JP2013223284A - Preventive maintenance device for motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a preventive maintenance device for a motor that can improve abnormality detection accuracy of the motor and perform preventive maintenance for the motor including abnormality monitoring and detection of ancillary facilities of the motor.SOLUTION: A preventive maintenance device for a motor operated on the basis of an operation amount input from a motor driving device comprises: state quantity acquiring means for acquiring a state quantity of the motor having a predetermined correlation with an operation amount; model storage means for storing a correlation model obtained by modeling a relation between the operation amount and the state quantity when the motor and ancillary facilities thereof are normal in accordance with the correlation beforehand; model state quantity calculating means for calculating the state quantity with respect to the operation amount at the time of operation of the motor in the correlation model stored by the model storage means; and abnormality detecting means for detecting abnormality of the motor and the ancillary facilities thereof by comparing the state quantity acquired by the state quantity acquiring means and the state quantity calculated by the model state quantity calculating means at the time of operation.

Description

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

  One of the main equipments constituting 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 the failure of the motor in advance (that is, preventive maintenance) by monitoring whether the motor is abnormal.

  As a conventional abnormality diagnosis method for an electric motor, a method is known in which vibration at the time of starting the electric motor is detected and loosening of the electric motor winding is diagnosed based on the detection result (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 60-0666647

  By the way, for example, a large motor used in a rolling mill of a steel mill or the like is often accompanied by ancillary equipment such as a unit cooler for cooling heat generated by the motor and a bearing oil supply device for supplying oil to the bearing. And even if a failure occurs in the incidental equipment of such a motor, it is necessary to stop the motor, so not only the main body of the motor but also the incidental equipment of the motor is monitored for abnormalities. It is necessary to prevent this beforehand.

  However, in the thing shown by patent document 1, the abnormality of the incidental equipment of an electric motor is not considered at all, and the preventive maintenance of the electric motor including abnormality monitoring and detection of the incidental equipment of an electric motor cannot be performed. There is a problem.

  The present invention has been made to solve such problems, and can improve the abnormality detection accuracy of the motor, and perform preventive maintenance of the motor including abnormality monitoring / detection of incidental equipment of the auxiliary motor. It is possible to obtain a preventive maintenance device for an electric motor that is possible.

  The preventive maintenance device for an electric motor according to the present invention is a preventive maintenance device for an electric motor that operates based on an operation amount input from an electric motor drive device, and calculates a state quantity of the motor that has a predetermined correlation with the operation amount. State quantity obtaining means for obtaining, and model storage means for preliminarily storing a correlation model obtained by modeling the relation between the manipulated variable and the state quantity when the electric motor and the incidental equipment of the electric motor are normal according to the correlation. In the correlation model stored in the model storage unit, a model state quantity calculation unit that calculates a state quantity with respect to the operation quantity during operation of the electric motor, and the state quantity acquired by the state quantity acquisition unit during operation By comparing the state quantity calculated by the model state quantity calculating means, an abnormality in the electric motor and incidental equipment of the electric motor is detected. And an abnormality detecting unit, comprising the features.

  In the preventive maintenance apparatus for an electric motor according to the present invention, the abnormality detection accuracy of the electric motor can be improved, and it is possible to perform preventive maintenance of the electric motor including abnormality monitoring / detection of incidental equipment of the auxiliary electric motor. There is an effect.

It is a block diagram which shows the whole structure of the preventive maintenance apparatus of the electric motor which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the electric motor which concerns on Embodiment 1 of this invention, and its incidental equipment. It is a block diagram which shows the functional structure of the preventive maintenance apparatus which concerns on Embodiment 1 of this invention. It is a graph which shows an example of the correlation model of the preventive maintenance apparatus of the electric motor which concerns on Embodiment 1 of this invention. It is a figure which shows an example of the abnormality determination of the preventive maintenance apparatus of the electric motor which concerns on Embodiment 1 of this invention. It is a block diagram which shows the functional structure of the preventive maintenance apparatus which concerns on Embodiment 2 of this invention. It is a block diagram which shows the functional structure of the preventive maintenance apparatus which concerns on Embodiment 3 of this invention.

