Motor drive for monitoring operating measurement data of an electric motor with at least one operating point

Abstract

Motor drive for monitoring operating measurement data (34) of an electric motor (12) with at least one operating point (78, 80, 82, 84), wherein the electric motor (12) is designed to drive a load (21), wherein the motor drive (10) comprises the following: - a measuring unit (14) for acquiring initial measurement data (118) for at least one of the operating points (78, 80, 82, 84) of the electric motor (12), wherein the initial measurement data include sensor data and / or estimation data; - a processing unit (26) for determining a baseline (58, 60, 62, 64) from the initial measurement data (118) for the at least one operating point (78, 80, 82, 84); an output unit (28); characterized in that the processing unit (26) is designed to generate at least one threshold level (36, 38, 40) for at least one specific baseline (58, 60, 62, 64) while the electric motor (12) is in an on state or an off state; where at least one threshold level (36, 38, 40) defines a deviation level from the determined baseline (58, 60, 62, 64), wherein the output unit (28) is designed to provide at least one threshold level (36, 38, 40), which leads to conditions for monitoring the operational measurement data (34) of the electric motor (12).

Description

[0001] The invention relates to a motor drive and a method for monitoring operating measurement data of an electric motor with at least one operating point.

[0002] Complex systems, such as electric motors, comprise many parts, so these systems have many sources and levels of failure. Early detection and repair of these failures can lead to longer system uptime and lifespan and reduce costs caused by shutdowns. To detect faulty components, the system has sensors that monitor these systems. The sensors collect sensor data that indicates the system's condition.

[0003] From US 7,991,586 B2, it is known to measure values ​​of a pump or drive motor. These measured values ​​are monitored and evaluated. Furthermore, the pump or drive motor comprises a memory that stores technological data of the pump or drive motor. Based on the measured values ​​and the technological data, a microcomputer calculates operating data. A display device shows the measured values ​​and / or the calculated operating data. Furthermore, the display device indicates a "good" condition, a warning condition, or an alarm condition for the pump assembly and can provide information about the operating points of the pump or drive motor. However, the determination of the conditions for the pump assembly is based on the technological data stored in the memory, which may be unsuitable for the actual operating point of the pump or drive motor.

[0004] Thus, the technical task may be to provide an improved motor drive for monitoring operating measurement data of an electric motor that is more accurate than the state of the art.

[0005] Claim 1 sets out the main features of the invention. Features of embodiments of the invention are subject to claims 2 to 12.

[0006] In one aspect of the invention, a motor drive is provided for monitoring operational measurement data of an electric motor having at least one operating point, the electric motor being configured to drive a load, the motor drive comprising: a measurement unit for acquiring initial measurement data for at least one of the operating points of the electric motor, the initial measurement data comprising sensor data and / or estimation data; a processing unit for determining a baseline from the initial measurement data for the at least one operating point; an output unit; the processing unit being configured to generate at least one threshold level for the at least one determined baseline while the electric motor is in an on-state or an off-state;wherein the at least one threshold level defines a deviation level from the determined baseline, wherein the output unit is configured to provide the at least one threshold level, resulting in conditions for monitoring the operating measurement data of the electric motor;

