Title :
On Liquid-Nitrogen-Cooled Copper-Wound Machines With Soft Magnetic Composite Core
Author :
Marignetti, Fabrizio
Author_Institution :
Dept. of Autom., Univ. of Cassino, Cassino, Italy
Abstract :
This paper illustrates the potential and the convenience of copper-wound electrical machines with liquid nitrogen (LN) cooling. Natural convection heat exchange coefficients in LN are very high. Moreover, the resistivity of copper decreases remarkably at cryogenic temperature, subsequently reducing Joule loss in copper windings. Hence, cryogenic copper-wound electrical machines use less copper to carry the same current compared to airor water-cooled machines, thereby improving the powerto-weight ratio. An experimental study is made of some practical issues related to the design of an LN-cooled machine using as an example the construction of a 220-N permanent magnet tubular linear actuator with a soft magnetic composite stator core.
Keywords :
cryogenics; linear machines; machine windings; natural convection; permanent magnet machines; soft magnetic materials; stators; 220-N permanent magnet tubular linear actuator; Joule loss; LN-cooled machine; copper windings; cryogenic copper-wound electrical machines; cryogenic temperature; liquid nitrogen cooling; liquid-nitrogen-cooled copper-wound machines; natural convection heat exchange coefficients; permanent-magnet machines; resistivity; soft magnetic composite stator core; Cryogenics; electric machines; linear synchronous motors; permanent-magnet (PM) machines; soft magnetic composites (SMCs); superconductors;
Journal_Title :
Industry Applications, IEEE Transactions on
DOI :
10.1109/TIA.2010.2045328
