JP2018136734A - Abnormality determination device, abnormality determination system, abnormality determination method, and abnormality determination program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely determine abnormalities of fans without reducing the cooling performance even in a layout of fans that triggers corotation.SOLUTION: Disclosed is an abnormality determination device for determining abnormalities of a plurality of second fans provided in a position to corotate by a first fan, which: compares the rotation frequencies of the plurality of second fans; and determines, when any deviation is observed in the rotation frequencies amongst the second fans, that the plurality of second fans have caused abnormalities.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an abnormality determination device, an abnormality determination system, an abnormality determination method, and an abnormality determination program.

  As the performance of the server apparatus is improved, the fan volume for cooling the server apparatus is increasing year by year. The fans used for cooling the modular server device 500 as shown in FIG. 10 have front fans 131 to 134 and rear fans 141 to 144 so that a necessary air volume can be secured even if one fan fails during operation. Are arranged in series so that their air blowing surfaces are in the same direction and parallel to each other. When the front fans 131 to 134 and the rear fans 141 to 144 are high air volume fans, for example, it is assumed that the rear fan 142 of the rear fans 141 to 144 has failed. At this time, because of the air volume from the front fan 132 present at the position facing the failed rear fan 142, the failed rear fan 142 rotates at a considerably high rotational speed.

  In a general server device, a predetermined threshold rotational speed is set, and if the threshold rotational speed is less than that, it is determined that the fan has failed. However, as the air volume increases, the fan rotates at a higher rotational speed. Therefore, it is difficult to detect a failure by such a determination method. Therefore, for example, techniques described in Patent Document 1 and Patent Document 2 have been proposed. In the technique described in Patent Document 1, it is determined whether the fan to be diagnosed has failed by reducing the number of rotations of the fan causing the co-rotation phenomenon. The technique described in Patent Document 2 includes an energization current detection circuit that detects an energization current of the fan motor and an abnormal rotation speed detection circuit that detects an abnormality in the rotation speed of the fan. When the current cannot be detected, a failure is detected by the energization current detection circuit.

JP 2010-073995 A Japanese Patent Laid-Open No. 2003-111478

  However, in the technique described in Patent Document 1, it is necessary to reduce the number of rotations of the fan that generates the phenomenon of co-rotation, so that a failure of the fan can be detected during operation of the server device that has increased in heat generation. However, although it is temporary, there is a problem that it is not appropriate to lower the cooling performance.

  Further, in the technique described in Patent Document 2, when an abnormality occurs in the energization current, a fan abnormality can be detected, but the rotation of the fan itself is not a target for abnormality detection. For this reason, there is a problem that when an abnormality occurs in the fan due to a cause other than the energizing current and the fan rotates together, the abnormality cannot be accurately detected.

  The present invention has been made to solve the above-described problems, and the object of the present invention is to accurately determine the abnormality of a fan without degrading the cooling performance even in the arrangement of the fans where co-rotation occurs. An object of the present invention is to provide an abnormality determination device, an abnormality determination system, an abnormality determination method, and an abnormality determination program.

  In order to solve the above problem, according to one aspect of the present invention, there is provided an abnormality determination device that determines an abnormality of a plurality of second fans provided at a position that rotates together with the first fan. The rotation speeds of the fans are compared, and when there is a difference in the rotation speeds between the second fans, it is determined that the plurality of second fans are abnormal.

  In order to solve the above-described problem, an aspect of the present invention provides a fan unit including a first fan and a plurality of second fans provided at positions co-rotating with the first fan, and the fan In an abnormality determination system comprising an abnormality determination device for determining an abnormality of the plurality of second fans of a unit, the abnormality determination device compares the rotation speeds of the plurality of second fans, When there is a discrepancy in the number of rotations, the plurality of second fans are determined to be abnormal.

  In order to solve the above problem, according to one aspect of the present invention, there is provided an abnormality determination method for determining an abnormality of a plurality of second fans provided at positions co-rotated by a first fan. The rotation speeds of the fans are compared, and when there is a difference in the rotation speeds between the second fans, it is determined that the plurality of second fans are abnormal.

  In order to solve the above problem, according to an aspect of the present invention, an abnormality determination program includes a plurality of computers that determine an abnormality of a plurality of second fans provided at a position that rotates together with the first fan. Comparing the rotational speeds of the second fans, and executing a procedure for determining that there is an abnormality in the plurality of second fans when the rotational speeds between the second fans are different. To do.

