METHOD FOR EVALUATING THE OPERATIONAL READINESS OF AN ELECTRIC MOTOR, ELECTRIC MOTOR, AND VENTILATOR

Abstract

A method is disclosed for evaluating an operational readiness of an electric motor, such as an electric motor of a fan. The method may be used during initial start-up. The method includes: initiating a run-up process of the electric motor, the speed being changed in several speed levels during the run-up process, generating at least one measured value by measuring a physical variable with a sensor of the electric motor in at least one of the speed levels, loading at least one parameter datum from a parameter memory of the electric motor, wherein the at least one parameter datum corresponds to the at least one measured value generated, and evaluating the at least one measured value for at least one of the speed levels using the at least one loaded parameter datum. Further disclosed are an electric motor with a parameter memory and a parameterization interface as well as a fan with this electric motor and an impeller.

Claims

1-18. (canceled)

19. A method for evaluating the operational readiness of an electric motor, the method comprising: initiating a run-up process wherein the electric motor speed is changed between a plurality of speed levels; generating at least one measured value by measuring a physical variable of the electric motor with a sensor of the electric motor during at least one of the speed levels; loading at least one parameter datum from a parameter memory of the electric motor, wherein the at least one parameter datum corresponds to the generated at least one measured value; and evaluating the at least one measured value for at least one of the speed levels using the at least one loaded parameter datum.

20. The method of claim 19, wherein the run-up process comprises increasing the speed level from a lower speed to an upper speed of the electric motor.

21. The method of claim 19, further comprising determining whether the electric motor speed has reached a set speed level prior to generating the at least one measured value.

22. The method of claim 19, wherein evaluating the at least one measured value comprises: determining whether the at least one measured value is compliant with a boundary condition; and outputting a warning message if the at least one measured value is not compliant with the boundary condition.

23. The method of claim 19, further comprising estimating a bearing service life, wherein estimating a bearing service life includes at least one of loading the parameter data and measuring the measured values.

24. The method of claim 19, wherein the at least one parameter datum comprises one or more of: reference values; design information about the electric motor; design information about a load operated by the electric motor; characteristics of the electric motor; characteristics of components of the electric motor; and information about the operating behavior of the electric motor.

25. The method of claim 19, wherein generating at least one measured value, loading at least one parameter datum, and evaluating the at least one measured value are carried out for each of the speed levels.

26. The method of claim 19, wherein during generating the at least one measured value one or more of an acceleration and a speed of vibration of the electric motor is measured using a vibration sensor of the electric motor and a vibration value is generated.

27. The method of claim 26, wherein the vibration value is generated at zero speed.

28. The method of claim 26, wherein loading at least one parameter datum comprises loading a maximum permissible vibration, and evaluating the at least one measured value comprises comparing the maximum permissible vibration with the generated vibration value.

29. The method of claim 26, wherein loading the at least one parameter datum comprises loading a calibration vibration value for a current electric motor speed, the calibration vibration value being generated during a calibration measurement of the electric motor, and wherein evaluating the at least one measured value comprises comparing the calibration vibration value with the generated vibration value.

30. The method of claim 26, further comprising determining a first vibration value while the electric motor is stopped and determining a second vibration value at a non-zero speed, wherein damage is determined to be present if a difference between the second vibration value and the first vibration value exceeds a calibration vibration value by a predetermined degree, the calibration vibration value being generated during a calibration measurement of the electric motor for the non-zero speed.

31. The method of claim 19, wherein generating the at least one measured value comprises measuring a spatial orientation of the electric motor.

32. The method of claim 31, wherein loading the at least one parameter datum comprises loading a permissible range of the spatial orientation of the electric motor, and evaluating the at least one measured value comprises determining whether the spatial orientation is within the permissible range.

33. An electric motor configured to carry out the method of claim 19, the electric motor comprising a parameter memory and an interface for transferring parameter data, wherein the parameter memory is configured to store parameter data transferred via the interface during a parameterization process.

