COMPARISON OF SOFT-MAGNETIC-COMPOSITES (SMC) AND LAMINATION ASSEMBLIES.

Soft-magnetic-composite (SMC) use in electric motors offers a significant growth opportunity to the PM industry. Barriers exist, however, that have prevented wide-scale adoption. Beyond the need for motor redesign, users need to understand the difference in performance and stated properties of SMCs and the dominant stator-core technology using lamination (electrical sheet) steels. Lamination steels used for stator cores have excellent magnetic properties within individual sheets. The comparison of these individual sheet properties, such as maximum saturation and permeability, with powder-based soft-magnetic-composite properties creates an unfavorable view of SMCs. The properties of lamination assemblies, however, are lower than individual sheets due to the stacking factor and the presence of insulation layers. Further, it is commonly understood that these stacks tend to work best at lower frequency, whereas SMCs are more suited to higher frequency. The number of direct comparisons of SMC and lamination steel stacks is limited in the literature, resulting in broad generalizations. In this study, test rings made with assemblies of 2 lamination steel grades and 2 grades of SMC have been evaluated under different test conditions. The effect of ring size and amount of lubricant are also discussed. The direct comparison between SMCs and lamination steel will enable users of the technology to understand the benefits and limitations of each approach, leading to the best engineering solutions. [ABSTRACT FROM AUTHOR]