wrote:
> In a message dated 08/12/2007, paleoartifact@......... writes:
>
> I did whip up 3 strapping steel units of a thickness of 0.022" and put
> them
> on the magnets, with plastic spacers, but without any beveled inside
> edges.
> I am seeing a levitation height of ~ 0.020"; which appears to be ~ 0.005"
> of a inch less than without any steel whatsoever on top.
>
> Hi Meredith,
>
> Instead of having the outer two strips coming to the exact edge of the
> magnets, try backing them off say 20 thou, then 40 thou? See if this
> improves matters?
>
> Out of curiosity, I removed the center iron strip. Now, the levitation
> height
> is about 0.025" above the 2 outside steel strips. This also means (for
> what its
> worth); that its levitation height above the center magnet to the bottom
> of the PG
> is a interesting ~.047"....which is almost twice the average levitation
> height with
> no steel at all. In a terminology way; its kind of a "U" channel setup in
> this
> configuration.
>
> What happens with the centre strip in place, but the two outer strips
> backed off / removed entirely?
>
> I suggest that you try narrowing the centre strip maybe 20 thou / 40
> thou and bevelling the edges?
>
> You could use pencil leads for joining the graphite strips? Maybe
> plastic drinking straws? Then you would likely need much less Al or Cu for
> the damping plate?
>
> Regards,
>
> Chris
>
>
Hi Chris,
I used a handy strene strip with a thickness of 0.022" (matches the thickness of the steel),
but it was 0.112" wide; and used that to back off the two outer plates away from the center
magnet. Here the levitation height of the PG was ~ 0.018". Thats about 0.007" less than
with no steel roughly.
I tried only having the center magnet steel in place, and got a levitation height of ~ 0.013";
and yes it still levitated.
I crudely checked last night the weight lifting ability, with acouple variations of iron sheet
and it seems to reduce the added weight lift capability anywhere from half to 2/3rds from
that with no steel. Bob was right....iron kills...ha. Irons helps smooth the magnetic field
nevertheless. All in all; it seems that any final model will eventually end up as a compromise
of all the factors involved....not near perfect, in all aspects.
Yes; diamagnetic pencil leads, are probably the best "interconnection" or "flag"
extension choice. With their uniform diamagnetic lift response, they also tend to center
the PG in its path for improved linarity and some minor reduced perpendicular "noise"
response.
I do have some K&S 0.005" thick copper sheet I could try for dampening.
Beveling steel edges is yet to come.
I do wonder about even thinner steel sheet....
Take care, Meredith
On Dec 8, 2007 7:51 AM, <
ChrisAtUpw@.......> wrote:
I did whip up 3 strapping steel units of a thickness of 0.022" and put them
on the magnets, with plastic spacers, but without any beveled inside edges.
I am seeing a levitation height of ~ 0.020"; which appears to be ~ 0.005"
of a inch less than without any steel whatsoever on top.
Hi Meredith,
Instead of having the outer two strips coming to the exact edge of the magnets, try backing them off say 20 thou, then 40 thou? See if this improves matters?
Out of curiosity, I removed the center iron strip. Now, the levitation height
is about 0.025" above the 2 outside steel strips. This also means (for what its
worth); that its levitation height above the center magnet to the bottom of the PG
is a interesting ~.047"....which is almost twice the average levitation height with
no steel at all. In a terminology way; its kind of a "U" channel setup in this
configuration.
What happens with the centre strip in place, but the two outer strips backed off / removed entirely?
I suggest that you try narrowing the centre strip maybe 20 thou / 40 thou and bevelling the edges?
You could use pencil leads for joining the graphite strips? Maybe plastic drinking straws? Then you would likely need much less Al or Cu for the damping plate?
Regards,
Chris