Hi
I am trying to extract the permeability of certain metal objects (coins) and my theory was that if the objects were passed through the air gap of a toroid inductor then the reluctance of the air gap would change (since reluctance is dependant on relative permeablity).
So there are two reluctances in series in the magnetic circuit : the reluctance of the windings and the air gap. And when the metal cuts through the air gap then the TOTAL reluctance of the toroid will change.
But I wasnt seeing any change in inductance at all (assuming the voltage across the coil will increase or decrease) when I passed magnetic metals through the air gap.
The gap is 3mm wide and the toroid - made of steel - has 27mm external diameter and 17mm internal diameter.
Could somebody verify my theory. I might be heading in the wrong direction.
Thanks
I am trying to extract the permeability of certain metal objects (coins) and my theory was that if the objects were passed through the air gap of a toroid inductor then the reluctance of the air gap would change (since reluctance is dependant on relative permeablity).
So there are two reluctances in series in the magnetic circuit : the reluctance of the windings and the air gap. And when the metal cuts through the air gap then the TOTAL reluctance of the toroid will change.
But I wasnt seeing any change in inductance at all (assuming the voltage across the coil will increase or decrease) when I passed magnetic metals through the air gap.
The gap is 3mm wide and the toroid - made of steel - has 27mm external diameter and 17mm internal diameter.
Could somebody verify my theory. I might be heading in the wrong direction.
Thanks