[0007] According to the invention, the motor drive generates at least one threshold level for a baseline from initial measurement data. The motor drive acquires the initial measurement data by initially operating the electric motor at at least one operating point. The initial operation can be a reference phase of the electric motor, wherein the reference phase is used to generate the initial measurement data. Alternatively, the initial operation can be the start of a normal operating phase of the electric motor. The generation of the threshold level is based on the initial measurement data acquired during operation of the electric motor at at least one operating point. The initial measurement data for the at least one operating point is used to determine the baseline for a particular operating point. When the electric motor is operated at different operating points, the motor drive generates a baseline for each operating point. At least one threshold level is determined for each baseline.More than one threshold level has different deviations from the baseline. This means that the threshold levels also deviate from one another. Thus, with respect to the baseline, one of the threshold levels may be the lowest threshold level, and another may be the highest threshold level. Each additional threshold level has a lower neighboring threshold level and a higher neighboring threshold level. The resulting threshold levels apply to specific operating points. The determined threshold levels reflect the failure probability of the electric motor with a high degree of accuracy because they are based on the specific operating points of the electric motor. In addition, the motor drive further provides thresholds for other operating points of the electric motor, so that the corresponding threshold levels are applied to each operating point. This increases the accuracy of the motor drive for monitoring operating metrics of an electric motor.Therefore, these threshold levels can be used as conditions for monitoring the electric motor. Furthermore, a threshold regime with increasing threshold levels can be provided by setting at least two different threshold levels for each baseline, i.e., for each operating point of the electric motor. Each threshold level can indicate a different failure probability, allowing the motor drive, the electric motor, or a user to react depending on the threshold level exceeded by the operating measurement data during operation of the electric motor. The threshold levels can also indicate which components of the electric motor have an increased failure probability.

[0008] The measurement data can, for example, be data on vibration, load, flux, torque, current, stator windings, temperature, humidity, lifetime, and / or operating hours, etc. Furthermore, the measurement data can include more than one data type, e.g., vibration data and flux data, or load data, current data, and vibration data. Thus, the motor drive provides baselines and threshold levels for combinations of several data types for the at least one operating point.

[0009] In one example, the measuring unit may be configured to receive operational measurement data for a current operating point of the electric motor, wherein the processing unit is further configured to determine the respective threshold levels exceeded by the operational measurement data corresponding to the current operating point.

[0010] The motor drive's processing unit can also be used to monitor the operational measurement data acquired after the threshold levels have been determined. Thus, the processing unit can determine whether the operational measurement data exceeds at least one threshold level for a specific operating point.

[0011] Furthermore, the processing unit may be configured to initially compare the operational measurement data with a lowest of the at least one threshold level, wherein the processing unit is further configured to compare the operational measurement data with a further one of the at least one threshold level if the operational measurement data exceeds all threshold levels that are lower than the further one of the at least one threshold level.

[0012] Thus, the processing unit first determines whether the operating measurement data for the current operating point of the electric motor exceeds the lowest of at least one threshold level. If the operating measurement data exceeds the lowest threshold level, the processing unit checks whether the operating measurement data exceeds the next threshold level.

[0013] The processing unit may further be configured to provide a monitoring signal indicating the number of threshold levels exceeded by the operational measurement data, wherein the operational measurement data preferably comprises more than one measurement signal and / or more than one estimation signal. The operational measurement data may be combinations of several measurement signals and / or estimation signals. The estimation signals are sensorless data that only estimate the monitored values.

[0014] The monitoring signal can be used to initiate maintenance processes for the electric motor. Depending on the number of threshold levels exceeded, the monitoring signal can initiate different maintenance processes. The monitoring signal can be used for condition-based maintenance or predictive maintenance of the electric motor.

[0015] In another example, the monitoring signal may be a warning signal if the measured value exceeds one of at least two threshold levels, wherein the monitoring signal is an alarm signal if the operational measurement data exceeds each threshold level.

[0016] This provides a gradual increase in the warning and / or alarm level. The monitoring signal will first indicate a warning when the operating measurement data exceeds the first threshold level. The warning becomes more intense as subsequent threshold levels are exceeded. If the operating measurement data also exceeds the highest threshold level, the monitoring signal will become an alarm signal, indicating a serious fault with the electric motor.

[0017] Furthermore, the processing unit may be designed to deliver the monitoring signal corresponding to the exceeding of a particular threshold level after a predetermined period of time which depends on the number of threshold levels exceeded, wherein the predetermined period of time is shorter the higher the number of threshold levels exceeded.

