Date: Mon, 24 Oct 2011 17:03:38

Author: --- "Rueckner, Wolfgang"

Subject: Re: Image Current Demo

Post:

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So what exactly is this "image current"? I just realized it's not eddy cur=
rents because they would create a repulsion of the current carrying wire, n=
ot attraction. If I had a similar copper bar (rather than iron) next to th=
e wire, I suppose I would get a repulsion?

On Oct 24, 2011, at 4:54 PM, Rueckner, Wolfgang wrote:

I'll bring my camera in tomorrow morning and take a picture for you. I'll=
measure the resistance of the whole shebang and calculate the current. My=
guess is 200 to 500 amps.

On Oct 24, 2011, at 4:51 PM, Adam Beehler wrote:

Well, there you have it. Thanks, Wolf! Would you mind sending me a pictur=
e offline? How much current do you estimate flows through your copper brai=
ded wire?

On 10/24/2011 2:25 PM, Rueckner, Wolfgang wrote:
I placed and iron bar (2"x4"x24") on the smooth cement floor in our demo ro=
om and laid down our braided copper conductor (that we use for repelling (o=
r attracting) current carrying wires) next to it. About 1" separation betw=
een iron bar and copper wire. Closed the moose knife switch to short out o=
ur truck battery (just for half a second, mind you) and the copper wire was=
attracted (and touched) the iron bar. -- Wolf

On Oct 24, 2011, at 4:15 PM, Zani, Gerald wrote:

Wolf,

What did you use for a ferromagnetic plate and how did you arrange it?

How much did it move?

- Jerry

On Mon, Oct 24, 2011 at 4:09 PM, Rueckner, Wolfgang > wrote:
Just tried it. It works remarkably well!

On Oct 24, 2011, at 3:54 PM, Adam Beehler wrote:

> I have an instructor that tends to believe we ought to be able to put
> together a demo showing "image currents." This is what he proposed to
> me. Run a current-carrying wire along the surface of a ferromagnetic
> plate/sheet. If the current is high enough, then there will be a force
> between the current-carrying wire and its "image current" running
> parallel to it in the ferromagnetic surface just next to it. This would
> need to be a whole lot of amps, like 500-1000!
>
> So...has anybody tried anything like this? Is there wire that can
> handle such currents for brief moments, yet not be so bulky that the
> attractive forced created is outweighed by the wire's bulk? I need
>

--
Gerald Zani
Demonstration Manager
Physics
Brown University
(401) 863-3964

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So what exactly is this "i=
mage current"? I just realized it's not eddy currents because they wo=
uld create a repulsion of the current carrying wire, not attraction. =
If I had a similar copper bar (rather than iron) next to the wire, I suppos=
e I would get a repulsion?On Oct 24, 2011=
, at 4:54 PM, Rueckner, Wolfgang wrote:I'll bring=
my camera in tomorrow morning and take a picture for you. I'll meas=
ure the resistance of the whole shebang and calculate the current. My=
guess is 200 to 500 amps.<=
div>On Oct 24, 2011, at 4:51 PM, Adam Beehler wrote:
=20

=20

Well, there you have it. Thanks, Wolf! Would you mind sendi=
ng me a
picture offline? How much current do you estimate flows through

On 10/24/2011 2:25 PM, Rueckner, Wolfgang wrote:
I placed and iron bar (2"x4"x24") on the smooth cement
floor in our demo room and laid down our braided copper conductor
(that we use for repelling (or attracting) current carrying wires)
next to it. About 1" separation between iron bar and copper wir=
e.
Closed the moose knife switch to short out our truck battery
(just for half a second, mind you) and the copper wire was
attracted (and touched) the iron bar. -- Wolf

On Oct 24, 2011, at 4:15 PM, Zani, Gerald wrote:

Wolf,

What did you use for a ferromagnetic plate and how did you
arrange it?

How much did it move?

- Jerry

On Mon, Oct 24, 2011 at 4:09 PM,
Rueckner, Wolfgang >
wrote:
Just
tried it. It works remarkably well!

On Oct 24, 2011, at 3:54 PM, Adam Beehler wrote:

> I have an instructor that tends to believe we ought
to be able to put
> together a demo showing "image currents." This i=
s
what he proposed to
> me. Run a current-carrying wire along the surfac=
e
of a ferromagnetic
> plate/sheet. If the current is high enough, then
there will be a force
> between the current-carrying wire and its "image
current" running
> parallel to it in the ferromagnetic surface just
next to it. This would
> need to be a whole lot of amps, like 500-1000!
>
> So...has anybody tried anything like this? Is
there wire that can
> handle such currents for brief moments, yet not be
so bulky that the
> attractive forced created is outweighed by the
wire's bulk? I need
>

--
Gerald Zani
Demonstration Manager
Physics
Brown University
(401) 863-3964

=

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