全閉スロット誘導電動機のブリッジ部インダクタンス

摘要

全閉スロット誘導電動機ブリッジ部インダクタンスの変rn化を明らかにするために，回転子単体を利用したサーチコrnイルによる測定とFEM解析による検討を行なった。更に，rn従来の数式による計算との比較も行った。これらの検討のrn結果，以下の知見が得られた。%Closed rotor slots are widely employed in low-power squirrel-cage induction motors with die-cast aluminum cage rotors. Die-cast aluminum cages with closed rotor slots can be manufactured commercially. They help reduce flux pulsation in air gaps, attenuate acoustic noises, and achieve high efficiency. However, it is difficult to calculate bridge inductance of a closed rotor slot accurately because the main flux passes through the bridge and iron saturation can be achieved depending upon the bar current.rnIn this study, bridge inductance was investigated by using a search coil and by FEM analysis and conventional equations. The bridge flux density and the bridge linkage flux were measured by using 4 P-0.75 kW motor with closed rotor slots, and the bridge inductance was calculated as a function of rotor bar current. The bridge inductance was also analyzed by FEM, and the results were analytically checked by using the calculated conventional equations. From these analyses, it is seen that the measured values of the bridge inductance are in good agreement with the values calculated by FEM and conventional methods. It is verified that the bridge inductance shows a trend similar to that of the μ-H curve of the rotor steel sheet.