Optimization of shield thickness of finite-length solid rotors for eddy-current loss minimization

Manoj R. Shah, Sang Bin Lee

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


A high-conductivity shield is often used for coating the rotor of solid-rotor synchronous machines for reducing the surface eddy-current losses due to armature-reaction space/time harmonics and/or tooth ripple. Since the design process for determining the optimal shield thickness can be complicated and time consuming, a simple analytical model based on Maxwell's equations was developed and presented in a previous paper to simplify the process. It has been shown that such an analytical tool can be used as a quick and effective "screening tool" for determining the range of the optimal shield thickness for minimizing rotor surface losses; however, the influence of finite rotor axial length including the end-face losses was not taken into account. In this paper, an additional step is introduced in the shield design process where a special finite-element (FE) method that accounts for the impact of finite rotor axial length is employed for refining the design obtained from the analytical solution. Comparisons are made for a number of shield thicknesses and rotor lengths for significant space and time harmonic combinations to verify the validity of the proposed two-step design process (analytical and FE) and to evaluate the impact of the finite length of solid rotors.

Original languageEnglish
Article number5238577
Pages (from-to)1947-1953
Number of pages7
JournalIEEE Transactions on Industry Applications
Issue number6
Publication statusPublished - 2009 Nov


  • Ac machines
  • Analytical and numerical harmonic analyses
  • Eddy currents
  • Electromagnetic shielding
  • Rotor surface losses
  • Solid rotor
  • Synchronous machines

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering


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