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Gearbox Reliability Collaborative Bearing Calibration

Description: NREL has initiated the Gearbox Reliability Collaborative (GRC) to investigate the root cause of the low wind turbine gearbox reliability. The GRC follows a multi-pronged approach based on a collaborative of manufacturers, owners, researchers and consultants. The project combines analysis, field testing, dynamometer testing, condition monitoring, and the development and population of a gearbox failure database. At the core of the project are two 750kW gearboxes that have been redesigned and rebuilt so that they are representative of the multi-megawatt gearbox topology currently used in the industry. These gearboxes are heavily instrumented and are tested in the field and on the dynamometer. This report discusses the bearing calibrations of the gearboxes.
Date: October 1, 2011
Creator: van Dam, J.
Partner: UNT Libraries Government Documents Department

Wind Turbine Generator System Acoustic Noise Test Report for the ARE 442 Wind Turbine

Description: This test was conducted on the ARE 442 as part of the U.S. Department of Energy's (DOE's) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, five turbines are being tested at the National Wind Technology Center (NWTC) as a part of this project. Acoustic noise testing is one of up to five tests that may be performed on the turbines, including duration, safety and function, power performance, and power quality tests. The acoustic noise test was conducted to the IEC 61400-11 Edition 2.1.
Date: November 1, 2010
Creator: Huskey, A. & van Dam, J.
Partner: UNT Libraries Government Documents Department

Duration Test Report for the Viryd CS8 Wind Turbine

Description: This report summarizes the results of a duration noise test that the National Renewable Energy Laboratory (NREL) conducted on the Viryd CS8 wind turbine. This test was conducted in accordance with Clause 9.4 of the International Electrotechnical Commission's (IEC) standard, Wind turbines - Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed. 2.0:2006-03. NREL researchers evaluated the turbine based on structural integrity and material degradation, quality of environmental protection, and dynamic behavior.
Date: June 1, 2013
Creator: Roadman, J.; Murphy, M. & van Dam, J.
Partner: UNT Libraries Government Documents Department

Wind Turbine Generator System Duration Test Report for the ARE 442 Wind Turbine

Description: This test is being conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, four turbines are being tested at the NWTC as a part of this project. Duration testing is one of up to 5 tests that may be performed on the turbines, including power performance, safety and function, noise, and power quality tests. The results of the testing provide manufacturers with reports that may be used for small wind turbine certification. The test equipment includes a grid connected ARE 442 wind turbine mounted on a 30.5 meter (100 ft) lattice tower manufactured by Abundant Renewable Energy. The system was installed by the NWTC Site Operations group with guidance and assistance from Abundant Renewable Energy.
Date: May 1, 2010
Creator: van Dam, J.; Baker, D. & Jager, D.
Partner: UNT Libraries Government Documents Department

Wind Turbine Safety and Function Test Report for the ARE 442 Wind Turbine

Description: This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, four turbines were tested at the National Wind Technology Center (NWTC) as a part of this project. Safety and function testing is one of up to five tests that were performed on the turbines, including power performance, duration, noise, and power quality tests. Test results provide manufacturers with reports that can be used for small wind turbine certification. The test equipment includes an ARE 442 wind turbine mounted on a 100-ft free-standing lattice tower. The system was installed by the NWTC Site Operations group with guidance and assistance from Abundant Renewable Energy.
Date: February 1, 2010
Creator: van Dam, J.; Baker, D. & Jager, D.
Partner: UNT Libraries Government Documents Department

Curvature-driven instabilities in a hot-electron plasma: radial analysis

Description: The theory of unfavorable curvature-driven instabilities is developed for a plasma interacting with a hot electron ring whose drift frequencies are larger than the growth rates predicted from conventional magnetohydrodynamic theory. A z-pinch model is used to emphasize the radial structure of the problem. Stability criteria are obtained for the five possible modes of instability: the conventional hot electron interchange, a high-frequency hot electron interchange (at frequencies larger than the ion cyclotron frequency), a compressional instability, a background pressure-driven interchange, and an interacting pressure-driven interchange.
Date: December 1, 1981
Creator: Berk, H.L.; Van Dam, J.W.; Rosenbluth, M.N. & Spong, D.A.
Partner: UNT Libraries Government Documents Department

Strategies for Refining IEC 61400-2: Wind Turbine Generator Systems - Part 2: Safety of Small Wind Turbines: Preprint

