Question regarding electromagnets - perplexed

[void109]

Assertions:

Current traveling through a medium induces a magnetic field

A coil around a ferrous material that is carrying current will induce an a magnetic field that is amplified by the ferrous material

The ferrous material contributes to the overall magnetic field because the induced field causes the atoms in the ferrous material to align their magnetic dipoles in the same direction as itself

Question:

If the above assertions are correct (they may not be) - If the ferrous material's atoms orient in the same direction as the induced field - why wouldnt a permanent magnet also cause this to occur?  Wouldn't say - a ferrite bar, if attached to a permanent magnet, also amplify its strength? (I dont believe this is the case).

I must not understand why a ferrous core amplifies an electromagnetic field.  Can anyone help show me where I'm mistaken, and or help explain our current understanding of this phenomenon?

[mscoffman]

Assertions:

Current traveling through a medium induces a magnetic field

A coil around a ferrous material that is carrying current will induce an a magnetic field that is amplified by the ferrous material

The ferrous material contributes to the overall magnetic field because the induced field causes the atoms in the ferrous material to align their magnetic dipoles in the same direction as itself

Question:

If the above assertions are correct (they may not be) - If the ferrous material's atoms orient in the same direction as the induced field - why wouldnt a permanent magnet also cause this to occur?  Wouldn't say - a ferrite bar, if attached to a permanent magnet, also amplify its strength? (I dont believe this is the case).

I must not understand why a ferrous core amplifies an electromagnetic field.  Can anyone help show me where I'm mistaken, and or help explain our current understanding of this phenomenon?

Formally, Historically, people would say that the ferrite material
doesn't amplify magnetic fields as much as it collects the magnetic
field so the lines of flux are concentrated inside the material
of a magnetic circuit. So ferrite core increases the inductance of
of a coil. Certain increases in energy associated with this are only
begining to be studied now. So formal magnetic amplifiers are
also called saturatable reactors and do not suppose to show
energetic increases. Pure magnetic field strength amplification
using strictly magnetic fields and certain ferrites was demonstrated
to some extent by the Austrialian Quinn on this web site. This seems
to have the potential to create a purely magnetic switch, and
a switch is a form of amplification, but he gave up on the idea
before he showed actual device mechanisms. For example a pure
magnetic switch could create a commutator for a pure magnetic
motor. Magnetic circuits are generally hobbled by not having high
quality magnetic insulators or sheilds so one has to think differently
about phyical layout in magnetic circuits and electrical ones. I think
this area would be a highly productive one for experimentation.

:S:MarkSCoffman

[Pirate88179]

I totally agree with Mark and would just add this:

Most of the time when coils are used, there are pulses involved.  Sometimes pulsed DC sometimes pulsed AC but, pulses non the less.  During these pulses, the ferrite, or other core material, becomes "magnetic" BUT, and this is important, it is how fast it can loose this magnetic effect that will create the large back EMF spikes that we all like to play with so much.  This is where the action is.

So, if we used a core that was, by itself, magnetic all the time, we would not experience the field collapse at all and therefore would not get any BEMF spikes.

This is why on the Joule Thief topic we hunted around for ferrite toroids that would "instantly" take a mag field and then "instantly" release it thereby creating the huge back EMF spikes that make the circuit do what it can do.

This is the same with Bedini devices, JT circuits, and many other devices on here you may read about.

To my knowledge, there is a slight amplification using the correct core but the real juice comes from the spikes of the BEMF.

I hope this helps.

Bill

[TechStuf]

These effects are amplified in the Magnetic Resonance Amplifier:

http://www.cheniere.org/misc/ferroelectric.htm

And the Magnetic Beam Amplifier as well:

http://www.freepatentsonline.com/5929732.pdf


World history since the time of discoveries like these, going back to the early 1900s, perhaps even earlier, has gone on to aptly demonstrate the old adage that power corrupts and absolute power corrupts absolutely.


TS