Evaluation of Insulating Magnetic Materials Composed of Epoxy Resin and Pure Iron Powder for Motor and Reactor Core Applications

Abstract

The insulation and magnetic properties of epoxy composed of pure iron powders were studied as a function of iron powder volume fraction (R Fe ) in the range of 0-70 vol% to achieve a good balance between the insulation and magnetic properties. Frequency-dependent impedance measurement revealed that the relative permittivity, ε r , at 10 kHz increased from 4.2 to 278.4 with increasing R Fe up to 50 vol%. The loss factor, ε r , increased from 0.2 to 86.1 and the electric conductivity, σ, increased from 9.9 × 10 −8 S/m to 4.8 × 10 −5 S/m at 10 kHz with increasing R Fe up to 50 vol%. The dependence of σ on R Fe was explained by the equivalent serial capacitor-resistor (CR) connection model. The initial maximum relative permeability, μ r max , increased from 3.7 to 8.9 with increasing R Fe up to 70 vol%. These data were compared with those for the "Reference" sample which has been in practical use in industrial electric machine applications.

Manufacturing of Pure Iron by Cold Rolling and Investigation for Application in Magnetic Flux Shielding

“…However, the pure iron strips have higher saturation flux density than Mu-metal and electrical steel (saturation flux density of Mu-metal is 0.6 T). This observation is in consonance with earlier findings reported in the literature [ 38 , 40 , 41 ]. Therefore, the use of pure iron strips can be investigated for certain applications of magnetic flux shielding.…”