Also worth noting that if you are dissatisfied with performance you can
pull the side panels off for a boost in performance, the shielding on the
panels has an added effect of lowering the primary Q (this was by design,
you get a coil with lower Q that is more fault tolerant and has a shielded
driver for extended demos where you wouldn't run full power anyway, or
longer sparks for short demos at full power).
If you're really intent on winding a new secondary I wouldn't go over
350KHz; much past that something will probably go. You could swap out the
IGBTs for 40N60's that have less gate charge, but from my experience those
are rather frail in DRSSTC duty (they would go bang at about 250A).
On Sun, Mar 22, 2015 at 2:44 PM, loneoceans <loneoceans@xxxxxxxxx> wrote:
> Why do you think the secondary is 'user unfriendly' - I don't think you'll
> need to adjust it much? If you're worried about the turns getting damaged,
> a few coats of polyurethane will keep them in place and protect them. The
> primary is a double PC board for increasing current handling capability.
> And like you said, since it's un-tunable due to the solder mask on the
> primary, I was puzzled why you wanted to then use half the primary. The
> OneTesla kit was specifically designed to be tuned optimally right out of
> the box so you shouldn't need to do anything.
>
> I wouldn't try changing the frequency, especially not to 500kHz. This
> requires the drivers to switch at two the frequency and twice the power. In
> addition, the IGBTs will be switching at a much higher frequency, and you
> run the risk of the IGBTs switching significant primary current since the
> resonant frequency is now twice, but the switching delays remain the same.
>
> On Sun, Mar 22, 2015 at 3:58 AM, b alex pettit jr via Tesla <
> tesla@xxxxxxxxxx> wrote:
>
> > Hi All,
> > I just finished the DRSSTC OneTesla coil kit. It works fine, but the
> > secondary is woundwith 1600 turns of # 38.5 (!) gauge wire = about as
> user
> > unfriendly as one can get, and the primary is a strange top/bottom PC
> board
> > connected double spiral that is for all practical concerns un-tunable.
> > QUESTION :JaveTC puts the operating frequency of this coil at 250 KHz.
> > If I rewind the secondary with 800 turns of #33 gauge wire ( more easily
> > handled ) anduse half the primary I can obtain a more physically robust
> > secondaryand a tunable primary .. using the same 0.068 uF pri capacitor
> ..
> > However, the resonant frequency changes to ~ 500 KHz .
> > >>> How does changing the Operating Frequency affect performance ??
> > Thanks,Alex
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> >
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