[TCML] First (or maybe 2nd) light on my medium-sized SG coil, PT current rating?

[bartb]

Hi David,

Your 20A service breaker is based on a continuous 20 amps. Your pulsing. 
Throw in a 40 or 50 amp breaker to handle those high current pulses and 
use an amp meter to keep the coil below a 20 amp average. Then you can 
turn that voltage up where it needs to be. I put my variac in a Hoffman 
box and usually let the current be my guide.
http://www.classictesla.com/temp/variac1.jpg

Take care,
Bart

David Rieben wrote:
> Hi Jim,
>
> My PT is just a regular run-of-the-mill 1.5 kVA rated (@ 30*C)
> 120:1 GE potential transformer. However, I have found PTs to
> be VERY conservatively rated since they are rated to put out
> their rated VA output with essentially zero voltage drop. After
> all, they are designed for metering a known fraction of primary
> line voltage so voltage accuracy is important. For this reason,
> most PTs can put out several times more VAs than their name-
> plate rating suggests. Of course my PT is made for 120 volt
> input, unlike your monster 5 kVA unit with a 240 volt input.
> Turth be told, you could probably run up to 20 kVA+ through
> that 5 kVA PT of yours if you kept the uninterrupted  run times 
> within reason! BTW, if you want to go even bigger on the
> transformer, why not just upgrade to a pole pig as they usually
> run much cheaper than equivalent sized PT combos?
>
> With that being said, my PT is running fine but I am finding it dif-
> ficult to "hold the reins" on it to keep the current draw within the
> limits of a standard 20 amp line service. I suppose running with
> 2 paralleled MOTs with their secondaries shorted as a ballast
> is what's taxing the electric service. You have to remember too
> that I have done gotten spoiled to the 12 to 14 ft. super bright
> discharges of my Green Monster coil running of up to 90 amps
> at 240 volts input and fired with a pole pig. I took on this project 
> to have a coil that I could run off a standard 120 volt service 
> but I still want to get all of the "bang for my buck" that I can 
> muster ;^) I am already getting 50 to 60" arcs with the variac
> only set at about 50 to 60 on the dial but if I try to roll it outside 
> and push it further, it will pretty quickly trip the 20 amp panel 
> breaker. That's why I was wondering about how much PFCs 
> would help to hold down the current draw. I suppose that I could 
> also cut back to one MOT and then be able to turn my variac knob
> up higher. 
>
> I also think that my .08 uFd primary C along with a relatively
> monsterous 6 x 30 top-load is also really sucking the amps for 
> a standard 120 volt service :^) It seems that a 6" coil is about
> at the size limit for firing at its full potetntial from a standard 120 
> volt, 20 amp electrical service.
>
> --
> David Rieben
>
>
>
> -------------- Original message -------------- 
> From: "Jim Mora" <wavetuner at gmail.com> 
>
>   
>> Hi David, 
>>
>> -----Original Message----- 
>> Hello David, 
>>
>> What is the current output of the PT? I have a 5KVA GE that I am planning on 
>> running on my 8" coil also wound with #22 to 35.5" so your results are 
>> interesting to me! I plan to use a smaller sat reactor and a combo static 
>> and dc motor rotary gap. This PT runs on 240v. I wish I had two of em! 
>>
>> Jim Mora 
>>
>> From: tesla-bounces at pupman.com [mailto:tesla-bounces at pupman.com] On Behalf 
>> Of David Rieben 
>> Sent: Monday, April 14, 2008 5:25 PM 
>> To: Tesla list 
>> Subject: [TCML] First (or maybe 2nd) light on my medium-sized SG coil 
>>
>> Hi all, 
>>
>> I have finally gotten my mid-sized SG coil project up and running 
>> A quick rough-up of the specs are about 28" of #22 AWG magnet 
>> wire wound on a 6" ID (6.5" OD) white PVC pipe for the secondary 
>> coil. The primary is 11 turns of 3/8" copper tubing wound in the 
>> classic Archemdian spiral with between 3/8" and 1/2" spacing be- 
>> tween each turn and the outermost turn has about a 12.5" radius 
>> (25"diameter). After initial tuning, the primary has been tapped at 
>> approx. 8 3/4 turns. The transformer is a 120:1 GE potential trans- 
>> former (14,400 volt output). 
>>
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>>     
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