  According to the present invention, it is possible to accurately determine an abnormality of a fan without degrading the cooling performance even in the arrangement of fans where co-rotation occurs.

It is a block diagram which shows the structure of the abnormality determination system by one Embodiment of this invention. It is a figure which shows the example which applied the abnormality determination system in the embodiment to a modular server apparatus. It is a figure which shows the data structure of the threshold value memory | storage part by the embodiment. It is a flowchart which shows the flow of the process by the abnormality determination apparatus of the embodiment. It is a figure which shows the determination result in case any one rear fan in the same embodiment has abnormality. It is a figure which shows the determination result in case all the fans are normal in the same embodiment. It is a figure which shows the determination result in case any one rear fan has abnormality in a general method. It is a figure which shows the determination result in case all the fans are normal in a general method. It is a figure which shows an example of arrangement | positioning of a rear fan and a front fan. It is a figure which shows arrangement | positioning of the front fan and back fan in a modular server apparatus. It is a figure which shows the minimum structure of an abnormality determination apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an abnormality determination system 1 according to an embodiment of the present invention. The abnormality determination system 1 includes a fan unit 50 and an abnormality determination device 10. The fan unit 50 includes a temperature sensor 20, front fans 31 to 34, and rear fans 41 to 44. The fan unit 50 is inserted into the modular server device 100 as shown in FIG. 2, for example, and a plurality of server modules inserted into slots of the modular server device 100 by blowing air in the modular server device 100 to create a wind flow. 70 is cooled. The temperature sensor 20 detects the temperature in the fan unit 50 or the housing of the modular server device 100. The front fans 31 to 34 and the rear fans 41 to 44 are arranged so that the air blowing surfaces are in the same direction and the air blowing surfaces are arranged in parallel so that a necessary air volume can be secured even if a failure occurs during operation. Are arranged in series. Therefore, even if an abnormality occurs in any of the rear fans 41 to 44, the rear fans 41 to 44 that are abnormal due to the wind blown by the front fans 31 to 34 existing at positions facing each other rotate together. Will occur.

  The abnormality determination device 10 is an abnormality determination device that determines the abnormality of a plurality of second fans provided at positions that rotate together with the first fan. The abnormality determination device 10 compares the rotation speeds of the plurality of second fans, and determines that there is an abnormality in the plurality of second fans when there is a difference in the rotation speeds between the second fans.

The abnormality determination device 10 includes at least a determination target selection unit 12 that selects any one second fan as a determination target. The determination target selection unit 12 determines that the determination target fan is abnormal when the rotation speed of the second fan to be determined is different from the fan rotation speed of the other second fan by a predetermined value or more. .
Details of the abnormality determination device 10 will be described below.

  The abnormality determination device 10 includes a rotation speed detection unit 11, a determination target selection unit 12, an average value calculation unit 13, a threshold storage unit 14, and an abnormality determination unit 15. The rotational speed detection unit 11 is connected to a sensor that detects the rotational speed of an encoder or the like provided in each of the rear fans 41 to 44, and detects the rotational speed of each of the rear fans 41 to 44. The determination target selection unit 12 selects one of the fans to be determined from the rear fans 41 to 44. The average value calculation unit 13 calculates the average value of the rotational speeds of the rear fans 41 to 44 other than any one of the rear fans 41 to 44 selected by the determination target selection unit 12. For example, when the determination target selection unit 12 selects the rear fan 42, the average value calculation unit 13 calculates the average value of the rotation speeds of the rear fans 41, 43, and 44.

  The threshold storage unit 14 has the data configuration shown in FIG. 3 and includes items of “environment temperature” and “abnormality determination threshold”. In the “environment temperature”, information indicating a temperature range in the fan unit 50 is written. In the example of FIG. 3, as information indicating the temperature range in the fan unit 50, for example, a case where the temperature is 25 ° C. or less is “25 ° C. environment”, and a case where the temperature is over 25 ° C. “When the temperature exceeds 30 ° C.,“ 35 ° C. environment ”is written. In the item of “abnormality determination threshold”, the number of revolutions serving as an abnormality judgment threshold corresponding to each environmental temperature is written in units of [rpm (revolution per minute)], that is, in units of revolutions per minute. .

