System and methods for fault diagnosis in machines
Systems and methods for fault detection and diagnosis in a machine. The method includes selecting fault characteristic frequencies of faults, implementing the fault characteristic frequencies as modulating signals, receiving a feedback signal from at least one sensor associated with a machine, applying active modulation using the modulating signals to the feedback signal to obtain modulated signals, and monitoring for a low-frequency fault indicative component from the modulated signals.
1. A method for fault detection and diagnosis in a machine, the method comprising:
selecting one or more fault characteristic frequencies of one or more faults;
implementing the one or more fault characteristic frequencies as modulating signals in separate loops to diagnose the one or more faults simultaneously;
receiving a feedback signal from at least one sensor associated with a machine;
applying active modulation using each modulating signal to the feedback signal to obtain modulated signals; and
monitoring for low-frequency fault indicative components from the modulated signals,
wherein if a low-frequency fault indicative component is detected, transmitting a notification that a fault has been detected.
2. The method of claim 1 , wherein the machine is an induction machine.
3. The method of claim 2 , wherein the induction machine is an alternating current (AC) motor.
4. The method of claim 3 , further comprising receiving, via the at least one sensor, information on a motor speed of the AC motor.
5. The method of claim 1 , wherein the at least one sensor is a current sensor.
6. The method of claim 1 , wherein the low-frequency fault indicative component is a slowest component in a modulated signal.
7. The method of claim 1 , wherein the one or more faults is selected from a stator short winding fault (SSWF), a broken rotor bar fault (BRBF), an eccentricity fault (EF), or a bearing fault (BF).
8. The method of claim 1 , wherein monitoring for a low-frequency fault indicative component further comprises:
monitoring a time between a runtime and an instance of the last zero-crossing point; and
determining whether the time is larger than a threshold.
9. The method of claim 1 , further comprising transmitting the notification to an electronic user interface.
10. The method of claim 1 , further comprising controlling the machine when a fault is detected.
11. A system for fault detection and diagnosis in a machine, the system comprising:
a database holding a plurality of fault characteristic frequencies;
a controller communicatively coupled to the database and configured to:
select one or more fault characteristic frequencies of one or more faults from the plurality of fault characteristic frequencies;
implementing the one or more fault characteristic frequencies as modulating signals in separate loops to diagnose the one or more faults simultaneously;
receive a feedback signal from at least one sensor associated with a machine;
apply active modulation using each modulating signal to the feedback signal to obtain modulated signals; and
monitor for low-frequency fault indicative components from the modulated signals;
wherein if a low-frequency fault indicative component is detected, transmit a notification that a fault has been detected.
12. The system of claim 11 , wherein the machine is an induction machine.
13. The system of claim 12 , wherein the induction machine is an alternating current (AC) motor.
14. The system of claim 13 , the controller further configured to receive, via the at least one sensor, information on a motor speed from the AC motor.
15. The system of claim 11 , wherein the at least one sensor is a current sensor.
16. The system of claim 11 , wherein the low-frequency fault indicative component is a slowest component in the modulated signal.
17. The system of claim 11 , the controller further configured to select the one or more faults from a stator short winding fault (SSWF), a broken rotor bar fault (BRBF), an eccentricity fault (EF), and a bearing fault (BF).
18. The system of claim 11 , the controller further configured to monitor for a low-frequency fault indicative component by:
monitoring a time between a runtime and an instance of the last zero-crossing point; and
determining whether the time is larger than a threshold.
19. The system of claim 11 , the controller further configured to transmit the notification to a user interface.
20. The system of claim 11 , the controller further configured to control the machine when a fault is detected.