency is identified in accordance with the spectral intensity P of the higher-order frequency calculated by the calculation unit 42. That is, if the calculation unit 42 calculates spectral intensities P of higher-order frequencies corresponding to two or more orders, the identification unit 43 can identify statistical information D at the higher-order frequencies corresponding to those orders. 【0058】 Furthermore, whenever the identification unit 43 identifies statistical information D relating to the time variation of the spectral intensity P of a higher-order frequency NΩ, it transmits the statistical information D to the determination unit 44. 【0059】The determination unit 44 receives statistical information D corresponding to higher frequencies transmitted from the identification unit 43 and determines an abnormality in the rotating equipment 10 based on the received statistical information D. Specifically, the determination unit 44 compares the received statistical information D with a preset threshold DT and determines that an abnormality has occurred in the rotating equipment 10 if the value of the statistical information D is greater than or equal to the threshold DT. 【0060】 Here, the threshold value DT used in the determination unit 44 is set in advance and stored in the storage unit 47. At that time, the threshold value DT is set in association with the "order" of the higher-order frequency corresponding to the spectral intensity P calculated by the calculation unit 42. 【0061】 When the determination unit 44 receives statistical information D corresponding to a specific high-order frequency from the determination unit 43, it compares the statistical information D for that specific high-order frequency with a threshold DT that is set in association with the same "order" as that specific order. If the value of the statistical information D is greater than or equal to the threshold DT as a result of the comparison, the determination unit 44 determines that an abnormality has occurred in the rotating equipment 10. 【0062】 Furthermore, in the determination unit 44, in order to set the threshold DT, a comparison is made with statistical information D of multiple different orders of higher frequencies, so each threshold DT may be set in association with the "order" of multiple different higher frequencies. In this case, after receiving statistical information D of multiple different orders of higher frequencies from the identification unit 43, the statistical information D and the threshold DT may be compared for each order. Then, if the value of the statistical information D becomes greater than or equal to the threshold DT for at least one order, it may be determined that an abnormality has occurred in the rotating equipment 10. 【0063】 In situations where damage occurs to a component of the rotating equipment 10, it can be difficult to predict at which higher frequency the abnormality-indicating phenomenon will appear as statistical information D. Therefore, by comparing statistical information D with a threshold DT at multiple different frequencies, it becomes possible to detect abnormalities more reliably. 【0064】The threshold value DT may be set based on the statistical normal information DS identified by the identification unit 43 when the rotating equipment 10 is operating normally (normal operation). Specifically, when the rotating equipment 10 is operating normally, the calculation unit 42 calculates the relationship between higher-order frequencies and spectral intensity P (see Figure 3), and the identification unit 43 identifies the statistical normal information DS regarding the time variation of spectral intensity P for each "order" of higher-order frequencies. Then, for each statistical normal information DS identified for each "order" of higher-order frequencies, it is identified as the standard deviation σnormal, and the value of Q × σnormal (where Q is a real number greater than 1.0) may be set as the threshold value DT. However, from the viewpoint of preventing abnormal judgment during normal operation, it is preferable that the real number Q be 2.5 or greater. 【0065】 By setting the threshold DT in this way, a situation in which the value of statistical information D becomes larger than the normal temporal variation of spectral intensity P that occurs during normal operation can be accurately determined as an abnormality in the rotating equipment 10. 【0066】 Alternatively, for the statistical normal information DS identified for each "order" of higher frequencies during the normal operation of the rotating equipment 10, the average value of all statistical normal information DS may be calculated, and a common threshold DT may be set based on the calculated average value. More specifically, the average value of all statistical normal information DS may be identified as the standard deviation σnormal, and a common threshold DT may be set for the value of Q × σnormal (where Q is a real number greater than 1.0). However, from the viewpoint of preventing abnormal judgments during normal operation, it is preferable that the real number Q be 2.5 or greater. 【0067】 Information regarding the threshold DT may be stored in the storage unit 47 in advance, and when the determination unit 44 performs an abnormality determination in the rotating equipment 10, it may be read from the storage unit 47 and used in the determination process. Alternatively, an operator of the rotating equipment 10 may input information regarding the threshold DT to the abnormality determination device 40 via the input unit 45, and the input threshold DT may be stored in the storage unit 47. 【0068】The determination unit 44 may determine the degree of abnormality in the rotating equipment 10 by comparing statistical information D regarding the time variation of the spectral intensity P of higher-order frequency NΩ with a threshold value DT. In this case, for example, the degree of abnormality may be classified into binary information such as "risk present" or "fault present" for determination. With respect to the statistical information D, if the value R is more than twice the threshold value DT, it may be determined to be "fault present," and if it is greater than or equal to the threshold value DT and less than twice the threshold value R, it may be determined to be "risk present." By setting the degree of abnormality in stages for determining abnormalities in the rotating equipment 10, a more appropriate determination becomes possible. 【0069】 In the abnormality detection device 40, if the detection unit 44 determines that an abnormality has occurred in the rotating equipment 10, the device may notify (display, etc.) the determination result regarding the occurrence of an abnormality or the degree of the abnormality via the output unit 46. Clearly notifying the occurrence of an abnormality allows workers to accurately grasp the situation. 【0070】 Furthermore, the abnormality detection device 40 may transmit the result of the determination in the determination unit 44 to a terminal device 50 connected via a network or the like, and the determination result may be displayed on a display device or the like in the terminal device 50. As the terminal device 50, for example, a mobile terminal such as a tablet terminal that can be carried by a worker in charge of maintenance and inspection may be used. By displaying the determination result on the mobile terminal, workers can quickly grasp that an abnormality has occurred and can promptly consider planning maintenance work. 【0071】 Next, the method for determining abnormalities in the rotating equipment 10 in this embodiment will be explained using Figure 4. Figure 4 is a flowchart showing the flow of the abnormality determination process in the method for determining abnormalities in the rotating equipment. 