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

 



   





In a message dated 08/12/2007, paleoartifact@......... writes:
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>
  
I did whip up 3 strapping steel units of a thickness of 0.022" a=
nd=20
  put them
  
on the magnets, with plastic spacers, but without any beveled inside=20
  edges.
  
I am seeing a levitation height of ~ 0.020"; which appears to be =
;~=20
  0.005"
  
of a inch less than without any steel whatsoever on=20
top.
Hi Meredith,
 
    Instead of having the outer two strips coming t=
o=20
the exact edge of the magnets, try backing them off say 20 thou, then 40=20
thou? See if this improves matters?
<=
FONT=20
  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>
  
Out of curiosity, I removed the center iron strip.  Now, th=
e=20
  levitation height
  
is about 0.025" above the 2 outside steel strips.  This also mea=
ns=20
  (for what its
  
worth); that its levitation height above the center magnet to the bot=
tom=20
  of the PG
  
is a interesting ~.047"....which is almost twice the average levitati=
on=20
  height with
  
no steel at all.  In a terminology way; its kind of a "U" channe=
l=20
  setup in this
  
configuration. 
    What happens with the centre strip in place, bu=
t=20
the two outer strips backed off / removed entirely?
 
    I suggest that you try narrowing the centre str=
ip=20
maybe 20 thou / 40 thou and bevelling the edges?
 
    You could use pencil leads for joining the grap=
hite=20
strips? Maybe plastic drinking straws? Then you would likely need much less=20=
Al=20
or Cu for the damping plate?
 
    Regards,
 
    Chris