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September 4, 2007 - 6:24pm
#1
Kind of a technical question...
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The magnets are stationary and do not move relative to each other in either of these configurations. No?
It's the right hand current rule. elementary basic electronics class. http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magfor.html
Current can only exist in a conductor. Additionally, there must be a complete circuit for current to flow. If a magnet's position changes relative to a conductor, then an EMF (electromotive force, i.e. voltage) will be induced in the conductor. If (and only if) a complete circuit exists, then current will flow.
So, passing one magnet over another does not create any current, providing the magnets are not in the presence of a circuit. Interaction between two magnets is not required. ANY movement of a permanent magnet relative to a conductor changes the magnetic flux to which the conductor is exposed because the magnetic field is changing with respect to the conductor.
The movement of the magnets relative to each other is important insofar as they are causing the local magnetic field to change. Far more important is the position of the conductor relative to the change. Where the conductor is located will determine what current is induced. In places where the field is changing more, a higher EMF will be induced. The geometric relationship of the field with the conductor is also important. Maximum EMF will be induced where the field is changing perpendicular to the length of the wire.
With regard to your question about magnetically suspended turntables and equipment supports, there would be a problem. Since the function of the designs would be to damp mechanical motion with magnets, some motion must then be translated by the magnets. A moving magnet - and the associated changing magnetic field - will always induce an EMF in a wire, and a current in a circuit. That spells bad news for audio equipment.
The magnitude of the field is unimportant if it is constant and there is no relative motion between the field and the circuit. However, in this situation, both the position and magnitude of the field will be changing.
I hope this helps.
Please, anyone feel free to add to or modify what I've said.
http://hyperphysics.phy-astr.gsu.edu/hbase/solids/ferro.html#c5
Carl, what the heck does ferromagnetism have to do with this?
Also, right hand rule is only useful in describing the direction of the induced EMF or the magnetic field. It does not answer Buddha's questions.
I'm glad you're posting academic links, but you need to find the right topics first. You're looking for "magnetic flux" and "electromagnetic induction". Get to it.
Without fero, without magnetism, their is no electromagnetic induction. The direction of current also effects the field of flux that is generated and what is dealt with. Just as the direction of magnetic flux affects the direction of current in the material. The direction of induced current thusly affects any effects that anyone is considering. Ahhh, Flux it. Just get a FuruShlecpt plastic demagnetizer.
I'll grant you that the direction of current does affect the flux experienced by the wire, as explained by Lenz's law. I still am not seeing any ferro relevance here, though. Copper wire is not ferromagnetic, and would be woefully ineffective if it were. Magnetic fields within conductors are detrimental to conductivity. For instance, one of the properties of superconductors that makes them so super is a lack of any internal magnetic field. (The other is zero resistance.)
Plastic demagnetizer, huh? That's just crazy enough to make absolutely no sense.
I always though magnets and cartrages mixed about as well as oil and water?
You'd be correct. As you are undoubtedly aware, cartridges produce a musical signal by electromagnetic induction. The movement of the stylus causes the magnet or the coil to move relative to the other, inducing a small voltage, and a weak current that can be amplified.
Because of the incredible sensitivity inherent in the electrical design of cartridges, any magnetic field other than the one produced by the cartridge's internal magnet is detrimental to accurate reproduction.
Oil and water, indeed.
Well, you know, this kind of comes back to the Continuum turntable, with something like an 84 pound platter suspended by magnets, only a few inches below the record surface. Then, it has a steel bearing, which would be conductive, no?
If anyone who is smart about magnets could work that table into the grand scheme of magnetism and current, I'd be grateful!
Wow, that's an interesting design. I don't know what to tell ya, Buddha! They clearly made it work, I just have no clue how.
You ain't demagnetizing your plastics? Come on, how can you be hearing everything, thoses magnetized records are full of all kinds of magnetical errors. they are selling a cure, so it must be a problem. It's even got an award, so it must be true. http://www.furutech.com/produ_2.asp?ProdNo=242 You ain't seen this before, how could you have missed it? A revier in a magazine found he could HEAR it's benefits.......you doubt it? come on, he uses one of these pricey TT's too. He gotta have superb hearing, since vinyl always sounds better on his planet. snap crackle pop...trained listeners know how to not hear that, they only hear the good parts. Mortals hear the noise and distortion. If no magnetic is in copper wires, how do solenoids work when they run current through the wires and solenoids, motors etc seem to work. They ain't magnetiizing the copper but teh iron cores etc, how do inductors work wound with copper wire? Must be magic
Induction is due to the relationship between magnetic fields and electric current. Exposing copper wire (electrically conducting, but non-magnetic) to a changing magnetic field induces current in the wire because of resistance to change in flux: Current in the wire will flow in a direction such that the resultant magnetic field opposes the change in the local magnetic field for which the permanent magnet is responsible. Wires are not magnetic, but rather are capable of creating magnetic fields when in the presence of magnets.
That's not magic, but the Furutech might be.
And the woofers in your HT speakers are "shielded" to prevent their magnetic fields from interferring with any CRT's in the same area. Magnetic shielding is not wizardry nor poorly understood; didn't Mr. Farady and Mr. Gauss figure all this out in the mid 1800's?
Shielding! hahaha Good call, Jan. You know that part up there where I said I had no clue how the Continuum worked? Yeah, I was just testing you.
What's Mu, i don't know, what's Mu with u. Mu metal......when things are fluxed up.