Abstract Early structural damage and resulting failures can be caused by vibration in AC electrical machines. Since the stator is under a magnetic field that varies with time, the stator… Click to show full abstract
Abstract Early structural damage and resulting failures can be caused by vibration in AC electrical machines. Since the stator is under a magnetic field that varies with time, the stator magnetic material contracts and expands due to the magnetostriction, producing noise and vibration. Therefore, a low magnetostriction value is desirable to minimize the effect of vibration and avoid earlier motor breakdowns. However, not only a low magnetostriction value is enough. Low values of magnetic losses avoid the material heating, consequently preventing magnetic properties degradation. To minimize these magnetic losses, a suitable material might have high resistivity and magnetic permeability, and also low coercive field. Fe-Ti alloys have low magnetostriction values and are soft magnetic material, making them good candidates for using in motors’ stators. In the present work, two Fe-Ti alloys with composition 6.9 wt% Ti (8 at.%) were studied. One of the alloys was studied after the as cast ingot annealing at 1200 °C. The other alloy was hot rolled from 7 mm down to 0.5 mm of thickness. The maximum magnetic induction of the rolled alloy was 1.74 T, about 12% higher than the not rolled one. In addition, the rolled Fe-Ti alloy magnetostriction is lower than 1 ppm up to 1.25 T, while in the not rolled condition is also 1 ppm, but only up to 0.75 T.
               
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