34. The electric motor of claim 33, wherein the at least one parameter datum comprises one or more of: a center of gravity of the electric motor or parts of the electric motor; a mass of the electric motor or parts of the electric motor; bearing adjustment forces; characteristic data of the bearing; a maximum permissible imbalance of the electric motor; geometric data of the electric motor; a permissible range of spatial orientations of the electric motor; a maximum permissible speed of the electric motor; and a characteristic curve of a magnetic attraction between a stator and a rotor of the electric motor.

35. A fan comprising the electric motor of claim 33 and an impeller, the electric motor further comprising a rotor, wherein the impeller is connected to the rotor.

36. The fan of claim 35, wherein the at least one parameter datum comprises one or more of: a maximum permissible imbalance of the fan; geometric data for the impeller; information about a design of the impeller; and an axial thrust-speed characteristic.

Description

[0043] There are various options for advantageously designing and refining the teaching of the present disclosure. For this purpose, reference is made, on the one hand, to the claims subordinate to the ancillary claims and, on the other hand, to the following explanation of exemplary embodiments with reference to the drawings. In connection with the explanation of various exemplary embodiments with reference to the drawings, various designs and refinements of the teaching are also explained. The figures show the following:

[0044] FIG. 1 is a block diagram with a system including an electric motor and a test system, with which parameter data can be transferred to a parameter memory;

[0045] FIG. 2 is a flow chart for storing parameter data in a parameter memory; and

[0046] FIG. 3 shows a flow chart of an exemplary embodiment of a method.

[0047] FIG. 1 shows a block diagram with a system including an electric motor 1 and a final testing system 2, the components that are most relevant here being shown in FIG. 1. The electric motor is connected to the final test system in order to carry out a test of the electric motor before it is delivered. On the one hand, sensors of the electric motor can be calibrated; on the other hand, parameter data are transferred to a parameter memory.

[0048] The electric motor 1 is part of a fan and generates vibrations during operation, which is shown by arrow 3, and a rotational speed, which is shown by arrow 4. The vibrations 3 are measured in at least one direction by an (internal) vibration sensor 5 of the electric motor. The vibration sensor 5 is an example of a sensor that can be used in the method disclosed herein. The measured values determined by the vibration sensor 5 are transferred to a processor 6, which is formed, for example, by a microcontroller. This processor 6 can, for example, carry out an analog-digital conversion and/or control the acquisition of the measured values. The processor 6 can thus determine vibration values from the measured values. In addition, the processor 6 is designed to determine the current rotational speed.

[0049] The processor 6 is connected to an interface 7 and an (internal) memory, which is designed as a non-volatile memory and functions as a parameter memory 8. The interface 7 represents a communication connection to the test system 2. Information can be sent to the test system 2 via an output OUT of the interface 7, and information from the test system 2 can be received via an input IN of the interface 7, in which the input channel and the output channel do not necessarily have to be implemented separately from one another, but may also use a common communication line, for example a bus.

[0050] The test system 2 includes at least one test sensor 9, a speed sensor 10, a data acquisition unit 11, a processor 12, and an interface 13. The test system is designed, inter alia, to calibrate the vibration sensor 5 using the at least one test sensor 9. The at least one test sensor 9 is designed to measure the vibrations 3 of the electric motor 1. For this purpose, the at least one test sensor 9 is coupled to the electric motor in terms of vibration. The speed sensor 10 measures the current rotational speed 4 of the electric motor 1. Both the test sensor(s) 9 and the speed sensor 10 transfer measured values to the data acquisition unit 11, which in turn can transfer information to the processor 12. The processor 12 is connected to a data output unit 14, via which, for example, a balance display can take place or the results of a final test can be output. The processor is also connected to interface 13 which, like interface 7, includes an input IN and an output OUT. The input IN of interface 13 is connected, in a communicating manner, to the output OUT of interface 7, while the output OUT of interface 13 is connected, in a communicating manner, to the input IN of interface 7. In addition, the input IN of interface 13 is connected to the data acquisition unit 11, and the output OUT of interface 13 is connected to a database 15 which represents a motor database for storing operating parameters of the electric motor 1. At the same time, the input IN of interface 13 is connected to a PPS database 16 (product planning and control) which stores information about the structure and condition of the electric motor 1.

