Re: New to tesla coils

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

Original poster: Esondrmn-at-aol-dot-com 

In a message dated 10/12/03 5:17:23 PM Pacific Daylight Time, 
tesla-at-pupman-dot-com writes:


>Ok,  I have made my primary, it's only 13.5 turns though, I used 50 feet
>of 1/4 inch copper refrigerator tubing.  Is this enough turns?  Also,
>the closest it is to the secondary is 1.75 inches.  Will it arc?  This
>is using a 12kv 60ma transformer.
>
>Also, right now, I have the secondary tube screwed down to the plywood
>supporting the secondary.  Is it important to use non-magnetic screws
>since this will effect the field?
>
>Also, for the RF ground.  Do I need to put a copper wire 6 feet into the
>earth?  Or can I just stick it in a foot or so?
>
>Thanks.
>--
>sean <sean-at-nc.rr-dot-com>


Sean,

13.5 turns should be fine, although I don't know the details of your 
system.  You want to design in some flexibility to allow experimenting with 
different toroid sizes, etc.  I think my primaries are both in the 13 to 14 
turn range.  You would like to design the system to tune when tapped at 
about turn 10 or 11 on the primary.  i.e. don't start out with the system 
needing to be tapped at turn 13.   1.75" clearance from the secondary 
should be good.

I use mostly nylon screws to mount the primary and secondary.  I do have a 
brass screw through the secondary base on one side which serves both as a 
mounting bolt and to carry the secondary ground down below the mounting 
plane to the ground system.  Then there are two other nylon bolts holding 
the secondary in place.  I cut one plastic circle out of .375" thick 
material about 3" larger in diameter than the secondary.  Then I cut two 
.50" thick circles just sized so they fit into the secondary form.  Now I 
stack these up and glue all three pieces together.  I used pvc for all 
three pieces.  This gives a nice base flange to mount the secondary on.  I 
have three nylon screws that go through the sides of the secondary at the 
bottom into this mounting base.  It could have been glued on as well.

I use copper clad steel ground rods and drive them in as far as I can get them.

Ed Sonderman