KR20130115977A - Apparatus for preventive maintenance of motor - Google Patents

Abstract

PURPOSE: A preliminary maintaining device for an electric motor is provided to enhance the accuracy of abnormality detection of a motor. CONSTITUTION: A preliminary maintaining device (7) includes a model memory unit (7a), a model state quantity calculator (7b), and a comparator (7c). The model memory unit memorizes in advance a correlation model between the operational quantity and the state quantity in a condition where an electric motor and its accessory equipment work normally. The model state quantity calculator applies the operational quantity obtained during the operation to the correlation model stored in the model memory unit and calculates the state quantity expected from the correlation model if the electric motor and its accessory equipment work normally. The comparator compares the state quantity calculated by the model state quantity calculator and the state quantity actually measured during the operation and detects abnormality of the electric motor or its accessory equipment if the difference is over a certain degree. [Reference numerals] (7a) Model memory unit; (7b) Model state quantity calculator; (7c) Comparator; (7d) Notice unit; (AA) Manipulation quantity; (BB) State quantity

Description

Preventive maintenance device of electric motor {APPARATUS FOR PREVENTIVE MAINTENANCE OF MOTOR}

The present invention relates to a preventive maintenance apparatus for an electric motor.

One of the main components of the plant is an electric motor. Electric motors are often an important factor in a plant, and the failure affects the entire plant. Therefore, in the operation of the plant, it is necessary to prevent (i.e. preventive maintenance) the failure of the motor in advance by monitoring whether or not an abnormality has occurred in the motor.

As a conventional method for diagnosing an abnormality of an electric motor, it is known to detect vibration at the start of the electric motor and diagnose the looseness of the motor winding based on the detection result (for example, refer to Patent Document 1).

Patent Document 1: Japanese Patent Application Laid-Open No. 60-066647

By the way, large sized electric motors used for rolling mills, etc. of steel mills, for example, are often accompanied by auxiliary equipment such as a unit cooler for cooling the heat generated by the electric motor and a bearing oil supply device for supplying the bearings. In addition, since the motor needs to be stopped even in the event of a failure in the auxiliary equipment of such a motor, it is necessary to monitor not only the main body of the motor but also the auxiliary equipment of the motor for abnormality, and to prevent the failure in advance. It is necessary.

However, in the patent document 1, the abnormality of the auxiliary equipment of an electric motor is not considered at all, and there exists a subject that the preventive maintenance of an electric motor including abnormality monitoring and detection of the auxiliary equipment of an electric motor is not possible.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem. The present invention provides a preventive maintenance apparatus for an electric motor that can improve the accuracy of detecting abnormality of an electric motor and can preventive maintenance of the electric motor including abnormality monitoring and detection of auxiliary equipment of the electric motor. To get.

The preventive maintenance device for an electric motor according to the present invention is a preventive maintenance device for an electric motor that operates on the basis of an operation amount input from an electric motor drive device, the state amount obtaining means for acquiring a state amount of the motor having a predetermined correlation with the operation amount; Model memory means for storing in advance a correlation model modeled according to the correlation between the operation amount and the state amount when the electric motor and the auxiliary equipment of the electric motor are normal; The model state amount calculating means for calculating a state amount with respect to the operation amount at the time of operation of the electric motor in the correlation model, and the state amount acquired by the state amount obtaining means at the time of driving and the state calculated by the model state amount calculating means. By comparing the state quantities, units of the electric motor and the electric motor It is set as the structure provided with the abnormality detection means which detects the abnormality of a facility.

The preventive maintenance device of the motor according to the present invention can improve the accuracy of detecting abnormality of the motor, thereby achieving the effect that the preventive maintenance of the motor including abnormality monitoring and detection of auxiliary equipment of the motor can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows the whole structure of the preventive maintenance apparatus of the electric motor which concerns on Embodiment 1 of this invention.
FIG. 2 is a diagram showing a configuration of an electric motor according to Embodiment 1 of the present invention and its associated equipment. FIG.
3 is a block diagram showing a functional configuration of a preventive maintenance apparatus according to Embodiment 1 of the present invention.
4 is a graph showing an example of a correlation model of a preventive maintenance device for an electric motor according to Embodiment 1 of the present invention.
5 is a diagram illustrating an example of an abnormality determination of a preventive maintenance device for an electric motor according to Embodiment 1 of the present invention.
6 is a block diagram showing a functional configuration of a preventive maintenance apparatus according to Embodiment 2 of the present invention.
7 is a block diagram showing a functional configuration of a preventive maintenance apparatus according to Embodiment 3 of the present invention.

