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Valentin Pricop. PhD review. Coercive force vs. polarization frequency. Material under test: M-15; Polarization waveform:. Theoretical values:.
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ValentinPricop PhD review
Coercive force vs. polarization frequency Material under test: M-15; Polarization waveform: Theoretical values: When testing materials close to quasi static conditions, the coercive force increases with a value directly proportional to the frequency of variation of the magnetic induction. Valentin Pricop - PhD review
Coercive force vs. polarization frequency Material under test: M 700-50 A; Polarization waveform: Theoretical values: M 700-50 A presents different behaviour, compared to M-15, when tested transversal to rolling direction. Valentin Pricop - PhD review
Epstein frame – voltage induced in the mutual coil Pickup coil of the mutual inductor. Theoretically, the flux leaking from the coils of the Epstein frame should not affect the voltage output of the secondary winding of the pickup coil. Valentin Pricop - PhD review
Epstein frame – magnetic circuit Relative permeability of the samples: current through the coils: . Y X Z Y X Z Flux seen by the mutual inductor: -1.3033 T∙mm2 Y X Z The magnetic field strength vector generated by each coil will be oriented along the vector normal to the surface of the coil. Valentin Pricop - PhD review
Epstein frame – magnetic circuit Relative permeability of the samples: current through the coils: . Y X Z Flux seen by the mutual inductor: -1.3033 T∙mm2 Y X Z With increasing permeability of the material, the leakage field along X and Z axis increase in strength. Valentin Pricop - PhD review
Epstein frame – magnetic circuit Relative permeability of the samples: current through the coils: . Y X Z Flux seen by the mutual inductor: -1.3033 T∙mm2 Y X Z With increasing permeability of the material, the leakage field along X and Z axis increase in strength. Valentin Pricop - PhD review
Epstein frame – magnetic circuit Relative permeability of the samples: current through the coils: ; coil position not symmetric. Y X Z Flux seen by the mutual inductor: -1.3033 T∙mm2 10 mm 10 mm Y X Z In case on non-symmetric arrangement of the Epstein frame coils, the leakage field will no longer be symmetric. Valentin Pricop - PhD review
Epstein frame – magnetic circuit Relative permeability of the samples: current through the coils: ; one coil short circuited. Y X Z Flux seen by the mutual inductor: -1.33032 T∙mm2 Y X Z In case the visible Epstein excitation coil is shorted, it will exist a strong leakage field. Valentin Pricop - PhD review
Epstein frame – mutual inductor flux measurements FEM simulations have confirmed the theory. If the mutual inductor is placed according to the specifications of the IEC 60404-2 standard (“in the centre of the space enclosed by the four coils, its axis being directed normal to the plane of the axes of these coils”), then the leakage flux from the Epstein frame has very little influence to the voltage output of the pickup coil of the mutual inductor. Valentin Pricop - PhD review