  The present invention will be described with reference to the accompanying drawings. Throughout the drawings, the same reference numerals indicate the same or corresponding parts, and the overlapping description is simplified or omitted as appropriate.

Embodiment 1 FIG.
1 to FIG. 5 relate to Embodiment 1 of the present invention, FIG. 1 is a block diagram showing the overall configuration of a preventive maintenance apparatus for an electric motor, and FIG. 2 is a diagram showing the configuration of the electric motor and its auxiliary equipment, FIG. 3 is a block diagram showing a functional configuration of the preventive maintenance apparatus, FIG. 4 is a graph showing an example of a correlation model of the preventive maintenance apparatus for an electric motor, and FIG. 5 is a diagram showing an example of abnormality determination of the preventive maintenance apparatus for an electric motor.

  In FIG. 1, 1 is an electric motor. Ancillary equipment 2 for the electric motor is attached. An example of a specific configuration of the electric motor 1 and the incidental equipment 2 of the electric motor is shown in FIG. The electric motor 1 has a rotor 1b that is rotatably provided in the electric motor 1, and a rotating shaft 1a that extends from the center of the rotor 1b and rotates integrally with the rotor 1b. A rotor winding 1c is provided on the outer periphery of the rotor 1b. A stator winding 1e wound around the stator core 1d is fixed and arranged in the electric motor 1 so as to face the rotor winding 1c.

  The electric motor 1 is provided with a unit cooler including a cooling fan 2a and a water-cooled heat exchanger 2b for cooling the heat generated in the electric motor 1. The cooling fan 2 a circulates air in the electric motor 1 to cool the heat generated in the electric motor 1. The air sent into the electric motor 1 is warmed as a result of cooling the heat in the electric motor 1, and the temperature rises. The air deprived of heat in the electric motor 1 is cooled by the water-cooled heat exchanger 2b and returned to cold air, and then sent back into the electric motor 1 by the cooling fan 2a.

  By performing such circulating cooling by the cooling fan 2a and the water-cooled heat exchanger 2b, the electric motor 1 is cooled and occurrence of problems such as seizure is prevented. The water-cooled heat exchanger 2b includes a cooling water pipe in which cooling water is circulated, and cools the air by exchanging heat between the air and the cooling water.

  In addition, a bearing stand 2c that rotatably supports the rotating shaft 1a is installed in the rotating shaft 1a portion of the electric motor 1. The bearing stand 2c is provided with a bearing oil supply device that supplies lubricating oil to the bearing. The water-cooled heat exchanger 2b, the cooling fan 2a, and the bearing stand 2c (bearing oil supply device) are an example of the auxiliary equipment 2 for the electric motor.

  The operation of the electric motor 1 is driven by the electric motor driving device 3. The electric motor 1 is connected to the communication network 6 via the electric motor side remote IO board 4 and the electric motor driving device 3 is connected to the communication network 6 via the driving apparatus side remote IO board 5, and the electric motor 1 and the electric motor driving device 3 communicate with each other. They can communicate with each other through the 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 includes information on 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.

  A preventive maintenance device 7 is connected to a communication network 6 that connects the electric motor 1 and the electric motor drive device 3. The preventive maintenance device 7 includes the motor 1 and the motor based on the operation amount of the operation signal input from the motor drive device 3 to the motor 1 and the state amount of the motor 1 that has a predetermined correlation with the operation amount. The preventive maintenance of the electric motor 1 is carried out by monitoring / detecting the abnormality of the incidental equipment 2 of FIG.

  Below, the case where the unit cooler (cooling fan 2a and the water cooling heat exchanger 2b) which is the auxiliary equipment 2 of an electric motor is made into the object which monitors and detects abnormality by the preventive maintenance apparatus 7 is demonstrated.