Description: This paper provides a status of the changes currently being made by IEC Maintenance Team 02 (MT02) to the existing IEC 61400-2 ''Safety of small wind turbines.'' In relation to the work done by IEC MT02, work has been done by NREL and Windward Engineering under the DOE/NREL Small Wind Turbine (SWT) Project. Aeroelastic models were built and measurements taken on a Whisper H40 turbine and an AOC 15/50. Results from this study were used to verify the simple design equations. This verification will be used to evaluate how changes made in the design load estimation section of the standard work out for a broad range of turbine configurations. The work presented here builds on work performed by Van Hulle (1996).
Date: October 19, 2001
Creator: van Dam, J. J. D.; Forsyth, T. L. & Hansen, A. C.
Partner: UNT Libraries Government Documents Department

Revisit to self-organization of solitons for dissipative Korteweg-de Vries equation

Description: The process by which self-organization occurs for solitons described by the Korteweg-de Vries (KdV) equation with a viscous dissipation term is reinvestigated theoretically, with the use of numerical simulations in a periodic system. It is shown that, during nonlinear interactions, two basic processes for the self-organization of solitons are energy transfer and selective dissipation among the eigenmodes of the dissipative operator. It is also clarified that an important process during nonlinear self-organization is an interchange between the dominant operators, which has hitherto been overlooked in conventional self-organization theories and which leads to a final self-similar coherent structure determined uniquely by the dissipative operator.
Date: March 1, 1995
Creator: Kondoh, Y. & Van Dam, J.W.
Partner: UNT Libraries Government Documents Department

Continuum damping of low-n toroidicity-induced shear Alfven eigenmodes

Description: The effect of resonant continuum damping is investigated for the low-mode-number, toroidicity-induced, global shear Alfven eigenmodes, which can be self-excited by energetic circulating alpha particles in an ignited tokamak plasma. Resonant interaction with the shear Alfven continuum is possible for these eigenmodes, especially near the plasma periphery, leading to significant dissipation, which is typically larger than direct bulk plasma dissipation rates. Two perturbation methods are developed for obtaining the Alfven resonance damping rate from the ideal fluid zeroth-order shear Alfven eigenvalue and eigenfunction. In both methods the real part of the frequency is estimated to zeroth order, and the imaginary part, which includes the damping rate, is then obtained by perturbation theory. One method, which is applicable when the eigenfunction is nearly real, can readily be incorporated into general MHD codes. In the second method, the zeroth-order eigenfunctions may be complex; however, the application of this method to general MHD codes needs more detailed development. Also, an analytical estimate is found for the next-order real frequency shift of the fluid global Alfven mode. Analytical and numerical studies of this continuum damping effect indicate that it can substantially reduce the alpha particle-induced growth rate. Thus, either it is possible to prevent instability, or if unstable, to use the Alfven resonance damping to estimate the saturation amplitude level predicted from quasilinear theory. 44 refs., 13 figs., 1 tab.
Date: September 1, 1991
Creator: Berk, H.L.; Van Dam, J.W.; Guo, Z. & Lindberg, D.M.
Partner: UNT Libraries Government Documents Department

Stability analysis of a hot electron EBT plasma

Description: Previous theoretical studies have predicted that an EBT-confined plasma will have a stable equilibrium for beta values of the toroidal core plasma comparable to the beta value for the hot electron annulus. We show that, when the ring is allowed to be perturbed, there is a new physical effect, enhanced compression of the core plasma; that in the limit of negligible ..beta../sub core/, the interchange mode is stable for ..beta../sub ring/ greater than about 20%, as was found before; but that when the core pressure is increased, the plamsa goes unstable again at values of ..beta../sub core/ significantly smaller than the value for ..beta../sub ring/.
Date: December 1, 1979
Creator: Van Dam, J. W. & Lee, Y. C.
Partner: UNT Libraries Government Documents Department

Safety and Function Test Report for the Viryd CS8 Wind Turbine

Description: This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. Several turbines were selected for testing at the National Wind Technology Center (NWTC) at the National Renewable Energy Laboratory (NREL) as a part of the Small Wind Turbine Independent Testing project. Safety and function testing is one of up to five tests that may be performed on the turbines. Other tests include duration, power performance, acoustic noise, and power quality. Viryd Technologies, Inc. of Austin, Texas, was the recipient of the DOE grant and provided the turbine for testing.
Date: October 1, 2013
Creator: Roadman, J.; Murphy, M. & van Dam, J.
Partner: UNT Libraries Government Documents Department