【0072】The abnormality detection process shown in Figure 4 may be started, for example, when the abnormality detection device 40 receives information that the rotating equipment 10 has started operation. Alternatively, it may be started when the input unit 45 of the abnormality detection device 40 receives an input signal indicating that the abnormality detection process should be started. It is preferable that the abnormality detection process be started after the operating state of the drive source unit 2 has increased from a stopped state to a steady speed. This is because, during the period from when the drive source unit 2 is stopped to when it increases to a steady speed, the rotational speed of the drive source unit 2 may be in an unsteady state, which could be a disturbance that reduces the accuracy of the abnormality detection of the rotating equipment 10. 【0073】 In step S11 of the abnormality detection process, the acquisition unit 41 acquires information regarding the load current value of the drive source unit 2 from the ammeter 30 and transmits the acquired load current value to the calculation unit 42. The processing in step S11 corresponds to the acquisition step in the present invention. 【0074】 In step S20, the calculation unit 42 determines whether or not information on Na pre-set load current values ​​has been collected. If the result of the determination is that information on Na load current values ​​has been collected (step S20: Yes), the process proceeds to step S21; if information on Na load current values ​​has not been collected (step S20: No), the process proceeds to step S11. 【0075】 In step S21, the calculation unit 42 performs frequency analysis of the load current value and calculates the spectral intensity P of a higher-order frequency NΩ with respect to the rotation frequency Ω of the drive source unit 2. The calculation unit 42 then transmits the information regarding the calculated spectral intensity P of the higher-order frequency NΩ to the identification unit 43. The processing in step S21 corresponds to the calculation step in the present invention. 【0076】In step S30, the identification unit 43 determines whether or not it has collected information on Ns of spectral intensity P, which is set in advance. If the result of the determination is that information on Ns of spectral intensity P has been collected (step S30: Yes), the process proceeds to step S31; if information on Ns of spectral intensity P has not been collected (step S30: No), the process proceeds to step S21. 【0077】 In step S31, the identification unit 43 identifies statistical information D relating to the time variation of the spectral intensity P at higher-order frequencies NΩ based on information on Ns spectral intensities P. The identification unit 43 then transmits the identified statistical information D to the determination unit 44. The processing in step S31 corresponds to the identification step in the present invention. 【0078】 In step S41, the determination unit 44 compares the statistical information D transmitted from the identification unit 43 with a preset threshold DT to determine if there is an abnormality in the rotating equipment 10. The determination unit 44 transmits the result of the determination of the abnormality in the rotating equipment 10 to the output unit 46. The processing in step S41 corresponds to the determination step in the present invention. 【0079】 In step S50, the output unit 46 receives the result of the determination transmitted from the determination unit 44 and outputs the result of the determination. The output unit 46 may also store the result of the determination (information on whether there is an abnormality and the degree of the abnormality) in the storage unit 47, along with information on the date and time the determination processing was performed by the determination unit 44. 【0080】 In step S60, the processing unit A determines whether or not to terminate the abnormality determination process based on the reception status of an external signal indicating the termination of the abnormality determination process. If the determination is made to terminate the abnormality determination process (step S60: Yes), the abnormality determination process is terminated; if it is determined not to terminate the abnormality determination process (step S60: No), the process proceeds to step S11. The abnormality determination device 40 may also automatically generate a signal to terminate the abnormality determination process when it detects that the rotating equipment 10 has stopped operating, and transmit this signal to the processing unit A. 【0081】Furthermore, the abnormality determination device 40 in this embodiment may implement an abnormality determination method for the rotating equipment 10. Specifically, the abnormality determination device 40 may implement an abnormality determination method for the rotating equipment 10, which includes an acquisition step of acquiring a load current value in the drive source unit 2, a calculation step of performing frequency analysis on the load current value acquired in the acquisition step and calculating the spectral intensity of higher-order frequencies with respect to the rotation frequency in the drive source unit 2, a identification step of identifying statistical information regarding the time variation of the spectral intensity of higher-order frequencies calculated in the calculation step, and a determination step of determining an abnormality in the rotating equipment 10 based on the statistical information identified in the identification step. 【0082】 As described above, by applying the abnormality detection device 40 for the rotating equipment 10 in this embodiment, or by implementing the abnormality detection method for the rotating equipment 10, it is possible to accurately detect the occurrence of abnormalities even when the scale of damage to the rotating equipment 10 is small. Specifically, by performing frequency analysis on the load current value in the drive source unit 2 and using statistical information on the time variation of the spectral intensity calculated by the frequency analysis to determine the abnormality, it is possible to accurately detect the occurrence of abnormalities even when the scale of damage is small. Furthermore, as shown in Figure 4, since the abnormality detection process can determine the abnormality while the rotating equipment 10 is in operation, it is possible to suppress a decrease in the operating rate of the rotating equipment. 【0083】Furthermore, the present invention is characterized by the use of statistical information D relating to the time variation of the spectral intensity P at higher frequencies. In the "abnormal stage 2" state described above, the average value of spectral intensity P at higher frequencies increases, as calculated by frequency analysis of the load current value. Therefore, the presence or absence of an abnormality can be determined by simply comparing the spectral intensity P value at each higher frequency with a specific threshold. In contrast, in the present invention, in order to detect the "abnormal stage 1" state described above, the determination can be made using information (statistical information D) relating to spectral intensity P that changes over time, at a stage where the average value of spectral intensity P at higher frequencies is low. Therefore, in determining abnormalities in the rotating equipment 10, the presence or absence of an abnormality can be detected with high accuracy at a stage before it develops into "abnormal stage 2" (abnormal stage 1). 【0084】 <Second Embodiment> Next, a second embodiment of the present invention will be described with reference to Figure 5. Figure 5 is a schematic diagram showing an example of the general configuration of the abnormality determination device 60 as the second embodiment. In the second embodiment, components that are the same as those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted. 【0085】 The anomaly detection device 60 is, for example, a general-purpose computer such as a workstation or personal computer. The anomaly detection device 60 has a calculation unit B and an analysis unit C. The calculation unit B has an acquisition unit 61 and a calculation unit 62. The analysis unit C has a identification unit 63, a determination unit 64, an input unit 65, an output unit 66, and a storage unit 67. The anomaly detection device 60 is connected to a host computer 70. The host computer 70 is, for example, a control computer that manages the operation of production equipment including the anomaly detection device 60. 