The principle of electric field shielding, magnetic field shielding, electromagnetic field shielding and magnetic insulating materials is these three kinds of shielding. The purpose of magnetic shielding is usually to protect electronic circuits from the interference of magnetic fields, such as permanent magnets, transformers, motors, coils, cables, etc. Of course, strong shielding of the source can prevent it from interfering with the function of nearby components. But the material that blocks the external magnetic field is actually iron itself. If we had a shell made of iron or steel, the steel parts in the shell would be protected from magnetic forces. Even if the object to be isolated is placed near a strong magnetic field, its accuracy will not be reduced. So you have to shield the magnetic field with ferromagnetic materials. We call this magnetic shielding.
There is also a material "silicon steel sheet", can be separated from the magnetic field, but not completely. Silicon steel sheet is a soft magnetic alloy of ferrosilicon with very low carbon content. Silicon can be added to increase the resistivity and maximum permeability of iron and reduce coercivity and magnetic aging. We call the silicon steel sheet between the two permanent magnets a magnetic isolation bridge.
The principle of magnetic separation bridge is to limit magnetic leakage through the saturation of magnetic flux at the magnetic bridge. Therefore, from the perspective of preventing magnetic leakage, the smaller the thickness of magnetic separation bridge, the better the magnetic separation effect. If considering the damage to the rotor structure caused by the centrifugal force generated by high-speed rotation of the rotor, the thickness of the magnetic separation bridge should be considered while satisfying the mechanical strength of the rotor.
In engineering, in order to make magnetic components do not affect other components; Or make the parts immune to external magnetic fields. Not "isolated"; Instead, the "conduction" method is used, which means shielding soft magnetic materials with high permeability.
