Recently, various kinds of non-oriented electrical steels with greatly improved properties have been developed and put to practical use in high-efficiency motors to cope with ever-tougher requirements for higher performance and energy savings in this field. For clarifying conditions of realizing higher performance, influence of magnetic properties of core material electrical steels on the performance of brushless dc motor and induction motor has been studied. In a three-phase induction motor, 0.5% higher efficiencies have been obtained by using JNA having higher magnetic flux densities. The efficiency of a brushless DC motor of concentrated winding type can well be estimated by the core material iron loss at 400Hz. By using low-core-loss high-flux-density electrical steels ME, 0.5 - 1.0% higher efficiencies have been obtained than conventional materials with equivalent torque constants in this motor.
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