【0086】 The acquisition unit 61, calculation unit 62, identification unit 63, and determination unit 64 in this embodiment may have the same functions as the acquisition unit 41, calculation unit 42, identification unit 43, and determination unit 44 in the first embodiment. The calculation unit B may be configured with a device capable of high-speed calculation processing, such as an FPGA (Field-Programmable Gate Array) or a PLC (Programmable Logic Controller). 【0087】 The calculation unit B is preferably configured using an FPGA. This is because FPGAs offer a high degree of programming flexibility and enable high-speed data processing, such as arithmetic operations. Specifically, in the calculation unit B, the acquisition unit 61 acquires information regarding the load current value at a period of 20 to 200 μs, and the calculation unit 62 performs frequency analysis targeting the number of data points Na (500 to 10,000 data points). Therefore, by configuring the calculation unit B using an FPGA, the spectral intensity P of higher-order frequencies with respect to the rotation frequency of the drive source unit 2 can be calculated at high speed. 【0088】 The analysis unit C may be composed of a PLC (Programmable Logic Controller). In this case, the PLC may have a CPU that executes the processing in the identification unit 63 and the determination unit 64, and a storage unit 67 that stores the programs, calculation formulas, preset threshold values ​​DT, etc., necessary for the processing in the identification unit 63 and the determination unit 64. The PLC may also have an input unit 65 that receives information on high-order frequency spectral intensity P transmitted from the calculation unit B, and an output unit 66 that outputs the result of the determination by the determination unit 64 to the host computer 70. 【0089】 Since the analysis unit C does not require high-speed computation compared to the calculation unit B, it is not necessarily required to apply an FPGA. When the analysis unit C acquires the high-order frequency spectral intensity P transmitted from the calculation unit B as 10 to 1000 data points Ns every 500 ms, it may identify statistical information D every 5 to 500 s. The determination unit 64 then uses the statistical information D to determine if there is an abnormality in the rotating equipment 10 and may transmit the determination result to the output unit 66. 【0090】 The output unit 66 may transmit the result of the determination by the determination unit 64 to a host computer 70 connected via a network or the like. When the host computer 70 receives a determination result from the abnormality determination device 60 indicating that there is an abnormality in the rotating equipment or the degree of the abnormality, it may display the determination result on a display device connected via the network. This clearly notifies that an abnormality has occurred during the operation of the rotating equipment, and enables operators of the rotating equipment to accurately recognize the abnormality in the rotating equipment. 【0091】 Here, the "abnormality of the rotating equipment" determined by the abnormality detection device or method for the rotating equipment 10 in this embodiment specifically refers to abnormalities occurring in the support section 5. On the other hand, the drive source section 2, such as the motor, can be detected early by, for example, performing trend management of insulation resistance through periodic inspections. The drive unit 4 can be detected as having abnormalities by evaluating whether or not it is performing its function as a drive unit, such as the output results during operation. The rotating shaft 3 can often have abnormalities detected by means such as magnetic particle testing during periodic inspections. 【0092】 On the other hand, with respect to the support section 5, even if minute damage occurs to, for example, the inner ring, outer ring, or cage of the bearing, it is difficult to check from the outside whether there is any damage or the extent of the damage. Therefore, there is a high need to accurately detect abnormalities at an early stage of damage. 【0093】 Furthermore, in the rotating equipment 10, damage or other abnormalities can occur not only in the support section 5 but also in various other components on the equipment. For this reason, the abnormality detection device or method for the rotating equipment 10 in this embodiment can be applied to detect abnormalities by measuring the load current value in the drive source section 2, and abnormalities occurring in other components on the equipment may also be detected, not just in the support section 5. For example, this method can be applied when an abnormality occurs in a coupling, belt, gear, etc., that transmits rotational power between the drive source section 2 and the drive unit 4. 【0094】 Furthermore, by applying the abnormality detection device or method for the rotating equipment 10 in this embodiment, it is possible to accurately detect whether or not an abnormality has occurred in the various pieces of equipment constituting the rotating equipment 10, even at a stage where the degree of damage is small. For this reason, even if the determination unit 44 and the determination unit 64 determine that there is an abnormality, the operation of the rotating equipment 10 does not need to be stopped immediately. The operation of the rotating equipment 10 may be stopped only if the determination of "abnormality" continues. 【0095】<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to Figure 6. Figure 6 is a schematic diagram showing an example of a general configuration in which a control device 80 is added to the rotating equipment 10 and the abnormality detection device 40 as the third embodiment. For each component in the third embodiment, components that are the same as in the first embodiment are denoted by the same reference numerals and their descriptions are omitted. Note that the abnormality detection device 40 in the third embodiment may be the same as the abnormality detection device 60 in the second embodiment. 【0096】 Power supply unit 1 may be an inverter power supply. Drive source unit 2 may be a three-phase induction motor. Therefore, power supply unit 1 may be a three-phase AC power supply. The control device 80 is connected to the power supply unit 1 and the abnormality detection device 40 in a communication manner. 【0097】 The control device 80 transmits a control signal to the power supply unit 1 in order to drive the drive source unit 2 at a predetermined rotational speed. When transmitting the control signal to the power supply unit 1, the control device 80 transmits a signal regarding the level of load applied to the drive device 4 (hereinafter referred to as "load level") to the abnormality detection device 40. The signal regarding the load level may include a signal regarding the height of the load applied to the drive device 4. The signal regarding the load level may include a "load" control signal that creates a load and a "unload" control signal that releases the load. In addition, the signal regarding the load level may include a control signal that controls the load applied to the drive device 4 to be within a predetermined range. 【0098】 For example, when the control device 80 transmits a control signal to the power supply unit 1 that indicates a low load state in the drive unit 4, it transmits a "low load signal (hereinafter referred to as the "first load signal")" to the abnormality detection device 40, which indicates a low load state in the drive unit 4. On the other hand, when the control device 80 transmits a control signal to the power supply unit 1 that indicates a high load state in the drive unit 4, it transmits a "high load signal (hereinafter referred to as the "second load signal")" to the abnormality detection device 40, which indicates a high load state in the drive unit 4. 