[0018] The processing unit therefore waits for a predetermined period of time before providing the monitoring signal for a particular threshold level after the operational measurement data has exceeded a threshold level. If the subsequently acquired operational measurement data does not exceed the particular threshold level during the predetermined period of time, the processing unit will not provide the monitoring signal for the particular threshold level. Furthermore, a counter of the predetermined period of time may be reset after the particular threshold level is no longer exceeded. The resetting of the counter may be delayed to check whether the operational measurement data remains below the threshold level for a certain period of time. The high threshold levels have shorter predetermined periods.This means that the waiting time for the processing unit to provide the monitoring signal for a particular threshold level is shorter for the high threshold levels than the predetermined period for the low threshold levels. Thus, serious errors are indicated by the monitoring signal more quickly than non-serious errors.

[0019] The monitoring signal can also indicate a non-fault condition of the electric motor if the operating measurement data does not exceed a threshold level.

[0020] Furthermore, the processing unit may be further configured to provide at least one automatically or manually provided value as the at least one generated threshold level, wherein the at least one automatically or manually provided value is preferably a factory default value for the electric motor.

[0021] The measuring unit may also be designed to acquire at least a portion of the initial measurement data during a transition of the electric motor between two of the plurality of operating points.

[0022] Thus, the processing unit also provides baselines and threshold levels for the transition phase between two operating points. If the electric motor transitions between two operating points, the motor drive can provide the corresponding threshold levels for the transition phase to check whether the operating measurement data exceeds the threshold levels corresponding to the transition phase. This results in continuous monitoring of the electric motor's operation.

[0023] The at least one operating point can be a speed profile of the electric motor.

[0024] The initial measurement data and the operating measurement data may comprise different data types, wherein the data types preferably comprise vibration data, load data, flux data, torque data, current data and / or stator winding data.

[0025] The measurement data can therefore be a combination of different data types, forming a multidimensional pattern. This further increases the accuracy of electric motor monitoring.

[0026] In one example, the measuring unit may be a frequency converter for driving the electric motor.

[0027] Thus, the frequency converter can be used as a sensor to monitor the condition of the electric motor that the frequency converter drives.

[0028] In another example, the at least one processing unit is connected to another cloud-based device, wherein the processing unit is configured to receive at least one threshold level for the at least one determined baseline by the cloud-based device as the at least one generated threshold level, wherein the cloud-based device is configured to determine a baseline from the initial measurement data for the at least one operating point.

[0029] The cloud-based device can therefore determine the baseline and generate the threshold instead of the processing unit. The cloud-based device receives all the data required to determine the baseline. From this baseline, the cloud-based device generates the threshold and delivers it to the processing unit. Data transmission can be provided, for example, via a wireless network or a LAN network.

[0030] Furthermore, the cloud-based device can receive the operating measurement data and check whether the operating data exceeds at least one threshold.

[0031] A method for monitoring operational measurement data of an electric motor having at least one operating point comprises, in particular, the following steps: acquiring initial measurement data for at least one of the operating points of the electric motor using a motor drive according to the preceding claims; receiving an operating point signal indicative of the operating point of the electric motor; determining a baseline from the initial measurement data for each operating point; generating at least one threshold level for each determined baseline; wherein the at least one threshold level defines a level of deviation from the determined baseline; and providing the at least one threshold level, resulting in conditions for monitoring the operational measurement data of the electric motor.

[0032] In one example, the method may further comprise the steps of receiving operational measurement data for an operating point of the electric motor and determining the threshold levels exceeded by the operational measurement data corresponding to the operating point.

[0033] Furthermore, the method may further comprise the step of providing a monitoring signal indicating the number of threshold levels exceeded by the operational measurement data.

[0034] The effects and further embodiments of the method are equivalent to the effects and embodiments of the motor drive according to the above-mentioned description. Therefore, reference is made to the above description of the motor drive.

[0035] The method may further comprise the step of initiating a maintenance process based on the monitoring signal if the monitoring signal indicates that the measured value exceeds at least one of the threshold levels.

[0036] Depending on the monitoring signal, customized maintenance can be scheduled for the electric motor. Maintenance can be performed by the electric motor, an external system, and / or a user.

