With the state of technology, the answer is currently not, but perhaps not for the reasons most assume or believe. It is self-evident that pitch bearings need lubrication to reduce their internal friction and wear, thereby giving predictable and repeatable behaviour. Also the properties of the chosen grease (as the lubricant universally used) need to […]
There are moves in the wind energy industry to extend the operational life of wind turbines beyond their nominal design life, typically 20 years. There are many issues to be dealt with to examine the technical risks and commercial returns associated with life extension, one of which is the continuing performance, reliability and life of […]
RGL Associates visited the University of Leicester’s Department of Engineering recently to review progress on 2 final year projects with the supervisor Dr Simon Gill. RGL suggested topics for the projects that involve assessment of inclusions from in-service exposed bearings (in terms of size, shape, composition, presence of cracks, local stress concentrations) and FE modelling […]
Rolling bearings and gears may suffer from surface and sub-surface initiated fatigue, termed “spalling” for bearings and “pitting” for gears. Life estimation for rolling bearings assumes the Palmgren-Miner linear damage law to account for steady and dynamic loads. Bearing manufacturers’ catalogues and international standards such as IEC 61400-4 for design of wind turbine gearboxes present […]
Bearings in wind turbines are subjected to both steady and dynamic loads during normal operation, but especially due to turbulence and wind shear that give rise to significant dynamic loads. Bearing life estimation methods currently use the Palmgren-Miner law to sum the cumulative effect of such loads. Bearing manufacturers’ catalogues present methods to do so, […]
White etching cracking and white structure flaking has afflicted wind turbine gearbox bearings for a number of years and root causes have not been definitively determined despite efforts by many researchers. We visited the University of Sheffield’s Department of Mechanical Engineering to discuss their postgraduate research in WEC/WSF in wind turbine gearbox bearings. There are […]
White etching cracks and white structure flaking failures have afflicted bearings in wind turbine gearboxes. Research has not led to a definitive root cause, but lubricant additives, roller skidding, lubricant breakdown, impact/impulsive loadings, hydrogen formation, water in oil, hydrogen content of bearing steel and electrical currents are thought to be contributors. It is also not […]
White etching cracks and white structure flaking failures have afflicted bearings in wind turbine gearboxes. Research has not led to a definitive root cause, but lubricant additives, roller skidding, lubricant breakdown, impact/impulsive loadings, hydrogen formation, water in oil, hydrogen content of bearing steel and electrical currents are thought to be contributors. It is also not […]
White etching cracks and white structure flaking failures have afflicted bearings in wind turbine gearboxes. Research has not led to a definitive root cause, but lubricant additives, roller skidding, lubricant breakdown, impact/impulsive loadings, hydrogen formation, water in oil, hydrogen content of bearing steel and electrical currents are thought to be contributors. It is also not […]
White etching cracks and white structure flaking failures have afflicted bearings in wind turbine gearboxes. Research has not led to a definitive root cause, but lubricant additives, roller skidding, lubricant breakdown, impact/impulsive loadings, hydrogen formation, water in oil, hydrogen content of bearing steel and electrical currents are thought to be contributors. It is also not […]
White etching cracks and white structure flaking failures have afflicted bearings in wind turbine gearboxes. Research has not led to a definitive root cause, but lubricant additives, roller skidding, lubricant breakdown, impact/impulsive loadings, hydrogen formation, water in oil, hydrogen content of bearing steel and electrical currents are thought to be contributors. It is also not […]
The presence of both dissolved and free water in wind turbine gearbox lubricants is known to reduce bearing fatigue life significantly and also promotes the onset of early life failure by white etching crack (WEC) and white structure flaking (WSF). Dissolved water below the saturation limit is still of importance, but many operators and maintenance […]