Testing and Modeling of a 3-MW Wind Turbine Using Fully Coupled Simulation Codes (Poster)

Description: This poster describes the NREL/Alstom Wind testing and model verification of the Alstom 3-MW wind turbine located at NREL's National Wind Technology Center. NREL,in collaboration with ALSTOM Wind, is studying a 3-MW wind turbine installed at the National Wind Technology Center(NWTC). The project analyzes the turbine design using a state-of-the-art simulation code validated with detailed test data. This poster describes the testing and the model validation effort, and provides conclusions about the performance of the unique drive train configuration used in this wind turbine. The 3-MW machine has been operating at the NWTC since March 2011, and drive train measurements will be collected through the spring of 2012. The NWTC testing site has particularly turbulent wind patterns that allow for the measurement of large transient loads and the resulting turbine response. This poster describes the 3-MW turbine test project, the instrumentation installed, and the load cases captured. The design of a reliable wind turbine drive train increasingly relies on the use of advanced simulation to predict structural responses in a varying wind field. This poster presents a fully coupled, aero-elastic and dynamic model of the wind turbine. It also shows the methodology used to validate the model, including the use of measured tower modes, model-to-model comparisons of the power curve, and mainshaft bending predictions for various load cases. The drivetrain is designed to only transmit torque to the gearbox, eliminating non-torque moments that are known to cause gear misalignment. Preliminary results show that the drivetrain is able to divert bending loads in extreme loading cases, and that a significantly smaller bending moment is induced on the mainshaft compared to a three-point mounting design.
Date: June 1, 2012
Creator: LaCava, W.; Guo, Y.; Van Dam, J.; Bergua, R.; Casanovas, C. & Cugat, C.
Partner: UNT Libraries Government Documents Department

Expanding Small Wind Turbine Certification Testing - Establishment of Regional Test Centers (Poster)

Description: Presented at the WINDPOWER 2010 Conference & Exhibition, 23-26 May 2010, Dallas, Texas. The rapid growth of the small wind turbine (SWT) market is attracting numerous entrants. Small wind turbine purchasers now have many options but often lack information (such as third-party certification) to select a quality turbine. Most SWTs do not have third-party certification due to the expense and difficulty of the certification process. Until recently, the only SWT certification bodies were in Europe. In North America, testing has been limited to U.S. Department of Energy (DOE) subsidized tests conducted at the National Wind Technology Center (NWTC) under the ongoing Independent Testing Project. The goal is to increase the number of certified turbines and gain greater consumer confidence in SWT technology. To reduce certification testing costs, DOE/NREL is assisting in establishing a network of Regional Test Centers (RTCs) to conduct SWT third-party certification testing. To jump-start these RTCs, DOE/NREL is providing financial and technical assistance for an initial round of tests. The goal is to establish a lower-cost U.S. small wind testing capability that will lead to increased SWT certification. This poster describes the project, describes how it fits within broader SWT certification activities, and provides current status.
Date: May 1, 2010
Creator: Jimenez, A.; Bowen, A.; Forsyth, T.; Huskey, A.; Sinclair, K.; van Dam, J. et al.
Partner: UNT Libraries Government Documents Department

Wind Turbine Drivetrain Condition Monitoring During GRC Phase 1 and Phase 2 Testing

Description: This report will present the wind turbine drivetrain condition monitoring (CM) research conducted under the phase 1 and phase 2 Gearbox Reliability Collaborative (GRC) tests. The rationale and approach for this drivetrain CM research, investigated CM systems, test configuration and results, and a discussion on challenges in wind turbine drivetrain CM and future research and development areas, will be presented.
Date: October 1, 2011
Creator: Sheng, S.; Link, H.; LaCava, W.; van Dam, J.; McNiff, B.; Veers, P. et al.
Partner: UNT Libraries Government Documents Department

Small Wind Turbine Testing Results from the National Renewable Energy Laboratory: Preprint

