Re: MOT Powered SSTC - First Tests Successful!!

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

Original poster: "Justin Hays by way of Terry Fritz <teslalist-at-qwest-dot-net>" <pyrotrons2000-at-yahoo-dot-com>

Hi Captain and All,

 > Utilizing my solid state switch circuit which was posted
 > previously, my initial tests of my new SSTC are successful!!

Cool!!! Very interesting design and well documented. I love the .pdf
schematics...but most of all, I like the fact that it arcs 30". I'm
sure that looks just plain awesome.

 > To get big output on a SSTC, you need big voltage input.

Dan I love your design, the high voltage definately seems to work and
all, but I absolutely disagree that using HV input (like from a MOT)
is the only route to huge arcs.

Input POWER is what is needed, regardless of the input voltage or
current.

 > But this design is flawed as it extremely limits the output of your
 > SSTC as input voltages are relatively low

I don't think it's that limited at all...sure, impedance matching is
a little more difficult with low input voltage (4 turn primary vs. 20
turns), but 6 foot + arcs arcs are WELL within the capabilities of
the H-bridge topology for an SSTC.

Recipe For Huge Arcs: 3 turn primary, 4" tall 6" O.D., 4" secondary
with #28, 240Vrms 1/2 wave DC input, and an H-bridge using 60+ amp
MOSFET's.

 > Many individuals try to improve upon the full-bridge topology by
 > adding elaborate feedback schemes and other efficiency increasing
 > changes

Can't say that I've run across any elaborate feedback schemes used
for an SSTC. Although, about the simplest I know of is Jan Wagner's
at:

http://www.hut.fi/~jwagner/tesla/SSTC/selfreso-sstc-demo.htm

...that uses a single IC to generate the drive signal, and is
definately quite efficient as you mention.

 > Just like its big brother, the conventional tesla coil, brute force
 > (voltage) is what is needed for big output.

Again, even with spark gap TC's, it's input power that is necessary
for huge arcs. This is a very well known concept. For instance: a 7kV
100mA coil can arc just as far as a 50kV 14mA coil. Same power (700W)
for both coils.

To finalize my thoughts, I will add that my friend Aron Koscho's SSTC
achieved a measured sparklength of 32" (Dan, no offense to that extra
2", it's just what it happened to be), using an H-bridge running off
of 240V. The reason it's not smeared across our website is because it
only lasted about 3 seconds due to using only 20A parts (IRFP460's -at-
20A Id). Aron used a 4 turn primary wound 5" tall, coupled to a 4"
secondary wound with #28.

Regards,

Justin Hays
KC5PNP
Email: justin-at-hvguy-dot-com
Website: www.hvguy-dot-com