JP6478462B2 - Anomaly detection apparatus and method - Google Patents

Description

  The present invention relates to an abnormality detection apparatus and method for detecting an abnormality of a blower housed in a housing.

  For example, in a vehicle air conditioner, a blower for blowing air to a heat exchanger is mounted. In this blower, imbalance may occur in the impeller due to thermal deformation, wear, adhesion of foreign matter, distortion due to aging of materials, etc., and adverse effects such as mechanical vibration, generation of noise, or reduction in machine life. For this reason, the periodic inspection of the outdoor blower or the indoor blower has been conventionally performed. As the periodic inspection, a primary inspection in which an inspector performs an inspection and a secondary inspection in which a precise test is performed on the blower that is determined to be abnormal in the primary inspection are performed.

  In the primary inspection, an inspector determines by ear whether or not there is an abnormal noise or an increase in noise from the blower while the blower is mounted on the vehicle. In the secondary inspection, the fan that has been determined to have an abnormality in the primary inspection is removed from the vehicle and mounted on the test bench, and the fan is operated with the vibration meter attached to the motor of the blower. The final pass / fail judgment is performed based on the magnitude of the vibration value detected by the above. When it is determined in the secondary inspection that the blower is abnormal, the balance of the blades is adjusted and the normal state is restored.

  By the way, a method for detecting an abnormality of a blower in a general stationary air conditioner has been proposed (see, for example, Patent Document 1). Patent Document 1 discloses a method of detecting an abnormal state by collecting sound during operation of a blower using a microphone and comparing it with a normal value obtained in advance using a filter of an AR model that is a linear prediction method. ing.

JP-A-10-133740

  As described above, since the secondary inspection needs to remove the blower from the vehicle and takes time and effort, it is desirable to perform a quality determination with high accuracy in the primary inspection. Therefore, it is conceivable to perform abnormality detection by an acoustic method using a microphone as in Cited Document 1 in the primary inspection. However, it is necessary to install a microphone inside the housing, and the accuracy may be deteriorated due to noise or the like.

  The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide an abnormality detection apparatus and method that can easily and accurately detect an abnormality of a blower.

The abnormality detection device of the present invention is an abnormality detection device that detects an abnormality of a blower that is housed in a housing and has a motor that is fixed to the housing with a frame as an outer shell, and an impeller that is driven by the motor. A vibration detection unit that is attached to the housing and detects vibration generated in the housing when the blower is driven as a vibration signal; and a motor vibration component from the vibration signal detected by the vibration detection unit. Filtering processing is performed using a motor component extraction unit that extracts and a bandpass filter that is provided in the motor component extraction unit and passes a predetermined frequency band including the motor component. and filtering means for extracting as a motor component, the motor component extracted by the motor component extraction unit, also the correlation between the vibration of the vibration and the frame of the housing Is larger than determined set threshold to includes an abnormality determination unit that determines that the blower is abnormal, the center frequency of the bandpass filter is one that has been set to the frequency of the rotation speed of the motor.

  According to the abnormality detection device of the present invention, the vibration component of the blower is extracted from the vibration signal obtained from the housing, and the quality of the blower is determined based on the vibration component, so that the blower is not taken out of the housing or the housing. Since the abnormality can be detected without moving the body itself, the abnormality of the blower can be easily and accurately performed.

It is a schematic diagram which shows the abnormality detection apparatus which concerns on Embodiment 1 of this invention. It is a graph which shows an example of the vibration signal detected by the vibration detection part of FIG. It is a graph which shows the frequency characteristic of the band pass filter memorize | stored in the filter processing means of FIG. It is a graph which shows an example of the motor component extracted in the motor component extraction part of FIG. It is a schematic diagram which shows an example of the test apparatus which attached the vibration detection sensor to the flame | frame of the motor in addition to the abnormality detection apparatus of FIG. 6 is a graph showing a relationship between a vibration signal of a housing not subjected to filter processing and a vibration signal of a motor in the test apparatus of FIG. 5. 6 is a graph showing a relationship between a motor component extracted by filter processing and a vibration signal of the motor in the test apparatus of FIG. It is a graph which shows an example at the time of setting a setting threshold value corresponding to the upper limit of the permissible vibration of the motor of FIG. It is a graph which shows an example at the time of setting a setting threshold value corresponding to the upper limit of the permissible vibration of the motor of FIG. It is a flowchart which shows preferable embodiment of the abnormality detection method of this invention. It is a schematic diagram which shows the abnormality detection apparatus which concerns on Embodiment 2 of this invention. It is a graph which shows an example of the vibration signal spectrum-analyzed in the spectrum analysis means of FIG. It is a schematic diagram which shows the abnormality detection apparatus which concerns on Embodiment 3 of this invention.