【0099】Here, we will explain the findings of the inventors regarding the determination of abnormalities in the rotating equipment 10, from the perspective of improving the accuracy of the determination. The inventors focused on the fact that when calculating the spectral intensity of higher-order frequencies while the torque and rotational speed are fluctuating in the drive device 4, fluctuations in torque and rotational speed can disturb the calculated spectral intensity values. They then focused on the fact that a state in which the fluctuations in torque and rotational speed in the drive device 4 are small, that is, a state in which the load in the drive device 4 can be considered constant within a predetermined range, is appropriate as a state in which fluctuations in the spectral intensity of higher-order frequencies can be reduced. Specifically, a state in which the load can be considered constant means that the standard deviation or RMS (root mean square) of the load fluctuation over time is within a preset range. In particular, they focused on the fact that when the torque and rotational speed are maintained at a low state in the drive device 4, the fluctuations in the load in the drive device 4 are reduced, resulting in a small standard deviation or RMS of the load fluctuation over time, and thus the fluctuations in the spectral intensity of higher-order frequencies are reduced. 【0100】 Based on this view, the inventors considered it preferable to start the abnormality detection process based on frequency analysis of the load current value when the torque and rotational speed of the drive unit 4 decrease. In other words, the inventors considered it preferable to start the abnormality detection process of the rotating equipment 10 when the load on the drive unit 4 becomes low. Here, "low load" means that the load acting on the drive unit 4 is low, and that the load acting on the drive unit 4 is within a generally constant range. 【0101】On the other hand, the inventors considered it preferable to terminate the abnormality detection process when the torque and rotational speed of the drive unit 4 increase. That is, the inventors considered it preferable to terminate the abnormality detection process of the rotating equipment 10 when the load on the drive unit 4 becomes high. This is because when the load on the drive unit 4 is high, the fluctuation in the load level often becomes large, and the variation in the calculated values ​​of the spectral intensity of higher frequencies tends to increase. In other words, a "high load state" means that the range of load applied to the drive unit 4 cannot be considered constant because the load applied to the drive unit 4 is high. 【0102】 Furthermore, in the third embodiment, the abnormality detection device 40 starts abnormality detection processing of the rotating equipment 10 when it receives a first load signal from the control device 80 (indicating a low load state in the drive device 4). On the other hand, the abnormality detection device 40 terminates abnormality detection processing of the rotating equipment 10 when it receives a second load signal from the control device 80 (indicating a high load state in the drive device 4). 【0103】 With regard to the load acting on the drive unit 4, it is preferable to specify in advance the conditions for a "low load state" and a "high load state". Specifically, with respect to the control signal (current command value) transmitted from the control device 80 to the power supply unit 1 in order to drive the drive source unit 2 at a predetermined rotational speed, it is preferable to specify that a "high load state" occurs when a control signal (current command value) exceeding 30 amperes is transmitted. On the other hand, it is preferable to specify that a "low load state" occurs when a control signal (current command value) of 30 amperes or less is transmitted to the power supply unit 1. By specifying that the control signal (current command value) is below a predetermined reference value for the "low load state", the conditions under which the load acting on the drive unit 4 is within a generally constant range become clear. 【0104】In other words, it is preferable to transmit a "first load signal" to the abnormality detection device 40 when the load is in a "low state" according to a predetermined value of the control signal (current command value) (for example, "30 amperes"). On the other hand, it is preferable to transmit a "second load signal" to the abnormality detection device 40 when the load is in a "high state" according to a predetermined value of the control signal (current command value) (for example, "30 amperes"). 【0105】 Furthermore, it is preferable that the value of the control signal (current command value) used to clearly identify the "low load state" and the "high load state" with respect to the load acting on the drive unit 4 (hereinafter referred to as the "reference current command value") be changed in accordance with the ever-changing operating state of the rotating equipment 10. That is, it is preferable to set a reference current command value (for example, 30 amperes) in advance based on the operating state of the rotating equipment 10, and then transmit the first load signal when a current command value of less than or equal to the reference current command value is transmitted (low load state). On the other hand, it is preferable to transmit the second load signal when a current command value exceeding the reference current command value is transmitted (high load state). 【0106】 Here, the status of the control signal (current command value) transmitted from the control device 80 to the power supply unit 1 and the load level signals (first load signal and second load signal) transmitted from the control device 80 to the abnormality detection device 40 over time will be explained using Figure 7. 【0107】 As shown in Figure 7, when the drive unit 4 is subjected to a high load, the control device 80 transmits a second load signal to the abnormality detection device 40 and increases the current command value transmitted to the power supply unit 1. The control device 80 then continues transmitting the second load signal for a predetermined period, including the state in which the current command value is increased to its maximum value. 【0108】Furthermore, when the drive unit 4 is brought to a low load state, the control device 80 reduces the current command value transmitted to the power supply unit 1 while maintaining the transmission of the second load signal to the abnormality detection device 40, prior to transmitting the first load signal to the abnormality detection device 40. Then, after the current command value becomes small, it transmits the first load signal to the abnormality detection device 40. The control device 80 continues to transmit the first load signal for the period until the second load signal is transmitted to the abnormality detection device 40. 【0109】 Next, the method for determining abnormalities in the rotating equipment 10 in the third embodiment will be explained using Figure 8. Figure 8 is a flowchart showing the flow of the abnormality determination process in the abnormality determination method for the rotating equipment in the third embodiment. For each step in the abnormality determination process of the third embodiment, steps that are the same as those in the abnormality determination process of the first embodiment (see Figure 4) are denoted by the same step reference numerals and their explanations are omitted. 【0110】 In the third embodiment, the abnormality detection process may be started, for example, when the abnormality detection device 40 receives information that the rotating equipment 10 has started operating. Alternatively, it may be started when the input unit 45 of the abnormality detection device 40 receives an input signal indicating that the abnormality detection process should be started. 【0111】 In the abnormality determination process in the third embodiment, the processing unit A determines in step S10 whether or not the first load signal has been received by the acquisition unit 41. If the determination result is that the first load signal has been received (step S10: Yes), the process proceeds to step S11 and the acquisition step of the present invention is executed. If the first load signal has not been received (step S10: No), step S10 is repeated. 