[0037] Further features, details, and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments based on the drawings. The drawings show: Fig. 1a, b schematic drawings of the motor drive for monitoring operating measurement data of the electric motor; Fig. 2a-d schematic diagrams showing the relationship between the initial measurement data and the threshold levels; Fig. 3 is a schematic diagram showing the use of threshold levels for operational measurement data; Fig. 4 a flowchart for monitoring operating measurement data of the electric motor; Fig. 5 another flowchart.

[0038] Fig. 1a shows the motor drive 10 for monitoring operating measurement data of the electric motor 12.

[0039] The motor drive 10 may include a frequency converter 22 that converts a frequency arriving from an input power supply line 18 into a variable output frequency for the electric motor 12. The output frequency is supplied to the electric motor 12 via the output line 16. The electric motor 12 has a drive shaft 20 that can rotate at different speeds. The different speeds of the drive shaft 20 define different operating points of the electric motor 12. The drive shaft 20 is connected to a load 21 so that the electric motor 12 drives the load 21. The load 21 may be a customer application. The load 21 may be, for example, a pump.

[0040] According to Fig. 1b, the frequency converter 22 as part of the motor drive 10 comprises a measuring unit 14, an input unit 24, a processing unit 26 and an output unit 28. In one example, the monitoring of the state of the electric motor can also be carried out on the Fig. 1a, where data is stored, processed, analyzed, and decisions are made. The motor drive 10 can transmit measurement data via a wireless network or a LAN network to the Fig. Cloud 23 shown in Figure 1a.

[0041] The measuring unit 14 is designed to acquire measurement data for at least one operating point of the electric motor. The measurement data can be initial measurement data or operating measurement data of the electric motor. Initial measurement data can be acquired while the electric motor is operating in the reference phase in order to acquire reference data about the electric motor. When the electric motor is not in the reference phase, operating measurement data can be acquired.

[0042] The measurement data can be of different types. For example, the measurement data can be one or a combination of vibration data, load data, flux data, torque data, current data, and / or stator winding data. Furthermore, the measurement data can be sensor data or estimation data.

[0043] The processing unit 26 is configured to determine a baseline from the initial measurement data for each operating point of the electric motor. Furthermore, the processing unit is configured to generate at least one threshold level for each determined baseline. The at least one threshold level defines a deviation level from the determined baseline. The processing unit 26 can determine the baseline and generate the threshold independently of the on and off states of the electric motor.

[0044] The processing unit 26 is further configured to determine the threshold levels exceeded by the operational measurement data corresponding to the operating point of the electric motor. The processing unit 26 initially compares the operational measurement data with a lowest threshold level of the at least one threshold level. If the processing unit 26 determines that the operational measurement data exceeds the lowest threshold level, the processing unit 26 compares the operational measurement data with the next lower threshold level. Thus, the processing unit 26 is configured to compare the operational measurement data with a particular threshold level if the operational measurement data exceeds all threshold levels that are lower than the particular threshold level.

[0045] Furthermore, the processing unit 26 is configured to provide a monitoring signal. The monitoring signal indicates the number of threshold levels exceeded by the operational measurement data. If the operational measurement data exceeds the lowest threshold level, the monitoring signal can be a warning signal. The warning level of the warning signal can increase if the operational measurement data exceeds further threshold levels. If the operational measurement data exceeds all threshold levels, the monitoring signal can be an alarm signal.

[0046] The processing unit 26 is configured to wait for a predetermined period of time before providing the monitoring signal indicating the exceeding of a particular threshold level. If the operational measurement data continues to exceed the particular threshold level after the predetermined period of time, the processing unit 26 provides the monitoring signal for the particular threshold level. If the operational measurement data no longer exceeds the particular threshold level after the predetermined period of time, the processing unit 26 may wait for a cooling-off period before refraining from providing the monitoring signal for the particular threshold level and resetting the predetermined period of time. If the operational measurement data exceeds the threshold level again during the cooling-off period, the processing unit 26 continues to wait for the predetermined period of time of the previous exceedance of the threshold level.