  The preventive maintenance device 7 monitors the abnormality of the unit cooler by using the load factor as the operation amount of the operation signal and the winding temperature rise value as the state amount of the motor 1 having a predetermined correlation with the operation amount (load factor). -Perform detection.

A predetermined correlation established between the load factor and the winding temperature rise value will be described below.
First, the load factor L is the ratio of the current value to the rated current value, and is determined by the following equation (1).

  L = i (current value) / i (rated value) × 100 [%] (1)

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

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

  Here, T is a target time for obtaining RMS, t1, t2,..., Tn is a sampling time obtained by dividing the target time T for obtaining RMS, L1, L2,..., Ln is each sampling time t1, t2,. It is a load factor at each of tn, and T = t1 + t2 + ... + tn.

  Then, when the expression (1) is substituted into the expression (2), the relationship of the following expression (3) is obtained.

  RMS ^ 2∝i ^ 2 (3)

  Next, the relationship between the winding temperature rise value ΔT and the winding current value i of the electric motor 1 is derived. Types of loss that occur in the electric motor 1 include iron loss, copper loss, stray load loss, mechanical loss, and the like. Among these, the copper loss, which is the amount of heat 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 electric motor 1, if the loss in the electric motor 1 and the copper loss are regarded as almost the same, the winding temperature rise value ΔT is equal to the copper loss, that is, the winding coil of the electric motor 1. It can be seen that it is proportional to the amount of heat generated at.

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

  Q = i ^ 2 · R · t (4)

  Then, using the fact that the winding temperature rise value ΔT described above is proportional to the calorific value Q, the following equation (5) is obtained between the winding temperature rise value ΔT and the winding current i from the equation (4). It is derived that there is a relationship shown.

  ΔT∝i ^ 2 (5)

  And the relationship shown in the following equation (6) can be derived from the equations (3) and (5).

  ΔT∝RMS ^ 2 (6)

  Thus, the winding temperature rise value ΔT is theoretically proportional to the square of the root mean square RMS of the load factor (RMS ^ 2), and when one changes, the other also changes accordingly. It can be seen that there is a relationship.

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

  Further, in order to obtain the winding temperature rise value ΔT which is one of the state quantities of the electric motor 1, the electric motor 1 includes two temperature measuring resistors 8 for measuring the winding temperature and two temperature measuring resistors 9 for measuring the refrigerant temperature. A resistance temperature detector (Resistance Temperature Detector) is attached. The temperature measuring resistor 8 for measuring the winding temperature is for detecting the temperature (exhaust temperature) of the winding portion in the electric motor 1, and the temperature measuring resistor 9 for measuring the refrigerant temperature is now transferred into the electric motor 1. This is for detecting the temperature of the refrigerant (air) to be introduced (air supply temperature).

  The preventive maintenance device 7 transmits two state quantities of the exhaust temperature detected by the resistance temperature measuring resistor 8 for measuring the winding temperature and the supply air temperature detected by the resistance temperature measuring resistor 9 for measuring the refrigerant temperature via the communication network 6. The winding temperature rise value ΔT is calculated by obtaining the difference between the exhaust temperature and the supply air temperature. The acquisition timing of the operation amount (load factor RMS) by the preventive maintenance device 7 and the acquisition timing of the state quantity (winding temperature rise value ΔT) are synchronized.

  Since the RMS of the load factor that is the operation amount obtained by the preventive maintenance device 7 and the winding temperature rise value ΔT that is the state amount are theoretically proportional to each other as shown in the equation (6), If the motor 1 and the auxiliary equipment 2 (unit cooler) of the motor are in a normal state, the load factor RMS and the winding temperature rise value ΔT show a strong correlation, and the square of the load factor RMS and the winding temperature rise value. ΔT can be modeled by a linear equation as shown in the following equation (7).

