Investigation on the AMDT Core Model Vibration by Harmonic Response Analysis and Validation of the Resonance Characteristics by Testing

Amorphous metal distribution transformer (AMDT) has lower no-load loss compared to traditional oriented silicon-steel distribution transformer (OSDT), but its vibration noise is larger than that of OSDT. It is conducive to the further promotion and application of AMDT if its vibration noise can be effectively reduced. In this paper, the model of finite element analysis (FEA) for AMDT core was established, and the natural frequency as well as model shape of the AMDT core were calculated by modal analysis with pre-stress, and the modal superposition method was utilized to the harmonic response analysis of the core. In the experiment, the frequency-domain waveform and noise sound pressure level (SPL) of different clamping stress applied to the top panel of SCBH 15-200/ 10 AMDT were compared to verify the noise reduction effect. The experimental results show that the vibration amplitude at 200 and 600 Hz in the three phases increases first, and then it decrease with the increasing of the applied stress. It means that the excitation frequency is closer to the natural frequency and causing AMDT to resonate when an external excitation source with appropriate size was added. Meanwhile, the vibration noise during AMDT operation also increases first, and then it decreases with the applied stress increases. Controlling the application of external excitation to AMDT is very helpful to reduce its vibration noise.