[218] Using creative synchronous averaging for detecting defects of a belt-driven bevel gearbox
S Ganeriwala
SpectraQuest Inc, USA
Condition monitoring of gearboxes in industrial settings is often based on trending vibration levels at gear mesh frequencies and sideband frequencies associated with mating shaft rotational speeds. However, it is debated on the vibration levels for setting different alarms related to the gearbox health. Another issue of controversy is what an indicator of fault severity is: is it energy in gear mesh frequencies or the energies in sidebands? In this work, we analysed the vibration signature caused by gear tooth seeded faults of different levels. The data is analysed in both time and frequency domains. The experimental study is conducted on a Machinery Fault Simulator™ (MFS). The pinion gear in the gearbox is intentionally faulted with increasing severities and a vibration signal was collected for each case using IEPE accelerometers. Data is also obtained using a high-resolution encoder. Signals are analysed using time synchronous averaging and traditional spectrum analysis. The results indicate that the vibration signature of a faulted bevel gear tooth is a pulse in the time domain. Because of this impulse signal, strong sidebands arise in the spectrum around the mesh frequency and the energy in sidebands is a better indicator of tooth defect severity.