  The abnormality determination unit 15 uses, as an abnormality determination value, a difference between the average value of the rotation speeds of the rear fans 41 to 44 other than the determination target calculated by the average value calculation unit 13 and the rotation speed of the determination target rear fans 41 to 44. calculate. In addition, the abnormality determination unit 15 reads an abnormality determination threshold value corresponding to the temperature detected by the temperature sensor 20 from the threshold storage unit 14, and determines whether or not the calculated abnormality determination value is larger than the read abnormality determination threshold value. . Further, when the calculated abnormality determination value is larger than the read abnormality determination threshold, the abnormality determination unit 15 determines that the determination target rear fans 41 to 44 are abnormal.

  Next, processing by the abnormality determination device 10 will be described with reference to the flowchart shown in FIG. The rotation speed detector 11 detects the rotation speed of each of the rear fans 41 to 44 (step S1). The determination target selection unit 12 selects any one of the rear fans 41 to 44 that is not determined as a determination target. Here, first, the rear fan 41 is selected (step S2). The average value calculation unit 13 calculates the average value of the rotation speeds of the rear fans 42 to 44 other than those selected by the determination target selection unit 12 (step S3). The abnormality determination unit 15 calculates a difference between the average rotation number calculated by the average value calculation unit 13 and the rotation number of the rear fan 41 selected by the determination target selection unit 12 as an abnormality determination value (step S4).

  The abnormality determination unit 15 reads an abnormality determination threshold value corresponding to the temperature value acquired from the temperature sensor 20 from the threshold storage unit 14. For example, when the temperature indicated by the temperature sensor 20 is 28 ° C., “6500 rpm” of “abnormality determination threshold” in which the item “environment temperature” is “30 ° C. environment” is read. The abnormality determination unit 15 determines whether or not the calculated abnormality determination value is larger than the read abnormality determination threshold value (step S5). If the abnormality determination unit 15 determines that the calculated abnormality determination value is larger than the read abnormality determination threshold value (step S5, Yes), the rear fans 41 to 44 selected by the determination target selection unit 12 are abnormal. Output (step S6), the process ends.

  On the other hand, when the abnormality determination unit 15 determines that the calculated abnormality determination value is not larger than the read abnormality determination threshold (No in step S5), all the rear fans 41 to 44 are selected by the determination target selection unit 12. It is determined whether or not it has been done (step S7). If the abnormality determination unit 15 determines that all the rear fans 41 to 44 have been selected by the determination target selection unit 12 (step S7, Yes), the process ends. On the other hand, if the abnormality determination unit 15 determines that all the rear fans 41 to 44 are not selected by the determination target selection unit 12 (Yes in Step S7), the process from Step S2, that is, the determination target selection unit 12 performs Then, any one of the rear fans 42 to 44 that are not determined is selected, and the processes after step S3 are performed. For example, when the rear fan 41 is the first determination target, the determination target selection unit 12 may sequentially select the rear fan 42 as the next determination target, or may select at random.

(Explanation of judgment result)
By performing the processing shown in FIG. 4, for example, the results shown in FIGS. 5 and 6 are obtained. The example illustrated in FIG. 5 is an example in which the processing illustrated in FIG. 4 is applied in a state where an abnormality has occurred in the rear fan 42 and the rear fan 42 rotates together with the wind from the front fan 32. . The rotational speed of the rear fan 42 is detected by the rotational speed detection unit 11 as 2000 [rpm] in a 25 ° C. environment, 5000 [rpm] in a 30 ° C. environment, and 8000 [rpm] in a 35 ° C. environment. On the other hand, the other rear fans 41, 43, and 44 have a rotational speed detection unit of 7200 [rpm] in a 25 ° C. environment, 12500 [rpm] in a 30 ° C. environment, and 16800 [rpm] in a 35 ° C. environment. 11 is detected.

  Therefore, when the rear fan 42 is selected as a determination target by the determination target selection unit 12, the average value calculation unit 13 sets the average value of the rotational speeds of the rear fans 41, 43, 44 as 7200 [ rpm] and 30 ° C., 12500 [rpm], and 30 ° C., 16800 [rpm].

(In the case of 25 ° C environment)
When the temperature indicated by the temperature sensor 20 is a 25 ° C. environment, the abnormality determination unit 15 calculates a difference between the average value of 7200 [rpm] and the rotation speed of the rear fan 42 of 2000 [rpm], that is, 5200 [rpm]. Calculated as an abnormality determination value. The abnormality determination unit 15 reads 4500 [rpm] corresponding to the case of the 25 ° C. environment from the threshold storage unit 14 as the abnormality determination threshold. Since the abnormality determination value 5200 [rpm] is larger than the abnormality determination threshold 4500 [rpm], the abnormality determination unit 15 outputs a determination result on the assumption that the rear fan 42 is abnormal.

