Increase Electromagnet Strength Without Additional Energy

In summary: How much?Not even close...Hmm well, it cannot be exact, but I would have expected that you can get a reasonable amplification. Well okay, you get an amplification...How much?
  • #1
Malverin
139
7
Hello,
If we have an electromagnet
370px-Electromagnet_with_gap.svg.png

with some lifting force, for example 10N, and make core area smaller at the ends, to concentrate the magnetic field (without saturating the core)

Magnetic-concentrators-used-in-Minisens.jpg


according to the formula, for magnetic flux

7e9e42656cdd33eb62af4b11645baae4.png


magnetic field density B , will be greater.

For example if we make area, 4 times smaller we will get 4 times greater B

Then electromagnet force will increase too, and become 4 time greater

0d4a229eb6eaca489af15547277399f7.png


So we get more force, without puting in additional energy.
But I have made a magnetic field simulation in FEMM
http://www.femm.info/wiki/HomePage

and there is an increase in B, but much smaller than this according to the formula.
Is there something wrong with the simulation, or my thoughts are wrong...?

http://en.wikipedia.org/wiki/Magnetic_flux

http://en.wikipedia.org/wiki/Electromagnet
 
Physics news on Phys.org
  • #2
and there is an increase in B, but much smaller than this according to the formula.
What do you get as result?

Is your distance between the magnets much smaller than the length scale of the surface, even with the smaller surface?
Is B homogeneous within that surface?
 
  • #3
mfb said:
What do you get as result?

Is your distance between the magnets much smaller than the length scale of the surface, even with the smaller surface?
Is B homogeneous within that surface?

The result was about 2 times increase in B, with area ratio of 5
Yes, the distance is much smaller than the length scale of the surface.
I have measured the field in the core too (in point near the smaler surface, and in point near the big surface)
Inside the core B change should be according to formula I think (there are minimum or no losses inside), but it is not...
 
  • #4
Here is a screenshot of Neodymium magnet simulation. Area ratio is 19 , B increase is about 3 times. So this means more then 80 per cent flux loss! How is that possible?
Permeability of air is so much smaller. Where did the flux go?
 

Attachments

  • Konus 9.jpg
    Konus 9.jpg
    54.5 KB · Views: 435
Last edited:
  • #5
That lacks the opposing magnet, the return yoke, and it looks too sharp. As you can see at the field lines, most of the field goes through the sides.
 
  • #6
mfb said:
That lacks the opposing magnet, the return yoke, and it looks too sharp. As you can see at the field lines, most of the field goes through the sides.

The return yoke to close the loop makes things worse...

This has no sense...:confused:
 

Attachments

  • Konus 19.jpg
    Konus 19.jpg
    44.5 KB · Views: 705
  • #7
This does not look like your original sketch. And 2 Tesla is a typical saturation strength... are you sure you do not have saturation?
 
  • #8
mfb said:
This does not look like your original sketch. And 2 Tesla is a typical saturation strength... are you sure you do not have saturation?

Saturation is not the problem. I have used weaker fields and the ratio is the same.
There can be many variants of this setup. The principal is important.
I have tried differen forms and ratios, and increase in B is never equal to this in the formula.
Not even close...
 
Last edited:
  • #9
Hmm well, it cannot be exact, but I would have expected that you can get a reasonable amplification. Well okay, you get an amplification...
 

What is electromagnetism?

Electromagnetism is a fundamental force of nature that describes the interactions between electrically charged particles. It is responsible for the behavior of electricity, magnetism, and light.

How does an electromagnet work?

An electromagnet is created by passing an electric current through a wire wrapped around a core made of a magnetic material, such as iron. This creates a magnetic field around the wire, making the core magnetized. The strength of the magnetic field can be increased by increasing the amount of current flowing through the wire.

Can the strength of an electromagnet be increased without using additional energy?

Yes, the strength of an electromagnet can be increased without using additional energy by using a ferromagnetic core with a higher magnetic permeability. This allows the magnetic field to be more concentrated, resulting in a stronger overall field without increasing the amount of current.

What are some ways to increase the strength of an electromagnet without using additional energy?

Aside from using a ferromagnetic core with higher magnetic permeability, other ways to increase the strength of an electromagnet without using additional energy include increasing the number of wire coils in the electromagnet, using a stronger power source, and using a different type of wire with lower resistance.

What are some practical applications of electromagnets with increased strength?

Electromagnets with increased strength have a wide range of applications, including in industrial equipment such as cranes and lifts, in medical devices such as MRI machines, and in everyday objects like speakers and doorbells. They are also used in research and development for particle accelerators and fusion reactors.

Similar threads

Replies
2
Views
960
  • Electromagnetism
Replies
5
Views
1K
Replies
8
Views
945
Replies
4
Views
803
Replies
11
Views
3K
  • Electromagnetism
Replies
2
Views
1K
Replies
1
Views
835
Replies
13
Views
2K
Replies
7
Views
1K
  • Electromagnetism
2
Replies
44
Views
4K
Back
Top