PRELIMINARY CONSIDERATIONS ABOUT THE ADOPTION OF UNCONVENTIONAL MAGNETIC-MATERIALS AND STRUCTURES FOR INDUCTION-MOTORS

The activity carried out and presented in this paper deals with the op portunity of utilizing high quality magnetic materials, such as amorph ous, microcristalline or cubic texture materials for the magnetic stru cture of medium size induction motors. In order to evaluate the benefi ts introduced by these materials for reducing the iron losses in a.c. motors, digital preliminary computations have been carried out conside ring the characteristic of such materials (induction versus specific l osses) and the obtained results for each solution have been compared. At the present, however, the above mentioned materials are costly, not easy to handle and to assemble and therefore a practical solution wit h grain oriented steel in a crossed structure obtained alternating she ets with orthogonal grain orientation, in order to simulate the cubic texture material (bi-oriented material) has been proposed. To verify t he obtained theoretical results with the digital computations, a proto type of 20 Hp, 380 V, three phases induction motor with this non conve ntional magnetic structure has been designed and built. The tests on t he prototype to evaluate the iron losses are in good agreement with th e digital simulation results.