Embodiment 1. FIG.
Hereinafter, Embodiment 1 of the abnormality detection device of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an example of the abnormality detection apparatus of the present invention. The abnormality detection apparatus 10 will be described with reference to FIG. The abnormality detection device 10 detects an abnormality of the blower 3 accommodated in the housing 2 and is used, for example, to detect an abnormality of the indoor fan or the outdoor fan of the vehicle air conditioner 1. In addition, although illustrated about the case where the abnormality detection apparatus 10 is applied to the air conditioning apparatus 1 for vehicles below, if the air blower 3 has a structure accommodated in the housing | casing 2, it will not be limited to this. For example, the present invention can be applied to a stationary air conditioner. Moreover, although the case where the abnormality detection apparatus 10 is attached to the vehicle air conditioner 1 mounted on the roof RF is illustrated, the abnormality detection apparatus 10 may be used for detecting an abnormality of the vehicle air conditioner 1 removed from the vehicle. Good.

  A vehicle air conditioner 1 will be described with reference to FIG. The vehicle air conditioner 1 is a vehicle air conditioner mounted on a roof RF of a vehicle, for example, and includes a heat pump type air conditioner capable of cooling operation and heating operation. The vehicle air conditioner 1 includes a refrigeration cycle circuit in which a compressor, a heat source side heat exchanger, an outdoor fan, and a use side heat exchanger are connected by a refrigerant pipe. Furthermore, the vehicle air conditioner 1 has a blower that blows air to the heat source side heat exchanger and a blower 3 that blows air to the use side heat exchanger. In FIG. 1, it has illustrated about the air blower 3 for ventilating to a utilization side heat exchanger. In addition, although illustrated about the case where the vehicle air conditioner 1 is mounted in the roof RF of a vehicle, you may install in the vehicle under floor.

  The refrigeration cycle circuit and the blower 3 are accommodated in a housing (main frame) 2 placed on the roof RF. The housing 2 is formed in a box shape having a hollow portion, and has a lower housing 2A and an upper housing 2B. The lower casing 2A is fixed to the roof RF, and the upper casing 2B is fixed on the lower casing 2A. An opening is formed on the upper surface side of the upper housing 2B, and a cover 6 is detachably attached to the opening. And the upper housing | casing 2B is provided with the fan attachment part 2C which protruded in the hollow part, and the bellmouth 4 in which the air blower 3 is accommodated in the fan attachment part 2C is being fixed.

  The blower 3 includes a motor 3 </ b> A and an impeller 3 </ b> B attached to the rotation shaft of the motor 3 </ b> A, and is housed in the housing 2 in a state surrounded by the bell mouth 4. Of the blower 3, the motor 3 </ b> A is fixed by a blower support portion 5 attached to the inner peripheral surface of the bell mouth 4. When the motor 3 </ b> A is driven, the impeller 3 </ b> B rotates, and intake is performed from one opening of the bell mouth 4 and exhaust is performed from the other opening. Vibration generated when the blower 3 is driven is transmitted from the frame of the motor 3 </ b> A to the housing 2 via the blower support 5 and the bell mouth 4.

  Here, when the impeller 3B of the blower 3 has an adhering substance DT such as dust, the rotor of the motor 3A and the impeller 3B cause rotation in an unbalanced state. Vibration is transmitted to the stator side of the motor 3A. When the unbalance is large, vibration and noise accompanying the vibration increase, and the blower 3 may be damaged. Therefore, periodic inspections are performed to determine whether there is an abnormality in the blower 3.

  In the inspection of the blower, a primary check that mainly screens the blower 3 that may be abnormal, and a final unbalance for the blower 3 that may be abnormal in the primary check. There is a secondary inspection to determine pass / fail. Here, the abnormality detection device 10 for detecting the abnormality of the blower 3 without directly measuring the vibration of the motor 3A in the blower 3 so that it can be judged by simple means when determining the quality of the primary inspection. Is used.