  ΔT = k · RMS ^ 2 + c (7)

  Therefore, the preventive maintenance device 7 monitors and detects an abnormality in the electric motor 1 and the incidental equipment 2 of the electric motor using the properties of the operation quantity and the state quantity that have such a predetermined correlation. The configuration of the preventive maintenance device 7 is shown in FIG. The preventive maintenance device 7 includes a model storage unit 7a, a model state quantity calculation unit 7b, a comparison unit 7c, and a notification unit 7d.

  The model storage unit 7a stores in advance a correlation model that models the relationship between the operation amount and the state amount when the motor 1 and the incidental equipment 2 of the motor are in a normal state. The modeling of the relationship between the operation amount and the state amount will be described by taking the load factor RMS and the winding temperature increase value ΔT described so far as examples.

  First, during normal operation of the electric motor 1 and the auxiliary equipment 2 (unit cooler) of the electric motor, a plurality of sets of data including a load factor RMS that is an operation amount and a winding temperature rise value ΔT that is a state quantity are stored for a certain period of time. collect. Next, based on the collected data, using a known regression analysis method such as the least square method, the coefficient k and the intercept c in the equation (7) are calculated, and the regression equation expressed in the form of the equation (7) And a correlation model that models the relationship between the operation amount and the state amount in a normal state is created.

  Then, a correlation model of the manipulated variable (RMS of load factor) and the state variable (winding temperature rise value ΔT) created in this way is stored in the model storage unit 7a. FIG. 4 shows an example of the relationship between the RMS square of the load factor and the winding temperature rise value ΔT in the correlation model stored in advance in the model storage unit 7a.

  During the operation of the electric motor 1 and the auxiliary equipment 2 of the electric motor, the preventive maintenance device 7 periodically acquires the operation amount and the 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 driving | operation to the correlation model which the model memory | storage part 7a memorize | stores, and is anticipated from a correlation model, and the motor 1 and the motor A state quantity (hereinafter referred to as a model state quantity) that will be taken if the incidental equipment 2 is normal is calculated.

  In the example of the conventional load factor RMS and winding temperature rise value ΔT, the preventive maintenance device 7 calculates the square of the load factor RMS within a certain period during the operation of the motor 1 and the auxiliary equipment 2 of the motor. Then, the model state quantity calculation unit 7b calculates the winding temperature increase value ΔT of the model state quantity by substituting the square of this RMS into the equation (7).

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

  This abnormality detection determination will be described with reference to FIG. In FIG. 5, 10 is a correlation model represented by the regression equation (7). A threshold 11 used for abnormality detection determination is set on the plus side of the ΔT axis by a predetermined reference from the straight line of the correlation model 10. When the state quantity actually detected during operation is equal to or greater than the threshold value 11 (detection point 12), it is detected that an abnormality has occurred in the motor 1 or the auxiliary equipment 2 of the motor.

  Here, the threshold 11 is set above the straight line of the correlation model 10 by a predetermined reference, but the straight line of the correlation model 10 is enlarged at a predetermined magnification (for example, 1.5 times) in the positive direction of the ΔT axis. This may be set as the threshold 11.

  When the notification unit 7d of the preventive maintenance device 7 detects that an abnormality has occurred in the motor 1 or the auxiliary equipment 2 of the motor by comparing the model state quantity and the actual state quantity in the comparison unit 7c, This is to notify the maintenance staff. As a notification form by the notification unit 7d, for example, it may be displayed on the display screen of the preventive maintenance device 7, or may be notified by sounding a buzzer or voice.

  In the preventive maintenance device for an electric motor configured as described above, a correlation model is created in which the relationship between the operation amount and the state amount when the electric motor 1 and the auxiliary equipment 2 of the electric motor are in a normal state is modeled in advance. Then, during operation of the motor 1 and the auxiliary equipment 2 of the motor, an abnormality of the motor 1 and the auxiliary equipment 2 of the motor is detected by comparing the model state quantity on the correlation model with the actual state quantity.

