Author: David VaesPublisher:
ISBN:
Category : Bearings (Machinery)
Languages : en
Pages : 22
Book Description
Investigation of Roller Sliding in Wind Turbine Gearbox High-speed-shaft Bearings
Author: David VaesPublisher:
ISBN:
Category : Bearings (Machinery)
Languages : en
Pages : 22
Book Description
Quantification of Roller Sliding Energy in Wind Turbine Gearbox High-speed Shaft Bearings
Author: Yi Guo (Research engineer)Publisher:
ISBN:
Category : Renewable energy
Languages : en
Pages : 22
Book Description
Roller Sliding in Wind Turbine Gearbox High-speed-shaft Bearings
Author: David VaesPublisher:
ISBN:
Category : Bearings (Machinery)
Languages : en
Pages : 27
Book Description
Characterization of the High-Speed-Stage Bearing Skidding of Wind Turbine Gearboxes Induced by Dynamic Electricity Grid Events
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Bearing behavior is an important factor for wind turbine drivetrain reliability. Extreme loads and dynamic excitations pose challenges to the bearing design and therefore its performance. Excessive skidding of the bearing rollers should be avoided because it can cause scuffing failures. Excitations coming from wind and the electricity grid can subject the drivetrain to fluctuating torque and nontorque loads. Wind-induced excitations have been investigated predominantly in literature. However, modern wind turbines are subjected more and more to grid-induced loads because of stricter electricity grid regulations. For example, during fault-ride-through events, turbines are required to stay connected for a longer period of time during the grid failure. This work investigates the influence of electrically induced excitations on the skidding behaviour of the tapered roller bearings on the high-speed stage of a wind turbine gearbox. This skidding behaviour during dynamic events is described as a potential bearing failure initiator by many researchers; however, only limited full-scale dynamic testing is documented. Therefore, a dedicated gridloss-type event is defined in the paper and conducted in a dynamometer test on a full-scale wind turbine nacelle. During the event, a complete electricity grid failure is simulated while the turbine is at rated speed and predefined torque levels. Particular focus is on the characterization of the high-speed shaft tapered roller bearing slip behavior. Strain-gauge bridges in grooves along the circumference of the outer ring are used to characterize the bearing load zone in detail. It is shown that during the torque reversals of the transient event, roller slip can be induced. This indicates the potential of the applied load case to go beyond the preload of the tapered roller bearing. Furthermore, the relation between the applied torque and skidding level is studied.
Investigating Main and High-Speed Shaft Bearing Reliability through Uptower Testing
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
The most prevalent failure modes in wind turbine drivetrains are main bearing failures stemming from micropitting, white etching or axial cracks in gearbox bearings, and generator bearing failures. These failures are neither well understood nor accounted for in design standards; consequently, the mitigation strategies being developed and fielded may only partially address the physics of failure and can take years to assess. The U.S. Department of Energy continues to support research programs to investigate the influence of rolling element sliding on the formation of bearing axial cracks and main bearing micropitting.
Investigation of Bearing Axial Cracking: Benchtop and Full-Scale Test Results
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
The most common failure mode in wind turbine gearboxes is axial cracking in intermediate and high-speed-stage bearings, also commonly called white-etching cracks (WECs). Although these types of cracks have been reported for over a decade, the conditions leading to WECs, the process by which this failure culminates, and the reasons for their apparent prevalence in wind turbine gearboxes are all highly debated. This paper summarizes the state of a multipronged research effort to examine the causes of WECs in wind turbine gearbox bearings. Recent efforts have recreated WECs on a benchtop test rig in highly loaded sliding conditions, wherein it was found that the formation of a dark etching microstructure precedes the formation of a crack, and a crack precedes the formation of white-etching microstructure. A cumulative frictional sliding energy criterion has been postulated to predict the presence of WECs. Bearing loads have also been measured and predicted in steady state and transient drivetrain operations in dynamometer testing. In addition, both loads and sliding at full scale will be measured in planned uptower drivetrain testing. If the cumulative frictional sliding energy is the dominant mechanism that causes WECs, understanding the amount of frictional sliding energy that wind turbine bearings are subjected to in typical operations is the next step in the investigation. If highly loaded sliding conditions are found uptower, similar to the examined benchtop levels, appropriate mitigation solutions can be examined, ranging from new bearing coatings and improved lubricants to changes in gearbox designs and turbine operations.
High-Speed Shaft Bearing Loads Testing and Modeling in the NREL Gearbox Reliability Collaborative
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 15
Book Description
Bearing failures in the high speed output stage of the gearbox are plaguing the wind turbine industry. Accordingly, the National Renewable Energy Laboratory (NREL) Gearbox Reliability Collaborative (GRC) has performed an experimental and theoretical investigation of loads within these bearings. The purpose of this paper is to describe the instrumentation, calibrations, data post-processing and initial results from this testing and modeling effort. Measured HSS torque, bending, and bearing loads are related to model predictions. Of additional interest is examining if the shaft measurements can be simply related to bearing load measurements, eliminating the need for invasive modifications of the bearing races for such instrumentation.
High-speed Shaft Bearing Loads Testing and Modeling in the NREL Gearbox Reliability Collaborative :.
Author: Brian McNiffPower Conversion and Control of Wind Energy Systems
Author: Bin WuPublisher: John Wiley & Sons
ISBN: 0470593652
Category : Technology & Engineering
Languages : en
Pages : 480
Book Description
The book presents the latest power conversion and control technology in modern wind energy systems. It has nine chapters, covering technology overview and market survey, electric generators and modeling, power converters and modulation techniques, wind turbine characteristics and configurations, and control schemes for fixed- and variable-speed wind energy systems. The book also provides in-depth steady-state and dynamic analysis of squirrel cage induction generator, doubly fed induction generator, and synchronous generator based wind energy systems. To illustrate the key concepts and help the reader tackle real-world issues, the book contains more than 30 case studies and 100 solved problems in addition to simulations and experiments. The book serves as a comprehensive reference for academic researchers and practicing engineers. It can also be used as a textbook for graduate students and final year undergraduate students.
Uptower Investigation of Main and High-speed-shaft Bearing Reliability
Author: Jonathan KellerPublisher:
ISBN:
Category : Bearings (Machinery)
Languages : en
Pages : 41
Book Description