  On the other hand, when the determination target selection unit 12 selects the rear fan 41 as a determination target, the average value calculation unit 13 calculates the average value of the rotational speeds of the rear fans 42, 43, and 44, that is, (2000 + 7200 + 7200) / 3. = 5467 [rpm] (rounded off after the decimal point). The abnormality determination unit 15 calculates 1733 [rpm], which is the difference between 7200 [rpm], which is the rotation speed of the rear fan 41, and 5467 [rpm], which is the average value, as an abnormality determination value. Since the abnormality determination value 1733 [rpm] is not larger than the abnormality determination threshold 4500 [rpm], the abnormality determination unit 15 determines that the rear fan 41 is not abnormal, that is, is normal, and the processing after step S7. I do.

(In case of 30 ℃ environment)
When the temperature indicated by the temperature sensor 20 is a 30 ° C. environment, the abnormality determination unit 15 calculates a difference between the average value of 12500 [rpm] and the rotational speed of the rear fan 42, which is 5000 [rpm], that is, 7500 [rpm]. Calculated as an abnormality determination value. The abnormality determination unit 15 reads 6500 [rpm] corresponding to the case of the 30 ° C. environment from the threshold storage unit 14 as the abnormality determination threshold. The abnormality determination unit 15 outputs the determination result because the rear fan 42 is abnormal because the abnormality determination value 7500 [rpm] is larger than the abnormality determination threshold 6500 [rpm].

  On the other hand, when the determination target selection unit 12 selects the rear fan 41 as the determination target, the average value calculation unit 13 calculates the average value of the rotational speeds of the rear fans 42, 43, and 44, that is, (5000 + 12500 + 12500) / 3. = 10000 [rpm]. The abnormality determination unit 15 calculates, as an abnormality determination value, 2500 [rpm] that is a difference between 12500 [rpm] that is the rotation speed of the rear fan 41 and 10000 [rpm] that is an average value. Since the abnormality determination value 2500 [rpm] is not larger than the abnormality determination threshold 6500 [rpm], the abnormality determination unit 15 determines that the rear fan 41 is not abnormal, that is, is normal, and the processing after step S7 I do.

(In the case of 35 ℃ environment)
When the temperature indicated by the temperature sensor 20 is an environment of 35 ° C., the abnormality determination unit 15 calculates a difference between the average value of 16800 [rpm] and the rotational speed of the rear fan 42 8000 [rpm], that is, 8800 [rpm]. Calculated as an abnormality determination value. The abnormality determination unit 15 reads 8000 [rpm] corresponding to the case of the 35 ° C. environment from the threshold storage unit 14 as the abnormality determination threshold. The abnormality determination unit 15 outputs the determination result because the rear fan 42 is abnormal because the abnormality determination value 8800 [rpm] is larger than the abnormality determination threshold value 8000 [rpm].

  On the other hand, when the determination target selection unit 12 selects the rear fan 41 as a determination target, the average value calculation unit 13 calculates the average value of the rotational speeds of the rear fans 42, 43, and 44, that is, (8000 + 16800 + 16800) / 3. = 13867 [rpm] (rounded off after the decimal point). The abnormality determination unit 15 calculates 2933 [rpm], which is the difference between 16800 [rpm], which is the rotational speed of the rear fan 41, and 13867 [rpm], which is the average value, as an abnormality determination value. Since the abnormality determination value 2933 [rpm] is not larger than the abnormality determination threshold value 8000 [rpm], the abnormality determination unit 15 determines that the rear fan 41 is not abnormal, that is, is normal, and the processing after step S7 I do.

  FIG. 6 shows a case where all the rear fans 41 to 42 are operating normally. In this case, the number of rotations of the rear fans 41 to 44 to be determined and the rear fans 41 to 44 other than the determination targets. The average value of the number of rotations is the same. Therefore, the value of the abnormality determination value, which is the difference between them, is 0, and none of them is larger than the abnormality determination threshold value. Therefore, it is determined that all the rear fans 41 to 44 are normal.

  On the other hand, in the general method described above, only one abnormality determination threshold value is used, and abnormality determination is performed based on whether the rotation speed of each of the rear fans 41 to 44 is smaller than the abnormality determination threshold value. ing. For example, as shown in FIG. 7, when the rear fan 42 is abnormal, if the abnormality determination threshold is 6500 [rpm], it is determined that the rear fan 42 is abnormal in the 25 ° C. environment and the 30 ° C. environment without error. To do. On the other hand, in the 35 ° C. environment, the rotation speed of the rear fan 42 is as high as 8000 [rpm], although it is co-rotating, it is erroneously determined to be normal. Further, as shown in FIG. 8, when the abnormality determination threshold is 8500 [rpm], it is determined that the rear fan 42 is normal in the 30 ° C. environment and the 35 ° C. environment without error. On the other hand, although the rear fan 42 is operating normally in the 25 ° C. environment, it is determined to be abnormal.

