Examination of eddy current between steel sheets without insulation and a criterion for determining the necessity of insulation

Akira Akagi, Norio Takahashi, Masanori Nakano, Yuhito Doi, Daisuke Miyagi

Research output: Contribution to journalArticle

Abstract

In the laminated core of transformers, motors, and so on, each electrical steel sheet is usually insulated in order to reduce the eddy current loss. It has been reported that insulation is not necessary in such a laminated core under some conditions. However, few studies have been performed in the form of a quantitative and systematic examination of the relationship between the insulation and eddy current. In this study, the eddy current losses of a core made of SPCC (cold rolled steel sheets) of different widths with and without insulation under various conditions are analyzed using the finite element method (FEM) and with the contact resistance taken into consideration. The equivalent circuit of a laminated core without insulation is presented, and can be used for determining the necessity of insulation. It is shown that the increase in the eddy current is affected by the ratio of the resistance of the steel to the contact resistance. An experimental investigation is also carried out.

Original languageEnglish
Pages (from-to)65-74
Number of pages10
JournalElectrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi)
Volume192
Issue number3
DOIs
Publication statusPublished - 2015 Aug 1

Keywords

  • contact resistance
  • eddy current
  • eddy current loss
  • finite element method
  • insulation

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

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