  The abnormality detection device 10 in FIG. 1 detects an abnormality of the blower 3 based on the vibration of the casing 2 that occurs during the operation of the blower 3, and includes a vibration detection unit 11, a motor component extraction unit 12, and a pass / fail determination unit. 13 is provided. The vibration detection unit 11 detects vibration of the housing 2 that occurs during operation of the blower as a vibration signal VS, and includes a vibration detection sensor 11A and a vibration meter 11B. The vibration detection sensor 11 </ b> A is detachably attached to the housing 2. For example, the vibration detection sensor 11 </ b> A is attached to the lower housing 2 </ b> A of the housing 2. Note that the vibration detection sensor 11A may be attached to the upper housing 2B, for example, regardless of the attachment position as long as it detects vibration of the housing 2.

  The vibration detection sensor 11A is composed of, for example, an acceleration sensor, and the vibration meter 11B detects vibration acceleration as a vibration signal VS. In addition, although the case where the vibration detection unit 11 detects vibration acceleration as the vibration signal VS is illustrated, speed and displacement may be detected as the vibration signal VS. FIG. 2 is a graph showing an example of the vibration signal VS detected by the vibration detection unit 11 of FIG. As shown in FIG. 2, the vibration signal VS includes vibrations from the blower 3 to the housing 2 that are attenuated in the transmission path and noise is superimposed, and includes various harmonics or subharmonics.

  The motor component extraction unit 12 shown in FIG. 1 extracts a motor component (rotation component) Vr from the vibration signal VS detected by the vibration detection unit 11. The motor component extraction unit 12 may be configured by a hardware circuit, or may be configured by a microcomputer or the like that performs software processing. The motor component extraction unit 12 includes filter processing means 12a that performs a filter process using a bandpass filter that passes a predetermined frequency band Δf including a motor component Vr that is a vibration component of the motor 3A. Then, the filter processing means 12a extracts the motor component Vr from the vibration signal VS using a bandpass filter.

  Specifically, FIG. 3 is a graph showing the frequency characteristics of the bandpass filter stored in the filter processing means 12a of FIG. The bandpass filter of FIG. 3 has a characteristic that the motor component Vr is included in the passband (gain = 1). That is, the frequency fr of the motor rotation number in the vibration signal VS can be obtained in advance by directly attaching and measuring the vibration detection sensor 11A to the motor 3A, and the characteristics of the bandpass filter are such that the frequency fr of the motor component Vr passes. Is set. Although FIG. 3 illustrates the case where the center frequency fc of the bandpass filter is the frequency fr of the motor rotation speed, it is only necessary that the frequency fr of the motor rotation speed is included in the pass band. FIG. 4 is a graph showing an example of the motor component Vr extracted by the motor component extraction unit 12 of FIG. As shown in FIG. 4, the waveform of the motor component Vr after the vibration signal VS is filtered by a band pass filter is in a state close to a sine wave.

  The quality determination unit 13 in FIG. 1 determines an abnormality of the blower 3 based on the motor component Vr extracted by the motor component extraction unit 12. The pass / fail judgment unit 13 is configured by, for example, a computer or a microcomputer. Here, as the vibration of the motor 3A becomes unbalanced, the vibration increases and the value of the motor component Vr increases. Therefore, the pass / fail judgment unit 13 stores a preset threshold value Vref in advance, and compares the motor component Vr with the preset threshold value Vref. When the motor component Vr is larger than the set threshold value Vref, the pass / fail determination unit 13 determines that an abnormality has occurred in the blower 3. On the other hand, when the motor component Vr is equal to or less than the set threshold value Vref, the quality determination unit 13 determines that the blower 3 is normal.

  The set threshold value Vref for the motor component Vr is a value corresponding to the allowable upper limit value of the motor 3A. That is, it is desirable that the motor 3A be used so as to be within an allowable vibration range (a range that can withstand an impact) even if vibration occurs due to a normal impeller 3B (load machine). The upper limit value of the permissible vibration is determined by the number of blade rotations, the blade deposit DT, the length of the rotation shaft, the motor capacity, or the like. On the other hand, when the deposit DT such as dust adheres to the impeller 3B and an imbalance occurs, vibration exceeding the upper limit value of the allowable vibration is generated. Therefore, when an imbalance such that the vibration of the motor 3A exceeds the upper limit value of the allowable vibration occurs in the impeller 3B, it is determined that an abnormality has occurred.