The present invention will be described with reference to the accompanying drawings. Like reference numerals denote like or equivalent parts throughout the drawings, and the description thereof will be appropriately simplified or omitted.

Embodiment Mode 1.

1 to 5 are related to Embodiment 1 of the present invention, FIG. 1 is a block diagram showing the overall configuration of a preventive maintenance apparatus of an electric motor, FIG. 2 is a diagram showing the configuration of an electric motor and its associated equipment; 3 is a block diagram showing a functional configuration of a preventive maintenance device, FIG. 4 is a graph showing an example of a correlation model of a preventive maintenance device of an electric motor, and FIG. 5 shows an example of an abnormality determination of the preventive maintenance device of an electric motor. It is a figure.

In FIG. 1, the code | symbol 1 is an electric motor. The auxiliary equipment 2 of the electric motor is attached. An example of the specific structure of these electric motors 1 and the auxiliary equipment 2 of an electric motor is shown in FIG. The electric motor 1 is provided with a rotor 1b rotatably provided inside the electric motor 1 and a rotating shaft 1a which extends from the center of the rotor 1b and rotates integrally with the rotor 1b. Have The rotor winding 1c is provided in the outer periphery of the rotor 1b. The stator winding 1e wound around the stator iron core 1d is fixedly arranged in the electric motor 1 so as to face the rotor winding 1c.

The electric motor 1 is provided with the unit cooler which consists of the cooling fan 2a and the water cooling heat exchanger 2b for cooling the heat which generate | occur | produced in the electric motor 1 inside. The cooling fan 2a circulates air into the motor 1 to cool the heat generated by the motor 1. The air fed into the electric motor 1 warms up as a result of cooling the heat in the electric motor 1, and the temperature rises. The air which lost heat in the electric motor 1 is cooled by the water-cooled heat exchanger 2b, returns to cold air, and is again supplied into the electric motor 1 by the cooling fan 2a.

By performing circulating cooling by such a cooling fan 2a and the water-cooled heat exchanger 2b, the electric motor 1 is cooled and generation | occurrence | production of incompatibility, such as sintering, is prevented. Moreover, the water-cooled heat exchanger 2b is equipped with the cooling water pipe in which the cooling water was circulated inside, and cools air by heat-exchanging between air and cooling water.

Moreover, the bearing stand 2c which rotatably supported the rotating shaft 1a is provided in the rotating shaft 1a part of the electric motor 1. As shown in FIG. This bearing base 2c is equipped with the bearing oil supply apparatus which supplied lubricating oil to the bearing. These water-cooled heat exchangers 2b, cooling fans 2a and bearing stands 2c (storage oil supply devices) are examples of the auxiliary equipment 2 of the electric motor.

The operation of the electric motor 1 is driven by the electric motor drive device 3. The motor 1 is connected to the communication network 6 via the motor-side remote IO board 4, and the motor drive device 3 is connected to the communication network 6 via the drive-side remote IO board 5, respectively. ) And the motor drive device 3 are capable of electrical communication with each other via the communication network 6.

The electric motor drive device 3 transmits an operation signal to the electric motor 1 via the communication network 6. This operation signal contains information about the operation amount of the electric motor 1, and the electric motor 1 operates according to the operation amount indicated by the received operation signal.

The preventive maintenance device 7 is connected to the communication network 6 which connects the electric motor 1 and the electric motor drive device 3. This preventive maintenance device 7 is based on the amount of operation of the operation signal input from the motor drive device 3 to the motor 1 and the state amount of the motor 1 which has a predetermined correlation with the operation amount. 1) and preventive maintenance of the electric motor 1 by performing abnormality monitoring and detection of the auxiliary equipment 2 of an electric motor.

