High-frequency core-loss characteristics of biased Fe79B16Si5amorphous metallic-alloy tape-wound cores

The core-loss characteristics of biased magneto-elastically resonant tape-wound cores manufactured from METGLAS® alloy 2605S-3 (composition Fe79B16Si5) are presented. These characteristics are measured under small-signal excitation (constant ΔB) over the frequency range from 10 kHz to 500 kHz using cores of three different sizes. Measurements of the impedance of the cores with windings are used to obtain the incremental relative permeability μrover the same frequency range. Both core-loss data and permeability data indicate strong magnetomechanical coupling, with the measured core loss being about 100 times greater at resonance than normal losses due to hysteresis and eddy currents. The dominant mode of mechanical resonance is experimentally confirmed to be due to the fundamental extensional mode of vibration. Young´s modulus EBfor constant ΔB is calculated at different dc-bias levels from the resonant frequencies obtained using incremental relative permeability data, and is plotted as a function of bias level for the three core sizes.