Re: PIRANHA-III Power control? (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Moderated and approved by: Gerry Reynolds <greynolds@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Fri, 22 Dec 2006 20:05:22 -0700
From: Terrell Fritz <terrellfone@xxxxxxxxxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: PIRANHA-III Power control? (fwd)

Hi,

At 01:20 PM 12/18/2006, you wrote:

>Date: Mon, 18 Dec 2006 10:25:39 -0700
>From: resonance <resonance@xxxxxxxxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: Re: PIRANHA-III Power control? (fwd)
>
>At present we are working on a similar circuit to eliminate variacs.
>
>We plan on using a series choke with the MOT primary.

Why???  I leave the shunts in, so the max current is about 25 amps in any 
case.  A MOT is one heck of a shunt already!!!  Why add another shunt to a 
BIG existing shunt? ;-)))

>We are winding up
>some 2 inch ID x 18 inch long PVC pipe filled with cut 1/8th inch dia. steel
>rods to add a small inductance to clip off the harshest peaks on the inrush
>current.

Sound's big and heavy...  Perhaps your circuit is different, but such an 
inductor seems like a waist to me.  PIRANHA has no big inrush 
current....  It might ring and kick back ;-))  but that's what big a** 
snubbers are for ;-))

>We plan on using one in each MOT primary.

Two of them!! :-|

>Unlike Terry's circuit,
>we our using a single MOT running around 16-18 Amps each running off a
>separate 120 VAC circuit

You meant "two MOTs total"...  Each run from different legs of the 120VAC 
to a site for "trick" 240 VAC access...  Lots of lights and "flip this plug 
stuff".

>  --- shooting for a 4.0 to 4.4 kVA total input into
>the system.  We are shooting fgor 7-7.5 ft long sparks on a portable coil
>that can run on two separate 120 VAC circuits and not require 220 volts for
>portable operation at schools, etc.

At that power you should get 9 feet form the "standard" Freau equation, 
"let alone" anything with a solid state gap.  Most "schools" will not 
"tolerate" anything with more than a "tiny" 2 foot (PIRANHA-I) spark length 
;-))  But maybe you know the "better" schools ;-))

I assume you are using BIG industrial MOTS for that power...  Easy to buy 
them from here:

http://www.amiparts.com/

PIRANHA can be changed to use the full AC line voltage as is, but the MOT 
saturation "waists" power then :-p  Variacs are not "THAT" bad at "this 
level", but if a "simple" little circuit could get rid of the variac while 
preserving the low MOT saturation, it would be sweet ;-))

I am now thinking of just making the PIRANHA do it 
"automatically"  *;-))  But such things are shrouded in mystical secrecy :o)))


>Brian V. is working together with us on this project.  I also want to
>eliminate the necessity of using heavy variacs for current control.

"voltage kills", not "current".  I'll probably still have contactors and 
breakers, so the cost / weight is not a giant issue really....  All though 
PIRANHA is cheap for "solid state", it still is not "cheap" compared to 
conventional...


>This posted opto-isolated circuit might prove to be the best answer as it is
>totally independent of the AC line for triggering.
>
>I will advise on how it works out.

I thought you were thinking of a circuit like mine.  But yours seems very 
different ;-)))  Maybe in the endzone, the "best" will be a "combination" 
of the two :-)))

Cheers,

         Terry



>Dr. Resonance
>
>
> >
> > Here is a "A High-Resolution Digital Dimmer" based on the 555 timer.  It
> > looks very nice.  I'm inspired!
> >................