Hereinafter, the case where the unit cooler (cooling fan 2a and water-cooled heat exchanger 2b) which are auxiliary equipment 2 of an electric motor is made into the object which performs abnormal monitoring and detection by the preventive maintenance apparatus 7 is demonstrated. .

The preventive maintenance device 7 monitors and detects an abnormality of the unit cooler by using a load temperature rise value as a state amount of the motor 1 that has a predetermined correlation with the load rate and the operation amount (load rate) as the operation amount of the operation signal. .

Hereinafter, a predetermined correlation established between the load ratio and the winding temperature rise value will be described.

First, the load factor L is a ratio of the current current value to the rated current value and is determined by the following equation (1).

L = i (present value) / i (rated value) x 100 [%]. (One)

The square of the root mean square (RMS) of the load factor (RMS ^ 2) is expressed by the following equation (2).

RMS ^ 2 = (L1 ^ 2 · t1 + L2 ^ 2 · t2 + ... + Ln ^ 2 · tn) / T. (2)

Where T is a target time for calculating RMS, t1, t2,... , tn is the sampling time obtained by dividing the target time T obtained from the RMS, L1, L2,... , Ln is a load factor at each sampling time t1, t2, ..., tn, and T = t1 + t2 + ... + tn.

Substituting Eq. (1) into Eq. (2) yields the relationship of Equation (3) below.

RMS ^ 2 ∝ i ^ 2… (3)

Next, the relationship between the winding temperature rise value? T and the winding current value i of the electric motor 1 is derived. The types of losses generated by the electric motor 1 include iron loss, copper loss, stray load loss, and mechanical loss. Among these, copper loss as a calorific value generated in the winding coil of the electric motor 1 occupies most of the loss of the electric motor 1. Since the winding temperature rise value ΔT is proportional to the loss in the motor 1, considering that the loss and the copper loss in the motor 1 are almost the same, the winding temperature rise value ΔT is the copper loss, that is, the motor 1. It can be seen that it is proportional to the amount of heat generated in the winding coil.

The calorific value Q of the winding coil is expressed by the following equation (4) when i is a winding current, R is a coil resistance, and t is time.

Q = i ^ 2 · R · t... (4)

Then, if the above-mentioned winding temperature rise value ΔT is proportional to the heat generation amount Q, the following equation (5) is obtained between the winding temperature rise value ΔT and the winding current i from equation (4). It is derived that there is a relationship indicated by.

ΔT ∝ i ^ 2. (5)

And the relationship shown by following formula (6) can be derived from Formula (3) and Formula (5).

ΔT ∝ RMS ^ 2... (6)

As such, the winding temperature rise ΔT is theoretically proportional to the square of the root mean square root of the load ratio (RMS ^ 2), and when one side changes, the other side changes accordingly. It can be seen.

The preventive maintenance device 7 can obtain a load factor which is an operation amount input to the electric motor 1 by acquiring an operation signal transmitted from the electric motor drive device 3 to the electric motor 1 via the communication network 6. .

Moreover, in order to obtain winding temperature rise value (DELTA) T which is one of the state quantities of the electric motor 1, in the motor 1, two of the RTD 8 for winding temperature measurement and the RTD 9 for refrigerant temperature measurement are included. A resistance thermometer is attached. The RTD 8 for winding temperature measurement is for detecting the temperature (exhaust temperature) of the winding part in the electric motor 1, and the RTD 9 for refrigerant temperature measurement is the refrigerant introduced into the electric motor 1 from now on. It is for detecting the temperature (air supply temperature) of (air).

The preventive maintenance device 7 stores two state quantities of the exhaust temperature detected by the RTD 8 for winding temperature measurement and the air supply temperature detected by the RTD 9 for refrigerant temperature measurement. The winding temperature increase value DELTA T is calculated by obtaining the difference between the exhaust air temperature and the exhaust air temperature. In addition, the acquisition timing of the operation amount (RMS of load factor) and the acquisition timing of the state amount (winding temperature rise value? T) by the preventive maintenance device 7 are synchronized.