【0112】 Furthermore, in step S61, processing unit A determines whether or not the second load signal has been received by the acquisition unit 41. If the second load signal has been received (step S61: Yes), this abnormality determination process is terminated; if the second load signal has not been received (step S61: No), the process proceeds to step S10. 【0113】By applying the abnormality detection device or method for the rotating equipment 10 in this embodiment, the spectral intensity of higher-order frequencies can be calculated in the drive unit 4 while the load fluctuation is reduced to a certain range. Therefore, fluctuations in the spectral intensity of higher-order frequencies can be suppressed when determining the occurrence of an abnormality in the rotating equipment 10, thereby improving the accuracy of the determination. 【0114】 Next, the results of implementing the abnormality detection device and abnormality detection method for rotating equipment in this embodiment will be described. First, the inventors artificially introduced a defect (flaw) into a part of the bearing of the first support part 5a of the rotating equipment 10 shown in Figure 1, and then performed an abnormality detection of the rotating equipment 10. This embodiment (Embodiment 1) was carried out with respect to the rotating equipment 10 when it was offline and its actual operation was stopped. 【0115】 A three-phase induction motor was used as the drive source unit 2. Specifically, a three-phase induction motor with an output of 0.75 kW, AC 200 V, 6 poles, and a rated rotational speed of 1200 r / min was used. Furthermore, an experimental device for generating a load on the drive source unit 2 was used as the drive device 4. Specifically, a device was manufactured to generate a load on the drive source unit 2 by applying a radial load (circumferential direction of the rotating shaft 3) to the rotating shaft 3, and this was applied to this embodiment. For the support unit 5, an NSK self-aligning roller bearing was used as the roller bearing. 【0116】 In this embodiment, the first support section 5a used a bearing with scratches on the outer ring and a bearing with scratches on the cage. Specifically, the size of the artificial scratches on the outer ring was approximately 3 mm in length and 0.5 mm in width. The size of the artificial scratches on the cage was approximately 0.5 mm in length and 0.5 mm in width. These components were lubricated and then assembled into the first support section 5a. 【0117】Anomaly detection was performed using an anomaly detection device 40 (see Figure 2). The acquisition unit 41 acquired the load current value at the drive source unit 2 via the current transformer 20 and the ammeter 30 at a time period of 100 μs. The calculation unit 42 performed frequency analysis of the load current value every 4096 pieces of information on the load current value, calculated the spectral intensity P of the higher-order frequency NΩ (where N is an odd number) with respect to the rotation frequency Ω of the drive source unit 2, and transmitted it to the identification unit 43 every 500 ms. 【0118】 The identification unit 43 identified statistical information D regarding the time variation of spectral intensity P every 10 data points related to spectral intensity P obtained from the calculation unit 42. The standard deviation Sd of the time variation of spectral intensity P was applied as statistical information D. The identification unit 43 identified the standard deviation Sd of spectral intensity P as statistical information D every 5 seconds and transmitted it to the determination unit 44. 【0119】 In the determination unit 44, the standard deviation Sn when using a normal bearing without defects in the first support part 5a was predetermined, and the threshold DT was set to 2.5Sn. A determination was then made based on a comparison between the standard deviation Sd and the threshold DT. When the standard deviation Sd of the spectral intensity P at higher-order frequencies NΩ became greater than or equal to the threshold DT, that is, when the standard deviation Sd became 2.5 times or more greater than the normal value, the rotating equipment 10 was determined to be "abnormal". The standard deviation Sn corresponds to the statistical normal information DS. 【0120】 Here, the time variation of spectral intensity P calculated by frequency analysis of the load current value will be explained using Figure 9. Specifically, Figure 9(a) shows the frequency-time variation of spectral intensity P in a specific frequency range when using the first support part 5a equipped with a bearing with a defect on the outer ring. On the other hand, Figure 9(b) shows the frequency-time variation of spectral intensity P in a specific frequency range when using the first support part 5a equipped with a bearing without a defect on the outer ring (a normal bearing). 【0121】More specifically, Figure 9(a) shows the frequency-time variation of spectral intensity P, calculated by frequency analysis of the load current value, when a bearing with a defect on the outer ring is used, with the frequency range limited to 400 to 530 Hz. That is, it shows the frequency-time variation of spectral intensity P (the change in the frequency at which spectral intensity P occurs with respect to time) at frequencies approximately 8.0 to 10.0 times the rotation frequency (50 Hz). The solid line in the figure shows the frequency-time variation at P = 41.7A, which is the highest spectral intensity P value in the frequency range of 400 to 530 Hz. 【0122】 Furthermore, Figure 9(b) shows the frequency-time variation of spectral intensity P, calculated by frequency analysis of the load current value, when a bearing without defects on the outer ring of the bearing is used, and the frequency range is limited to 400 to 530 Hz. The solid line in the figure shows the frequency-time variation at P = 28.1A, which is the highest value of spectral intensity P in the frequency range of 400 to 530 Hz. As shown in Figure 9(b), it was confirmed that when the rotating equipment 10 is operated with the bearing in a normal condition, the fluctuation of spectral intensity P in frequency bands higher than the rotation frequency (50 Hz) is small. 【0123】 In contrast, when a bearing with a defect on the outer ring was used, as shown in Figure 9(a), it was confirmed that the temporal variation of the spectral intensity P in the frequency band higher than the rotation frequency (50 Hz) became larger. From this result, it was confirmed that abnormalities in the rotating equipment 10 can be determined by focusing on the variation in the spectral intensity P of the load current value in the frequency band higher than the rotation frequency. 【0124】The statistical information D identified in this embodiment will be explained using Figure 10. Figure 10 shows the statistical information D of spectral intensity P at rotational frequency Ω (50 Hz) and higher-order frequency NΩ. Specifically, Figure 10 shows the standard deviation Sd as statistical information D of spectral intensity P at rotational frequency Ω and identified higher-order frequency NΩ (N = 9, 11, 15). The values ​​for the case where the outer ring is damaged ("damaged outer ring" in Figure 10) and the case where the cage is damaged ("damaged cage" in Figure 10) are shown as the standard deviation Sd of spectral intensity P at each frequency. The values ​​for the case where a normal bearing is used ("normal" in Figure 10) are also shown as the standard deviation Sn of spectral intensity P at each frequency. 【0125】 As shown in Figure 10, at rotational frequency Ω, the standard deviation Sd values ​​for "damaged outer ring" and "damaged cage" are larger than the standard deviation Sn value for "normal," but the difference in standard deviation is small. On the other hand, at higher-order frequencies NΩ (N = 9, 11, 15), it was confirmed that the standard deviation Sd values ​​for "damaged outer ring" and "damaged cage" are significantly larger than the standard deviation Sn value for "normal." From these results, it can be concluded that misjudgments are likely to occur when abnormalities are judged based on the standard deviation of spectral intensity P at rotational frequency Ω. 