Re: Mini OLTC is working!

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

Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>

Hi Steve,

WOW COOL!!!

I am happy to see you driving the IGBTs with like 30 volts.  They like that 
;-))  That may be over spec but running Ic at like 750 amps peak is over 
spec too :o)))  At about 50 volts the gates really will blow out, but but 
beyond that hard limit, party hardy!!

Your use of smaller coils to overcome some of the problems with my big coil 
is especially interesting as is you transformer coupling technique to 
enforce current sharing of the IGBTs.  Major interesting things there!!

As you found. Winding the secondary of OLTCs is a pain ;-))  Programs like 
FANTC help us get pretty close the first time.

I am happy to see you got great results and innovated on some things and 
your's did not blow up either ;-))  OLTC's seem pretty darn tough.  I think 
because we us conventional components pretty much like they are supposed to 
be over stressed ;-))

I am also happy to see a nice high resonate frequency!!  36kHz like mine is 
pretty hard to deal with.  But 120kHz is right up in the "normal" zone for 
Tesla coils.

I wonder if your OLTC could be adapted to a simple PC board Tesla coil 
design.  Just a PC board with normal components plugged into the wall and 
the coil to make a nice little TC without the usual high voltage 
hassels.  It would be cool to have a nice little TC design that was pretty 
conventional and CE mark friendly that would also be adaptable to be made 
by the "mass produced PC board electronic stuff" techniques.

I am a "little behind" on my many projects, but this is a very exciting 
development!!

Cheers,

         Terry





At 11:34 PM 3/4/2003 +0000, you wrote:
>Hey Tesla dudes
>
>I've been building a mini version of the OLTC originally made by Terry 
>Fritz. Mine has a 5.5" x 9" secondary and runs at 125 kHz. It uses two of 
>those IR IGBTs. I got it working today, it consumes about 45 watts at 
>110bps and produces a 5" arc to ground. I'm hoping to develop it to 
>400bps, 200 watts and 10" or more. There are pictures and scope traces on 
>my website, go to http://www.scopeboy-dot-com/tcintro.html and look in the 
>'Tesla Three' section. I'm looking forward to hearing any comments or 
>suggestions from the OLTC folk.
>
>Happy Coiling
>
>Steve C.
>