Dynamic Behavior of Magnetostriction-Induced Vibration and Noise of Amorphous Alloy Cores

Although the amorphous alloy core distribution transformers (AMDTs) have the advantage of lower no-load losses over orientation silicon-steel distribution transformers, a high noise level is inevitable. The vibration and noise for different positions of cores are still unknown. Understanding the vibration and noise behaviors of cores under operation is vital to reduce the noise of AMDT. In this paper, two cores from 10 kVA AMDT and 24-turn coils were used as the testing objects, and the ac voltage of 54.3 V was applied to the coils until the magenetic flux density attained 1.337 T. The finite-element method was used to analyze the cores´ magnetic-field distribution. An attempt was made to find the largest amplitude position of the cores by vibration sensors. Sensors were arranged on the surface of the cores according to the magnetic flux density distribution. A personal computer data acquisition platform was set up for signal measurement. Fast-Fourier transform and wavelet packet transform were integrated to analyze the vibration signals. The vibration amplitude related with time and frequency was discussed at different positions of the cores, and experimental results indicated that the position with the largest amplitude was in the middle of the core´s yoke and limb at 200 Hz. The experimental results suggested that magnetostriction played a major role in exciting noise and vibration. A filler of silicon rubber and foam under the cores can lessen the vibration energy. This performs well in reducing noise. All the above testing results and analysis are helpful to optimize the design and improve the manufacturing technology of AMDT.