Method for monitoring an electrodynamic machine

• US 8,378,645 B2
• Filed: 10/12/2010
• Issued: 02/19/2013
• Est. Priority Date: 04/15/2008
• Status: Active Grant

• Current Assignee: General Electric Technology GmbH (GE Aerospace)
• Original Assignee: Alstom Technology Ltd. (Alstom SA)
• Inventors: Hobelsberger, Max, Mark, Bernhard
• Primary Examiner(s): Cuevas, Pedro J
• Application Number:
  US12/902,346
• Publication Number:
  US 20110084671A1
• Time in Patent Office: 861 Days
• Field of Search: 322/99
• US Class Current: 322/99
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence
• CPC Class Codes: G01R 31/343 in operation

Abstract

A method for monitoring an electrodynamic machine a stator and a rotor arrangement mounted along a rotatable shaft. The rotor arrangement is disposed within the stator and forms an air gap between the rotor arrangement and the stator. At least one sensor is disposed in the air gap and/or within the stator. Measurement signals are detected that are dependent on a magnetic field produced by the electrodynamic machine. The measurement signals are used as a basis for detecting oscillations of the shaft.

Claims

1. A method for monitoring an electrodynamic machine comprising:

providing an electrodynamic machine including;

a stator,

a rotor arrangement mounted along a rotatable shaft, the rotor arrangement being disposed within the stator and forming an air gap between the rotor arrangement and the stator, and

at least one sensor disposed in at least one of the air gap and the stator;

detecting measurement signals using the at least one sensor that are dependent on a magnetic field produced by the electrodynamic machine;

analyzing the measurement signals so as to determine oscillations of the shaft, wherein the oscillations of the shaft comprises at least one of torsional oscillations and pendulum oscillations.

2. The method as recited in claim 1, wherein the oscillations of the shaft include bending oscillations.

3. The method as recited in claim 2, further comprising evaluating at least one of the measurement signals and derived signals from the measurement signals so as to determine natural frequencies of the oscillations of the shaft.

4. The method as recited in claim 1, further comprising detecting rotor turn shorts using the at least one sensor.

5. The method as recited in claim 1, wherein the at least one sensor includes at least one of a coil, a conductor loop, a Hall sensor and a magnetoresistive measurement sensor.

6. The method as recited in claim 1, further comprising analyzing the detected measurement signals in at least one of a time domain and a frequency domain, and analyzing at least one of the phase, frequency and amplitude behavior of the detected measurement signals at at least one of a rated rotor rotation frequency and a multiple of the rated rotor rotation frequency.

7. The method as recited in claim 1, further comprising investigating the detected measurement signals for the inclusion of at least one of frequency modulations and amplitude modulations.

8. The method as recited in claim 6, further comprising sampling the detected measurement signals at a sampling rate corresponding to a rated rotor rotation frequency or an integer multiple of the rated rotor rotation frequency.

9. The method as recited in claim 6, further comprising determining phase or frequency fluctuations of the detected measurement signals at at least one of the rated rotor rotation frequency and the multiple of the rated rotor rotation frequency,

assessing the rotor rotational movement at the rated rotor rotation frequency based on the phase or frequency fluctuations, and

wherein the phase or frequency fluctuations provide a measure for at least one of torsional oscillations of the shaft and pendulum oscillations of the shaft.

10. The method as recited in claim 6, further comprising simultaneously analyzing a plurality of frequency bands of the detected measurement signals and investigating the presence of correlated phase fluctuations.

11. The method as recited in claim 10, further comprising determining a value for an assessment of rotor movement based exclusively on correlated phase fluctuations.

12. The method as recited in claim 6, further comprising monitoring predetermined limit values of the phase or frequency fluctuations, and generating a signal or shutting down the electrodynamic machine if the limit values are exceeded.

13. The method as recited in claim 6 further comprising determining amplitude fluctuations and assessing the amplitude fluctuations as a measure for bending oscillations.

14. The method as recited in claim 6, further comprising simultaneously analyzing a plurality of frequency bands of the detected measurement signals, and investigating the plurality of frequency bands for correlated amplitude fluctuations.

15. The method as recited in claim 14, further comprising determining a value for assessment of the rotor movement based exclusively on the correlated amplitude fluctuations.

16. The method as recited in claim 13, further comprising monitoring a predetermined limit value of the amplitude fluctuations, and generating a signal or shutting down the electrodynamic machine if the limit value is exceeded.

17. The method as recited in claim 13, wherein the at least one sensor includes an inductive air-core coil for detecting bending oscillations, and further comprising applying a higher-frequency current or a voltage signal to the inductive air-core coil, and evaluating impedance changes of the inductive air-core coil.

18. The method as recited in claim 6, wherein at least one of torsional, pendular and bending oscillations of the shaft are initiated by transient processes, and wherein at least one of the transient phase modulations, frequency modulations and amplitude modulations occurs in a spectrum of the detected measurement signals or a spectrum of demodulated signals.

19. The method as recited in claim 18, further comprising assessing transient phase modulations of the harmonics of the rated rotor rotation frequency as an indication of torsional oscillations.

20. The method as recited in claim 18, further comprising evaluating at least one of a part of the spectrum of detected measurement signals and a part of the spectrum of demodulated signals containing the at least one of transient phase modulations, frequency modulations and amplitude modulations so as to determine natural frequencies of the oscillations of the shaft.

21. A method for monitoring an electrodynamic machine comprising:

providing an electrodynamic machine including;

a stator,

a rotor arrangement mounted along a rotatable shaft, the rotor arrangement being disposed within the stator and forming an air gap between the rotor arrangement and the stator, and

at least one sensor disposed in at least one of the air gap and the stator;

detecting measurement signals using the at least one sensor that are dependent on a magnetic field produced by the electrodynamic machine;

analyzing the measurement signals so as to determine oscillations of the shaft;

analyzing the measurement signals in at least one of a time domain and a frequency domain, and analyzing at least one of the phase, frequency and amplitude behavior of the detected measurement signals at at least one of a rated rotor rotation frequency and a multiple of the rated rotor rotation frequency;

determining phase or frequency fluctuations of the detected measurement signals at at least one of the rated rotor rotation frequency and the multiple of the rated rotor rotation frequency; and

assessing the rotor rotational movement at the rated rotor rotation frequency based on the phase or frequency fluctuations,

wherein the phase or frequency fluctuations provide a measure for at least one of torsional oscillations of the shaft and pendulum oscillations of the shaft.