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Bearing currents in doubly-fed induction generators
2005 European Conference on Power Electronics and Applications, 2005An increasing demand on the quality of wind power systems affects also more and more the fields of lifetime and reliability. But, problems like bearing damages because of bearing currents counteract these desired demands. Especially doubly fed induction generators, which are wide spread in use for wind turbines up to the MW-class can be limited in ...
J. Zitzelsberger +3 more
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Eddy current losses in passive magnetic bearings
Journal of Applied Physics, 2002Passive magnetic bearings built with permanent magnets, such as NdFeB (neodynium–iron–boron) or SmCo (samarium–cobalt), are very reliable systems when used for industrial applications such as centrifuges or flywheels, as they do not require any electromagnetic coil supply. Nevertheless, during the rotational motion, gyroscopic effects (like precession)
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Ocean Currents, Jet Streams, and Polar Bears
2021Abstract This chapter is divided into four sections, describing various impacts of glacier melt on different Earth ecosystems, including the effects of melting ice and water temperature on changes to ocean currents, on the global air Jet Stream, and on land surfaces, such as the popping up effect (the surface rebound effect) of the Earth
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Analysis of an Eddy Current Journal Bearing
Journal of Tribology, 1988Nearly all magnetic bearings which have found use in modern technology are based on the attractive force between a magnet and a magnetic material. A distinct disadvantage is that such devices are inherently unstable and require active feedback for operation.
K. A. Connor, J. A. Tichy
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Research of bearing voltage and bearing current in induction motor drive system
2016 Asia-Pacific International Symposium on Electromagnetic Compatibility (APEMC), 2016To solve bearing electric corrosion of motor drive system, the mechanism of bearing voltage and bearing current is studied. To validate the mechanism, the motor driven by high frequency PWM pulse system is established. The model of drive system based on MATLAB/SIMULINK is introduced.
Zhuxia Fan +4 more
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Influence of bearing currents on the bearing lifetime for converter driven machines
2012 XXth International Conference on Electrical Machines, 2012The possibility to calculate motor bearing currents from motor geometry and the mechanisms that lead to these currents are known today [1], [2]. The precise mechanical and electrical procedures which lead to the well known corrugated patterns, a “mountain/valley” structure in the bearing raceway, which reduces the bearing lifetime, are still unknown ...
M. Kriese +5 more
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Minimizing Electric Bearing Currents in ASD Systems
IEEE Industry Applications Magazine, 1999During recent years, an increase in bearing failures has been seen in ASD-fed electric motors, as well as in gearboxes, and other connected machinery, caused by electric current flow through such bearings. The theories presented in this paper focus on bearing currents in ASDs of the voltage source pulse width modulated (PWM) type, for use with AC ...
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Experimental Investigation of an Eddy-Current Bearing
1989An AC-electromagnetic bearing based on eddy-current repulsion has been built and tested. The bearing was found to be inherently stable and able to provide support in five degrees of freedom, i.e. a short rotor was fully supported by a single bearing without any feedback control. However, with the current design configuration, the load carrying capacity
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``Constant Current'' Magnetic Bearing
Review of Scientific Instruments, 1971openaire +1 more source
Bearing Currents in Induction Motor Drives
AUTOMATYKA, ELEKTRYKA, ZAKLOCENIA, 2019Jaroslaw GUZINSKI +1 more
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