RE: Where to get 4kv 20ma NST?

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

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-hp-dot-com>

>Ah - the use of a variac has to be cheating IMO. You will be starting 
>the race on an uneven footing right from the word go if variacs are 
>allowed. Sans variac, the transformers *will* in fact be equal.

Yes, I think when Dan specified a 120V requirement on the primary, he was
just trying to ensure that no one boosts the nominal mains voltage with a
variac.  If you had a 240V version of the SAME 4/20 NST, I'm sure that
would be acceptable.
 
>> I'm not trying to barr anyone from entering any type of "contest."  The
>> event was mainly for a few individuals which attend a private tesla event
>> each year, but now its seems to be expanding out worldwide.  The whole goal
>> of the competition was to be a competition in efficiency and build design.
>> By using the same model transformer and same exact input requirements, this
>> contest would be somewhat fair and accurate.  Now by introducing all these
>> other types of transformers etc... there is too much variability.  

>Well, I will just have to watch the competition from the sidelines in 
>that case. I'm not willing to part with in excess of NZ$150 to 
>qualify. To the best of my knowledge, those transformers are not 
>available here.
>
>I would like to propose an amendment to the "rules": restrict the 
>input voltage to Vmains. That'll sort the design skills out.

I think that was the intent.

As far as requiring a specific NST model number, if this was a truly a
competition with a material prize, I could see the need to strictly govern
the power supply specification.  But I think what we're actually doing goes
beyond picking and rewarding the best and discarding all other entries.  If
the results of all entries are detailed and documented, that would give
folks an opportunity to learn what works and what doesn't.  

Perhaps if the "competition" were broadened to 3 separate categories, that
might keep more people eligible and happy:
1. Entries using the specified Franceformer 4020SE Open Frame transformer
(4kV/20mA > rated with 115VAC input and with >     shunts installed)
2. Entries using any similar 4kV/20mA NST with short-circuit current not to
exceed t.b.d. mA.
3. Entries using any other nominally 80VA faceplate-rated NST.

Not everyone may feel this way but I would welcome the opportunity to
compare the results with my Franceformer 4020SE against Malcolm's results
with a 240V input brand-X 4/20 NST, even if it is a green apples vs. red
apples comparison.  Purists are welcome to ignore categories 2 & 3.

Gary Lau
MA, USA