Do permanent magnets have an electric current surrounding them?

Question

Permanent magnets seems to have different properties to electromagnets, such that electromagnets can be used for induction and energy transfer if a conductor is placed within their changing magnetic field.

So I understand that an electromagnet will have a changing magnetic field, which in turn generates a changing electrical current in a conductor placed within this magnetic field.

My question is, do permamant magnets generate this same electric current if a conductor is placed within their magnetic field?

I.e. if I had a strong permanent magnet, would I be able to generate a current in a coil if it was brought into the permananet magnet's magnetic field?

Answer 1

To answer your question in one word, "Yes"

Now, onto the explanation:-

According to Faraday's Law, you will get a current in a conductor when the amount of magnetic flux linked with the conductor changes.

Note that it is immaterial whether the source of the magnetic field is a permanent magnet or an electromagnet. All that needs to happen for you to detect a current in the conductor is for the flux to change.

In case of the electromagnet, when you change the strength of the field; the flux linked with the coil changes and current is induced.

In case of the permanent magnet, your field is fixed; you can't change it. But, if there is relative motion between the permanent magnet and the coil; then the flux linked with the coil will change and if that happens,current will definitely be induced.

Answer 2

According to Faraday's law of induction, $$\mathcal{E} = -N {{d\Phi} \over dt}$$ you will need a change in the magnetic flux $\Phi$ in order to get an EMF or an electric field.

So if you just put your coil in the magnetic field of the permanent magnet, you will not measure a current. There will only be a current, if you move the coil around so that the flux changes.

Answer 3

There is no current present if a coiled magnet simply remains static. But if you spin it with enough force you then would be inducing a current. Once there is enough induction, it would seem that the coiled magnet will spin on its own due to a self induced current that will tend to perpetuate itself until overcome by friction.