SISG Testing

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Mark Dunn" <mdunn@xxxxxxxxxxxx>


My SISG test coil is really cooking now.  I've made runs up to 2 minutes
continuously choking the basement full of ozone.  Can't believe how
quiet it is(No spark gap).  Can run at night without waking up the
kids.I've got an IR thermometer coming tomorrow so I can start measuring
IGBT temperatures.

I've increased the impedence on the MOT's by modifying the shunts and
doubled the tank capacitor from 38 nF to 76 nF.

I now draw near 100 VAC at only 15 amps for the (4) pack of MOT's. You
might recall a few weeks ago I was at 50 to 60 VAC and 35 amps(at 1000
BPS!!).

Don't know what the break rate has dropped to, but think it is around
500 BPS. Have to get the scope back and check it out.

I am up to using (3) SISG boards, which is a threshold voltage of 11.8
kV.
4 foot plus streamers.

This re-shunting of the MOT's is really interesting.  Surprised no one
has wanted to discuss it further.

How about this... The RSG operated coil(in the basement) disrupted the
TV(on the 1st floor) during operation.  We all know that's because of
the RF.  But the SISG operated coil is not disrupting the TV.
Obviously, the RF from the spark gap was the culprit.  The HF RF from
the coil does not affect the TV significantly.

Here is what Terry had to say about it...
I never thought about this before but it makes sense.  In a spark gap
coil there is significant capacitance right around the spark
gap.  When the gap fires (a few hundred pico seconds) Shorting that
capacitance cause a massive RF pulse that you and everyone in the
neighborhood sees on the TV.

The energy is roughly  10000 = 1/100pF x I x 100e-15  so the current
is 10M amps and the instant power is 100 Giga-watts!!  That is what
you see on the TV.  A 100pS 10GW burst of energy.

But in the case of the SISG the turn on time is vastly less.  Say
500nS or 5 million times slower and the current is only "2" amps for
20kW.  Same energy but spread 5,000,000 times longer.  The TV and all
are used to "small" noise like that.   The down side is that the
slower pulse is much more likely to radiate along the AC power lines
and wiring to get a "better antenna".  But electronic stuff is still
very immune to noise in that region.

So the SISG might have another claim to fame as being less RF noisy
:-)))

Maybe I can get this thing up to Dr. R's Labor Day party.

Mark