Re: Designing Primary Coil - Which resonant frequency??

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

Original poster: "D.C. Cox by way of Terry Fritz <twftesla-at-qwest-dot-net>" <DR.RESONANCE-at-next-wave-dot-net>


The best way is just use some scrap # 12 AWG house type wiring and approx 24
turns on the primary.  Hold it up in some scrap cardboard --- cut slits in
the cardboard to hold the wire.  Scrap away a bare spot every turn so you
can adjust tuning clip. Stagger these bare spots around the primary so they
don't all line up and cause a flashover.

Run the coil and try every tap to see which one gives you the best resonance
with the pri cap you are using.  After you know, for example, 12 turns works
best, then throw away the scrap wire and make yourself a nice copper tubing
primary with a few extra turns, ie, 14 in this example, to allow for fine
tuning.  Do all your tuning at around 20-25% on the variac.  After you find
the "sweet spot" then you can bring the power up.

At full power you will probably have to tap down around 1/8th to 1/4 turn
due to the larger electric field above the coil's torus.

Using some scrap wire saves time and allows you to get the dial-in right
before you put the "slicks" on.

Best regards,

Dr. Resonance



----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, July 06, 2002 9:12 PM
Subject: Designing Primary Coil - Which resonant frequency??


> Original poster: "Daniel McCauley by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <dhmccauley-at-spacecatlighting-dot-com>
>
> Another quick question regarding the design of the Primary Coil.
>
> I've chosen my power supply and am using a 15kV, 60mA NST with calculated
> output impedance of 250k ohms.
> >From this my tank cap should be 0.0106uF.
>
> My question is from everyone's experience, how should i go about designing
> my primary coil?  Do i choose some arbitrary resonant frequency say
between
> 100-200kHz from the tank circuit and then design the secondary coil to
match
> it or is there some "magic" resonant frequency i should try to meet.
>
> Thanks again for the help!!!
>
> BTW, my second-gen SSTC passed the first test with 360VAC input and the
> results are spectacular.  Maybe tomorrow we'll move up to 480VAC,
> half-rectified and see what happens.  See if those 1000V FETs can take
> it!!!!
>
> Dan
>
>
>
>
>
>