Re: is the magnetic field really moving?

----------------------------
<phil-news-nospam@[EMAIL PROTECTED]
> wrote in message 
news:g6vde602abd@[EMAIL PROTECTED]
> On Tue, 29 Jul 2008 18:08:59 -0700 Salmon Egg <SalmonEgg@[EMAIL PROTECTED]
> 
> wrote:
>
> | In article <g6ana402oca@[EMAIL PROTECTED]
>, phil-news-nospam@[EMAIL PROTECTED]
> | wrote:
> |
> |> Is the magnetic field really moving if the magnets move but the field

> remains
> |> the same?
> |
> | No! How would you go about checking for motion?
>
> How about a variation of Faraday's Homopolar Generator ... the one with
a 
> big
> round magnet above the disk, and another below the disk, where the
magnets
> rotate with the disk?
>
> The flaw in Faraday's design is that the connection loop between the
axle 
> and
> the edge brushes is within the "extraneous" field.  This loop is 
> stationary
> but in a field sourced from rotating magnets.  This experiment is 
> ambiguous
> because it can be explained in terms of a rotating field inducing 
> potential
> in the "extraneous" connections.
>
> So what is needed is to eliminate the effect of the extraneous
connections 
> in
> an extraneous field, by eliminating those connections altogether.  I 
> suggested
> a model for such a thing in another post, but I don't know if anyone 
> really
> understood it.  So what I will do here is explain something simpler.
>
> The problem is that to measure the potential, we have to form a circuit,

> which
> will be a loop in the field.  While all of that loop will be within the 
> same
> field, it won't all have the same motion relative to the expected 
> potential.
>
> Imagine a loop of wire (with some on board means to detect current in
that
> loop at some small point in the loop).  You draw an arrow around the
loop 
> to
> show an expected current direction.  Part of the loop is moving in on 
> direction
> relative to that arrow and field, and part is moving in the opposite 
> direction
> relative to that arrow.  We can see that if there is going to be a 
> potential
> produced, half the loop will produce it in one direction, and half in
the
> other direction.  The two potentials will buck each other and no net 
> current
> can be detected.
>
> The simplified design I suggest is this.  There are 2 spokes going
outward 
> from
> the axle to the edge of the disk at 180 degree opposite directions. 
There 
> is a
> circular rim all the way around the disk.  The 2 spokes connect to each 
> other
> at the axle.  They both also connect to the rim.  The spokes and rim are

> metal
> to be conductive (for example, copper wire).  The rest of the disk will
be 
> some
> non-conductive material (for example a round piece of plastic).
>
> With a single uniform magnet, the 2 spokes will have a bucking
potential. 
> So
> instead of that, we have split magnets shaped as half circles.  On half
of 
> the
> disk, we arrange the magnets so the field direction is reversed relative

> to
> the other half.  The spoke conductors are aligned to be in the middle of

> each
> of the magnets.  There are 2 magnets on one side of the disk, one with N

> facing
> the disk, and the other with S facing the disk.  On the other side of
the 
> disk
> there are 2 more magnets, one with S facing the N magnet from the first 
> side,
> and one with N facing the S magnet from the first side.  With the
reversed
> field on one of the spokes, its potential should boost the other spoke 
> instead
> of buck against it.
>
> The rim should not have a potential along its running length since the 
> motion
> of the rim is along the length, not at 90 degrees from it.

In one case you can measure the axle to rim voltage  but in your case with
2 
magnets it becomes a problem  as the spokes are in parallel. In this case 
you need to either open the loop or somehow measure any circulating
current 
in the loop. A bit of a problem if you are trying to avoid extraneous 
connections. However there are devices that can be put in line that 
chemically measure charge transfer and using one of these and running for 
some time, you would, at least, get an indication whether there was a 
current.
However, all you will have is an awkward equivalent to a coil rotating in
a 
field. It will not be a homopolar generator. -- 

Don Kelly dhky@[EMAIL PROTECTED]
 the X to answer

>
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