How would you find the magnetic force on a piece of metal by an electromagnet?

In summary, the magnetic properties of the metal being attracted play a role in calculating the force of attraction between an electromagnet and the metal. The force is proportional to the square of the field strength at the face of the electromagnet, with a field strength of one Tesla resulting in a pull force of 58 pounds per square inch. Other factors that affect the field strength include air gaps and layers of paint or rust. Additionally, there may be assumptions about the geometry and substrate of the electromagnet that need to be considered when using this calculation. Ultimately, using a simulation tool like FEMM may be the most accurate way to determine the force on a metal in a specific electromagnet setup.
  • #1
breadandbacon
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Does the metal being attracted make a difference?
How would you find the force on the metal knowing the field strength there?
How would you even calculate the field strength of an electromagnet with a core? In my case, it is one of those junkyard electromagnets.
thanks
 
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  • #2
When you grab something with an electromagnet, you are making a magnetic circuit. To learn how to calculate, search magnetic circuit. The magnetic properties of the metal being attracted are part of the calculation. Keep in mind that the field strength is strongly affected by any air gaps, and that a layer of paint or rust is an air gap.

The force of attraction is proportional to the square of the field strength at the face of the electromagnet where it contacts the metal. A field strength of one Tesla has a pull force of 58 pounds per square inch of pole area.
 
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  • #3
jrmichler said:
The force of attraction is proportional to the square of the field strength at the face of the electromagnet where it contacts the metal. A field strength of one Tesla has a pull force of 58 pounds per square inch of pole area.
A useful number...there must be some assumption about the rest of the geometry, though? I am guessing this is for a "long" magnet with flat pole on a semi-infinite substrate??Any assumptions about substrate (obviously ferromagnetic I guess) but does it somehow not matter?I would find this a very useful thing to know but don't understand when to apply it. Thanks
 
  • #4
yall i ended up just using FEMM and it worked out fine
 

1. How does an electromagnet create a magnetic force on a piece of metal?

An electromagnet is created by passing an electric current through a coil of wire. This creates a magnetic field around the coil, which can attract or repel magnetic materials such as metal.

2. What factors affect the strength of the magnetic force on a piece of metal by an electromagnet?

The strength of the magnetic force depends on the strength of the electric current passing through the coil, the number of turns in the coil, and the distance between the electromagnet and the piece of metal.

3. How can you calculate the magnetic force on a piece of metal by an electromagnet?

The magnetic force can be calculated using the formula F = BIL, where B is the strength of the magnetic field, I is the electric current, and L is the length of the metal in the magnetic field.

4. How can you measure the strength of the magnetic field created by an electromagnet?

The strength of the magnetic field can be measured using a tool called a gaussmeter, which measures the magnetic flux density in units of gauss or tesla.

5. Can the direction of the magnetic force on a piece of metal be changed by an electromagnet?

Yes, the direction of the magnetic force can be changed by reversing the direction of the electric current in the coil. This will change the direction of the magnetic field, and therefore the direction of the force on the metal.

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