Electromagnetic force required to levitate an object

In summary: However, if I add a permanent magnet to the solenoid, then the magnetic field outside the solenoid will be much stronger and I'll need to take that into account when calculating the force.
  • #1
bks008
2
0
I'm trying to use some home-made electromagnets to lift a small object. I am a college student, but this is a personal project, so while I may reference something from a textbook, its not a homework problem.

I know that I can get some iron bar, coil it with wire, run some current through it and see if it works, but I want to know the math behind it. I know I'm trying to make a solenoid with a core, and the formula my book gave me for the B field is B=μo*i*n where μo is the permeability of free space, i is the current in amps, and n is the number of coils. My book leads me to believe that B is in Teslas, but when I try out different numbers in Mathcad I get resulting units of Tesla-meters. I found on wikipedia B=[μo*i*n]/L where L is the length of the solenoid, and this gives me the units I'm looking for. Can someone point me into the right direction here?

Next question is, how do I relate the magnetic field of my electromagnet to the mass of the object I want to lift? I know I need to set the electromagnetic force equal to m*g*h, but I'm not sure where to go from there.

Am I even on the right track? If I'm not, I'd appreciate all the help I can get. I've searched and searched online trying to find this stuff but I haven't found anything overly helpful.
 
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  • #2
hey the n (for the B field is B=μo*i*n where μo is the permeability) you mentioned first time is no. of turns per unit length
the n you mentioned the second time is no. of turns N

n=N/L
L- length of the solenoid



As to the basic question , what you are trying to do is impossible because magnetic field of a solenoid OUTSIDE it is ZERO (practically negligible)
 
  • #3
rohans said:
hey the n (for the B field is B=μo*i*n where μo is the permeability) you mentioned first time is no. of turns per unit length
the n you mentioned the second time is no. of turns N

n=N/L
L- length of the solenoid



As to the basic question , what you are trying to do is impossible because magnetic field of a solenoid OUTSIDE it is ZERO (practically negligible)


Thanks for the help with the first part. I'm embarrassed I didn't see that before.

As for the second part, if I add a ferromagnetic core (loosely quoting wikipedia), then the same equation holds true as long as I take into account the permeability of the core.
 

1. How does electromagnetic force allow an object to levitate?

The principle behind electromagnetic levitation is that an object can be suspended in the air by using the force of repulsion between two magnets. When two magnets with like poles facing each other are brought close enough, they will repel each other and create a force that can hold an object in place.

2. What determines the strength of the electromagnetic force required to levitate an object?

The strength of the electromagnetic force required to levitate an object depends on the weight and size of the object, as well as the strength of the magnets used. The larger and heavier the object, the stronger the magnets need to be in order to create enough force to overcome the pull of gravity.

3. Can any object be levitated using electromagnetic force?

In theory, yes. However, the size and weight of the object may make it difficult or impractical to levitate using electromagnets. Additionally, the shape and material of the object can also affect its ability to be levitated, as some materials may not interact well with magnetic fields.

4. How can the levitation height be controlled using electromagnetic force?

The height at which an object can be levitated using electromagnetic force can be controlled by adjusting the distance between the two magnets. The closer the magnets are to each other, the stronger the force will be and the higher the object will levitate. The height can also be controlled by adjusting the strength of the magnets.

5. Are there any practical applications for using electromagnetic force to levitate objects?

Yes, there are several practical applications for electromagnetic levitation. It is commonly used in high-speed trains and magnetic levitation (maglev) trains, as well as in some types of bearings and suspensions for machinery. It is also being explored as a potential method for transporting goods and materials in warehouses and factories.

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