  Here, in general, when an abnormality is detected based on a state quantity that changes in accordance with a change in the operation amount, the state quantity serving as a reference for abnormality detection is changed according to the value of the operation amount during operation. By doing so, more accurate abnormality detection can be performed. However, the amount of operation of data sampled in a normal state does not always match the actual amount of operation during operation. Therefore, when the operation amount of the data sampled in the normal state does not match the actual operation amount during driving, there arises a problem of how to set the abnormality detection reference value.

  With respect to such a problem, in the preventive maintenance device for an electric motor according to the present invention, a state quantity serving as a reference for abnormality detection is set using a correlation model that models a relationship between an operation amount and a state quantity in a normal state. Therefore, an appropriate reference value can be set according to the actual operation amount, and it is possible to realize abnormality detection with higher accuracy.

  In addition, when looking at the number of normal operation and state data required to set the reference value, when the correlation model is not used, more data can be set by setting the reference value in order to increase the accuracy of abnormality detection. Number is needed. On the other hand, when using a correlation model, it is only necessary to have the number of data required to create a correlation model that can obtain a correlation of a certain level or more, that is, an abnormality with higher accuracy with a smaller number of data. Detection can be realized.

  Further, for example, a unit cooler that is an auxiliary equipment 2 of an electric motor, a cooling water pipe provided in the unit cooler may be contaminated inside the pipe when used for a long time, and the pipe may be gradually clogged. Since this clogging lowers the cooling function of the unit cooler, there is a risk that the motor will eventually fail. However, it is very difficult to directly detect such abnormalities in the unit cooler as clogged cooling water pipes.

  However, if the cooling function of the unit cooler is reduced due to such clogging of the cooling water pipe, the winding temperature rise value ΔT (state quantity) is larger than that in the normal state even at the same load factor (operation amount). Become. For this reason, it is possible to indirectly detect such an abnormality of the auxiliary equipment 2 of the motor by detecting a deviation of the actual state quantity from the model state quantity in the correlation model at the normal time.

  Furthermore, abnormalities accompanying deterioration that gradually progresses over time, such as clogging of the cooling water pipe of the unit cooler, are very difficult to detect because they take a long time to appear. However, since the accuracy of abnormality detection can be improved by setting the standard for abnormality detection using the correlation model at the normal time, it is possible to detect such deterioration that gradually progresses over a long period of time. Is possible.

  The preventive maintenance device for an electric motor configured as described above is a resistance temperature detector that is a state quantity acquisition means for acquiring a state quantity of the electric motor having a predetermined correlation with an operation quantity input from the electric motor drive apparatus to the electric motor. In the correlation model stored in the model storage means, the model storage means that stores in advance the correlation model modeled according to the correlation, the relationship between the operation amount and the state quantity when the motor and the incidental equipment of the motor are normal, By comparing the model state quantity calculation means for calculating the state quantity with respect to the operation quantity during operation of the electric motor, the state quantity obtained by the state quantity acquisition means during the operation and the state quantity calculated by the model state quantity calculation means, And a comparison unit that is an abnormality detection means for detecting an abnormality in the electric motor and the incidental equipment of the electric motor.

  Therefore, the abnormality detection accuracy of the motor can be improved, the preventive maintenance of the motor including abnormality monitoring / detection of the auxiliary equipment of the auxiliary motor can be performed, and the deterioration of the auxiliary equipment of the motor can be judged accurately. can do. In addition, therefore, it is possible to know in advance the signs of the failure of the incidental equipment of the motor, and to appropriately carry out maintenance according to the symptoms, so that sudden failure of the motor that affects the operation of the entire plant can be prevented. It is possible to prevent.

Embodiment 2. FIG.
FIG. 6 relates to Embodiment 2 of the present invention and is a block diagram showing a functional configuration of the preventive maintenance apparatus.
The second embodiment described here is a model that takes into account factors that affect the state quantity other than the operation quantity having a predetermined correlation with the state quantity of the motor in the configuration of the first embodiment described above. The state quantity is calculated.

