This is correct if you calculate the new inductance of the coil each time you move the sludge. The lift of the sludge is measured from the beginning of the coil up to where the sludge is moved.hi mik3,

I tried to calculate the force F= [(Imax^2)*(Inductance of the coil)]/[2*Lift of slug]. Is that right?

It is better to write the equation as

F={(I^2)*[μ*A*(N^2)]}/[2*(x^2)]

Find the point where F=m*g

where m=mass of the sludge

g=10 m/s^2 approx.

The sludge should lift up to this point.