[0047] The higher the threshold level, the shorter the predetermined period of time in which the processing unit 26 waits whether the operational measurement data remains above the threshold level or not.

[0048] The output unit 28 is configured to provide the at least one threshold level. The at least one threshold level can be stored in a memory (not shown) of the frequency converter or in a cloud-based storage and later used as a condition for monitoring the operating measurement data of the electric motor.

[0049] Fig. Figures 2a to 2d show various diagrams used to explain how the processing unit determines the threshold levels from the initial measurement data.

[0050] According to Fig. Figure 2a shows a graph plotting the speed 66 of the electric motor's drive shaft over time 30. Different speed profiles correspond to different operating points. In an initial phase, the curve includes a ramp 94 in which the speed 66 is increased to a first operating point 78. The speed 66 then remains constant. At this starting point 86, sampling of the initial measurement data is started. The initial measurement data can be fault detection data.

[0051] The acquisition of the initial measurement data starts with a first plateau phase 98. After the first plateau phase 98, the speed 66 is slowly increased to another operating point in a transition phase 106. A second plateau phase 100 starts, in which the speed 66 remains constant. At the end of the plateau phase 100, another transition phase 106 is started, in which the speed 66 is slowly increased. When the speed 66 reaches a third operating point, a third plateau phase 102 starts. After another transition phase 106, a fourth plateau phase 104 begins, which corresponds to a final operating point 84. At the end of the plateau phase 104, a ramp-down phase 96 is started, in which the speed 66 is ramped down.

[0052] Fig. 2b shows a diagram with the same elements as the diagram of Fig. 2a. The same reference numbers denote the same elements, so that the description of Fig. 2a. The diagram of Fig. 2b and the diagram of Fig. 2a differ in the starting point 86 of the sampling of the initial measurement data. In Fig. 2b, the starting point 86 is at the beginning of a transition phase 106, where the starting point 86 is in Fig. 2a is at the beginning of a plateau phase. Thus, the sampling of the initial measurement data starts in Fig. 2b with a transition phase 106 and not with a plateau phase 98 as Fig. 2a.

[0053] The diagram in Fig. Figure 2c shows an error signature 56 versus time 30. The error signature 56 can, for example, be based on the vibration as initial measurement data 118 measured by the measuring unit. The curve of the diagram shows the initial measurement data 118. The transition phase 106 of Fig. 2a and Fig. 2b corresponds to sections 116 in Fig. 2c. Plateau phases 98, 100, 102 and 104 of Fig. 2a and Fig. 2b correspond respectively to sections 108, 110, 112 and 114 of Fig. 2c.

[0054] The diagram in Fig. Figure 2d shows the error signature 56 versus the speed 66. The axis of speed 66 denotes the operating points 78, 80, 82 and 84. The processing unit uses the initial measurement 118 of Fig. 2c to determine baselines 68 for each operating point 78, 80, 82 and 84. For example, baseline 58 corresponds to operating point 78, baseline 60 corresponds to operating point 80, baseline 62 corresponds to operating point 82 and baseline 64 corresponds to operating point 84.

[0055] The baseline 58, 60, 62 and 64 may include some error 132, which indicates a region in which the corresponding baseline 58, 56, 62 and 64 may also be located with a certain probability.

[0056] For each operating point 78, 80, 82 and 84, the processing unit generates at least one threshold level 70. According to Fig. 2d, the processing unit generates three threshold levels 70. The operating point 78 includes the threshold levels 36, 38, and 40. The operating point 80 includes the threshold levels 36', 38', and 40'. The operating point 82 includes the threshold levels 36'', 38'', and 40''. The operating point 84 includes the threshold levels 36''', 38''', and 40'''.

[0057] The processing unit further interpolates each threshold level between the operating points. For example, threshold levels 36, 36', 36'', and 36''' are connected via line 72 to provide threshold levels for the electric motor operating points between the designated operating points 78, 80, 82, and 84. Line 74 connects threshold levels 38, 38', 38'', and 38''', and line 76 connects threshold levels 40, 40', 40'', and 40'''.

