RE: Ballast

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

Original poster: "Mike Wood by way of Terry Fritz <twftesla-at-qwest-dot-net>" <mike.wood-at-opennw-dot-com>


Hi Matt

ballast might be required if your transformer isn't current-limited (like a
distribution transformer) or doesn't current-limit very much (like a
microwave oven transformer).  Your 12/60 neon will be internally
current-limited, with shunts in the core (that experienced/brave souls can
remove to increase output) so no ballast is needed.

There are a lot of ways of making a safety gap - these can range from a
hook-shaped loop of sturdy wire from the NST output terminal bent close to
the (grounded) metal transformer case, to little works of art with brass
corona balls.  My safety gap leans more towards function than form (i.e.
it's not that pretty) but it's just:

a central terminal connected to ground (I used an offcut bit of copper tube)

2 adjustable terminals, one on each side, from the output legs of the
transformer (I used brass domehead nuts.  These are on bolts passed through
mini-angle brackets so the nuts are held close to the central copper tube,
and the threaded bolts allow easy adjustment of the gap spacings)

so it's not too technical.  Make sure you choose something to build it on
that's safe (i.e. that won't carbon-track/burst into flames/arc to the bit
you're holding) and you should be ok.

hope this helps.  I'm sure I've seen various photos of other peoples safety
gaps before - you might want to try browsing around some list members
websites and see if you can come up with an idea of what their solutions
have been too.

cheers

Mike
Wellington, NZ




Ok, well I ve been studying up on the tesla coil and reading through some of
the past archives. I ve been reading that a form of ballast is needed in the
circuit.  Right now I have a stationary spark gap, MMC capacitor bank,
primary,
secondary, and 12/60 transformer.  Do I really need a ballast and if so when
is
the cheapest way of going about getting or making one.  Also I don t know
exactly how to make the safety gap. What should I do for either of these?