In a message dated 14/11/2007, tchannel1@............ writes:

Hi Folks,   I did record the 7.7M This  AM.   It is visible but not 
impressive, which lead me to a  question.  Why was it inferior?   The idea of a ball 
hanging  from a magnet is good, the period is about 1.5 seconds? this should be  
okay.  The coil and magnets are okay.   The only defect I could  see is that 
the pendulum was free to move in a circle, and not forced to move  across the 
wraps.   I would welcome your opinions, we learn a lot  from failures.   So if 
I can pin point why this was an inferior set  up and recording if would be 
helpful in new  designs.



Hi Ted,
 
    If the arm is about 36" long and the end  has the main mass, the period 
should be 1.8 to 1.9 seconds.
 
    If you stuck a wood T to the top of the dowel, you  could mount two pens 
on it, but stick them to opposite ends of the same support  magnet. This would 
give a ~constant direction of swing.
 
    The plating on the Neo magnets is Nickel.  I wouldn't expect it to last 
very long in contact with a moving ball. When  the plating wears through, the 
Neo magnet will start to corrode rapidly.  You would be better attaching small 
pieces of SS razor blade to the magnet  to provide a very hard contact 
surface.  
 
    I presume that the two magnets have N and S faces  with the joint at 
right angles to the swing direction?
 
    What are the dimensions of the coil?
 
    Regards,
 
    Chris Chapman



   






In a message dated 14/11/2007, tchannel1@............ writes:
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  style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
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Hi Folks,   I did record the 7.=
7M This=20
  AM.   It is visible but not impressive, which lead me to a=20
  question.  Why was it inferior?   The idea of a ball hangin=
g=20
  from a magnet is good, the period is about 1.5 seconds? this should be=20
  okay.  The coil and magnets are okay.   The only defect I c=
ould=20
  see is that the pendulum was free to move in a circle, and not forced to m=
ove=20
  across the wraps.   I would welcome your opinions, we learn a lo=
t=20
  from failures.   So if I can pin point why this was an inferior=20=
set=20
  up and recording if would be helpful in new=20
designs.

Hi Ted,
 
    If the arm is about 36" long and the=20=
end=20
has the main mass, the period should be 1.8 to 1.9 seconds.
 
    If you stuck a wood T to the top of the dowel,=20=
you=20
could mount two pens on it, but stick them to opposite ends of the same supp=
ort=20
magnet. This would give a ~constant direction of swing.
 
    The plating on the Neo magnets is Nickel.=20
I wouldn't expect it to last very long in contact with a moving ball. W=
hen=20
the plating wears through, the Neo magnet will start to corrode rapidly=
..=20
You would be better attaching small pieces of SS razor blade to the mag=
net=20
to provide a very hard contact surface.  
 
    I presume that the two magnets have N and S fac=
es=20
with the joint at right angles to the swing direction?
 
    What are the dimensions of the coil?
 
    Regards,
 
    Chris Chapman