In this way, since the RMS of the load ratio which is the operation amount obtained by the preventive maintenance device 7 and the winding temperature rise value ΔT which is the state quantity are in a proportional relation as expressed by the equation (6), the electric motor 1 and If the auxiliary equipment 2 (unit cooler) of the motor is in a normal state, there is a strong correlation between the load factor RMS and the winding temperature rise value ΔT, and the RMS square of the load rate and the winding temperature rise value ΔT are as follows. It can be modeled by the linear equation as shown by (7).

ΔT = kRMS ^ 2 + c... (7)

Therefore, the preventive maintenance device 7 monitors and detects the abnormality of the electric motor 1 and the auxiliary equipment 2 of the electric motor using the properties of the operation amount and the state amount which have such a predetermined correlation. The structure of this preventive maintenance apparatus 7 is shown in FIG. The preventive maintenance apparatus 7 is provided with the model memory | storage part 7a, the model state quantity calculation part 7b, the comparison part 7c, and the notification part 7d.

The model storage unit 7a stores in advance a correlation model in which the electric motor 1 and the auxiliary equipment 2 of the electric motor model a relationship between an operation amount and a state amount in a normal state. The modeling of the relationship between the operation amount and the state amount will be described with reference to the RMS of the on-load rate and the winding temperature rise value? T as an example.

First, in the normal operation of the electric motor 1 and the auxiliary equipment 2 (unit cooler) of the electric motor, for a predetermined period of time, the pair of the RMS of the load factor, which is an operation amount, and the winding temperature rise value? T, which is a state amount, Collect multiple data. Next, based on the collected data, the coefficient (k) and the intercept (c) in (7) are computed using the known regression method, such as the least square method, and (7) A regression equation expressed in the form of is obtained and a correlation model is modeled that models the relationship between the manipulated variable and the state quantity in a normal state.

Then, the correlation model of the manipulated value (RMS of load factor) and state amount (winding temperature rise value? T) thus created is stored in the model storage unit 7a. An example of the relationship between the square of RMS of the load factor and the winding temperature rise value (DELTA) T in the correlation model previously memorize | stored in the model memory | storage part 7a is shown in FIG.

During operation of the electric motor 1 and the auxiliary equipment 2 of the electric motor, the preventive maintenance device 7 regularly acquires an operation amount and a state amount. And the model state quantity calculation part 7b with which the preventive maintenance apparatus 7 is equipped applies the operation amount acquired during operation to the correlation model memorize | stored in the model memory | storage part 7a, and the motor ( 1) and the state quantity (henceforth a model state quantity) which will be taken, if the auxiliary equipment 2 of an electric motor is normal.

As an example of the RMS of the load factor and the winding temperature rise value (DELTA) T so far, the preventive maintenance apparatus 7 has the RMS of the load ratio in the fixed period during the operation of the motor 1 and the auxiliary equipment 2 of the motor. The square state is calculated, and the model state amount calculating unit 7b calculates the winding temperature rise value ΔT of the model state amount by substituting this square of RMS into the equation (7).

The comparator 7c included in the preventive maintenance device 7 compares the model state amount calculated by the model state amount calculation unit 7b with the state amount actually detected during operation, and is actually detected during operation with respect to the model state amount. When the state quantity is more than a predetermined reference, it is detected that an abnormality has occurred in the electric motor 1 or the auxiliary equipment 2 of the electric motor.

This abnormality detection determination is demonstrated referring FIG. In FIG. 5, the code | symbol 10 is a correlation model represented by the regression formula (7). And the threshold value 11 used for abnormality detection determination is set on the plus side of the (D) axis | shaft by the predetermined | prescribed reference | standard rather than the straight line of this correlation model 10. As shown in FIG. And when the state quantity actually detected during operation is more than this threshold value 11 (detection point 12), it is detected that an abnormality occurred in the electric motor 1 or the auxiliary equipment 2 of the electric motor.

In addition, although the threshold value 11 was set above the straight line of the correlation model 10 by a predetermined reference | standard, the straight line of the correlation model 10 is predetermined magnification (for example, 1.5) in the positive direction of the (DELTA) T axis | shaft. The enlarged magnification may be set as the threshold value 11.

The notification part 7d of the preventive maintenance device 7 is that an abnormality has occurred in the electric motor 1 or the auxiliary equipment 2 of the electric motor by comparison between the model state amount in the comparator 7c and the actual state amount. If detected, it informs maintenance personnel and the like. As a notification form by this notification part 7d, you may display on the display screen of the preventive maintenance apparatus 7, for example, and may make a buzzer, a sound, etc. sound, and notify.

