Re: 4kV/20mA Transformers for Contest

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <dhmccauley-at-spacecatlighting-dot-com>

> Specifying a VA rating rather than a specific transformer would seem fair
> and to allow wider competition, but I fear that the underlying intent
would
> be compromised - that being to ensure that all start with the same basic
> power supply, with innovations and efficiencies being made downstream.  A
> different NST of the same volt/Amp rating may have different shunt
> configurations and (removing) different shunts will surely have a profound
> effect on performance.  Also, it has been widely suggested that higher
> voltages have an inherent efficiency advantage, so an 8kV/10mA may be more
> efficient than a 4/20, despite having the same VA rating.

I agree.  In fact I just tested this theory.  With all shunts installed I
ran my coil with a 4kV/20mA transformer and a 6kV/10mA open frame
transformer I have as well.  I used the correct resonant cap size for each
transformer (easily made with a bunch of MMCs i have laying around) and
adjusted the gap size appropriately for the voltage output.

Anyways, the 4kV,20mA put out about 5-6 inch streamers)

The 6kV/10mA put about about 9-10 inch streamers

As you can see even though the 4kV/20mA has a 25% higher VA rating, the
higher voltage transformer out performed the other one easily.

So as the person who originally came up with this competition idea, I am
going to set in stone that to keep this contest as fair as possible, a
Franceformer Model 4020SE 4kV/20mA transformer is the only transformer
allowed as any other transformer would defeat the whole purpose.

If you don't have availability of these transformers, I can get them for
about $25.00 (not including tax or delivery)

Or if you live in a different part of the world that does not have access to
these transformers, you could research and find a similar sized transformer
thats readily available in your neck of the woods.  And you could run a
separate contest using that transformer.

Dan