  With the configuration of the above embodiment, in the abnormality determination system 1, the front fans 31 to 34 as the first fan and the second fan that is arranged at a position that rotates together with the wind from the first fan. Rear fans 41 to 44 are provided. The determination target selection unit 12 selects any one of the rear fans 41 to 44. The average value calculation unit 13 calculates the average value of the rotation speeds of the rear fans 41 to 44 other than the rear fans 41 to 44 selected by the determination target selection unit 12. The abnormality determination unit 15 calculates a difference between the calculated average value and the rotational speed of the rear fans 41 to 44 selected by the determination target selection unit 12 as an abnormality determination value. The abnormality determination unit 15 acquires the temperature from the temperature sensor 20 and reads an abnormality determination threshold corresponding to the acquired temperature from the threshold storage unit 14. The abnormality determination unit determines that the rear fans 41 to 44 selected by the determination target selection unit 12 are abnormal when the calculated abnormality determination value is larger than the read abnormality determination threshold. Therefore, the abnormal rear fans 41 to 44 can be accurately determined without performing the erroneous determination as shown in FIGS. 7 and 8. Further, since the speed of the front fans 31 to 34 that cause the co-rotation is not reduced, it is possible to accurately determine the abnormality of the fan without reducing the cooling performance.

  Moreover, in the structure of said embodiment, even if abnormality generate | occur | produces in either of the front fans 31-34 and rotation of a fan stops, it is for the wind which the rear fans 41-44 which exist in the position which opposes blow. In addition, co-rotation occurs in the front fans 31 to 34 in which an abnormality has occurred. In this case, the configuration of the above embodiment may be applied to the front fans 31 to 34 with the rear fans 41 to 44 as the first fans and the front fans 31 to 34 as the second fans. That is, the rotation speed detection unit 11 detects the rotation speed of the front fans 31 to 34. The determination target selection unit 12 selects any one of the front fans 31 to 34 as a determination target. The average value calculation unit 13 calculates the average value of the rotation speeds of the front fans 31 to 34 other than the front fans 31 to 34 selected by the determination target selection unit 12. The abnormality determination unit 15 calculates a difference between the rotation speed of the front fans 31 to 34 selected by the determination target selection unit 12 and the average value calculated by the average value calculation unit 13 as an abnormality determination value. The abnormality determination unit 15 reads an abnormality determination threshold corresponding to the temperature indicated by the temperature sensor 20 from the threshold storage unit 14, and determines whether or not the calculated abnormality determination value is larger than the read abnormality determination threshold. When the calculated abnormality determination value is larger than the read abnormality determination threshold, the abnormality determination unit 15 determines that the front fans 31 to 34 selected by the determination target selection unit 12 are abnormal.

  Moreover, in the structure of said embodiment, based on the rotational speed of any one rear fan 41-44 and the average value of the rotational speed of the remaining rear fans 41-44, between the rear fans 41-44. Although an abnormality is detected from a difference caused by a variation in the rotational speed, the configuration of the present invention is not limited to the embodiment. Any method may be used as long as it is a method capable of detecting variations in the rotational speed of the rear fans 41 to 44, that is, the degree of deviation.

  In the above embodiment, an example in which the number of front fans 31 to 34 is four and the number of rear fans 41 to 44 is four is shown. However, the configuration of the present invention is not limited to this embodiment, and at least three or more. There may be four or more. Moreover, as shown in FIG. 9, the structure by which the one front fan 30 is arrange | positioned so as to oppose four of the rear fans 41-44 may be sufficient.

  Moreover, in said embodiment, although the number of the rear fans 41-44 is four, the structure of this invention is not restricted to the said embodiment. As the number of rear fans 41 to 44 increases, even if a fan other than the determination target includes a failed fan, the average value calculated for the fans other than the determination target is the normal fan. Since the rotational speed approaches, the range that can be selected as the abnormality determination threshold value is widened. Therefore, when there is an overlapping range of abnormality determination threshold ranges that can be selected at each temperature, the same abnormality determination value can be selected. In this case, the same abnormality determination value may be applied to all temperatures without using different abnormality determination values for each temperature.

