| Computer simulation was carried out to investigate the behavior of magnetic field and eddy current property using FLUX2D on an amorphous mold core. Magnetostatics analysis shows that flux density distributes uniformly throughout the amorphous core and its value was about 0.92 T. It was found that when the direction of magnetic path changes drastically within the angle of 90°in an amorphous core, an uniform magnetic flux density was obtained throughtout the core. Magnetodynamics analysis at the frequency of 30 ㎑ revealed that eddy current was concentrated on both sides of edge, but almost cancelled out at the center. The Flux density induced by eddy current shows almost similar behavior. This can be interpreted that the eddy currents formed at each shell on center were cancelled out each other, while those on both sides of edge remain alive. A Weak leakage of fluxes was detected and it might act as EMI noise. Since the EMI noise can cause some errors on operation and increase the temperature of system, shield materials are useful to reduce leakage flux. The skin depth was calculated to be about 0.17 ㎜ from the equation of skin effect, while the penetration was totally achieved at the most outer and its neighboring shell on both sides of edge by simulation. Although the skin depth obtained from equation corresponds to 1/e of its real value, there was a little difference between simulation and calculation. It may be assumed that the relative permeability and electrical conductivity of a amorphous core would drastically reduce after molding. |
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