In the preventive maintenance apparatus of the electric motor comprised in this way, the correlation model which modeled the relationship of the operation amount and state quantity in the normal state by the electric motor 1 and the auxiliary equipment 2 of the electric motor is created previously. During the operation of the electric motor 1 and the auxiliary equipment 2 of the electric motor, abnormality of the electric motor 1 and the auxiliary equipment 2 of the electric motor is detected by comparing the model state amount on the correlation model with the actual state amount.

Here, in general, when an abnormality detection is to be performed based on a state amount that changes in response to a change in the operation amount, more accurate abnormality detection can be performed by changing the state amount that is the reference for abnormal detection in response to the value of the operation amount during operation. have. However, the manipulation amount of the data sampled in the normal state and the actual manipulation amount during operation cannot necessarily be the same. Therefore, when the manipulation amount of the data sampled in the normal state and the actual manipulation amount during operation do not match, there arises a problem of how to set the reference value for abnormal detection.

In response to such a problem, in the preventive maintenance apparatus of the motor according to the present invention, since the state quantity serving as the reference for abnormality detection is set using a correlation model that models the relationship between the manipulated variable and the state quantity in a normal state, In response, an appropriate reference value can be set, and it is possible to realize abnormality detection with higher accuracy.

In addition, when the number of data of the normal operation amount and the state amount required for setting the reference value is examined, when the correlation model is not used, more data numbers are required for setting the reference value in order to increase the abnormality detection accuracy. On the other hand, when the correlation model is used, it is sufficient that the number of data necessary for the preparation of the correlation model capable of obtaining a certain or more correlation is sufficient, that is, the abnormality detection with higher precision can be realized with a smaller data number.

In addition, for example, the unit cooler which is the auxiliary equipment 2 of an electric motor, the coolant pipe which a unit cooler is equipped with may adhere to the inside of a pipe by using for a long time, and a pipe may be clogged gradually. This blockage lowers the cooling function of the unit cooler, which may eventually lead to failure of the electric motor. By the way, it is very difficult to detect the abnormality of the unit cooler, such as the blockage of a coolant pipe | tube directly, directly.

However, if the cooling function of the unit cooler decreases due to clogging or the like of such a cooling water pipe, the winding temperature rise value? T (state amount) increases even at the same load ratio (operation amount) as compared with normal operation. For this reason, it is possible to indirectly detect such abnormality of the auxiliary equipment 2 of the electric motor by detecting the deviation of the actual state quantity from the model state quantity in the normal correlation model.

In addition, the abnormality associated with deterioration that gradually progresses over time, such as clogging of the cooling water pipe of the unit cooler, is very difficult to detect because it takes a long time to manifest. However, since the accuracy of abnormality detection can be improved by setting a reference for abnormality detection using a normal correlation model, it is also possible to detect such a degradation gradually progressing over such a long period.

The preventive maintenance device for an electric motor configured as described above is a case where the temperature resistance resistor which is a state quantity acquisition means for acquiring a state quantity of an electric motor which has a predetermined correlation with an operation amount input to an electric motor from a motor drive device, and a motor and the auxiliary equipment of an electric motor are normal. Calculate the state amount for the operation amount at the time of operation of the motor in the model storage means which stores in advance the correlation model which modeled the relationship between the operation amount and state quantity in accordance with the correlation, and the correlation model which the model storage means stores. A comparison unit which is an abnormality detecting means for detecting abnormality of the electric motor and the auxiliary equipment of the motor by comparing the model state quantity calculating means to be compared with the state quantity acquired by the state quantity obtaining means at the time of operation and the state quantity calculated by the model state quantity calculating means. It is equipped.

For this reason, the abnormality detection accuracy of an electric motor can be improved, the preventive maintenance of an electric motor including the abnormality monitoring and detection of the auxiliary equipment of an electric motor can be performed, and the deterioration of the auxiliary equipment of an electric motor can be judged correctly. In addition, it is possible to prevent the sudden failure of the electric motor that affects the operation of the entire plant, since the indication of the failure of the auxiliary equipment of the electric motor can be known in advance, and the maintenance according to the symptom can be appropriately performed. Do.

