Edward Green wrote:
On May 14, 5:40�pm, "Androcles" wrote:
"Kevin G. Rhoads" wrote in ...
| If you are going to snip, ******, I will too.
| Now behave or **** off, a field rotates with a magnet
|
| Since you have resorted to ad hominem name calling, I
| decline to further engage you in discourse.

Good!
�*plonk*

That's rich.

Heh. Just ignore Andro. Note his use of not only the ad hominem
attack but also the time-honored "proof by assertion" as well. I know
that always convinces me when I'm confused about obscure points.

"Benj" wrote in message
...

OK, so dig. if these forces are due to the relative frames of the
flowing magnetic field and the frame of the charged particle, now
whether or not a magnetic field is "attached to" or "rotates with"
it's "source" becomes a VERY important question! See?

Yes, a definitive experiment should have been conducted by this time to
answer this question one would think.
I wonder what would happen if you created the magnet/field in a rotating
frame? From what I remember of DePalma's writings he used an electromagnet
in his homopolar experiments. Is a solenoid an exact equivalent of a
permanent magnet in this context? If so it would be much easier than
'magnetizing' a permanent magnet in a rotating frame.
A faraday disk arrangement should shed some light. In fact, if you were to
switch on the current while the solenoids were spinning and you did induce a
current in the disk, a plethora of associated problems with the homopolar
generator should also disappear.
Regards,
Vince

On Jun 15, 3:44 am, "Vince Morgan" vinharAtHereoptusnet.com.au
wrote:
"Benj" wrote in message

...

OK, so dig. if these forces are due to the relative frames of the
flowing magnetic field and the frame of the charged particle, now
whether or not a magnetic field is "attached to" or "rotates with"
it's "source" becomes a VERY important question! See?

Yes, a definitive experiment should have been conducted by this time to
answer this question one would think.
I wonder what would happen if you created the magnet/field in a rotating
frame? From what I remember of DePalma's writings he used an electromagnet
in his homopolar experiments. Is a solenoid an exact equivalent of a
permanent magnet in this context? If so it would be much easier than
'magnetizing' a permanent magnet in a rotating frame.
A faraday disk arrangement should shed some light. In fact, if you were to
switch on the current while the solenoids were spinning and you did induce a
current in the disk, a plethora of associated problems with the homopolar
generator should also disappear.
Regards,
Vince

All experiments I've seen have shown that a solenoid and a permanent
magnet give identical results. I'd have thought that someone would
have performed one of the electrostatic experiments to answer this
question long ago too, but that doesn't seem to be the case. Of
course, who knows, there may be several master's EE theses sitting on
some dusty university library shelves that have the answer in them.
But everybody has long forgotten where they are!

"Benj" wrote in message
...
On Jun 15, 3:44 am, "Vince Morgan" vinharAtHereoptusnet.com.au
wrote:
"Benj" wrote in message


...

All experiments I've seen have shown that a solenoid and a permanent
magnet give identical results. I'd have thought that someone would
have performed one of the electrostatic experiments to answer this
question long ago too, but that doesn't seem to be the case. Of
course, who knows, there may be several master's EE theses sitting on
some dusty university library shelves that have the answer in them.
But everybody has long forgotten where they are!

I'm astonished. Truly astonished!!
This thread asks one of, perhaps the, most important question in
electrodynamics. A question that really should have been resolved
definitively a very long time ago, most especially considering how simple
the experiments could be.
This, along with the reality, or otherwise, of the motional E field is not
only fundamental to EE I would think, but may very well hold keys to places
few have ever been.
It's taken until this day for me to realize just how important the answer to
this question is. I'm a bit slow evidently, but where are those who aren't?
That competent persons haven't done this experiment to death is almost
alarming.
Vince

On Jun 15, 12:44 am, "Vince Morgan" vinharAtHereoptusnet.com.au
wrote:
"Benj" wrote in message

...

OK, so dig. if these forces are due to the relative frames of the
flowing magnetic field and the frame of the charged particle, now
whether or not a magnetic field is "attached to" or "rotates with"
it's "source" becomes a VERY important question! See?

Yes, a definitive experiment should have been conducted by this time to
answer this question one would think.
I wonder what would happen if you created the magnet/field in a rotating
frame? From what I remember of DePalma's writings he used an electromagnet
in his homopolar experiments. Is a solenoid an exact equivalent of a
permanent magnet in this context? If so it would be much easier than
'magnetizing' a permanent magnet in a rotating frame.
A faraday disk arrangement should shed some light. In fact, if you were to
switch on the current while the solenoids were spinning and you did induce a
current in the disk, a plethora of associated problems with the homopolar
generator should also disappear.

I guess nobody noticed my mention that Benj might include an old-
fashioned record-player turntable in his experiments.


Mark L. Fergerson

wrote:

I guess nobody noticed my mention that Benj might include an old-
fashioned record-player turntable in his experiments.

Mark L. Fergerson

Very funny. Actually I have several "old-fashioned record-player
turntables" but haven't included them in my experiments. For the
record I DID use my mini lathe to spin magnets and satisfied myself
that you really cannot determine if the field is rotating or not if
you use a sensing loop! It let me attain much higher rpm values than
a turntable. Anyway my primary turntable died. It was one of my own
design with a synchronous motor driven from a synthesized frequency
generator. Nice. Only lightning struck nearby and blew out the power
semiconductors that drive the motor. One of these days I'll have to
get in there and repair it (want to transfer some old records to
CDs).

----------------------------
" wrote in message
...
On Jun 15, 12:44 am, "Vince Morgan" vinharAtHereoptusnet.com.au
wrote:
"Benj" wrote in message

...

