Re: Early versions of Tesla's coil

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

Original poster: "Ed Phillips by way of Terry Fritz <teslalist-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
 >
 > Original poster: "Ed Phillips by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <evp-at-pacbell-dot-net>
 >
 > Tesla list wrote:
 >  >
 >  > 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

	I took a look at your pictures and find them most interesting.  First
of all, one of the resistors in there is a carbon composition of the
type which hasn't been used since WW2, at least here in the U.S.  I once
saw some very cheap French resistors which were supposed to be post war
but they had sheet metal leads and not wire leads.  Second, the
transformer and neon indicator relatively recent while the switch could
be of almost any age.  Any idea when the thing was made?

	Second, you didn't specifically state where the TC was mounted.  In the
head, I presume?

	Third, had you disassembled the device and mounted the parts on a
board?  Kinda looks that way.

	Fourth, how are the spark gap contacts adjusted in use?

Ed