RE: how to tune a medium sized coil

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

Original poster: "Ted Rosenberg by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Ted.Rosenberg-at-radioshack-dot-com>

Shaun:
The simplest and maybe the safest method is to pick a primary tap point
based on one of the many excellent web based TC formula. Or tap it mid way.
Then bring up your variac slowly until you see breakout because you have
placed a breakout point, strip etc on or across your toroid. My breakout
occurred at about 80VAC in.

Then, if nothing arcs where it shouldn't or smells strange, bring the variac
up more and note how long the streamers are.
Shut it down and move the tap by a turn in or out. Repeat. Keep doing that
until you find the tap that gives the longest streamer. Make a note of the
turn. Fractions of a turn are NOT to be ignored either. Sometimes a 1/2 can
make a difference.

This assumes you have an adjustment to change primary/sec coupling. I
started with the first turn of the secondary level with the flat primary.
Some suggest (with good reason) an inch or so below.

Hope I've been of some help.

Safety First

Ted

Subject: how to tune a medium sized coil


Original poster: "Shaun Epp by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<scepp-at-mts-dot-net>

Hello you'll,

I need your help again

I'm nearly complete my TC running a 12Kv at 60mA tranny.  I have a variac
too and I was wonder if it would be safe to tune with power through the
variac (run low at first), or
do I need pre-tune first with a oscilloscope and signal generator?

I've read that I need to check the secondary with top load frequency and
then the primary tank cct and tune it to match.  I guess adjusting coupling
would be easier with test equipment but this all sound like a tedious
process.

What experiences have the readers had on this, Any input guys??

Shaun Epp,   slowly building a tesla coil.