[0058] Fig. Figure 3 shows two diagrams. The diagram on the left shows the fault signature 56 versus time 30, comprising the operational measurement data 34. The diagram on the right shows the fault signature 56 versus a delay time 48. Both diagrams include threshold levels 36, 38, and 40.

[0059] During a period 32, the operational measurement data 34 in the left-hand diagram remains below the lowest threshold level 36. After the period 32, the operational measurement data 34 exceeds the threshold level 36. The processing unit detects the time at which the operational measurement data 34 exceeds the threshold level 36 and initiates the transmission of a monitoring signal, which is a warning signal 42. Before sending the warning signal 42, the processing unit waits for a predetermined period 50, which is shown in the right-hand diagram. The processing unit checks whether the operational measurement data 34 remains above the lowest threshold level 36 during the period 50. If the operational measurement data 34 continues to exceed the lowest threshold level 36, the processing unit sends the warning signal 42.If the operational measurement data 34 falls below the lowest threshold level 36, the processing unit waits for a further predetermined period of time before resetting a time counter for the predetermined period 50. If the operational measurement data 34 remains below the threshold level 36 after the further predetermined period of time, the processing unit resets the predetermined period of time 50. If not, the processing unit continues to wait for the predetermined period of time 50 and transmits the monitoring signal after the predetermined period of time 50.

[0060] If the operational measurement data 34 exceeds the further threshold level 38 after exceeding the lowest threshold level 36, the processing unit waits for a further predetermined period 52, which is shorter than the predetermined period 50, before sending a further warning signal 44. During the predetermined period 52, the processing unit checks whether or not the operational measurement data 34 falls below the threshold level 38. If the operational measurement data 34 continues to be above the threshold level 38, the processing unit will send the further warning signal 44 as a monitoring signal. If the operational measurement data 34 falls below the threshold level 38, the processing unit waits for a further predetermined period before resetting a counter for the predetermined period 52.If the operational measurement data 34 remains below the threshold level 38 after the further predetermined period of time, the processing unit resets the predetermined period of time 52. If not, the processing unit continues to wait for the predetermined period of time 52 and transmits the monitoring signal after the predetermined period of time 52. The further warning signal 44 provides a higher warning level than the warning signal 42.

[0061] If the operational measurement data 34 exceeds the highest threshold level 40 after exceeding the threshold levels 36 and 38, the processing unit waits for the last predetermined period 54, which is shorter than the predetermined period 52, before sending an alarm signal 46. During the predetermined period 54, the processing unit checks whether or not the operational measurement data 34 falls below the threshold level 40. If the operational measurement data 34 continues to be above the threshold level 40, the processing unit will send the alarm signal 46 as a monitoring signal. If the operational measurement data 34 falls below the threshold level 40, the processing unit waits for a further predetermined period before resetting a counter for the predetermined period 54. If the operational measurement data 34 continues to be below the threshold level 40 after the further predetermined period, the processing unit resets the predetermined period 54.If not, the processing unit continues to wait for the predetermined period of time 54 and sends the monitoring signal after the predetermined period of time 54. The alarm signal 46 is intended to alert the system or a user that the electric motor has a serious fault that may cause damage and soon failure.

[0062] Fig. 4 shows a flowchart of a method 500 for monitoring operating measurement data of the electric motor with at least one operating point.

[0063] In a first step 502, initial measurement data for at least one of the operating points of the electric motor is acquired by a motor drive for monitoring operating measurement data of the electric motor as described above. A measurement unit of the motor drive can acquire the initial measurement data. Furthermore, the initial measurement data can be one or a combination of the group of vibration data, load data, flux data, torque data, current data, stator winding data, temperature, humidity, service life and / or operating hours data, etc.

[0064] In the further step 504, an operating point signal is received that indicates the operating point of the electric motor. An input unit of the motor drive can receive the operating point signal. Furthermore, the operating point can be a speed profile of the electric motor.