【0126】 Here, with respect to the standard deviation of the spectral intensity P at rotational frequency Ω and higher-order frequency NΩ, the ratio of the standard deviation Sd value in the "defective outer ring" and "defective cage" cases to the standard deviation Sn value in the "normal" case (-: dimensionless number) will be explained using Figure 11. In Figure 11, the values ​​shown for each frequency are the ratio of the standard deviation Sd value in the "defective outer ring" case to the standard deviation Sn value in the "normal" case, and the ratio of the standard deviation Sd value in the "defective cage" case to the standard deviation Sn value in the "normal" case, for each frequency. 【0127】As shown in Figure 11, at rotational frequency Ω, the ratio of the standard deviation Sd value in the "outer ring has a defect" and "cage has a defect" states to the standard deviation Sn value in the "normal" state is small. Therefore, at rotational frequency Ω, it is difficult to determine whether the state has become "outer ring has a defect" or "cage has a defect" compared to the "normal" state. 【0128】 In contrast, at higher-order frequencies NΩ (N = 9, 11, 15), the ratio of the standard deviation Sd for "defects on the outer ring" and "defects on the cage" is large compared to the standard deviation Sn for "normal" bearings. Therefore, by focusing on the standard deviation of spectral intensity P at higher-order frequencies NΩ, abnormalities in the bearing can be accurately determined. 【0129】 For example, regarding the setting of the threshold DT for the standard deviation Sd (statistical information D) at higher-order frequencies NΩ, the standard deviation σnormal (standard deviation Sn) in the "normal" state is used to define DT = Q × σnormal (where Q is a real number greater than 1.0). By setting Q to between 2.5 and 5.0, abnormalities in the rotating equipment 10 can be determined with high accuracy. 【0130】 In this case, when determining an anomaly, a threshold DT may be set for each "order" of higher frequencies. For example, at a higher frequency NΩ (N=9), the value of the standard deviation Sn at the 9th frequency may be taken as the standard deviation σnormal, and the value calculated as 2.5 × σnormal may be set as the threshold DT, and this threshold DT may be set as the threshold for the standard deviation Sd at the 9th frequency. 【0131】 Alternatively, a common threshold DT may be set in the determination of anomalies. For example, first, the average value of all standard deviations Sn at the 9th, 11th, and 15th order is calculated. Then, the average value of the calculated standard deviations Sn is taken as the standard deviation σnormal, and the value calculated as 2.5 × σnormal is taken as the threshold DT, and this threshold DT may be set as the threshold for the standard deviation Sd at all higher-order frequencies. 【0132】Next, we will explain the results of implementing the abnormality detection device and abnormality detection method for the rotating equipment in this embodiment during actual online operation of the rotating equipment 10. In this embodiment (Embodiment 2), the implementation focused on rotating equipment installed in a hot rolling mill for steel materials and driven as a conveying table device for steel materials. Specifically, the drive device 4 in the rotating equipment 10 was adapted for a steel material conveying device. 【0133】 A three-phase induction motor was used as the drive source unit 2. Specifically, a three-phase induction motor with an output of 12 kW, AC 330 V, 4 poles, and a rated rotational speed of 2000 r / min was used. The support unit 5 was a roller bearing, and a deep groove ball bearing was used. The bearing used in the support unit 5 was one that had been continuously used since the operation of the rotating equipment 10, and was selected to have a risk of malfunction. Hereinafter, in this embodiment, a case in which a determination of "abnormality occurred" was reached as a result of using a configuration that has a risk of malfunction in the support unit 5 will be referred to as "abnormality." 【0134】 Anomaly detection was performed using an anomaly detection device 60 (see Figure 5). The acquisition unit 61 acquired the load current value at the drive source unit 2 via the current transformer 20 and the ammeter 30. The calculation unit B was configured with an FPGA, and the analysis unit C was configured with a PLC. The acquisition unit 61 of the calculation unit B acquired the load current value at the drive source unit 2 with a time period of 100 μs. Every 4096 pieces of information regarding the load current value, the calculation unit 62 performed frequency analysis of the load current value, calculated the spectral intensity P of the higher-order frequency NΩ (where N is an odd number) with respect to the rotation frequency Ω of the drive source unit 2, and transmitted it to the identification unit 63 of the analysis unit C every 500 ms. 【0135】 The identification unit 63 identified statistical information D regarding the time variation of spectral intensity P every 10 data points related to spectral intensity P obtained from the calculation unit 62. The standard deviation Sd of the time variation of spectral intensity P was applied as statistical information D. The identification unit 63 identified the standard deviation Sd of spectral intensity P as statistical information D every 5 seconds and transmitted it to the determination unit 64. 【0136】The calculation unit 62 selected all odd-numbered higher-order frequencies from the third to the ninth order and calculated the corresponding spectral intensity P. The identification unit 63 obtained information on the spectral intensity P of the third, fifth, seventh, and ninth higher-order frequencies calculated by the calculation unit 62 and identified the standard deviation Sd (statistical information D) of the spectral intensity P corresponding to each order. 【0137】 The determination unit 64 then pre-identifies the standard deviation Sn (statistical normal information DS) for the normal state at the 3rd, 5th, 7th, and 9th higher-order frequencies, and sets a threshold value DT of 2.5 times the standard deviation Sn at each higher-order frequency during normal conditions, and makes a determination of abnormality. Specifically, the threshold value DT for the standard deviation Sd (statistical information D) is defined as DT = Q × σnormal (where Q is a real number greater than 1.0), using the standard deviation σnormal (standard deviation Sn) in the "normal" state, and Q is set to 2.5. Hereinafter, in this embodiment, the case using a configuration that does not pose a risk of abnormality occurring in the support unit 5 will be referred to as "normal conditions". 【0138】 The determination unit 64 determined that an abnormality had occurred in the rotating equipment 10 if any of the standard deviations Sd of the spectral intensities P of the third, fifth, seventh, and ninth higher frequencies exceeded the threshold DT. In this embodiment, abnormality determination using the abnormality determination device 60 was continuously performed for one year while the rotating equipment 10 was in operation (online). 【0139】 The standard deviation of spectral intensity P for each frequency identified in this embodiment will be explained with reference to Figure 12. As shown in Figure 12, in this embodiment, the identification unit 63 identified the standard deviation of spectral intensity P for a continuous range of frequencies. 【0140】 Figure 12(a) shows the standard deviation Sn of spectral intensity P at the third, fifth, seventh, and ninth higher-order frequencies identified by the specific unit 63 for the "normal" state. Figure 12(b) shows the standard deviation Sd of spectral intensity P at the third, fifth, seventh, and ninth higher-order frequencies identified by the specific unit 63 for the "abnormal" state. 