System and method for proactive motor wellness diagnosis based on potential mechanical faults

• US 7,117,125 B2
• Filed: 06/02/2004
• Issued: 10/03/2006
• Est. Priority Date: 06/18/2003
• Status: Active Grant

• Current Assignee: Eaton Intelligent Power Limited (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Nowak, Michael P., Habetler, Thomas G., Dimino, Steven A., Krstic, Slobodan, Liu, Yanzhen, Obaid, Ramzy R.
• Primary Examiner(s): Bui, Bryan
• Assistant Examiner(s): Lau, Tung S.
• Application Number:
  US10/859,508
• Publication Number:
  US 20050021301A1
• Time in Patent Office: 853 Days
• Field of Search: 702/185, 702/182, 361/24, 318/254, 318/700, 318/685, 493/350, 493/464, 493/8, 731/16, 180/407, 180/402, 701/22
• US Class Current: 702/185
• CPC Class Codes: G01R 31/343 in operation
• CPC Class Codes: G05B 2219/37351 Detect vibration, ultrasound
• CPC Class Codes: G05B 23/0229 knowledge based, e.g. expert systems; genetic algorithms
• CPC Class Codes: G05B 23/0245 based on a qualitative model, e.g. rule based; if-then decisions
• CPC Class Codes: G05B 23/0254 based on a quantitative model, e.g. mathematical relationships between inputs and outputs; functions: observer, Kalman filter, residual calculation, Neural Networks
• CPC Class Codes: H02H 7/0822 Integrated protection, motor control centres

Abstract

The present invention is directed to a system and method for proactively determining motor wellness arising from potential mechanical faults of the motor. A controller is configured to detect indicia of impending mechanical motor faults. The controller includes a processor configured to determine motor parameters of a given motor including a load and generate a set of baseline data for the given motor. The processor is also configured to acquire current spectrum data from the given motor during operation, map at least one from a plurality of load bins based on the load, and generate a mechanical fault signature from the current spectrum. The processor is caused to compare the mechanical fault signature to baseline data from the set of baseline data corresponding to the mapped bin and determine amplitude variances within the mechanical fault signature indicative of an impending mechanical fault prior to an actual mechanical fault occurrence.

Claims

1. A controller configured to detect indicia of impending mechanical motor faults and having a processor configured to:

determine motor parameters of a given motor connected to a load, the load operable along a range of operation defined by a plurality of load steps;

generate a set of baseline data for the given motor;

acquire current spectrum data from the given motor during operation;

select a load bin of a plurality of load bins, the plurality of load bins corresponding to the plurality of load steps;

map the current spectrum data to the load bin corresponding to a load step of the plurality of load steps defining current operation of the load;

generate a mechanical fault signature from the current spectrum;

compare the mechanical fault signature to baseline data from the set of baseline data corresponding to the mapped bin; and

determine amplitude variances within the mechanical fault signature indicative of an impending mechanical fault prior to an actual mechanical fault occurrence.

2. The controller of claim 1 wherein the processor is further configured to isolate sidebands within the current spectrum data and sum the current spectrum data within the sidebands to generate the mechanical fault signature.

3. The controller of claim 1 wherein the processor is further configured to select the desired sidebands selected based on a system frequency of the given motor.

4. The controller of claim 1 wherein the processor is further configured to dynamically notch filter the current spectrum data to remove a fundamental frequency of the given motor.

5. The controller of claim 4 wherein the processor is further configured to track the fundamental frequency of the given motor over an operational range for use with an inverter.

6. The controller of claim 1 wherein the processor is further configured to digitize and decimate the current spectrum data to acquire a desired resolution for comparison with the baseline data.

7. The controller of claim 1 wherein the processor is further configured to receive raw current data and compute at least one fast Fourier Transform (FFT) to generate the current spectrum data.

8. The controller of claim 7 wherein the processor is further configured to average the current spectrum data to stabilize the current frequency spectrum data.

9. The controller of claim 1 wherein the processor is further configured to generate the mechanical fault signature by calculating a root mean square (RMS) of the current spectrum data.

10. The controller of claim 1 wherein the processor is further configured to determine a number of poles of the given motor.

11. The controller of claim 1 wherein the processor is further configured to acquire power data from the given motor and map the power data into the load bin to determine a monitoring state of the mapped load bin.

12. The controller of claim 11 wherein if the monitoring state of the mapped load bin is a learning mode, the processor is further configured to generate the set of baseline data by continuously averaging the mechanical fault signature of the given motor under known healthy conditions.

13. The controller of claim 1 wherein the processor is further configured to determine a noise pattern indicative of potential motor misalignment from the fault signature of the given motor by detecting amplitude variances within motor shaft running speed components within the current spectrum data.

14. The controller of claim 13 wherein the processor is further configured to communicate a proactive alert over a communications bus upon determining amplitude variances in the shaft running speed components greater than a threshold.

15. The controller of claim 14 wherein the processor is further configured to set the threshold according to one of a user selected threshold, a dynamically learned threshold, and a lookup table.

16. The controller of claim 1 wherein the processor is further configured to perform at least one of a root sum square (RSS) value calculation and a polynomial estimation to compensate for energy leakage within the current data.

17. The controller of claim 16 wherein the processor is further configured to estimate an instantaneous amplitude of components of running shaft speed of the given motor as a function of neighboring components of running shaft speed of the given motor to perform the polynomial estimation.

18. The controller of claim 16 wherein the processor is further configured to perform the RSS value calculation for a plurality of frequency components in the desired sidebands surrounding a shaft frequency of the given motor.

19. The controller of claim 1 wherein the processor is further configured to communicate preventative maintenance alerts over a communications bus to an operator display upon detecting indicia of at least one of motor misalignment and motor imbalance within the motor fault signature.

20. The controller of claim 1 wherein the processor is further configured to:

acquire power data from the given motor during operation;

generate a mechanical fault signature of the given motor from the power data; and

determine indicia of at least one of motor misalignment and motor imbalance within the motor fault signature.

21. The controller of claim 20 wherein the power data includes instantaneous power data.