[0065] In step 506, a baseline is determined from the initial measurement data for each operating point. A processing unit of the motor drive can perform this step, with the processing unit receiving the initial measurement data from the input unit.

[0066] In a step 508, at least one threshold level may be generated for each determined baseline. Additionally, the processing unit may perform this step. Furthermore, the at least one threshold level defines a level of deviation from the determined baseline.

[0067] In step 510, the at least one threshold level is provided as conditions for monitoring the electric motor. The threshold levels can be used to check whether the operational measurement data indicates electric motor faults.

[0068] In step 512, operational measurement data for an operating point of the electric motor can be received. The motor drive's measurement unit can perform this step.

[0069] In step 514, the threshold levels exceeded by the operational measurement data corresponding to the operating point are determined. This means checking whether the operational measurement data exceeds a particular threshold level. The processing unit can perform this step.

[0070] In a further step 516, a monitoring signal is provided indicating the number of threshold levels exceeded by the operational measurement data. The monitoring signal can be a warning signal or an alarm signal. A warning signal is provided if the operational measurement data exceeds a threshold level that is lower than the highest threshold level. If the operational measurement data exceeds the highest threshold level, the alarm signal is provided. The processing unit can perform this step.

[0071] In step 518, a maintenance process based on the monitoring signal may be initiated. The monitoring signal indicates that the operating measurement exceeds at least one of the threshold levels. The electric motor and the external system and / or a user may perform the maintenance. The processing unit may also perform step 518.

[0072] Fig.5 shows a flowchart with a specific embodiment of the method 500. The same reference numbers indicate the same elements of the method 500.

[0073] The flowchart includes a baseline component 126, a threshold component 128, and a monitoring component 130.

[0074] The process steps performed by the measuring unit are shown as steps 502 and 512. The operating measurement data 34 and the initial measurement data 118 are indicated as arrows.

[0075] In the baseline component 126, the rotational speed 66 is received as an operating point in step 504. Furthermore, the initial measurement data 118 is received so that further steps can use the initial measurement data 118. In step 506, a baseline is determined from the initial measurement data for each operating point. Furthermore, in an optional step 522, a rotational speed profile can be generated. This rotational speed profile can be fed to the motor controller of the electric motor in a further optional step 524 to obtain the data of the rotational speed 66 as operating points for the electric motor.

[0076] In the threshold component 128, after calculating the thresholds in step 508, the threshold levels and the drive unit operating points may be stored as a threshold array in a memory in step 520.

[0077] In monitoring component 130, the speed threshold arrays 66 may be received as operating points in step 510 to provide the at least one threshold level as conditions for monitoring the electric motor operating measurement data. Furthermore, in step 512, the operating measurement data 34 for the electric motor operating point may be received. The threshold levels 36, 38, and 40 are provided and received in step 514. Step 514 determines whether the threshold operating measurement data exceeds threshold levels for the corresponding operating point.

[0078] If the operating measurement data exceeds any of the threshold levels 36, 38, and 40, a monitoring signal indicating the number of threshold levels exceeded is provided in step 516. The provided monitoring signal can trigger maintenance in step 518.

[0079] The invention is not limited to any of the aforementioned embodiments. It can be modified in many ways.

[0080] All features and advantages arising from the claims, the description and the drawings, including constructional details, spatial arrangements and procedural steps, may be essential to the invention, both individually and in various combinations. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 7,991,586 B2

[0003]