  Hereinafter, as in the case of the first embodiment, as an example, a case where the load factor RMS is used as the operation amount and the winding temperature increase value ΔT is used as the state amount will be described. The winding temperature rise value ΔT, which is the state quantity, is not limited to the load factor (RMS), which is the operation quantity, for example, It also varies depending on the air volume of the cooling fan 2a.

  Specifically, for example, when the temperature of the cooling water is 20 ° C. under the same operating conditions, the winding temperature rise value ΔT is 30 ° C., and the cooling water temperature is 25 ° C. When the winding temperature increase value ΔT is 32 degrees, the correction amount for the cooling water temperature is +2 degrees. In this way, the correction amount for the cooling water temperature, the correction amount for the cooling water flow rate, and the correction amount for the fan air volume are evaluated according to the operating conditions.

  If these correction amounts are α1, α2, and α3, respectively, the regression equation of the correlation model that takes these correction amounts as correction terms is expressed by the following equation (8).

  ΔT = k · RMS ^ 2 + c + α1 + α2 + α3 (8)

  The preventive maintenance device 7 according to the second embodiment uses a regression equation having a correction term such as the equation (8) for calculation of a model state quantity used for setting a reference value for abnormality detection. . That is, as shown in FIG. 6, the preventive maintenance device 7 further includes a correction amount storage unit 7e in addition to the model storage unit 7a, the model state quantity calculation unit 7b, the comparison unit 7c, and the notification unit 7d.

  The correction amount storage unit 7e stores in advance, as a correction amount, the influence of elements other than the operation amount on the state amount (that is, the amount of change in the state amount given by the element other than the operation amount). The correlation model stored in the model storage unit 7a is of a form that does not include a correction term as in the expression (7) of the first embodiment. Then, when calculating the model state quantity in the correlation model stored in the model storage unit 7a, the model state quantity calculation unit 7b takes into account the correction amount stored in the correction amount storage unit 7e, thereby obtaining the equation (8). The model state quantity is calculated accordingly.

In this way, in the calculation of the model state quantity, it is possible to create a correlation model by separating the elements that affect the state quantity other than the manipulated variable from the part representing the correlation between the manipulated variable and the state quantity and treating them as correction terms. The abnormality detection using the calculated model state quantity can be performed in the same manner as in the first embodiment, and the abnormality detection can be performed in consideration of factors affecting the state quantity other than the operation quantity.
Other configurations are the same as those in the first embodiment, and detailed description thereof is omitted.

  In addition to the configuration of the first embodiment, the preventive maintenance device for an electric motor configured as described above further includes a correction amount storage unit that previously stores, as a correction amount, a change amount of a state amount given by an element other than the operation amount. The model state amount calculation unit calculates a state amount with respect to the operation amount during operation of the motor in the correlation model stored in the model storage unit, taking into account the correction amount stored in the correction amount storage unit.

  For this reason, in addition to being able to achieve the same effects as in the first embodiment, the correlation model can be corrected in consideration of elements other than the manipulated variable without using multiple regression analysis, and complex data It is possible to further improve the abnormality detection accuracy without undergoing processing.

Embodiment 3 FIG.
FIG. 7 is a block diagram illustrating a functional configuration of the preventive maintenance apparatus according to Embodiment 3 of the present invention.
The third embodiment described here counts the number of times that the state quantity actually detected during operation with respect to the model state quantity is more than a predetermined reference in the configuration of the first embodiment described above. When this number of times becomes equal to or greater than a predetermined number of times, the occurrence of an abnormality in the motor and its associated equipment is detected.

