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Re: A new mini-coil competition winner!



Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Karl,

That's fine. I have no problem with what ever rules one sets up. Just as a passing spectator, I thought a 18 inch spark from a 4K 20ma source was very very impressive since the JF formula predicts 15 inches and it is suppose to be hard to achieve this with small power coils. A 4K 38ma source has a JF formula spark length of 21 inches so a 18 inch length sounds more achievable. If the rules allow 50ma, then the JF spark length is 24 inches. I wonder why you stopped at 38ma. I would have gone for the entire 50ma. Seems like a 4K 20ma transformer modified for 4K 50ma is no different than a transformer designed for 4K 50ma and left unmodified.

Gerry R.

Original poster: "Karl L." <karl@xxxxxxxxxxxxxxxxx>

Hi Gerry,

Removing shunts up to a point is allowed. When 1/2 the shunts were removed, I measured 36.5 mA. @ 117 VAC. The rules (found here: http://www.laushaus.com/tesla/minicoilcontest/ ) state:

Rules for Category 1

Category 1 is for entries powered only by faceplate-rated 4kV/20mA NST's. The rules are more restrictive here so that this is the purist form of competition - everyone starts with the same power supply.

1) The power supply must be a 4kV/20mA NST. Any manufacturer, and either 120V or 240V mains voltage is okay.

2) NST primary voltage may not exceed the faceplate value, typically 120/240VAC. If your mains voltage is abnormally high, you must Variac down. If you must overdrive your 4/20 NST, you may enter it under category 2.

3) Removing some NST current limit shunts IS allowed. Short circuit secondary current must be measured with nominal primary voltage applied, and this current may not exceed 50mA.

Take care,

Karl

On Jun 8, 2006, at 10:45 AM, Tesla list wrote:

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

That seems like changing the contest. The contest is now a 4KV 38ma contest instead of a 4KV 20ma contest. Is that allowed in the rules.
If so, one may not want to advertise it as  4KV 20ma

Gerry R.



Original poster: "Karl L." <karl@xxxxxxxxxxxxxxxxx>

Hi Dr. R.

Yes, I removed 1/2 of the shunts, as did several others in the competition. The NST ratings originally were 4kV by 20 mA. Once the shunts were removed, the mA increased to about 36 - 38 for everyone.

Karl