Re: PIRANHA-III Power control? (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Gerry Reynolds <greynolds@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Sun, 17 Dec 2006 14:16:41 +0000
From: Chris Rutherford <chrismrutherford@xxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: PIRANHA-III Power control? (fwd)

Hi All,

Having briefly looked on the Internet the system described at the link below
looks like it might be useful.  Although it has 4 channels, you could use
one channel for each of your 2 MOTs, or even a parallel series combination
using 4 MOTs.

http://www.epanorama.net/circuits/dimmer4.html

I think the key to these designs is the linking the PWM ramp voltage timing
to the mains phase.  i.e. The ramp starts when the mains is at 0v and allows
the output stage to conduct until the ramp voltage reaches the trigger
voltage and then stops conducting, that way you basically allow the mains to
conduct for x% of each cycle.  This may help minimise 'distortion' on your
power line feeding the MOTs.  You could probably use a 555 circuit or a
digital counter/comparator/ ADC circuit to produce the ramp.

Thanks

Chris R



On 12/17/06, Tesla list <tesla@xxxxxxxxxx> wrote:
>
> Original poster: Gerry Reynolds <greynolds@xxxxxxxxxx>
>
>
>
> ---------- Forwarded message ----------
> Date: Sat, 16 Dec 2006 19:08:32 -0700
> From: Terrell Fritz <terrellfone@xxxxxxxxxxxxxxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: PIRANHA-III  Power control?
>
> Hi,
>
> I am working on PIRANHA III issues today.  A dual MOT system that runs off
> a 120VAC 20A circuit with ease.  It is in the 8 foot arc to ground
> range...  About 2kW input at ~90% efficiency.
>
> These coils like to run with the MOT input voltage at about 95-105 volts
> to
> stay out of the MOT saturation range which just waists precious
> current.  Normally that is done with a 15 -20 amp variac...
>
> http://drsstc.com/~piranha/PIRANHA/PIRANHA-3/PIRANHA-III-001.gif
>
> Variacs are very nice, but they are real heavy and not real "modern" or
> solid state.  The charging circuit (MOT / Primary Cap loop) is resonant
> too
> to drive up to a 15000 volt firing voltage...  But the waveforms are
> pretty
> "tame" and the power factor is excellent without any fiddling.
>
> http://drsstc.com/~piranha/PIRANHA/PIRANHA-3/PIRANHA-III-002.gif
>
> It would be super cool to use a beefy lamp dimmer circuit or some similar
> cheap but very reliable solid state thing to control power other than the
> variac.  The PIRANHA input section is very forgiving of sloppy input wave
> forms and all so no big deal there.  Ceiling fans are made for inductive
> loads...
>
> I don't know much about dimmer circuits and such so I can't guess at what
> to do and feed the computer models well.  0:-|
>
> If anyone knows what to do to make a cheap hardy dimmer type circuit that
> could run two MOTs (~2kW)  I am all ears ;-))
>
> Cheers,
>
>         Terry
>
>
>
>
>