I have an experimental set-up where I place a conductive wire in a magnetic field created by an electromagnet like so: enter image description here

There is current flowing in a wire as well(aside from the electromagnet) displayed in this diagram:

enter image description here

(Ignoring the Lorentz force acting on the wire and possibly the electromagnet)The magnetic field created by the electromagnet(that is composed of multiple turns and a ferromagnetic core like soft iron to increase the magnetic field) is \$B\$ acting on the wire that has current flowing within it. Likewise, the wire will induce it's own magnetic field \$B_W\$ as shown here: enter image description here

Usually, the \$B_W\$ is insignificant due to the distance and the amount of current flowing within it,

enter image description here

However, if(neglecting resistance and fusing on the wire) the current was quite high enough to generate a magnetic field where this condition \$B_W\$ > \$B\$ is true, what would happen to \$B\$?

  • \$\begingroup\$ It's all linear, so add the fields as vectors. \$\endgroup\$ – George Herold Apr 8 '16 at 1:37
  • \$\begingroup\$ @GeorgeHerold Would the field of the wire affect the magnetization of the ferromagnetic core? If it is indeed was higher than B? Assume the gap was much much smaller, the field lines of the wire will be perpendicular to the applied field, and to the ferromagnetic core, possibly changing it's magnetization? Image: i.imgur.com/C970tC3.jpg \$\endgroup\$ – Pupil Apr 8 '16 at 2:05
  • \$\begingroup\$ OK if the fields are near the saturation of the ferromagnetic material then indeed there can be some effect. Because of non-linearity in the magnetic material. (sorry for my quick response, with not enough thought.) \$\endgroup\$ – George Herold Apr 8 '16 at 12:44
  • \$\begingroup\$ @GeorgeHerold If there is indeed a change in magnetization, is it possible that the magnetic field produced by the electromagnet is weakened? Due to the core's regional moments changing their direction? \$\endgroup\$ – Pupil Apr 16 '16 at 8:20

Assuming it's a 2D problem for simplicity, the net magnetic field would strengthen on one side of the coil and would weaken on the other side of the coil: -

enter image description here

The picture above shows lines of flux adding at the top and subtracting at the bottom producing this effect (and a force): -

enter image description here

See slide 24 on this page for source of pictures.

  • \$\begingroup\$ Thanks Andy, if the wire is large or the gap was smaller in a way it's near the magnet/ferromagnetic core would that in anyway effect the magnetization of the ferromagnet(if the magnetic field of the wire was greater)? \$\endgroup\$ – Pupil Apr 12 '16 at 7:22
  • \$\begingroup\$ I'm not sure what you are asking. \$\endgroup\$ – Andy aka Apr 12 '16 at 7:29
  • \$\begingroup\$ Let me use an example to give you an idea of what I mean, let's say we had an electromagnet with multiple turn and a soft-iron core to make the field stronger, that electromagnet is capable of creating a 1T magnetic field of a gap of 10mm, introduce a conducive slab in that gap and run high current within it like the diagrams above, the slab's area is equal to the ferromagnet and the distance between it and the core is roughly 1mm, that slab creates a field of 2T(for example), now the core begins to magnetize in the direction of the slab's magnetic field. Similar to the diagram above. \$\endgroup\$ – Pupil Apr 12 '16 at 7:48
  • \$\begingroup\$ Even with your diagrams and multiple wires where the area of the wires = the area of the magnet's poles the field is no perpendicular. \$\endgroup\$ – Pupil Apr 12 '16 at 7:49
  • \$\begingroup\$ I'm not sure how you want me to comment. \$\endgroup\$ – Andy aka Apr 12 '16 at 7:55

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.