OK, so dig. if these forces are due to the relative frames of the
flowing magnetic field and the frame of the charged particle, now
whether or not a magnetic field is "attached to" or "rotates with"
it's "source" becomes a VERY important question! See?

Yes, a definitive experiment should have been conducted by this time to
answer this question one would think.
I wonder what would happen if you created the magnet/field in a rotating
frame? From what I remember of DePalma's writings he used an
electromagnet
in his homopolar experiments. Is a solenoid an exact equivalent of a
permanent magnet in this context? If so it would be much easier than
'magnetizing' a permanent magnet in a rotating frame.
A faraday disk arrangement should shed some light. In fact, if you were
to
switch on the current while the solenoids were spinning and you did
induce a
current in the disk, a plethora of associated problems with the homopolar
generator should also disappear.
---------------
If the field of the magnet is radially symmetric (i.e. B is the same at any
given distance from the axis, in all directions), why should spinning change
the field at any point in space? You don't actually have "flux lines"
attached to the magnet as shown for visualization. No change in B- then
what? If the magnet is not symmetric-then there could be a voltage induced
(causing current). There is no need to consider various frames of reference.

Now, if you move the magnet with respect to the faraday disc (not rotating
it on its axis but rotating it about the axis of the disc- there is a
voltage induced. I've done this and eddy currents will be induced causing
induction motor action- the disc, if free will be dragged along.

As for energising a spinning magnet- what will that show? The field will
grow from 0 to its final value as the current rises from 0 to its final
value - giving a changing field in the location of the disc whether or not
the magnet is spinning.

I fail to see the problems with homopolar machines- sure it is clear using
Coulomb's force law, that the induced voltage can be found- and the result
agrees with the use of Faraday's Law (which appears to present problems to
some).



--

Don Kelly
remove the X to answer

On May 6, 1:54 pm, Benj wrote:
Uncle Al wrote:
Benj wrote:


apparent problem, however, is that if you use a closed loop there is
an equal and opposite emf induced in the back side of the loop and the
output is zero whether or not the field actually rotates and the
experiment is indeterminant.
Doesn't that answer your question?
Maybe the rotation of the field lines is irrelevant because the
unavoidable geometry of the system provides an equal and opposite EMF.
Maybe you can't set up a geometry for this type of experiment where
this cancellation doesn't occur.

Benj
(who notes that answering the rotating magnet question is a "good
first step" toward finding that precise arrangement of magnets that
will produce "free energy"!)
Idiot.

Humor-impaired! :-)

1) Time is homogeneous.
2) Noether's theorem
3) Mass-energy is locally conserved.

yes, yes.

Uncle Al doesn't see any asterisks referring to strobes, magnets,
ceramic supercons, liquid nitrogen fog, or a salvaged manual
transmission from a 1970 Honda Civic (the classic infinite energy
source after removal of its ****anium restraining shim).

WHOA! I never heard about the ****anium restraining shim before!
Could that be my reason for failure up to now?

Benj

"Don Kelly" wrote in message
news:PcB5k.11995$Jx.5774@pd7urf1no...

If the field of the magnet is radially symmetric (i.e. B is the same at
any
given distance from the axis, in all directions), why should spinning
change
the field at any point in space? You don't actually have "flux lines"
attached to the magnet as shown for visualization. No change in B- then
what? If the magnet is not symmetric-then there could be a voltage induced
(causing current). There is no need to consider various frames of
reference.

I see your point Don. The field would be homogeneous at any given point
from the radius, rotating or otherwise. However, that leaves the question
of why rotating the faraday disk 'will' induce current I would think?

I fail to see the problems with homopolar machines- sure it is clear using
Coulomb's force law, that the induced voltage can be found- and the result
agrees with the use of Faraday's Law (which appears to present problems to
some).

I was thinking primarily of the brush problem in the generator now that I
think about it. If you could make a faraday disk where the disk was
stationary with respect to the lab frame current transfer becomes a lot
simpler.

A question I would like to know the answer to, and haven't seen asked
specifically, is whether it is possible to create a magnetic field that
rotates about it's axis. And if not, why not?
It's also occurred to me recently that the earth rotating about it's own
axis might actually be a giant homopolar generator wherein a conducting
fluid core might undergo forces that contribute to tectonics. Just a
thought I might add.
Vince

On Jun 16, 6:32 pm, Darwin123 wrote:
On May 6, 1:54 pm, Benj wrote:

Uncle Al wrote:
Benj wrote:

apparent problem, however, is that if you use a closed loop there is
an equal and opposite emf induced in the back side of the loop and the
output is zero whether or not the field actually rotates and the
experiment is indeterminant.

Doesn't that answer your question?

No. the rotation question is "indeterminant".

Maybe the rotation of the field lines is irrelevant because the
unavoidable geometry of the system provides an equal and opposite EMF.
Maybe you can't set up a geometry for this type of experiment where
this cancellation doesn't occur.

The rotation of field lines isn't "irrelevant" because it relates to
the important questions of what reference frame the magnetic field is
attached to. And yes and equal and opposite EMF is set up which is why
you can't determine if the fields is stationary or rotating with a
detector loop. And No, you can't set up a geometry WITH A DETECTOR
LOOP where cancellation does not occur. This is why electrostatic
measurements have been proposed. For example you divide a Faraday disk
into concentric rings. You short the rings and then spin a magnet in
front of it. While the magnet is still spinning (inducing perhaps an
emf in the disk IF the field is rotating) you "unshort" the rings.
Later the rings act like a capacitor storage device and IF you find an
EMF there you can conclude the field rotates with the magnet (or
coil). Note however that NO "loops" are used and the induced voltage
will be REALLY low which is not conducive to easy electrostatic
experiments. Not such a simple thing. Electron beam deflection
experiments have also been proposed.