Instantaneous angular speed monitoring of gearboxes under non-cyclic stationary load conditions

• Published in: Mechanical systems and signal processing Vol. 19; no. 4; pp. 817 - 835
• Main Authors: Stander, C.J., Heyns, P.S.
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.07.2005; Elsevier
• Subjects: Applied sciences; Drives; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Industrial metrology. Testing; Mechanical engineering. Machine design; Physics; Shafts, couplings, clutches, brakes; Solid mechanics; Structural and continuum mechanics; Vibration, mechanical wave, dynamic stability (aeroelasticity, vibration control...); Averaging method; Vibration; Speed measurement; Rotation speed; Non stationary condition; Hydraulic machine; Maintenance; Cyclostationary; Modeling; Gear; Production management; Modulation; Cyclic load; Signal processing; Fault diagnostic; Monitoring; Gear box
• ISSN: 0888-3270; 1096-1216
• DOI: 10.1016/j.ymssp.2004.10.006

Recent developments in the condition monitoring and asset management market have led to the commercialisation of online vibration-monitoring systems. These systems are primarily utilised to monitor large mineral mining equipment such as draglines, continuous miners and hydraulic shovels. Online monitoring systems make diagnostic information continuously available for asset management, production outsourcing and maintenance alliances with equipment manufacturers. However, most online vibration-monitoring systems are based on conventional vibration-monitoring technologies, which are prone to giving false equipment deterioration warnings on gears that operate under fluctuating load conditions. A simplified mathematical model of a gear system was developed to illustrate the feasibility of monitoring the instantaneous angular speed (IAS) as a means of monitoring the condition of gears that are subjected to fluctuating load conditions. A distinction is made between cyclic stationary load modulation and non-cyclic stationary load modulation. It is shown that rotation domain averaging will suppress the modulation caused by non-cyclic stationary load conditions but will not suppress the modulation caused by cyclic stationary load conditions. An experimental investigation on a test rig indicated that the IAS of a gear shaft could be monitored with a conventional shaft encoder to indicate a deteriorating gear fault condition.