Re: PIRANHA-III Power control? (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Gerry Reynolds <greynolds@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Mon, 18 Dec 2006 16:13:00 -0700
From: resonance <resonance@xxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: PIRANHA-III Power control? (fwd)



This turned out to be a horrible tech note.  When printed out, even with 
just trying to read it before printing, the values are blurred so bad they 
are not decipheriable.

Dr. Resonance
>
>
> ---------- Forwarded message ----------
> 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.  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.  We plan on using one in each MOT primary.  Unlike Terry's 
> circuit,
> we our using a single MOT running around 16-18 Amps each running off a
> separate 120 VAC circuit --- 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.
>
> Brian V. is working together with us on this project.  I also want to
> eliminate the necessity of using heavy variacs for current control.
>
> 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.
>
> Dr. Resonance
>
>
>>
>> Here is a "A High-Resolution Digital Dimmer" based on the 555 timer.  It
>> looks very nice.  I'm inspired!
>>
>> http://archive.chipcenter.com/analog/tn046.htm.
>>
>> Again the TRIAC driver stage is opto isolated(MOC3022), which is aways a
>> benefit in HV systems, but in reality how much is this going to help
>> defend
>> against a 1MV strike?
>>
>> Of course the challenge would be adapting the output stage to cope with
>> inductive loads.  The consensus seems to be the use of a snubber circuit
>> (cap + mov), other filters and a healthy amount of capacity over-kill 
>> i.e.
>> TRIAC rating of *5 voltage and *2 current of values seen.
>>
>> I cant really see the EM switching emissions being a problem in this case
>> :)
>>
>> Chris R
>>
>>
>>
>> On 12/17/06, Tesla list <tesla@xxxxxxxxxx> wrote:
>>>
>>> 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<http://drsstc.com/%7Epiranha/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<http://drsstc.com/%7Epiranha/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
>>> >
>>> >
>>> >
>>> >
>>> >
>>>
>>>
>>>
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