  As described above, the vibration signal VS is not detected directly from the motor 3A of the blower 3, but is detected from the housing 2. Therefore, the frequency extracted as the motor component Vr and the set threshold value used for pass / fail judgment are set in the correlation between the vibration of the housing 2 and the vibration of the motor 3A. Therefore, the correlation between the vibration of the housing 2 and the vibration of the motor 3A is determined in advance using a test apparatus 50 as shown in FIG.

  FIG. 5 is a schematic diagram showing an example of a test apparatus 50 in which a vibration detection sensor 51 is attached to the frame of the motor 3A in addition to the abnormality detection apparatus of FIG. The vibration detection sensor 51 directly detects the vibration (vibration acceleration) of the frame of the motor 3A of the blower 3 as the vibration signal VS10. In addition, the test apparatus 50 includes a signal processing device 53 that acquires the vibration signals VS and VS10 directly detected by the vibration detection unit 11 and performs various data processing.

  FIG. 6 is a graph showing the relationship between the vibration signal VS of the casing 2 that has not been filtered and the vibration signal VS10 of the motor 3A in the test apparatus 50 of FIG. 5, and FIG. 7 is a graph of the test apparatus 50 of FIG. 4 is a graph showing the relationship between the motor component Vr extracted by the filtering process and the vibration signal of the motor 3A. 6 and 7 show the vibration of the casing 2 for each of the blowers 3 of a plurality of vehicle air conditioners 1 of the same model when the state of the deposit DT or the rotational speed of the impeller 3B is different. The relationship between the signal VS or the motor component Vr and the vibration signal VS10 of the motor 3A is plotted. As illustrated in FIG. 6, when the vibration signal VS in the housing 2 is not subjected to the filter processing in the band pass filter, the variation becomes large. On the other hand, as shown in FIG. 7, the signal value of the motor component Vr extracted by the filter process is small but distributed in a narrow range.

  As described above, the upper limit value of the allowable vibration of the motor 3A is determined by the number of blade rotations, the blade deposit DT, the length of the rotation shaft, the motor capacity, and the like. In FIGS. 6 and 7, it is abnormal when the vibration signal VS10 of the motor 3A is larger than the upper limit value of the allowable vibration, and normal when the vibration signal VS10 of the motor 3A is less than or equal to the upper limit value of the allowable vibration. means. The set threshold value Vref is set so that the pass / fail determination based on the vibration signal VS10 of the motor 3A can be made based on the pass / fail determination based on the vibration signal VS of the housing 2.

  FIG. 8 and FIG. 9 are graphs showing an example when the set threshold value Vref is set corresponding to the upper limit value of the allowable vibration of the motor 3A of FIG. 6 and FIG. As shown in FIG. 8, when the vibration signal VS is not filtered, the upper limit value of the allowable vibration of the motor 3A is within the allowable range, but the determination of the set threshold value Vref is abnormal. Although the upper limit value of the allowable vibration of the motor 3A is exceeded, the erroneous determination area for determining that the setting threshold value Vref is normal increases. On the other hand, as illustrated in FIG. 9, when the motor component Vr is extracted by performing the filtering process on the vibration signal VS, the above-described erroneous determination region is narrowed. For this reason, even if it does not detect the vibration of the motor 3A directly, the quality determination of the air blower 3 can be accurately performed based on the vibration of the housing 2.

  The pass / fail judgment unit 13 in FIG. 1 stores a set threshold value Vref corresponding to the upper limit value of the allowable vibration of the motor 3A described above. And the quality determination part 13 compares the motor component Vr which filtered the vibration signal VS with the setting threshold value Vref, and performs quality determination. The set threshold value Vref is different for each product specification or model, and the measurer can change the setting threshold value Vref via an input unit (not shown) according to the product specification. At this time, the pass / fail judgment unit 13 has a table in which, for example, a set threshold value Vref is set for each model, and the pass / fail judgment unit 13 corresponds to the designated model when the measurer designates the model. The set threshold value Vref to be set may be set.

  FIG. 10 is a flowchart showing a preferred embodiment of the abnormality detection method of the present invention. The abnormality detection method will be described with reference to FIGS. Note that when the blower 3 is inspected, the blower 3 is operated while the refrigeration cycle circuit described above is stopped. When the blower 3 is activated, vibration is generated from the blower 3, and this vibration is transmitted from the motor 3 </ b> A to the blower support portion 5, the bell mouth 4, the upper housing 2 </ b> B, and the lower housing 2 </ b> A in this order. This vibration is detected by the vibration detection sensor 11A, and is detected as a vibration signal VS by the vibration meter 11B (step ST1). At this time, the vibration signal VS is detected in a state where the vibration signal VS is attenuated by the vibration transmission path and noise is superimposed (see FIG. 2). In addition, the vibration signal VS is in a state in which the magnitude of vibration has changed due to variations among devices.

