System and method for proactive motor wellness diagnosis

• US 7,336,455 B2
• Filed: 05/22/2006
• Issued: 02/26/2008
• 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: Liu, Yanzhen, Nowak, Michael P., Obaid, Ramzy R., Habetler, Thomas G., Dimino, Steven A., Krstic, Slobodan
• Primary Examiner(s): Leykin; Rita
• Application Number:
  US11/419,549
• Publication Number:
  US 20060196265A1
• Time in Patent Office: 645 Days
• Field of Search: 361/24, 361/93.1, 318805-808, 324/772, 702/183, 702/185
• US Class Current: 361/24
• 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 power meter or overload relay including a housing and a plurality of sensors configured to monitor operation of a motor. A processor disposed within the housing and configured to receive operational feedback from the plurality of sensor and proactively determine an operational wellness of the motor from the operational feedback.

Claims

1. A power meter comprising:

a housing;

a plurality of sensors configured to monitor operation of a motor; and

a processor disposed within the housing and configured to;

receive operational feedback from the plurality of sensors;

identify data in two frequency sidebands of a system frequency in the operational feedback; and

determine an impending mechanical fault of the motor from the identified data before occurrence of the mechanical fault.

2. The power meter of claim 1 wherein the processor is further configured to output impending mechanical fault alerts to a display.

3. The power meter of claim 2 wherein the impending mechanical fault alerts include pump cavitation alerts, motor alignment alerts, and motor rotational unbalance alerts.

4. The power meter of claim 1 wherein the plurality of sensors includes a sensor configured to monitor a three-phase current and voltage of the motor.

5. The power meter of claim 1 further comprising a notch filter configured to remove a fundamental frequency of the motor from the operational feedback.

6. The power meter of claim 5 wherein the notch filter is configured to be adaptive to track the fundamental frequency of the motor and an accompanying inverter.

7. The power meter of claim 1 wherein the processor is further configured to generate baseline data from the operational feedback during known healthy operation of the motor.

8. The power meter of claim 7 wherein the processor is further configured to perform a fast Fourier Transform (FFT) on the operational feedback to compare a frequency spectrum of the operational feedback to the baseline data to determine an operational wellness of the motor.

9. An overload relay comprising:

a relay housing;

a power meter disposed within the relay housing and configured to receive a motor current spectrum from a motor and perform motor fault protection; and

a wellness system disposed within the housing and configured to;

analyze data in two frequency sidebands in the motor current spectrum; and

proactively determine a wellness condition of the motor from the analyzation before a fault occurrence to generate condition-based maintenance alerts indicating an imminent fault occurrence.

10. The overload relay of claim 9 wherein the wellness system is further configured to detect pump cavitation, motor misalignment, and motor rotational unbalance from the analyzed data to determine the wellness condition of the motor.

11. The overload relay of claim 10 wherein pump cavitation, motor misalignment, and motor rotational unbalance are detected non-invasively while the motor is operational.

12. The overload relay of claim 9 wherein the wellness system is further configured to communicate the condition based maintenance alerts upon determining the an imminent fault occurrence.

13. The overload relay of claim 10 wherein the wellness system is further configured to determine a first range for each of the two frequency sidebands for the pump cavitation detection and to determine a second range for each of the two frequency sidebands for the detection of motor misalignment and motor rotational unbalance, the first range having more frequencies than the second range.

14. The overload relay of claim 12 wherein the wellness system is further configured to communicate the condition based maintenance alerts without tripping the motor.

15. The overload relay of claim 9 further comprising a circuit configured to provide feedback regarding trip times and dates and trip causes including at least motor overload, phase unbalance, and ground fault.

16. A kit configured to retrofit a relay comprising:

a housing having dimensions substantially similar to an overload relay;

an interface configured to receive feedback from a plurality of sensors monitoring a motor; and

a wellness system disposed within the housing and configured to;

receive the feedback from the interface;

analyze two frequency sidebands in the feedback; and

determine from the analyzation whether preventative maintenance is required on the motor based on a prediction of a fault condition of the motor to prevent the fault condition.

17. The kit of claim 16 wherein the wellness system is further configured to compare the feedback to historical data and output preventative maintenance alerts if the feedback is outside a tolerance.

18. The kit of claim 17 wherein the preventative maintenance alerts include cavitation alerts, motor alignment alerts, and motor rotational unbalance alerts.

19. The kit of claim 16 further comprising a communications interface configured to be connected to a communications bus to communicate preventative maintenance alerts to an operator display.

20. The kit of claim 16 wherein the predicted fault condition includes at least one of a cavitation fault and a mechanical fault.