Re: Early versions of Tesla's coil

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

Original poster: "RMC by way of Terry Fritz <teslalist-at-qwest-dot-net>" <RMC-at-richardcraven.plus-dot-com>

Ed

 >  > >As far as I know all of the "Tesla coil" leak
 >  > >detector spark coils operate in this way and are probably being built
 >  > >still.  I have one built by Rogers Electric in 1916 which works this
way
 >  > >and puts out about a 1" spark.


I have a pair of these vacuum leak testers, both made by a British company
(Edwards High Vacuum, I think - they're not to hand at the moment). They are
wired as convential Tesla coils which I now describe. They are not induction
coil hybrids.

Both are identical and use a primary of about 3 turns on a 1" diameter, 22
swg or similar. the secondary is conical and gives an excellent brush
discharge into free space. The spark gap is a large relay contact
arrangement - two facing W pads and a cam-shaped bakelite lever that presses
a phosphor-bronze element holding one of the faces towards the other.

The primary cap is a couple of nF and the mains transformer is a
single-ended 2 or 3 kV output at a few mA.  It is a very small coil but is
very nice to see working.

Cheers

RMC, England