  Next, in the motor component extraction unit 12, the vibration signal is subjected to filter processing by a band pass filter, and the motor component Vr is extracted from the vibration signal VS on which noise or the like is superimposed (step ST2). Thereafter, the pass / fail determination unit 13 compares the motor component Vr and the set threshold value Vref (step ST3), and determines whether an abnormality of the blower 3 has occurred based on the comparison. When the motor component Vr is larger than the set threshold value Vref, it is determined that an abnormality has occurred (step ST4). On the other hand, when the motor component Vr is equal to or less than the set threshold value Vref, it is determined that there is no abnormality (step ST5).

  Thus, when determining the quality of the blower 3 accommodated in the housing 2, the vibration of the motor 3A of the blower 3 is not directly detected, but is simply and accurately accommodated in the housing 2. An abnormality of the blower 3 can be detected. That is, although it is necessary to predict the vibration of the motor 3 </ b> A due to vibration with moderate accuracy, the vibration of the housing 2 does not correspond to the vibration of the motor 3 </ b> A on a one-to-one basis due to attenuation or noise, and has a large variation. Therefore, the determination becomes difficult. Moreover, even if it is the air conditioner 1 for vehicles of the same model, it is possible that it will vary from the subtle difference of a vibration transmission path. For this reason, when the pass / fail determination unit 13 performs pass / fail determination based on the set threshold value Vref, the erroneous detection region becomes large, and determination with high accuracy cannot be performed (see FIGS. 6 and 8). Thus, when the motor component extraction unit 12 performs the filtering process on the vibration signal VS using a bandpass filter and then performs the quality determination based on the set threshold value Vref, it is possible to realize a quality determination with high accuracy (see FIG. 7 and FIG. 7). (See FIG. 9). Furthermore, since the abnormality of the blower 3 in the housing 2 can be detected simply by attaching the vibration detection sensor 11A to the housing 2, the inspection work can be simplified.

Embodiment 2. FIG.
FIG. 11 is a schematic diagram showing an abnormality detection apparatus according to Embodiment 2 of the present invention. The abnormality detection apparatus 100 will be described with reference to FIG. In addition, in the abnormality detection apparatus 100 of FIG. 11, the same code | symbol is attached | subjected to the site | part which has the same structure as the abnormality detection apparatus 10 of FIG. 1, and the description is abbreviate | omitted. The abnormality detection device 100 in FIG. 11 differs from the abnormality detection device 10 in FIG. 1 in that the motor component extraction unit 112 has a spectrum analysis unit 112a.

  The spectrum analysis unit 112a in FIG. 11 performs spectrum analysis such as FFT processing, and converts the vibration signal VS into a spectrum for each frequency to extract the motor component Vr. Here, FIG. 12 is a graph showing an example of the vibration signal VS subjected to spectrum analysis by the spectrum analyzing means 112a of FIG. As shown in FIG. 12, a peak value in a predetermined frequency band Δf is extracted as a motor component Vr. In the frequency domain, since the peak at the motor component Vr is always obtained, detection is easy.

  In the abnormality detection apparatus 100 of FIG. 11 as well as in the first embodiment, the motor component Vr is extracted from the vibration signal VS on which various components are superimposed, and the pass / fail judgment is performed, whereby the blower 3 can be easily and accurately inspected. It can be carried out.

Embodiment 3. FIG.
FIG. 13 is a schematic diagram showing an abnormality detection apparatus according to Embodiment 3 of the present invention. The abnormality detection apparatus 200 will be described with reference to FIG. In the abnormality detection device 200 of FIG. 13, parts having the same configurations as those of the abnormality detection devices 10 and 100 of FIG. 1 and FIG. The abnormality detection device 200 in FIG. 13 is different from the abnormality detection devices 10 and 100 in FIGS. 1 and 10 in that the motor component extraction unit 212 includes both the filter processing unit 12a and the spectrum analysis unit 112a.