  As shown in FIG. 6, the preventive maintenance device 7 according to the third embodiment further includes a counting unit 7f in addition to the model storage unit 7a, the model state quantity calculation unit 7b, the comparison unit 7c, and the notification unit 7d. . The comparison unit 7c compares the model state quantity calculated by the model state quantity calculation unit 7b with the state quantity actually detected during driving, and the state actually detected during driving with respect to the model state quantity It is determined whether the amount is more than a predetermined reference.

  The counting unit 7f counts the number of times that the comparison unit 7c determines that the actual state quantity is more than a predetermined reference with respect to the model state quantity. And when this frequency | count becomes more than a predetermined frequency | count during a fixed period, abnormality generation | occurrence | production of the electric motor 1 or the incidental equipment 2 of an electric motor is detected.

  In the same way as in the first embodiment, the notification unit 7d notifies the maintenance staff or the like by screen display, voice, 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. Here, the time when the comparison unit 7c determines that the actual state quantity has deviated by more than a predetermined reference with respect to the model state quantity is recorded, and at the time of notification by the notification unit 7d, The number of times may be informed to maintenance personnel by screen display or the like.

  In the configuration of Embodiment 1, the preventive maintenance device for an electric motor configured as described above is configured so that the comparison unit and the counting unit, which are abnormality detection units, calculate the state quantity obtained by the state quantity obtaining unit during operation as a model state quantity. The abnormality of the motor and the incidental equipment of the motor is detected when the number of times away from the predetermined reference amount with respect to the state quantity calculated by the unit becomes a predetermined number of times or more within a certain period. .

  For this reason, in addition to being able to achieve the same effects as those of the first embodiment, it is possible to suppress erroneous detection of the occurrence of abnormality and realize early and highly accurate abnormality detection, and at the appropriate time for maintenance and inspection. Can be informed.

DESCRIPTION OF SYMBOLS 1 Electric motor 1a Rotating shaft 1b Rotor 1c Rotor winding 1d Stator core 1e Stator winding 2 Motor incidental equipment 2a Cooling fan 2b Water-cooled heat exchanger 2c Bearing stand 3 Motor drive device 4 Motor side remote IO board 5 Drive Device side remote IO board 6 Communication network 7 Preventive maintenance device 7a Model storage unit 7b Model state quantity calculation unit 7c Comparison unit 7d Notification unit 7e Correction amount storage unit 7f Counting unit 8 Resistance temperature detector for measuring winding temperature 9 Refrigerant temperature measurement RTD 10 Correlation model 11 Threshold 12 Detection point

Claims (3)

A preventive maintenance device for an electric motor that operates based on an operation amount input from an electric motor drive device,
State quantity acquisition means for acquiring a state quantity of the electric motor having a predetermined correlation with the operation quantity;
Model storage means for storing in advance a correlation model obtained by modeling the relationship between the operation amount and the state amount when the motor and the incidental equipment of the motor are normal according to the correlation;
Model state quantity calculating means for calculating a state quantity with respect to the manipulated variable during operation of the electric motor in the correlation model stored by the model storage means;
Abnormality detection means for detecting an abnormality in the motor and the incidental equipment of the motor by comparing the state quantity acquired by the state quantity acquisition means during the operation with the state quantity calculated by the model state quantity calculation means. And a preventive maintenance device for an electric motor. Correction amount storage means for preliminarily storing, as a correction amount, a change amount of the state amount given by an element other than the operation amount;
The model state quantity calculating means calculates a state quantity with respect to the manipulated variable during operation of the electric motor in the correlation model stored by the model storage means in consideration of the correction amount stored by the correction quantity storage means. The preventive maintenance apparatus for an electric motor according to claim 1.   The abnormality detection means is configured so that the number of times that the state quantity acquired by the state quantity acquisition means during the operation is more than a predetermined reference amount with respect to the state quantity calculated by the model state quantity calculation means is within a certain period. 3. The preventive maintenance apparatus for an electric motor according to claim 1, wherein an abnormality of the electric motor and an incidental facility of the electric motor is detected when the predetermined number of times is exceeded.

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