Description: In 2008, the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) began testing small wind turbines (SWTs) through the Independent Testing project. Using competitive solicitation, five SWTs were selected for testing at the National Wind Technology Center (NWTC). NREL's NWTC is accredited by the American Association of Laboratory Accreditation (A2LA) to conduct duration, power performance, safety and function, power quality, and noise tests to International Electrotechnical Commission (IEC) standards. Results of the tests conducted on each of the SWTs are or will be available to the public on the NREL website. The results could be used by their manufacturers in the certification of the turbines or state agencies to decide which turbines are eligible for state incentives.
Date: April 1, 2010
Creator: Bowen, A.; Huskey, A.; Link, H.; Sinclair, K.; Forsyth, T.; Jager, D. et al.
Partner: UNT Libraries Government Documents Department

Small Wind Turbine Testing Results from the National Renewable Energy Lab

Description: The independent testing project was established at the National Renewable Energy Laboratory to help reduce the barriers of wind energy expansion. Among these barriers is a lack of independent testing results for small turbines.
Date: July 1, 2009
Creator: Bowen, A.; Huskey, A.; Link, H.; Sinclair, K.; Forsyth, T.; Jager, D. et al.
Partner: UNT Libraries Government Documents Department

Multiplicity of low-shear toroidal Alfven eigenmodes

Description: An enlarged spectrum of ideal toroidal Alfven eigenmodes is demonstrated to exist within a toroidicity-induced Alfven gap when the inverse aspect ratio is comparable to or larger than the value of the magnetic shear. This limit is appropriate for the low-shear region in most tokamaks, especially those with low aspect ratio. The new modes may be destabilized by fusion-product alpha particles more easily than the standard toroidal Alfven eigenmodes.
Date: January 1, 1996
Creator: Candy, J.; Breizman, B.N.; Van Dam, J.W. & Ozeki, T.
Partner: UNT Libraries Government Documents Department

Commercial rabbit raising.

Description: A guide to raising rabbits commercially, for production of meat, fur, and wool.
Date: October 1971
Creator: Casady, Robert B., 1917-; Sawin, Paul B. (Paul Baldwin), 1900- & Van Dam, J.
Partner: UNT Libraries Government Documents Department

Observation of Modes at Frequencies Near the Second Alfvin Gap in TFTR

Description: Modes has been observed in the frequency range of the second Alfvenic gap in H-minority ICRF heated plasmas in TFTR. This observation is surprising in that the second gap is generally considered to be small in circular cross section plasmas. The mode is inferred to be a core mode, i.e., localized in some sense within the q=1 surface. This follows from the observation that the time dependence of the mode frequency is consistent with the changes in the central density, with the appearance of the mode in the latter part of the sawtooth period when the central fast ion beta has peaked up, and with the direction of propagation, the last of these being explained by a hollow first ion beta profile, which is only present in the core region. The modes are generally not observed during on-axis H-minority heating, but commonly observed during off-axis heating on the high field side (with the resonant layer outside the q=1 surface). A model has been proposed that the beta of the fast ions opens the second gap, allowing instability. For TFTR parameters, the model predicts a gap width of approximately 10 kHz, which is 2.5% of the second gap frequency. If the backwards mode propagation is due to a hollow fast ion profile (as indicated in the TRANSP calculations), then instability due to wave-particle resonance at the magnetic curvature precessional frequency can occur only if the precessional frequency is reversed--which can indeed be the case for off-axis heating on the high field side. Thus, trapped fast ion pressure effects seem to explain several of the observed features of these second gap fluctuations.
Date: April 1, 1999
Creator: E., Fredrickson.; Van Dam, J.W.; Budny, R.V.; Darrow, D.; Fu, G.Y.; Hosea, J. et al.
Partner: UNT Libraries Government Documents Department

Observation of modes at frequencies near the second Alfven gap in TFTR

Description: Modes have been observed near the frequency of the second Alfven gap during off-axis H-minority heating experiments in the circular cross-section Tokamak Fusion Test Reactor. The observation of these modes is surprising in that the second gap, which is generally opened with ellipticity, is expected to be small, of order (r/R){sup 2}. A model is proposed in which the second gap is opened by the fast ion beta, which is shown to be able to introduce mode coupling, much as toroidal effects introduce mode coupling for Toroidal Alfven Eigenmodes (TAE). The modes are seen with and without accompanying TAE mode activity.
Date: April 26, 2000
Creator: Fredrickson, E.; Van Dam, J.W.; Budny, R.V.; Darrow, D.; Fu, G.Y.; Hosea, J. et al.
Partner: UNT Libraries Government Documents Department