Re: ASRG

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "tesla by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla-at-paradise-dot-net.nz>

Hi Terry et al
To amplify
My first attempt at your design featured tunsten tips brazed onto a brass
rod. Brass as you know is an excellent conductor of heat so the rod got hot
over much of its length.
This is different than your rotor made entirely of tungsten.
My current design is now two tngsten rods (to get the reqd 226mm length)
brazed into a brass sleeve in the centre.

My rotor is 226mm long. As you may imagine the amount of expansion due
heating is a proportional to temperature and the length.

Your design features much longer metal electrodes than conventional axial
elctrodes fastened into insulating rotors hence the potential for rotor
expansion is much greater. As you comment  end play is not an issue in this
design it is possible to achieve very close spacing between static and
rotating electrodes.

This is not a problem if you account for it. My inital set up clearances
were very very close so I was asking for trouble  in my first attempt using
15mm long tungsten tips on brass rod. (The brazing melted BTW)

I use a "feeler guage" now to set up my spacing and now have no problem
noting that I am now using tungsten the entire length. As you comment with
this technique centre heating is minimal.

I hope this clarifies my comments



 > Hmm,
 >
 > While the entire rotor is metal and long, numerous people have checked the
 > rod after a run and found that it was cool near the center.  The heat did
 > not travel that far down the length.  But I will check this out in more
 > detail.
 >
 > Not sure what you mean by point #2. Every RSG I have seen is set up so
that
 > as the electrodes expand, they will tend to close the gap.  Can you give a
 > photo example of what you mean?
 >
 > One thing I now notice about this design.  It is not sensitive to play in
 > the motor bearings.  So a worn or lose bearing will not cause unwanted
 > contact.
 >
 > Terry Blake
 > Coiling in Chicago