DIAGNOSIS METHOD OF DEFECTS IN A MOTOR AND DIAGNOSIS DEVICE THEREOF

• US 20100145639A1
• Filed: 04/08/2009
• Published: 06/10/2010
• Est. Priority Date: 12/10/2008
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Hsu, Ming-Hsiu, Hsu, Chen-Kai, Fu, Chia-Lin
• Granted Patent: US 8,768,634 B2
• Time in Patent Office: Days
• US Class Current: 702/56
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence

Abstract

A diagnosis method of defects in a motor and a diagnosis device thereof are described. A vibration sensing module can generate a vibration signal corresponding to a vibration of a motor during operation of the motor. Then, a data pre-processing procedure is performed to eliminate noises of the vibration signal. After the data pre-processing procedure, an analyzing procedure is performed to determine a first harmonic of spectrum features in the spectrum of the pre-processed vibration signal. And, other spectrum feature(s) is(/are) retrieved from the spectrum of the pre-processed vibration signal according to the first harmonic. Finally, a comparison procedure is performed with a defect spectrum feature database according to the retrieved spectrum features, so as to determine a defect type of the motor.

Claims

1. A diagnosis method of defects in a motor, comprising:

generating a vibration signal corresponding to a vibration of a motor by a vibration sensing module during operation of the motor;

performing a data pre-processing procedure to pre-process the vibration signal, so as to eliminate noises of the vibration signal;

performing an analyzing procedure to analyzing a spectrum of the vibration signal pre-processed after the data pre-processing procedure, so as to retrieve a first harmonic of a plurality of spectrum features in the spectrum of the vibration signal;

retrieving at least one of the other of the spectrum features in the spectrum of the vibration signal according to the first harmonic; and

performing a comparison procedure with a defect spectrum feature database according to the retrieved spectrum features, so as to determine a detect type of the motor.

2. The diagnosis method according to claim 1, further comprises generating a sound signal corresponding to a sound of the operation of the motor by a sound sensing module during the operation of the motor.

3. The diagnosis method according to claim 2, wherein the step of performing the data pre-processing procedure further comprises pre-processing the sound signal to eliminate noises of the sound signal.

4. The diagnosis method according to claim 3, wherein the step of performing the analyzing procedure further comprises determining the retrieved first harmonic according to a spectrum of the sound signal after the data pre-processing procedure.

5. The diagnosis method according to claim 4, wherein after the step of determining the retrieved first harmonic, the method further comprises:

setting common features between the spectrum of the vibration signal and the spectrum of the sound signal as composite features; and

retrieving a position of a harmonic frequency of a maximum composite feature of the composite features in the spectrum of the vibration signal.

6. The diagnosis method according to claim 5, wherein the step of retrieving the at least one of the other of the spectrum features comprises retrieving the at least one of the other of the spectrum features from the spectrum of the vibration signal according to the retrieved first harmonic and the position of the harmonic frequency.

7. The diagnosis method according to claim 1, wherein the step of performing the data pre-processing procedure comprises performing an integral procedure to integrate the vibration signal.

8. The diagnosis method according to claim 1, wherein the defect type comprises one of unbalance, misalignment, looseness, shaft bending, bearing and combination thereof.

9. A diagnosis device of defects in a motor equipment, comprising:

a vibration sensing module, for generating a vibration signal corresponding to a vibration of a motor during operation of the motor;

a defect spectrum feature database, for storing a plurality of data of detects to spectrum features;

a signal processing module, for receiving the vibration signal, analyzing a spectrum of the vibration signal to determine retrieve a first harmonic of a plurality of spectrum features in the spectrum of the vibration signal, retrieving at least one of the other of the spectrum features from the spectrum of the vibration signal according to the retrieved first harmonic, and looking up the defect spectrum feature database according to the retrieved spectrum features to determine a defect type of the motor;

a display module, for displaying data output from the signal processing module; and

a communication interface module, for transmitting the data output from the signal processing module.

10. The diagnosis device according to claim 9, further comprising:

a power module, for supplying power to the vibration sensing module, the defect spectrum feature database, the signal processing module, the display module, and the communication interface module; and

a start switch, for turning on or turning off the power module.

11. The diagnosis device according to claim 9, further comprising:

a sound sensing module, for generate a sound signal corresponding to a sound of the operation of the motor during the operation of the motor.

12. The diagnosis device according to claim 11, wherein the signal processing module determines the retrieved first harmonic according to a spectrum of the sound signal, sets common features between the spectrum of the vibration signal and the spectrum of the sound signal as composite features, retrieves a position of a harmonic frequency of a maximum composite feature of the composite features in the spectrum of the vibration signal, and retrieves the at least one of the other of the spectrum features from the spectrum of the vibration signal according to the retrieved first harmonic and the position of the harmonic frequency.

13. The diagnosis device according to claim 12, wherein the defect type comprises one of unbalance, misalignment, looseness, shaft bending, bearing and combination thereof.

14. The diagnosis device according to claim 9, wherein the vibration sensing module is an accelerometer.

15. The diagnosis device according to claim 9, wherein the sound sensing module is a microphone.

16. The diagnosis device according to claim 9, wherein the display module is a liquid crystal display (LCD).

17. A method for retrieving spectrum features of a signal, comprising:

receiving a vibration signal corresponding to a vibration of a motor during operation of the motor;

transforming the received vibration signal in a speed spectrum and an acceleration spectrum;

obtaining a maximum value of a plurality of spectrum values in the speed spectrum and a maximum value of a plurality of spectrum values in the acceleration spectrum;

sorting and determining the spectrum values in the speed spectrum and the acceleration spectrum according to the obtained maximum values;

when two positions where the acceleration spectrum has the maximum value and the speed spectrum has the maximum value correspond to each other, identifying the position where the maximum value occurs as a position of a fundamental frequency of the vibration signal; and

when two positions where the acceleration spectrum has the maximum value and the speed spectrum has the maximum value do not correspond to each other, identifying the position where the maximum value in the speed spectrum occurs as the position of the fundamental frequency of the vibration signal.

18. The method according to claim 17, further comprising:

normalize all of the a plurality of spectrum values in the speed spectrum and the acceleration spectrum with the obtained maximum value of the a plurality of spectrum values.

19. The method according to claim 17, further comprising:

deriving at least one of the plurality of spectrum features from the spectrum of the vibration signal according to the identified position of the fundamental frequency.

20. The method according to claim 17, further comprising:

receiving a sound signal corresponding to a sound of the operation of the motor during the operation of the motor;

transforming the received sound signal in a sound spectrum; and

determining the identified position of the fundamental frequency according to the sound spectrum of the sound signal.