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Re: Thoughts about sync..



Before building a rotor consider building a better spark gap first.

I use a RQ spark gap with 8 gaps .025  to .028 each gap. The 9 copper tubes
are all 3/4" dia. 2" long.  The gap is built in a 4" diameter PVC pipe 6"
long.  One end has a toilet flange on it to hold the gap up vertical and to
block off air flow on one end of the pipe.  The top end of the gap has a
vacuum cleaner fan mounted to it.  I cut 8 slots in the sides of the PVC pipe
1/8" wide 2" long directly in front of each gap for air to get in.  I use a
variac to adjust the fan speed.  I use this on all my coils from 1.5" diameter
up to 10" diameter. On the 120 watt coil I have to use a jumper wire to short
out all the gaps except 3 and I run the fan very slow about 1/4 speed. On my
750 watt coil I use 7 gaps and run the fan about 1/3 speed.  On my 1350 watt
coil I use all 8 gaps and run the fan about 40% speed.  On my 10" coil 10,000.
watts I get 128" sparks from the top load and I use all 8 gaps with the fan
running about 90% speed.

By adjusting the number of gaps and fan speed you can fine tune the spark
gap.  If the fan is running too slow or too fast you can see the output sparks
get longer or shorter as you turn the variac to adjust the fan speed.  It
works great.  Its a lot easier to build than a rotor.

Gary Weaver


Tesla List wrote:

> Original Poster: "Bunnykiller" <bigfoo39-at-idt-dot-net>
>
> Tesla List wrote:
> >
> > Original Poster: "Wayne Scott" <wsirons-at-sonic-dot-net>
> >
> > Hi all,
> >
> > My first coil has been up and running for about a month now.  My thanks
> > to everybody for being so helpful.  There's no way I could have achieved
> > this without my daily reading of the Tesla List.  Enough kissing up,
> > down to business.
> > Specs: 15/30 NST, 4.5 x 22.5 (5:1) secondary, 1/4 in -at- 1/4 in 13 turns
> > primary -at- ~35-40 deg and too far away from the secondary ~2.5 in.  The
> > cap is 10 GE Dielektrol III's .1 uF -at- 2000 VDC, .01 uF total (in about
> > 1x2x2 oval metal can) in series which I expected to explode the first
> > day I fired it up, but it still seems to work.  The gap is 4 copper
> > tubes for only 3 gaps and looks like about an 1/8 in between each.
> > Topload is 3x13 and 4x17 aluminum duct.  It gives 3 or 4 18 to 24 in
> > purple streamers that really like the extra (unpowered) referegator in
> > the back of the garage.  It doesn't have much in the way of an RF
> > ground, just a big plate of aluminum under it's box.  I just won another
> > eBay 15/30 NST and am looking forward to getting closer to the 48 in I'm
> > hearing about from even 30ma systems.  It sounds like the only way to
> > break that barrier is to go rotary.  I was wondering if anybody has
> > tried using some kind of closed loop motor control to set bps as opposed
> > to modifying rotors to be in line sync.  Some kind of analog feedback
> > signal routed through the necessary analog electronics could drive for
> > sync, or perhaps a basic stamp running a PID from digital feedback.  I
> > know that the RF shielding of sensitive electronics would be
> > interesting, but not impossible.  Would also make it easy to auto-sync
> > to the zero crossing.  Thoughts?
> >
> > Wayne in Santa Rosa, CA
> >
> > I need to build an MMC!
>
> Hi Wayne ...
>
> congrats on the coil ...    but if you plan on upping the power ( adding
> the extra NST) consider deeply the idea of a RF ground system....
> with out it you will be more than likely to blow out the NST's or get
> some serious feedback thru the AC lines    i fried a 20 amp Corcom RFI
> filter cuz i forgot to hook up the ground wire  sooo  obviously the
> power found its way back thru the AC supply ...
>
> Scot D