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Suspended Primary for Mini-TC?



Original poster: "Jolyon Vater Cox by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>

Are there any real advantages in using a "suspended" primary -as opposed to 
a board-mounted primary in a Tesla Coil, particularly a mini-TC other than 
for purely aesthetic reasons?

My mini coil has been put "on ice" for the last year since I was having 
proplems with space needed for saltwater caps and the like
despite best performance of any coil I have built e.g 6 inches of spark 
when powered from a rectified ignition coil.

My secondary was a 10.375"high x 2.89" dia winding of 880t of 32SWG wire
(the diameter of the former upon which it was wound was 2.94").
the primary was 11.75 turns 24SWG tinned copper wire (too thin?) fastened 
to a plywood board with terminal blocks to make a 12" diameter flat spiral
allowing very little clearance between the inner turn and the secondary 
-not nice!

Worst of all it needed a whopping great 24" bicycle wheel as a topload 
BEFORE it would even produce the 6-inch spark -not really a "mini" TC 
although the performance might be. The tank capacitor needed to be in the 
region of 20nF, necessitating a rectifier. Perhaps some analysis tool would 
be helpful here- any suggestions?

I have a coil of aluminium sculptor's "armature" wire (the type used to 
make the "armature" that supports a clay sculpture as it is modelled); wire 
is a misnomer as it actually strap (it is rectangular in section) I am 
thinking of using it to replace the horrible primary with a neater primary 
of "suspended" design -would this likely be an improvement?

Or is wire diameter likely to be of little importance  to spark length? in 
which case I am thinking of a big spiderweb primary odd number of 
insulating spars (wood? perspex?) radiating from the base of the secondary 
with holes along their length for the wire to pass between the upper and 
lower sides of the winding an air-spaced spiderweb primary if you like.
Any thoughts?