Embodiment 2:

6 is a block diagram showing a functional configuration of a preventive maintenance apparatus according to Embodiment 2 of the present invention.

In the second embodiment described herein, the model state amount is calculated in consideration of the factors affecting the state amount other than the operation amount having a predetermined correlation with the state amount of the motor in the configuration of the above-described first embodiment. will be.

In the following, as in the first embodiment, an example will be described in which the RMS of the load factor is used as the operation amount and the winding temperature rise value ΔT is used as the state amount. The winding temperature rise value ΔT, which is a state quantity, is the temperature, flow rate, and cooling fan of the cooling water in the water-cooled heat exchanger 2b of the unit cooler, which is, for example, the unit equipment 2 of the electric motor, in addition to the load factor (RMS) of the operation amount. It also varies depending on the amount of air in (2a).

Specifically, for example, the winding temperature rise value ΔT is 30 degrees when the temperature of the coolant is 20 degrees and the winding temperature rise value ΔT when the coolant temperature is 25 degrees under different preconditions. ) Is 32 degrees, the correction amount for the coolant temperature is +2 degrees. In this way, the correction amount concerning the cooling water temperature, the correction amount regarding the cooling water flow rate, and the correction amount regarding the fan air flow amount are respectively evaluated in accordance with the operating conditions.

And when these correction amounts are alpha 1, alpha 2, and alpha 3, respectively, the regression equation of the correlation model which takes these correction amounts as a correction term becomes as follows (8).

ΔT = kRMS ^ 2 + c + α1 + α2 + α3... (8)

The preventive maintenance device 7 according to the second embodiment uses a regression equation having a correction term as in (8) to calculate the model state quantity used for setting the reference value for abnormality detection. That is, the preventive maintenance device 7 further stores the correction amount in addition to the model storage unit 7a, the model state amount calculation unit 7b, the comparison unit 7c, and the notification unit 7d as shown in FIG. The part 7e is provided.

The correction amount storage unit 7e stores in advance the influence (ie, the amount of change in the state amount given by elements other than the operation amount) that elements other than the operation amount have as the correction amount. The correlation model stored in the model storage unit 7a is of a form that does not include a correction term, as in equation (7) of the first embodiment. And when calculating the model state amount in the correlation model which the model memory | storage part 7a memorize | stores, the model state quantity calculation part 7b adds the correction amount which the correction amount memory | storage part 7e memorize | stores to (8) Formula. The model state quantity is calculated.

As described above, in the calculation of the model state quantity, in the portion showing the correlation between the manipulated variable and the state quantity, by creating a correlation model or calculating the calculated model state quantity by separating elements that affect the state quantities other than the manipulated quantity and treating them as correction terms. In the same procedure as in the first embodiment, the abnormality detection and the like can be performed in the same manner as in the first embodiment.

In addition, about another structure, it is the same as that of Embodiment 1, and the detailed description is abbreviate | omitted.

In addition to the structure of Embodiment 1, the preventive maintenance apparatus of the electric motor comprised as mentioned above further includes the correction amount memory | storage part which memorizes the amount of change of the state quantity which elements other than an operation amount give as a correction amount previously, and the model state amount calculation part is a correction amount storage part, By adding the correction amount to be stored, it calculates the state amount with respect to the operation amount at the time of operation of an electric motor in the correlation model which a model memory part memorize | stores.

Therefore, in addition to being able to achieve the same effects as in the first embodiment, the correlation model can be corrected in consideration of factors other than the manipulated variable without using regression analysis again, so that abnormality detection can be performed without complicated data processing. It is possible to further improve the precision.

Embodiment 3

7 is a block diagram showing a functional configuration of a preventive maintenance apparatus according to Embodiment 3 of the present invention.

The third embodiment described herein counts the number of times that the state amount actually detected during operation with respect to the model state amount falls more than a predetermined reference with respect to the model state amount, and this number within a predetermined period is When the number of times is abnormal, the occurrence of abnormality of the electric motor or the auxiliary equipment of the motor is detected.