[0051] FIG. 2 shows a flow chart which indicates, by way of example, the storage of parameter data in the parameter memory 8. In step 20, system-internal characteristics of the fan or its motor or its components are loaded from the PPS database 16. This parameter data can include: [0052] Centers of gravity and masses (e.g. rotor, impeller, stator bushing) [0053] Bearing adjustment forces [0054] Axial thrust-speed characteristic (caused by impeller) [0055] Magnetic attraction between stator and rotor (radial force) [0056] Characteristic data of the bearings and the greasing thereof, possibly including the date of manufacture of the bearings [0057] Maximum permissible imbalance and/or actual residual imbalance from the final test [0058] Additional features of the bearing, e.g. Nilos ring etc., which have an influence on the estimation of the bearing service life [0059] Geometric data of the electric motor or the fan [0060] Permitted or standard installation positions [0061] Maximum permissible speed-vibration value pairs or characteristic curve

[0062] These or similar parameter data can originate from various sources in the PPS database 16. Thus, it would be conceivable that individual pieces of information come from CAD (Computer Aided Design) data sets. Other information can come from the technical design or from measurements on an identical electric motor. In addition, parameter data can result from the calibration measurements and can also be loaded or collected in step 20.

[0063] In step 21, the parameter data that were loaded or collected in step 20 are transferred to interface 13 for parameterization. From there, they are transferred to the database 15 and to interface 7 of the electric motor 1. The database 15 can store a “digital twin” of the electric motor, and the parameter data can be stored there as part of the “digital twin.” In step 22, the parameter data that have been transferred to interface 7 are received by the electric motor and stored in the parameter memory 8.

[0064] FIG. 3 shows a flow chart of an exemplary embodiment of a method that uses this parameter data. In step 25, a supply voltage is applied to the electric motor 1, so that the motor electronics are supplied with energy and started up. In step 26, there is a check as to whether the electric motor is being placed into operation for the first time after the final test. If this question is answered in the negative, there is a change to step 27, in which the process sequence ends. If the question is answered in the affirmative, the actual evaluation process begins with step 28. The commissioning run is started here. In step 29, a run-up process begins, in which the rotational speed of the electric motor is increased in several speed levels, from a speed of zero to a nominal speed.

[0065] In step 30, measured values from sensors of the electric motor are collected, which are measured in steps 31, 32, and 33. In step 31, the spatial orientation of the electric motor or its shaft is determined by an inclination measuring unit. In step 32, vibrations of the electric motor are measured by a vibration sensor, and vibration values are determined. In step 33, the rotational speed of the electric motor is determined. In some embodiments, steps 32 and 33 can be carried out for all speed levels, even if the flow chart shows only one run-up for the sake of clarity. In most application scenarios, the installation position can only be measured once, as the installation position should not change.

[0066] In step 34, parameter data corresponding to the recorded measured values are loaded from the parameter memory. In the present case, these parameter data are a permissible range of a spatial orientation of the electric motor, a maximum permissible imbalance of the electric motor, a maximum permissible vibration, and vibration values from the final test of the electric motor. This is symbolized by field 46 which represents the parameter data stored in the parameter memory 8.

[0067] In step 35, the spatial orientation of the electric motor measured by the inclination measuring unit is compared with the parameter datum “permissible range of spatial orientation,” and the measured value of the spatial orientation of the electric motor is thus evaluated. If the measured spatial orientation is outside the permissible range, a warning message is output in step 36, according to which the installation position is outside the permissible range. The procedure can then be canceled. If the measured spatial orientation is within the permissible range, there is a change to step 37.

