Abstract
One of the main cause of acoustic noise from iron core in electrical machines is magnetostriction. However, good reproducibility of magnetostriction measurement cannot be expected due to its ppm-order value. To measure the magnetostriction accurately, it is required to clarify principal factors affecting the measurement accuracy. In this paper, a high-resolution method of measuring magnetostriction by means of an open-type single sheet tester equipped with double laser Doppler vibrometers is investigated. It is revealed that the odd components of a magnetostriction waveform should be removed as noises because the reproducibility of odd harmonic components is low. To improve the reproducibility, the friction between a test specimen and a support plate installed under the specimen should be reduced. Furthermore, it is demonstrated that the developed measuring system can be also applied to magnetostriction measurement of Fe-based amorphous sheets.
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