  In the above embodiment, an example in which the fan unit 50 is applied to the modular server device 100 has been described. However, the configuration of the present invention is not limited to the embodiment. As shown in FIG. 1, a rack unit is configured by arranging fan units arranged in parallel in the vertical direction after being arranged in series in the horizontal direction like the front fans 31 to 34 and the rear fans 41 to 44. You may make it apply to.

  In the above embodiment, the temperature sensor 20 is provided in the fan unit 50. However, the temperature sensor 20 may be located in the vicinity of the rear fans 41 to 44, and not in the fan unit 50 but in a modular manner. The server device 100 may be provided.

  In addition, in the comparison of numerical values in the above-described embodiment, the comparison such as “whether it is greater than” is an example, and instead of the comparison “whether it is greater than”, the comparison “whether it is greater than or equal to” is performed. Also good.

FIG. 11 is a diagram showing the minimum configuration of the abnormality determination device.
The abnormality determination device 10 determines the abnormality of a plurality of second fans provided at positions that rotate together with the first fan. The abnormality determination device 10 compares at least the rotation speeds of the plurality of second fans, and determines that the plurality of second fans have an abnormality when there is a deviation in the rotation speeds between the second fans. What is necessary is just to provide the determination part 15. FIG.

  You may make it implement | achieve the abnormality determination apparatus 10 in embodiment mentioned above with a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed. Here, the “computer system” includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” dynamically holds a program for a short time like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. In this case, a volatile memory inside a computer system serving as a server or a client in that case may be included and a program held for a certain period of time. Further, the program may be a program for realizing a part of the above-described functions, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system. You may implement | achieve using programmable logic devices, such as FPGA (Field Programmable Gate Array).

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Abnormality determination system 10 Abnormality determination apparatus 11 Rotation speed detection part 12 Judgment object selection part 13 Average value calculation part 14 Threshold storage part 15 Abnormality determination part 50 Fan unit 20 Temperature sensor 31-34 Front fan 41-44 Rear fan

Claims (8)

An abnormality determination device for determining an abnormality of a plurality of second fans provided at positions co-rotated by a first fan,
The rotation speeds of the plurality of second fans are compared, and when there is a deviation in the rotation speeds between the second fans, it is determined that there is an abnormality in the plurality of second fans. Abnormality judgment device. A determination target selection unit that selects any one of the second fans as a determination target;
The determination target fan is determined to be abnormal when the rotation speed of the second fan to be determined is different from a fan rotation speed of another second fan by a predetermined value or more. Abnormality judgment device. An average value calculating unit for calculating an average value of the rotation speeds of the second fans other than the second fan selected as the determination target;
Based on the number of rotations of the second fan to be determined, the average value calculated by the average value calculation unit, and a predetermined abnormality determination threshold, the second fan to be determined is abnormal. An abnormality determination unit for determining whether or not,
The abnormality determination device according to claim 1, further comprising: A different abnormality determination threshold is associated with each piece of information indicating temperature,
The abnormality determination unit
The abnormality determination threshold corresponding to information indicating the temperature in the vicinity of the second fan, the fan rotation speed of the second fan to be determined, and the average value of the fan rotation speed calculated by the average value calculation unit The abnormality determination device according to claim 3, wherein it is determined whether or not the determination-target second fan is abnormal. The abnormality determination device according to any one of claims 1 to 4, wherein the first fan is a plurality of fans provided at positions facing each of the plurality of second fans. . A fan unit comprising a first fan and a plurality of second fans provided at positions co-rotating with the first fan, and an abnormality for determining an abnormality of the plurality of second fans of the fan unit An abnormality determination system comprising a determination device,
The abnormality determination device is
The rotation speeds of the plurality of second fans are compared, and when there is a deviation in the rotation speeds between the second fans, it is determined that there is an abnormality in the plurality of second fans. Abnormality judgment system. An abnormality determination method for determining an abnormality of a plurality of second fans provided at positions co-rotated by a first fan,
The rotation speeds of the plurality of second fans are compared, and when there is a deviation in the rotation speeds between the second fans, it is determined that there is an abnormality in the plurality of second fans. Abnormality judgment method. A computer for determining an abnormality of a plurality of second fans provided at positions co-rotated by the first fan,
To compare the rotational speeds of the plurality of second fans, and to execute a procedure for determining that there is an abnormality in the plurality of second fans when the rotational speeds between the second fans are different. Abnormality judgment program.

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