Unbalanced magnet pull in large brushless rare-earth permanent magnet motors with rotor eccentricity

Publication Type:
Journal Article
IEEE Transactions on Magnetics, 2009, 45 (10), pp. 4586 - 4589
Issue Date:
Full metadata record
Files in This Item:
Filename Description Size
Thumbnail2009000515.pdf678.99 kB
Adobe PDF
Permanent magnet motors are now the focus of application in larger drive and generator systems. They often utilize rare-earth magnets where attractive forces are large and unbalanced magnetic pull (UMP) will be generated even when unexcited. In this paper, a 4-pole machine design is utilized which has either surface magnets or consequent poles. Dynamic eccentricity up to 80% is put into the machine model and a variety of simulations carried out to investigate the UMP. It is found that with strong and thick magnets the machine is robust and the UMP is almost load independent. The consequent pole rotor arrangement produces much higher UMP when the dynamic eccentricity aligns with the steel poles. In the simulations, the different stress components are investigated to assess the validity of a commonly held approximation where the radial force is taken to be a function of the square of the radial air-gap flux.
Please use this identifier to cite or link to this item: