Re: DRSSTC - I think I heard Cross Conduction...

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Sue Gaeta <sgsparky@xxxxxxxxxxx>

Hi Colon,

Antennas and TCs give me the willies! When I was using an antenna, some 
strange things would happen, like odd screetching noises that made it sound 
like it was possessed. That was one reason for naming it "The Beast". I 
have had great results with a commercial CT that was a dumpster diving 
prize :-). It is a Vitec 57P1688. These are used in switchmode supplies, 
and it is ideal for the frequency range that we work with. The Data sheet 
is online somewhere.

You just need the correct phasing and feedback level and you're in 
business. If your coil fails to start, just swap the wires on the CT(either 
the primary or secondary-not both).You need that 10K resistor in series 
though (Dan's schematic shows this). When I left out the resistor, I would 
get erratic operation, and one time as I turned the power up the 
interrupter cut out, and I got CW operation! However I shut down very fast, 
and when I powered up again, The interrupter worked fine. That was probably 
due to noise. When I put the 10K in series with the CT, I had absolutely no 
problem at all. It's like too much feedback was overwhelming, and I seemed 
to remember seeing a huge spike when there was no resistor.

Before I made improvements to my coil, I actually needed more feedback. I 
had to wire two of them in series parallel to get the coil to start. Then 
this slowly became too much as I made improvements. First I needed to cut 
back to one CT, and then later on I needed the 10K. If you change one 
parameter somewhere, expect something else to change somewhere else.

Tesla list <tesla@xxxxxxxxxx> wrote:
Original poster: "colin heath"

hi sue,
you said
The ones I own have both common mode,
and differential chokes. I think most of the commercial ones are made that
way.
yes they are mostly made that way. i only noticed as iv just read up on
filtering and common/differntial filtering.
my coil will have filter on the control electronics mains setup. this should
stop anything coming back from the bridge.
im also using armoured flex cable which makes a nice shield for the wiring.
the whole setup will be in a shielded enclosure.
i have a feeling that using c/t method is asking for trouble with noise also
as i havent got one running properly on one yet but have got all my coils
running fine on antenna.
cheers
colin