[0068] In step 37, pairs of values from a rotational speed and an associated vibration value are compared with tolerance limits, the tolerance limits being defined by the previously loaded parameter data. If the vibration value is outside the tolerance limits, there is a reaction to this in step 38. On the one hand, a warning message is issued that the vibration value is greater than the maximum permissible vibrations. On the other hand, the rotational speed can be reduced, which should reduce the vibrations. If the vibrations are reduced considerably with a relatively small change in speed, it can be concluded that a resonance point is present. In this case, the procedure can in principle be continued. If the speed reduction does not result in a significant reduction in the vibrations, the process can be terminated completely. The same can be done if the vibration value is significantly above the maximum permissible vibration value.

[0069] In step 39, a currently measured vibration value is compared with the vibration values that were carried out during the final test of the electric motor. If the currently measured vibration values are significantly greater than the vibration values from the final test, it is very likely that the electric motor has been damaged or incorrectly installed. When evaluating the currently measured vibration values, the vibrations in the installation environment are also taken into account. For this purpose, vibrations at a speed of zero for the electric motor are recorded and subtracted from the vibration values at a speed not equal to zero. This prevents an incorrect decision due to vibrations from the installation environment. If the vibration values from the calibration measurement are significantly exceeded, it can be indicated in step 40 that transport damage or an assembly fault is very likely. In this case, too, the execution of the further method can be interrupted, so that further damage to the electric motor or the fan can be prevented.

[0070] In step 41, the nominal speed of the electric motor is reached, and the run-up process is completed. The forces actually acting on the bearings can then be calculated in step 42. For this purpose, the spatial orientation recorded in step 31, the vibration values recorded in step 32, and the rotational speed recorded in step 33 are processed. In addition, further parameter data are loaded from the parameter memory, which can include, for example, bearing adjustment forces, geometric information on the electric motor, geometric information on the impeller, an axial thrust/speed characteristic curve, and information on the masses of parts of the electric motor.

[0071] The bearing service life is then estimated as an initial value in step 43 from the actually acting forces calculated in this way. This can be specified as the nominal bearing service life L10h. This is defined in Standard ISO 281 and indicates the service life that is achieved by 90% of the bearings tested under the same operating conditions. The nominal service life L10h thus stands for a 10 percent failure probability.

[0072] In step 44, the initial value of the bearing service life and data that have been obtained over the course of the method are stored in an internal memory of the motor electronics.

[0073] Furthermore, it is indicated in step 45 that nominal operation has been started. The method then ends in step 27, which represents the nominal operation of the electric motor.

[0074] In addition, the measured values obtained during the course of the method and/or the results of the evaluations can be transferred to the database 15. For example, the initial value of the nominal service life L10h and measured values for the vibrations in the installation environment can be transferred to the database and supplement the “digital twin.” Additionally or alternatively, it is also conceivable that the information obtained, for example in an industrial 4.0 environment, is sent to a monitoring unit, in which the monitoring unit would monitor safe operation of the electric motor.

[0075] With regard to further advantageous embodiments of the method according to various embodiments, reference is made to the general part of the description and to the appended claims in order to avoid repetition.

[0076] Finally, it is to be expressly noted that the above-described exemplary embodiments are used solely to explain the claimed teaching, but do not restrict it to the exemplary embodiments.

LIST OF REFERENCE NUMERALS

[0077] 1 Electric motor [0078] 2 Final test system [0079] 3 Vibrations [0080] 4 Rotational speed [0081] 5 Vibration sensor [0082] 6 Processor [0083] 7 Interface [0084] 8 Parameter memory [0085] 9 Test sensor [0086] 10 Rotational speed sensor [0087] 11 Data acquisition unit [0088] 12 Processor [0089] 13 Interface [0090] 14 Data output unit [0091] 15 Database [0092] 16 PPS database