| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 105 === Many rotating machines are driven by induction motors and the life of induction motors usually lasts for decades. However, during certain conditions such as load variation, the bearing would suffer fatigue failures. These failures begin from incipient faults and would cause catastrophic disasters if unattended. Therefore, previous literatures concluded several failure modes of the rotating machine and developed condition monitoring techniques to achieve fault diagnosis and replacing abnormal components in advance.
In order to understand the behavior of failure modes, several sensors were installed on the rotating machine in previous literatures to measure the vibration, current, and voltage of the bearing fault condition, and compared the measurement to the normal condition. The knowledge could be applied to the monitoring of the non-stop rotating machine in the industry.
The failure mode and effect analysis of the rotating machine failures were elaborated in this thesis. Both the physical definition and frequency spectrum of the failure were discussed. The criterion to determine the machine condition were proposed by applying signal analysis technique on the vibration signal of the normal and faulty bearing. The electrical discharge through the oil film between the shaft and bearing were generated by applying AC current to the shaft and housing, and the time-domain, frequency spectrum, and enveloping spectrum of the vibration signals were analyzed. Amplitude modulation could be observed when there are inner and outer ring faults. Through the impact test and the sweeping test, the resonant frequency of the bearing could be found and used to develop enveloping spectrum. The fatigue failure test was conducted and an amplitude threshold was set.
|
|---|