【0141】As shown in Figure 12, the standard deviation Sd identified under "abnormal conditions" is larger than the standard deviation Sn identified under "normal conditions," particularly at higher frequencies of the third, fifth, seventh, and ninth orders. 【0142】 Regarding the identified standard deviation, the results of calculating the ratio of the standard deviation Sd under "abnormal conditions" to the standard deviation Sn under "normal conditions" (-: dimensionless number) will be explained using Figure 13. Specifically, Figure 13 shows the ratio of the standard deviation Sd to the standard deviation Sn at rotational frequency and higher-order frequencies of the 3rd, 5th, 7th, and 9th order. 【0143】 As shown in Figure 13, at the third, fifth, seventh, and ninth order frequencies, the standard deviation Sd during "abnormal conditions" is larger than the standard deviation Sn during "normal conditions." Furthermore, at the fifth and ninth order frequencies, it was confirmed that the value exceeded the value with the vertical axis set to "2.5" (see the dotted line in the figure). That is, at the fifth and ninth order frequencies, considering the threshold DT set in advance as DT = 2.5 × σnormal, it was confirmed that the standard deviation Sd exceeds the threshold DT. Therefore, in this embodiment, it was determined that an abnormality had occurred in the rotating equipment 10. 【0144】 Based on this determination, the operation of the rotating equipment 10 was stopped and the rotating equipment 10 was inspected, and it was found that a crack had occurred in the spring constituting the coupling of the rotating shaft 3 that connects the drive source unit 2 and the first support unit 5a. In other words, the abnormality detection method for the rotating equipment 10 using the abnormality detection device 60 prevented a situation in which the coupling would have broken and caused a major operational problem. Therefore, the abnormality detection method for the rotating equipment 10 in this embodiment prevented the escalation of operational problems caused by damage to the coupling, etc. 【0145】 Next, we will explain the results of implementing an abnormality detection device and abnormality detection method for rotating equipment using a configuration in which a control device 80 is added to the rotating equipment 10 and abnormality detection device 40 (see Figure 6). In this embodiment (Embodiment 3), a hydraulic pump was applied to the drive device 4 in the rotating equipment 10. The power supply unit 1 had a rated voltage of 400V and a rated output of 132kW. 【0146】 In this embodiment, first, the load current value of the drive source unit 2 was acquired during the period when the rotating equipment 10 was operating normally (normal operation) and the control device 80 was transmitting the first load signal. The acquired load current value was then used to identify statistical normal information DS. Specifically, as statistical normal information DS, the standard deviation Sn of the normal state at the 5th, 7th, and 9th order higher frequencies NΩ with respect to the rotation frequency Ω of the drive source unit 2 was calculated. The calculated standard deviation Sn of the normal state is shown in Figure 14. 【0147】 In this embodiment, when determining abnormalities in the rotating equipment 10, a threshold value DT was set to 5.0 times the standard deviation Sn of each higher-order frequency NΩ under normal conditions. Subsequently, during the operation of the rotating equipment 10 (online), the standard deviation Sd of the spectral intensity P at the 5th, 7th, and 9th higher-order frequencies NΩ with respect to the rotation frequency Ω was calculated. In this embodiment, if any of the standard deviations Sd of the spectral intensity P at the 5th, 7th, and 9th higher-order frequencies NΩ exceeded the threshold value DT, it was determined that an abnormality had occurred in the rotating equipment 10. 【0148】 Here, before the supply of grease (described later), the ratio of the standard deviation Sd during "abnormal conditions" to the standard deviation Sn during "normal conditions" is calculated, as shown in Figure 15. In Figure 15, the vertical axis represents the standard deviation Sn during "normal conditions". The value shown at the top of the graph for each higher frequency represents the ratio of the standard deviation Sd during "abnormal conditions" to the standard deviation Sn during "normal conditions". As shown in Figure 15, at the 9th higher frequency relative to the rotation frequency Ω of the drive source unit 2, the ratio of the standard deviation Sd during "abnormal conditions" to the standard deviation Sn during "normal conditions" became greater than or equal to the threshold DT. For this reason, it was determined that an abnormality had occurred in the rotating equipment 10. 【0149】 Subsequently, the person in charge of operations stopped the operation of the rotating equipment 10 and inspected the support section 5. It was confirmed that there was insufficient grease in the bearing section of the support section 5. Therefore, the pump that supplies grease to the bearing section of the support section 5 was adjusted, and a sufficient amount of grease was supplied to the bearing section. 【0150】 The inventors, after supplying sufficient grease to the support part 5, resumed operation of the rotating equipment 10 and recalculated the standard deviation Sd of the spectral intensity P at the 5th, 7th, and 9th higher-order frequencies NΩ with respect to the rotation frequency Ω. Then, for each higher-order frequency NΩ, they calculated the ratio of the standard deviation Sd under "abnormal conditions" to the standard deviation Sn under "normal conditions". Figure 16 shows the results of calculating the ratio of the standard deviation Sd under "abnormal conditions" to the standard deviation Sn under "normal conditions" after supplying grease to the support part 5. 【0151】 In Figure 16, the vertical axis represents the standard deviation Sn under "normal conditions." The value shown at the top of the graph for each higher frequency represents the ratio of the standard deviation Sd under "abnormal conditions" to the standard deviation Sn under "normal conditions." As shown in Figure 16, it was confirmed that supplying grease to the support part 5 made the standard deviation Sd of the spectral intensity P at higher frequencies NΩ equal to or smaller than the standard deviation Sn under normal conditions. In other words, supplying grease to the support part 5 suppressed the time fluctuation of the spectral intensity at higher frequencies, and as a result of suppressing the development of damage that occurs in the very early stages of abnormal stage 1, normal operation of the rotating equipment 10 became possible. 【0152】 In this case, if the supply of grease to the support section 5 of the rotating equipment 10 was insufficient, the lubrication inside the support section 5 would be impaired, potentially causing seizing on the sliding surface and leading to damage to the support section 5. However, in this embodiment, the abnormality detection of the rotating equipment 10 allowed for appropriate action to be taken before damage occurred to the support section 5, thus preventing operational problems with the rotating equipment 10. 【0153】Here, the inventors calculated the average value (RMS value) of spectral intensity P under "normal" and "abnormal" conditions as reference for the examples. The calculated average value (RMS value) of spectral intensity P will be explained using Figure 17. Specifically, Figure 17(a) shows the average value of spectral intensity P at the 3rd, 5th, 7th, and 9th higher frequencies calculated under "normal" conditions. Figure 17(b) shows the average value of spectral intensity P at the 3rd, 5th, 7th, and 9th higher frequencies calculated under "abnormal" conditions. 【0154】 As shown in Figures 17(a) and 17(b), the average spectral intensity P calculated under "abnormal" conditions tends to be slightly higher than the average spectral intensity P calculated under "normal" conditions. However, no clear difference was observed between "normal" and "abnormal" conditions regarding the average spectral intensity P. 