In the third embodiment, the preventive maintenance device 7 is, in addition to the model storage unit 7a, the model state quantity calculating unit 7b, the comparing unit 7c and the notifying unit 7d, as shown in FIG. And a counter 7f. The comparison unit 7c compares the model state amount calculated by the model state amount calculation unit 7b with the state amount actually detected during operation, and whether or not the state amount actually detected during operation has dropped by more than a predetermined reference with respect to the model state amount. Determine.

The counter 7f counts the number of times determined by the comparator 7c with respect to the model state amount that the actual state amount has dropped by more than a predetermined reference. And when this number of times becomes more than the predetermined number of times in a fixed period, abnormality occurrence of the electric motor 1 or the auxiliary equipment 2 of an electric motor is detected.

In the same manner as in the first embodiment, the notification unit 7d notifies the maintenance worker and the like by the screen display, the sound, or the like when it is detected that an abnormality has occurred in the electric motor 1 or the auxiliary equipment 2 of the electric motor. . In this case, when the comparison unit 7c determines that the actual state amount has dropped by more than a predetermined reference with respect to the model state amount, the time and the number of times are also reported when the notification unit 7d reports. The maintenance worker may be notified by the screen display.

As for the preventive maintenance apparatus of the electric motor comprised as mentioned above, in the structure of Embodiment 1, the comparator and counting part which are abnormal detection means are the state quantity acquired by the state quantity acquisition means at the time of operation to the state quantity computed by the model state quantity calculating part. When the number of times the predetermined reference amount or more falls to the predetermined number of times or more within a predetermined period, the abnormality of the electric motor and the auxiliary equipment of the electric motor is detected.

For this reason, the same effects as those of the first embodiment can be achieved, in addition, the false detection of abnormal occurrences can be suppressed, and abnormality detection can be realized early and with high accuracy, and an appropriate time for maintenance inspection can be notified. .

1: Electric motor
1a: axis of rotation
1b: rotor
1c: rotor winding
1d: stator iron core
1e: stator winding
2: auxiliary equipment of electric motor
2a: cooling fan
2b: water cooled heat exchanger
2c: bearing rack
3: electric motor drive device
4: Motor IO remote IO board
5: Remote IO board at drive unit side
6: communication network
7: preventive maintenance device
7a: model memory
7b: model state quantity calculating unit
7c: comparison unit
7d: notification unit
7e: Correction amount memory
7f: counter
8: RTD for measuring winding temperature
9: RTD for measuring refrigerant temperature
10: correlation model
11: threshold
12: detection point

Claims (3)

As a preventive maintenance device of an electric motor which operates based on the operation amount input from an electric motor drive device,
State quantity acquiring means for acquiring a state quantity of the electric motor having a predetermined correlation with the operation amount;
Model storage means for storing in advance a correlation model in which the relationship between the operation amount and the state amount in the case where the electric motor and the auxiliary equipment of the electric motor is normal is modeled according to the correlation;
Model state amount calculation means for calculating a state amount with respect to the operation amount at the time of operation of the electric motor in the correlation model stored by the model storage means;
And an abnormality detecting means for detecting an abnormality of the electric motor and the auxiliary equipment of the electric motor by comparing the state quantity acquired by the state quantity obtaining means with the state quantity calculated by the model state quantity calculating means at the time of the operation. Preventive maintenance device of an electric motor characterized by the above-mentioned. The method of claim 1,
A correction amount storage means for storing a change amount of the state amount given by elements other than the operation amount as a correction amount in advance;
The model state amount calculating means calculates a state amount with respect to the operation amount at the time of operation of the electric motor in the correlation model stored by the model memory means, taking into account the correction amount stored by the correction amount storage means. Preventive maintenance device of electric motor to make. 3. The method according to claim 1 or 2,
The abnormality detecting means is characterized in that the number of times that the state amount acquired by the state amount obtaining means at the time of operation is more than a predetermined reference amount with respect to the state amount calculated by the model state amount calculating means becomes a predetermined number or more within a predetermined period. In the case, abnormality of the said electric motor and the auxiliary equipment of the said electric motor is detected, The preventive maintenance apparatus of the electric motor characterized by the above-mentioned.

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