  Then, the filter processing unit 12a performs a filter process using a band pass filter that passes a predetermined frequency band Δf including the motor component Vr (see FIGS. 2 to 4). Thereafter, the spectrum analysis unit 112a performs a spectrum analysis of the vibration signal VS filtered by the filter processing unit 12a, and extracts a motor component Vr from the vibration signal VS converted into a spectrum for each frequency. At this time, the spectrum analysis unit 112a extracts the peak value having the largest signal value from the filtered vibration signal VS as the motor component Vr.

  As described above, by analyzing the spectrum of the vibration signal VS after the bandpass filter and extracting the motor component Vr, the noise included in the motor component Vr can be further reduced, and the abnormality of the blower 3 can be accurately detected. The determination can be made based on the vibration of the housing 2.

  Embodiment of this invention is not limited to the said Embodiment 1-3. For example, in each of the first to third embodiments, the case where the abnormality detection device 10 is used for primary inspection is illustrated, but the present invention can be applied to inspection at any stage. 1 to 13 exemplify the case where the blower 3 is fixed to the upper housing 2B via the bell mouth 4, but if the blower 3 is accommodated in the housing 2, the fixing method is used. Is not limited as long as the vibration of the motor 3 </ b> A of the blower 3 is transmitted to the housing 2.

  DESCRIPTION OF SYMBOLS 1 Vehicle air conditioner, 2 housing | casing, 2A lower housing | casing, 2B upper housing | casing, 2C Blower attachment part, 3 air blower, 3A motor, 3B impeller, 4 bell mouth, 5 air blower support part, 6 cover, 10, 100, 200 Abnormality detection device, 11 Vibration detection unit, 11A, 51 Vibration detection sensor, 11B Vibrometer, 12, 112, 212 Motor component extraction unit, 12a Filter processing means, 13 Pass / fail judgment unit, 50 Test device, 53 Signal processing Equipment, 112a spectrum analysis means, DT deposit, fc center frequency, fr motor rotation frequency, Vr motor component, Vref setting threshold, RF roof, VS housing vibration signal, VS10 motor vibration signal, Δf frequency Band.

Claims (6)

An anomaly detection device that detects an anomaly of a blower having a motor housed in a housing and having a frame as an outer shell and fixed to the housing by a blower support and an impeller driven by the motor,
A vibration detector that is attached to the housing and detects vibration generated in the housing when the blower is driven as a vibration signal;
A motor component extraction unit that extracts a vibration component of the motor as a motor component from the vibration signal detected by the vibration detection unit;
Filtering is performed using a band-pass filter provided in the motor component extraction unit and passing a predetermined frequency band including the motor component, and a component of the predetermined frequency band is extracted as the motor component from the vibration signal. Filtering means;
When the motor component extracted by the motor component extraction unit is larger than a set threshold value determined based on a correlation between the vibration of the casing and the vibration of the frame, the fan is determined to be abnormal. An abnormality determination unit that performs ,
A center frequency of the band-pass filter is set to a frequency of the rotational speed of the motor .   The motor component extraction unit includes a spectrum analysis unit that performs spectrum analysis of the vibration signal and extracts the motor component from the vibration signal converted into a spectrum for each frequency. The abnormality detection device described. The motor component extraction unit,
And wherein the pre-SL performs a spectrum analysis of the filtered the vibration signal in the filtering means, from the vibration signal converted into a spectrum for each frequency that includes a spectral analysis means to extract said motor component The abnormality detection device according to claim 1. The abnormality detection apparatus according to claim 3 , wherein the spectrum analysis unit extracts a peak component in a predetermined frequency band as the motor component. The setting threshold value, according to claim 4, characterized in that the vibration of the upper limit of the vibration tolerance of the motor is set to the vibration value transmitted to the housing when generated in the motor Anomaly detection device. An abnormality detection method for detecting an abnormality of a blower having a motor housed in a housing and having a frame as an outer shell and fixed to the housing by a blower support and an impeller driven by the motor,
Detecting the vibration generated in the housing when the blower is driven as a vibration signal;
Extracting the vibration component of the motor as a motor component from the detected vibration signal,
A center frequency is set to the frequency of the rotation speed of the motor, a filter process is performed using a bandpass filter that passes a predetermined frequency band including the motor component, and a component in a predetermined frequency band of the vibration signal is Extracted as a motor component,
It is determined that the blower is abnormal when the extracted motor component is larger than a set threshold value determined based on a correlation between the vibration of the casing and the vibration of the frame. Detection method.

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