【0155】 Specifically, for the average values ​​of spectral intensity P at the third, fifth, seventh, and ninth higher frequencies, the ratio of the values ​​in the "abnormal" state to the values ​​in the "normal" state was 1.11, 0.93, 1.61, and 1.61, respectively. Therefore, it is conceivable to set the threshold DT used for determining abnormalities to approximately 1.5, for example, for the ratio of the "abnormal" state to the "normal" state. However, in that case, the average value of spectral intensity P in the "normal" state also changes due to changes in the operating conditions of the rotating equipment 10, making it difficult to accurately determine abnormalities. 【0156】 Next, the inventors verified the time-dependent fluctuations of the load current value under "normal" and "abnormal" conditions as reference for the embodiments. The time-dependent fluctuations of the load current value under "normal" and "abnormal" conditions will be explained using Figure 18. Specifically, Figure 18(a) shows the time course of the load current value under "normal" conditions. Figure 18(b) shows the time course of the load current value under "abnormal" conditions. 【0157】The load current values ​​shown in Figure 18 are the load current values ​​measured by the ammeter 30 when the previously described embodiment (Embodiment 3) was carried out. The load current values ​​shown in Figure 18 are the load current values ​​obtained by measuring the U-phase current between the power supply unit 1, which is an inverter power supply, and the drive source unit 2, which is a three-phase induction motor. Specifically, Figure 18(a) is a diagram showing the current value when statistical normal information DS is identified from the load current value in the "normal" state. Figure 18(b) is a diagram showing the time evolution of the load current value measured after an abnormality in the rotating equipment 10 was determined during the operation of the rotating equipment 10. 【0158】 As shown in Figure 18, it was observed that the fluctuation in the load current value after an abnormality was detected (0.22A) tended to be larger than the fluctuation in the load current value during normal operation (0.11A). Therefore, it is considered possible to determine that an abnormality has occurred in the rotating equipment 10 when a load current value exceeding a predetermined current is measured, using the load current value during normal operation as a reference and setting a threshold value for the fluctuation in the load current value. 【0159】 However, as shown in Figure 18, the load current value after an abnormality is detected remains at approximately 1.0 to 2.0 times the load current value during normal operation. In other words, when setting a threshold value based on the load current value during normal operation, the threshold value will be set to approximately 1.0 to 2.0 times the load current value during normal operation. In this case, because the set threshold value is small, there is a possibility of misjudging abnormalities caused by unexpected factors such as disturbances during the operation of the rotating equipment 10. 【0160】 In contrast, in the previous embodiment (Embodiment 3), the threshold value DT was set to 5.0 times the standard deviation Sn of each higher-order frequency under normal conditions, allowing for the determination of abnormalities in the rotating equipment 10. That is, in the abnormality determination according to the previous embodiment (Embodiment 3), the operating conditions under abnormal conditions can be identified (determined) more clearly than under normal conditions, and erroneous determination of abnormal conditions can be suppressed. 【0161】1 Power supply unit 2 Drive source unit 3 Rotating shaft 4 Drive device 5 Support unit 5a First support unit 5b Second support unit 20 Current transformer 30 Ammeter 40, 60 Anomaly detection device 41, 61 Acquisition unit 42, 62 Calculation unit 43, 63 Identification unit 44, 64 Judgment unit 45, 65 Input unit 46, 66 Output unit 47, 67 Storage unit 50 Terminal device 70 Higher-level computer 80 Control unit A Processing unit B Calculation unit C Analysis unit

Claims

1. A rotating equipment abnormality determination device for determining abnormalities in rotating equipment having a drive source unit that generates rotational power from a power supply unit, a rotating shaft that rotates by receiving the rotational power from the drive source unit, a drive device that is driven by receiving the rotational power from the rotating shaft, and a support unit that supports the rotating shaft, comprising: an acquisition unit that acquires a load current value in the drive source unit; a calculation unit that performs frequency analysis on the load current value acquired by the acquisition unit and calculates the spectral intensity of higher-order frequencies with respect to the rotation frequency in the drive source unit; an identification unit that identifies statistical information relating to the time variation of the spectral intensity of higher-order frequencies calculated by the calculation unit; and a determination unit that determines an abnormality in the rotating equipment based on the statistical information identified by the identification unit.

2. The abnormality detection device for rotating equipment according to claim 1, wherein the higher-order frequency is a frequency of the third order or higher and the 21st order or lower with respect to the rotation frequency in the drive source unit.

3. The abnormality detection device for rotating equipment according to claim 1 or 2, wherein the statistical information is the standard deviation or variance relating to the time variation of the spectral intensity of the higher-order frequencies.

4. A method for determining abnormalities in rotating equipment, comprising: a drive source unit that generates rotational power from power supply units; a rotating shaft that rotates by receiving the rotational power from the drive source unit; a drive device that is driven by receiving the rotational power from the rotating shaft; and a support unit that supports the rotating shaft, the method comprising: an acquisition step of acquiring a load current value in the drive source unit; a calculation step of performing frequency analysis on the load current value acquired in the acquisition step and calculating the spectral intensity of higher-order frequencies with respect to the rotational frequency in the drive source unit; an identification step of identifying statistical information relating to the time variation of the spectral intensity of higher-order frequencies calculated in the calculation step; and a determination step of determining an abnormality in the rotating equipment based on the statistical information identified in the identification step.

5. The method for determining abnormalities in rotating equipment according to claim 4, wherein the higher-order frequency is a frequency of the third order or higher and the 21st order or lower with respect to the rotation frequency in the drive source unit.

6. The method for determining abnormalities in rotating equipment according to claim 4 or 5, wherein the statistical information is the standard deviation or variance relating to the time variation of the spectral intensity of the higher-order frequencies.

7. The method for determining an abnormality in a rotating equipment according to any one of claims 4 to 6, wherein the determination step determines an abnormality in the rotating equipment based on the statistical information identified in the identification step and the statistical normal information collected during the normal operation of the rotating equipment.

8. The method for determining abnormalities in rotating equipment according to any one of claims 4 to 7, wherein the acquisition step is performed after receiving a first load signal transmitted when a current command value less than or equal to a preset reference current command value is transmitted to the power supply unit.

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