Roll on the 20th June

[exxcomm0n]

A compass that never moves (it's housing) is not a very useful tool.
Most compasses are in something that moves, or else why care about where north is?
But I'll give that to ya. It takes external influence to move the housing of the compass.

Ever heard of a Faraday disk?
The first and very inefficient generator. To lean on Wikipdeia again:

In 1831-1832 Michael Faraday discovered the operating principle of electromagnetic generators. The principle, later called Faraday's law, is that a potential difference is generated between the ends of an electrical conductor that moves perpendicular to a magnetic field. He also built the first electromagnetic generator, called the 'Faraday disc', a type of homopolar generator, using a copper disc rotating between the poles of a horseshoe magnet. It produced a small DC voltage, and large amounts of current.

This design was inefficient due to self-cancelling counterflows of current in regions not under the influence of the magnetic field. While current flow was induced directly underneath the magnet, the current would circulate backwards in regions outside the influence of the magnetic field. This counterflow limits the power output to the pickup wires, and induces waste heating of the copper disc.

Later homopolar generators would solve this problem by using an array of magnets arranged around the disc perimeter to maintain a steady field effect in one current-flow direction.

You need a magnetic field to make electricity.
You get a magnetic field when you use it.

So, it also takes motive force (work) to create electricity. I think we're all comfortable with that phenomenon.

With out the magnetic field that work becomes friction (heat), and very little of it.

Lets just cut to the chase and let me ask you if you can have electricity without magnetism.

If you can, you're right and I'm talking out of my posterior orifice.

Now lets be clear. You can use a coil to decrease inductance, but get rid of it?

When electric notation stops referring to negative as "ground", I'll stop thinking that electricity and magnetics are not so intrinsically woven together.

As to "real" physics, it all depends on what time period it is as to what "real physics" is.

Einstein went against "real physics" of his time, and that was such a dismal failure now, wasn't it?

Stop thinking everything that can be done, has been done.

Look @ the donut, not @ the hole.

[dirt diggler]

an electromagnetic field is present when electricity is flowing (with or without a conductor)

an electromagnet is just a special coil of metal/wire designed to focus that field in a certain direction.

They dont "store" energy,. they simply WASTE energy - to perform the same task a permanent magnet does.
The same electromagnet could be turned on for 30-45 seconds, and polarize a piece of iron of sufficient mass. which could then perform the same task as that electromagnet -for decades without any further energy input into it.  The electromagnet, however, must have constant supply of wasted electricity to generate its field.

We use them because they are controllable. we can turn them on/off, change their strength at our will.
It is advantages like this, that make them the perfered choice in industry. and worth the additional costs.
(how would the junk-yard worker drop the car if his crane had a permanent magnet??)

Actually, the last junkyard crane I saw did use a permanent magnet, and had a center post that was hydraulicly push to force the magnet off. seemed to work really well, and could be used on any number of machines around the yard, with no electrical connections.

[onesnzeros]

But as to a magnet not being a source of energy, I think you're just looking at it the way necessary to see that facet.

Oh wait! A viable (even if extremely tiny) example is a compass.

It has no energy source outside of it's magnet, and the magnetic fields of the earth.
It will unerringly (given the probability that another locally stronger magnetic field is not present) point North (or NNE if you want to get technical) given time and stability.

Please explain why this is not a viable example.

Actually, this is not a viable example. The compass needle does not move until the compass is moved. moving the compass represents an input of energy however tiny. A small amount of energy is needed to move the needle out of alignment and to overcome the tiny amount of friction in the bearing.



1n0s

[itanimuLLi]

@ Archer and all,
How about this drawing i made.
two cogwheel from Teflon or plastic the center axis from non magnetic metal like stainless steel, cogwheels drilled so you can put the magnet in on a repelling mode.
The outside magnets will repell so the wheels are on imbalance.
Is it worth trying to make it?
regards.

oh sorry about the arrows they shoud direct into the same direction.

[legendre]

A compass that never moves (it's housing) is not a very useful tool.
Most compasses are in something that moves, or else why care about where north is?
But I'll give that to ya. It takes external influence to move the housing of the compass.

My point was, that in an ideal compass, the needle never actually has to move. The needle is a point of reference, a fixed datum, and the housing of the compass moves around it. It takes no energy to keep the needle in position, as movement is resisted by the force of the Earth's magnetic field. The needle of the compass is doing no useful work; in fact, it never moves.

Ever heard of a Faraday disk?

Yes, I'm quite comfortable with Homopolar generators.

You need a magnetic field to make electricity.

Now there you go again making that unsupported statement that I have already refuted on several counts. If you can support it, and answer my refutations then please do. Otherwise, you should probably stop saying that before you start to look like a screwball.

In the meantime, could you please tell me where magnetism comes into the operation of the Seebeck (thermocouple) effect? To give you a primer: Two wires of dissimilar metals are joined at a junction point. The junction is heated and a voltage appears at the unconnected ends of the wires. If the ends are connected, an electrical current flows (and of course, produces a magnetic field).

But where in the production of this electricity (that is, the electrical potential or voltage, which is a form of potential energy..) is magnetism present? Note that energy was input in the form of heat, not a changing magnetic field..

Lets just cut to the chase and let me ask you if you can have electricity without magnetism. If you can, you're right and I'm talking out of my posterior orifice.

At this point, I think you're in a good position to answer that question yourself.

Now lets be clear. You can use a coil to decrease inductance, but get rid of it?

Not really sure exactly what you're asking, here. There are established techniques for increasing or decreasing the inductance of an element in an electrical circuit.. but how is this relevant to the current points?

When electric notation stops referring to negative as "ground", I'll stop thinking that electricity and magnetics are not so intrinsically woven together.

What are you talking about? In a bi-polar power supply, 'ground' looks negative from the positive rail - BUT 'ground' looks positive from the negative rail. Ground is wherever you decide to put it.. as in older UK vehicles, which had a positive ground system (battery + tied to chassis).

Stop thinking everything that can be done, has been done.

You're quite big on unfounded conclusions, aren't you? Pure crap.

-L