| 摘要 |
PROBLEM TO BE SOLVED: To provide a method capable of highly accurately predicting noise generated in a transformer.SOLUTION: In order to predict noise generated in a transformer by using a directional electromagnetic steel sheet sample, a magnetic flux density waveform in an iron core when the iron core is excited to a predetermined magnetic flux density is obtained, then exciting voltage for causing generation of the magnetic flux density waveform in the iron core in the sample is applied to the sample to predict magnetostriction vibration generated in the sample, the influence of fastening of a directional electromagnetic steel sheet in an iron core structure is added to the measured magnetostriction vibration to predict noise. The waveform of the voltage is provided by the following expression (1), in which t is time, f is a frequency, A is a superimposition ratio of a tertiary harmonic component to a fundamental wave component, and θ is a phase angle, phase angles θ are sampled within the range of - 180° or more to + 180° or less and at the interval of 45° or less, magnetostriction vibration is measured in each sampled phase angle, and the average value of magnetostriction vibration among the measured phase angles is set as generated magnetostriction vibration. A is 0.05 to 0.2. Note [Expression (1)]SELECTED DRAWING: None |