Claims

[1] Motor drive for monitoring operating measurement data (34) of an electric motor (12) having at least one operating point (78, 80, 82, 84), wherein the electric motor (12) is designed to drive a load (21), wherein the motor drive (10) comprises: - a measuring unit (14) for acquiring initial measurement data (118) for at least one of the operating points (78, 80, 82, 84) of the electric motor (12), wherein the initial measurement data comprise sensor data and / or estimation data; - a processing unit (26) for determining a baseline (58, 60, 62, 64) from the initial measurement data (118) for the at least one operating point (78, 80, 82, 84); an output unit (28); characterized by that the processing unit (26) is designed to generate at least one threshold level (36, 38, 40) for the at least one specific baseline (58, 60, 62, 64) while the electric motor (12) is in an on-state or an off-state; wherein the at least one threshold level (36, 38, 40) defines a level of deviation from the determined baseline (58, 60, 62, 64), wherein the output unit (28) is designed to provide the at least one threshold level (36, 38, 40), which results in conditions for monitoring the operational measurement data (34) of the electric motor (12). [2] Motor drive according to claim 1, characterized by in that the measuring unit (14) is designed to receive operating measurement data (34) for an operating point (78, 80, 82, 84) of the electric motor (12), wherein the processing unit (26) is further designed to determine the threshold levels (36, 38, 40) exceeded by the operating measurement data (34) corresponding to the operating point (78, 80, 82, 84). [3] Motor drive according to claim 2, characterized byin that the processing unit (26) is designed to initially compare the operational measurement data (34) with a lowest threshold level (36) of the at least one threshold level (36, 38, 40), wherein the processing unit (26) is further designed to compare the operational measurement data (34) with a further one of the at least one threshold level (36, 38, 40) if the operational measurement data (34) exceeds all threshold levels (36, 38, 40) that are lower than the further one of the at least one threshold level (36, 38, 40). [4] Motor drive according to claim 2 or 3, characterized by in that the processing unit (26) is further designed to provide a monitoring signal indicating the number of threshold levels (36, 38, 40) exceeded by the operational measurement data (34), wherein the operational measurement data (34) preferably comprise more than one measurement signal and / or more than one estimation signal. [5] Motor drive according to claim 4, characterized byin that the monitoring signal is a warning signal (42, 44) if the measured value exceeds one of the at least one threshold level (36, 38, 40), wherein the monitoring signal is an alarm signal (48) if the operating measurement data (34) exceed all of the at least one threshold level (36, 38, 40). [6] Motor drive according to claim 4 or 5, characterized by in that the processing unit (26) is designed to deliver the monitoring signal corresponding to the exceeding of a particular threshold level (36, 38, 40) after a predetermined period of time (50, 52, 54) which depends on the number of threshold levels (36, 38, 40) exceeded, the predetermined period of time (50, 52, 54) being shorter the higher the number of threshold levels (36, 38, 40) exceeded. [7] Motor drive according to one of claims 1 to 6, characterized byin that the processing unit (26) is further designed to provide at least one automatically or manually provided value as the at least one generated threshold level (36, 38, 40), wherein the at least one automatically or manually provided value is preferably a factory default value for the electric motor (12). [8] Motor drive according to one of claims 1 to 7, characterized by in that the measuring unit (14) is designed to acquire at least a portion of the initial measurement data (118) during a transition of the electric motor (12) between two of the plurality of operating points (78, 80, 82, 84). [9] Motor drive according to one of claims 1 to 8, characterized by that the at least one operating point (78, 80, 82, 84) is a speed profile of the electric motor (12). [10] Motor drive according to one of claims 1 to 9, characterized byin that the initial measurement data (118) and the operating measurement data (34) comprise different types of data, wherein the data types preferably comprise vibration data, load data, flux data, torque data, current data, stator winding data, temperature, humidity, service life and / or operating hour data, etc. [11] Motor drive according to one of claims 1 to 10, characterized by that the measuring unit (14) is a frequency converter for driving the electric motor (12). [12] Motor drive according to one of claims 1 to 11, characterized byin that the at least one processing unit (26) is connected to a further cloud-based device (23), wherein the processing unit (26) is designed to receive at least one threshold level for the at least one determined baseline (58, 60, 62, 64) by the cloud-based device (23) as the at least one generated threshold level (36, 38, 40), wherein the cloud-based device (23) is designed to determine a baseline (58, 60, 62, 64) from the initial measurement data (118) for the at least one operating point (78, 80, 82, 84).

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