# Force produced by current carrying coil to the sludge(Steel rod).

#### mik3

Joined Feb 4, 2008
4,843
hi mik3,
I tried to calculate the force F= [(Imax^2)*(Inductance of the coil)]/[2*Lift of slug]. Is that right?
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.

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.

#### rvb53

Joined Apr 21, 2008
28
hi mik3,
Thanx alot for ur information.
I think that F= m*a, where m= mass of slug and a= acceleration of the slug against g(gravity), so it(a) should be more than g.
When I tried to solve using kinematics concept, I came up with F= (2*m*g) , this is ideal force, means my acutal force 'F' will face some losess due inductance of coil + relative permeability of the steel.
Finally, F= (2*m*g)-constant(losess).

#### mik3

Joined Feb 4, 2008
4,843
hi mik3,
Thanx alot for ur information.
I think that F= m*a, where m= mass of slug and a= acceleration of the slug against g(gravity), so it(a) should be more than g.
When I tried to solve using kinematics concept, I came up with F= (2*m*g) , this is ideal force, means my acutal force 'F' will face some losess due inductance of coil + relative permeability of the steel.
Finally, F= (2*m*g)-constant(losess).
If you put the values on both the equations you get almost the same result?

#### thingmaker3

Joined May 16, 2005
5,083
Is there any link where we can find
$image=http://forum.allaboutcircuits.com/mimetex.cgi?%5Cmu&hash=f36076f427b81e21ed200a725066616d$
r of steel?
Values for some compositions, mainly 300 series stainless varieties, are given by MatWeb. I also have some others in a couple of my metallurgy books. (My other hobby is metal working.) Those used in transformers are available from manufacturer's websites.

Nickel increases the permeability of steel, but also lowers the Curie point. Once the Curie point drops below ambient, permeability falls to near unity.

#### rvb53

Joined Apr 21, 2008
28
hi thingmaker3,
Thanx alot for information.
I think the slug which we are using is made of steel used in rapper coil in Electro Static Percipitators(ESP).

#### rvb53

Joined Apr 21, 2008
28
hi everyone,
I found the formulae for the lift of slug which LIFT = 2*g*t^2.
where g = gravity, t= time period. using kinematics concept. Is this right?

#### thingmaker3

Joined May 16, 2005
5,083
Doesn't seem right to me. Wouldn't more lift raise the slug in less time?

#### rvb53

Joined Apr 21, 2008
28
hi thingmaker3,
thanx for ur suggestions....can U comment more in detail...?
Can U help me more on this problem...?

#### thingmaker3

Joined May 16, 2005
5,083
All of the material I have on "lift" deals with airplane wings and helicopter blades.

#### rvb53

Joined Apr 21, 2008
28
Hi everyone,
I need some information.....does the phase angle between the voltage and current give me when does the slug starts moving upward in the coil....?Is phase between the voltage and current help in any way for the problem....?

#### rvb53

Joined Apr 21, 2008
28
hi everyone,
pls try to help me in the phase issue....I came up[ with formulas and trying to validate them .Does phase angle between voltage and current give any sort of information....pls do help me?

#### thingmaker3

Joined May 16, 2005
5,083
The slug responds to the magnetic field, which is in turn generated by the current. Phase angle might be useful for determining when things happen, but I don't see how it could help with calculating the force produced.

#### rvb53

Joined Apr 21, 2008
28
hi thingmaker3,